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Manual Yamaha YW125Y_

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  • Yamaha YW125Y_ - page 1

    2009 MOTORCYCLE SERVICE MANUAL Model : YW125Y_ 32SF819770E0 *32SF819770E0* www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 2

    EAS00000 YW125Y 2009 SER VICE MANU AL ©2008 by Y amaha Motor T aiwan Co., Ltd. First edition, July 2008 All rights reserved. Any reproduction or unauthorized use without the written permission of Y amaha Motor T aiwan Co., Ltd. is expressly prohibited. www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 3

    EAS20070 IMPORT ANT This manual was produced b y the Y amaha Motor T aiwan Company , Ltd. primar ily for use b y Y amaha dealers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual. Theref ore , any one who uses this book to perf or m maintenance and repairs on Y amaha vehicles should have a ba ...

  • Yamaha YW125Y_ - page 4

    EAS00007 HO W T O USE THIS MANU AL This manual is intended as a handy , easy-to-read ref erence book f or the mechanic. Comprehensiv e e xplanations of all installation, remov al, disassembly , assembly , repair and chec k procedures are laid out with the individual steps in sequential order . 1 The manual is divided into chapters. An abbreviation ...

  • Yamaha YW125Y_ - page 5

    GEN INFO SPEC CHK ADJ ENG TRBL SHTG CHAS -+ ELEC 4 M B LS Ne w M G COOL 12 34 56 78 90 qw er i s hj EAS00008 SYMBOLS The following symbols are not relevant to every vehicle. Symbols 1 to 9 indicate the subject of each chapter . 1 General information 2 Specifications 3 P eriodic checks and adjustments 4 Chassis 5 Engine 6 Cooling system 7 Fuel injec ...

  • Yamaha YW125Y_ - page 6

    EAS00011 T ABLE OF CONTENTS GENERAL INFORMA TION SPECIFICA TIONS PERIODIC CHECKS AND ADJUSTMENTS CHASSIS ENGINE FUEL INJECTION SYSTEM ELECTRICAL SYSTEM TR OUBLESHOO TING -+ GEN INFO SPEC CHK ADJ CHAS ENG FI ELEC TRBL SHTG 1 2 3 4 5 6 7 8 www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 7

    1-13 GEN INFO CHAPTER 1 GENERAL INFORMA TION SCOO TER IDENTIFICA TION ................................................................... 1 - 1 VEHICLE IDENTIFICA TION NUMBER ............................................. 1 - 1 MODEL LABEL .................................................................................. 1 - 1 FEA TURES ............ ...

  • Yamaha YW125Y_ - page 8

    1-1 GEN INFO SCOO TER IDENTIFICA TION EAS00015 GENERAL INFORMA TION SCOO TER IDENTIFICA TION EAS00017 VEHICLE IDENTIFICA TION NUMBER The vehicle identification number 1 is stamped into the frame. EAS00018 MODEL LABEL The model label 1 is affixed to the frame under the seat. This inf or mation will be needed to or- der spare par ts. 1 1 www.Scooter ...

  • Yamaha YW125Y_ - page 9

    1-2 GEN INFO EAS00896 FEA TURES OUTLINE OF THE FI SYSTEM The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti- mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera- ture. In the conventional carburetor system, the air-fuel ratio of the mixture that is supplie ...

  • Yamaha YW125Y_ - page 10

    1-3 GEN INFO FEA TURES EAS00897 FI SYSTEM The fuel pump delivers fuel to the fuel injector via the fuel filter . The pressure regulator maintains the fuel pressure that is applied to the fuel injector at only 250 kP a (2.5 kgf/cm 2 , 35.6 psi). Accordingly , when the energizing signal from the ECU energizes the fuel injector , the fuel passage open ...

  • Yamaha YW125Y_ - page 11

    1-4 GEN INFO FEA TURES O 2 sensor The O 2 sensor has been adopted to enable the catalyst to function at a high degree of efficiency by maintaining the air-fuel mixture near the stoichiometric ratio (14.7:1). This sensor , which is a zirconia type, utilizes the oxygen ion conductivity of the solid electrolyte for detecting the oxygen concentra- tion ...

  • Yamaha YW125Y_ - page 12

    1-5 GEN INFO IMPORT ANT INFORMA TION EAS00020 IMPOR T ANT INFORMA TION PREP ARA TION FOR REMO V AL AND DISAS- SEMBL Y 1. Bef ore removal and disassemb ly , remov e all dir t, mud, dust and f oreign mater ial. 2 . Use only the proper tools and cleaning equipment. Ref er to the “SPECIAL T OOLS”. 3. When disassembling, always keep mated par ts tog ...

  • Yamaha YW125Y_ - page 13

    1-6 GEN INFO IMPORT ANT INFORMA TION EAS00023 LOCK W ASHERS/PLA TES AND CO TTER PINS After removal, replace all lock washers/plates 1 and cotter pins. After the bolt or nut has been tightened to specification, bend the lock tabs along a flat of the bolt or nut. EAS00024 BEARINGS AND OIL SEALS Install bearings and oil seals so that the manuf acturer ...

  • Yamaha YW125Y_ - page 14

    1-7 GEN INFO IMPORT ANT INFORMA TION EAS00021 EQUIPMENT PREP ARA TION T urn Rivet (T urn type) Assembly status of the turn rivet(turn type). Dissembling 1. Press center pin 1 inward to release the lock. 2. Remove the push rivet main body 2 . Assembling 1. Restore the center pin, replace the turn rivet main body . 2. T ur n in the center pin until l ...

  • Yamaha YW125Y_ - page 15

    1-8 GEN INFO CHECKING THE CONNECTIONS EAS00026 CHECKING THE CONNECTIONS Check the leads, couplers, and connectors for stains, rust, moisture, etc. 1 . Disconnect: 8 lead 8 coupler 8 connector 2 . Check: 8 lead 8 coupler 8 connector Moisture J Dr y with an air blo wer . Rust/stains J Connect and disconnect several times. 3 . Check: 8 all connections ...

  • Yamaha YW125Y_ - page 16

    1-9 GEN INFO T ool NO . T ool name / Function Illustration 90890-01085 (M8) YU-01083-2 90890-01084 YU-01083-3 90890-01235 YU-01235 90890-01268 YU-01268 90890-01304 YU-01304 90890-01337 YM-33285 90890-01311 YM-08035-A 90890-01326 YM-01326 90890-01294 YM-01300-1 90890-01348 YM-01348 Slide hammer bolt (8mm) 1 Weight 2 These tools are needed to remove ...

  • Yamaha YW125Y_ - page 17

    1-10 GEN INFO T ool NO . T ool name / Function Illustration SPECIAL T OOLS 90890-01189 YM-01189 90890-01367 YM-A9409-7 90890-01368 YM-A9409-4 90890-01384 YM-33299 90890-01403 YU-A9472 90890-01701 YS-01880-A 90890-03079 YM-34483 90890-03081 YU-33223 90890-03112 YU-03112-C 90890-03174 90890-06760 Flywheel puller This tool is used for removing the AC ...

  • Yamaha YW125Y_ - page 18

    1-11 GEN INFO T ool NO . T ool name / Function Illustration SPECIAL T OOLS 90890-03141 YU-03141 90890-04101 90890-04019 YM-04019 90890-04108 YM-04108 90890-04116 YM-04116 90890-04117 YM-04117 90890-04118 YM-04118 90890-06754 YM-34487 90890-03182 YU-03182 90890-03153 YU-03153 90890-03186 Timing light This tool is used to check the ignition tim- ing. ...

  • Yamaha YW125Y_ - page 19

    1-12 GEN INFO SPECIAL T OOLS T ool NO . T ool name / Function Illustration 90890-85505 ACC-11001-05-01 Y amaha bond NO .1215 Sealant (Quick Gasket ® ) This sealant (bond) is used to apply on crankcase mating surfaces. www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 20

    2-32 SPEC CHAPTER 2 SPECIFICA TIONS GENERAL SPECIFICA TIONS ................................................................. 2 - 1 ENGINE SPECIFICA TIONS ..................................................................... 2 - 2 CHASSIS SPECIFICA TIONS ................................................................. 2-12 ELECTRICAL SPECIFICA TIO ...

  • Yamaha YW125Y_ - page 21

    2-1 SPEC SPECIFICA TIONS GENERAL SPECIFICA TIONS Item Standard Limit GENERAL SPECIFICA TIONS Model Code 32S1 (USA) … 32S2 (CAN) … Dimensions Overall length 1910mm (75.2in) … Overall width 765mm (30.1in) … Overall height 1110mm (43.7in) … Seat height 780mm (30.7in) … Wheelbase 1290mm (50.8in) … Minimum ground clearance 125mm (4.9in) ? ...

  • Yamaha YW125Y_ - page 22

    2-2 SPEC ENGINE SPECIFICA TIONS Item Standard Limit ENGINE SPECIFICA TIONS Engine Engine type Air-cooled, 4-stroke, SOHC … Displacement 0.125L (125cm 3 , 7.63cu-in) … Cylinder arrangement Forward inclined … single cylinder Bore × stroke 52.4 × 57.9mm (2.06 × 2.28in) … Compression ratio 10:1 … Engine idle speed 1700 ~ 1900r/min … V ac ...

  • Yamaha YW125Y_ - page 23

    2-3 SPEC Item Standard Limit ENGINE SPECIFICA TIONS Oil filter Oil filter type Wire mesh … Oil pump Oil pump type T rochoid … Inner rotor to outer rotor tip clearance 0.15mm (0.006in) or less 0.23mm (0.009in) Outer rotor to pump housing clearance 0.07 ~ 0.12mm 0.19mm (0.003 ~ 0.005in) (0.008in) Starting system type Electric star ter … Spark p ...

  • Yamaha YW125Y_ - page 24

    2-4 SPEC Item Standard Limit ENGINE SPECIFICA TIONS A B A B Camshaft Drive system Chain drive (left) … Intake camshaft lobe dimensions Measurement A 25.267 ~ 25.367mm 25.167mm (0.995 ~ 0.999in) (0.991in) Measurement B 21.069 ~ 21.169mm 20.969mm (0.829 ~ 0.833in) (0.826in) Exhaust camshaft lobe dimensions Measurement A 25.275 ~ 25.375mm 25.175mm ( ...

  • Yamaha YW125Y_ - page 25

    2-5 SPEC Item Standard Limit B C D A Head Diameter Face Width Seat Width Margin Thickness ENGINE SPECIFICA TIONS Timing chain Model/number of links Morse 92RH2005/94 … T ensioning system Automatic … V alve, valve seats, valve guides V alve clear ance (cold) Intake 0.10 ~ 0.14mm … (0.004 ~ 0.006in) Exhaust 0.16 ~ 0.20mm … (0.006 ~ 0.008in) V ...

  • Yamaha YW125Y_ - page 26

    2-6 SPEC ENGINE SPECIFICA TIONS Item Standard Limit V alve stem to v alve guide clear ance Intake 0.015 ~ 0.042mm 0.08mm (0.0006 ~ 0.0017in) (0.0031in) Exhaust 0.030 ~ 0.057mm 0.1mm (0.0012 ~ 0.0022in) (0.0039in) V alve stem runout … 0.01mm (0.0004 in) V alve seat width Intake 0.9 ~ 1.1mm (0.035 ~ 0.043in) 1.6mm (0.063in) Exhaust 0.9 ~ 1.1mm (0.0 ...

  • Yamaha YW125Y_ - page 27

    2-7 SPEC Item Standard Limit ENGINE SPECIFICA TIONS V alve springs F ree length Intake 41.88mm (1.649in) 39.786mm (1.566in) Exhaust 41.88mm (1.649in) 39.786mm (1.566in) Installed length (valve closed) Intake 30mm (1.18in) … Exhaust 30mm (1.18in) … Compressed spring force (installed) Intake 137 ~ 157N/mm … (13.97 ~ 16.01kgf/mm, 30.83 ~ 35.33lb ...

  • Yamaha YW125Y_ - page 28

    2-8 SPEC Item Standard Limit H D ENGINE SPECIFICA TIONS T B B T Piston Piston-to-cylinder clearance 0.010 ~ 0.035mm 0.15mm (0.0004 ~ 0.0014in) (0.0059in) Diameter D 52.375 ~ 52.390mm … (2.0620 ~ 2.0626in) Height H 7.0mm (0.28in) … Piston pin bore (in the piston) Diameter 15.002 ~ 15.013mm 15.043mm (0.5906 ~ 0.5911in) (0.5922in) Offset 0.35 ~ 0. ...

  • Yamaha YW125Y_ - page 29

    2-9 SPEC ENGINE SPECIFICA TIONS Item Standard Limit B T Oil ring Dimensions (B × T) 2.0 × 2.5mm … (0.0787 × 0.0984in) End gap (installed) 0.2 ~ 0.7mm … (0.0079 ~ 0.0276in) Ring side clearance 0.04 ~ 0.12mm … (0.0016 ~ 0.0047in) www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 30

    2-10 SPEC Item Standard Limit ENGINE SPECIFICA TIONS Rocker arm/rocker arm shaft Rocker arm inside diameter 10.000 ~ 10.015mm … (0.3937 ~ 0.3943in) Rocker arm shaft outside diameter 9.981 ~ 9.991mm … (0.3930 ~ 0.3933in) Arm-to-shaft clearance 0.009 ~ 0.034mm … (0.0004 ~ 0.0013in) Connecting rod Connecting rod length 93.45 ~ 93.55mm … (36.79 ...

  • Yamaha YW125Y_ - page 31

    2-11 SPEC Item Standard Limit ENGINE SPECIFICA TIONS T ransmission T ransmission type V -belt automatic … Primary reduction system Helical gear … Primary reduction ratio 40/15 (2.667) … Secondary reduction system Spur gear … Secondary reduction ratio 44/11 (4.0) … Single speed automatic 2.398 ~ 0.823:1 … Maximum main axle runout … 0.0 ...

  • Yamaha YW125Y_ - page 32

    2-12 SPEC CHASSIS SPECIFICA TIONS CHASSIS SPECIFICA TIONS Item Standard Limit Frame F rame type Steel tube underbone … Caster angle 27° … T rail 90mm (3.54in) … Front wheel Wheel type Cast wheel … Rim Size J12 × MT2.75 … Material Aluminum … Wheel travel 78mm (3.07in) … Wheel runout Maximum radial wheel runout … 1.0mm (0.04in) Maxi ...

  • Yamaha YW125Y_ - page 33

    2-13 SPEC Item Standard Limit CHASSIS SPECIFICA TIONS Rear tire Tire type T ubeless … Size 13 0 /70-12 56L … Model (manufacturer) K761 (KEND A) … Tire pressure (cold) 0 ~ 90kg (0 ~ 198lb) 200kPa (2.0kgf/cm², 29psi) … 90kg (198lb)~ maximum load 225kP a (2.25kgf/cm², 33psi) … Minimum tire tread depth … 0.8mm (0.03in) Front brake Brake t ...

  • Yamaha YW125Y_ - page 34

    2-14 SPEC CHASSIS SPECIFICA TIONS Item Standard Limit Front suspension Suspension type T elescopic … F ront f or k type Coil spring/oil damper … F ront f or k tra vel 90mm (3.54in) … Spring F ree length 252.1mm (9.93in) 247mm (9.72in) Installed length 230.9mm (9.09in) … Spring rate (K1) 7.1N/mm (0.72kgf/mm, … 1.60lbf/in) Spring rate (K2) ...

  • Yamaha YW125Y_ - page 35

    2-15 SPEC Item Standard Limit ELECTRICAL SPECIFICA TIONS ELECTRICAL SPECIFICA TIONS System voltage 12V … Ignition system Ignition system type T ransistor ized coil ignition … Ignition timing 5° BTDC at 1800r/min … Advancer type Digital … Pickup coil resistance/color 248 ~ 372 Ω at 20°C (68°F) … /white/red - white/blue Ignition coil Mo ...

  • Yamaha YW125Y_ - page 36

    2-16 SPEC ELECTRICAL SPECIFICA TIONS Item Standard Limit Electric starting system System type Constant mesh … Star ter motor Model (manufacturer) 5S9 00 (T -MORIC) … Suction voltage 12V … P ower output 0.35kW … Brushes Overall length 10.0mm (0.39in) 3.5mm (0.14in) Quantity 2 … Spring force 5.52 ~ 8.28N/mm … (0.56 ~ 0.84kgf/mm, 1.24 ~ 1. ...

  • Yamaha YW125Y_ - page 37

    2-17 SPEC ELECTRICAL SPECIFICA TIONS Item Standard Limit Fuel sender Model (manufacturer) 5S9 (AISAN) … Sender unit resistance-full 4 ~ 10 Ω … Sender unit resistance-empty 90 ~ 100 Ω … Fuel level gauge Gauge type (manufacture) Analog (CHAOLONG) … Starting circuit cut-off relay Model (manufacturer) 4HC1 (MA TSU SHIT A) … Coil resistance ...

  • Yamaha YW125Y_ - page 38

    2-18 SPEC EAS00030 GENERAL TIGHTENING TORQUE SPECIFICATIONS This chart specifies tightening torques for stan- dard fasteners with a standard ISO thread pitch. Tightening torqu e specifications for spe- cial components or assemblies are provided for each chapter of this manual. To avoid warpage, tighten multi-fastener assemblies in a crisscross patt ...

  • Yamaha YW125Y_ - page 39

    2-19 SPEC P ar t to be tightened P ar t name Thread size Q ’ ty Tightening torque Remark s TIGHTENING T ORQUES 4 TIGHTENING T ORQUES ENGINE Crankcase (left and right) together tightening. Cylinder head and cylinder Spark plug Cylinder head (timing chain side) Exhaust pipe stud bolt Breather V alve cov er Stopper plate (camshaft) Guide stopper 2 V ...

  • Yamaha YW125Y_ - page 40

    2-20 SPEC TIGHTENING T ORQUES Remarks Cylinder head tightening sequence Plate (V -belt guide) Idle gear plate Plate Clutch housing Primary fixed sheave Star ter motor AC magneto rotor Stator coil Crankshaft position sensor Ignition coil O 2 sensor Engine temperature sensor Clamp holder Bolt Bolt Bolt Nut Nut Bolt Nut Screw Screw Screw - - Bolt P ar ...

  • Yamaha YW125Y_ - page 41

    2-21 SPEC P ar t to be tightened Thread size Tightening torque Remarks TIGHTENING T ORQUES CHASSIS LT ft•lbf Nm m•kgf F rame and engine br ac ket 2 Engine bracket 2, compression rod and engine Compression rod and frame Sidestand (bolt and stand) Sidestand (bolt and nut) Centerstand Swingarm Rear shock absorber and frame Rear shock absorber and ...

  • Yamaha YW125Y_ - page 42

    2-22 SPEC TIGHTENING T ORQUES TIP 1. First, tighten the ring nut (lower) approximately 38Nm (3.8m • kgf, 27.5ft • lbf) by using the torque wrench, then loosen the ring nut 1/4 turn. 2. Second, tighten the ring nut (lower) approximately 14Nm (1.4m • kgf, 10.1ft • lbf) by using the torque wrench. 3. Installing the r ub ber washer . 4. Then fi ...

  • Yamaha YW125Y_ - page 43

    2-23 SPEC Lubrication P oint Lubricant LS LS M 4 4 4 4 4 4 4 4 4 4 M LUBRICA TION POINTS AND LUBRICANT TYPES EAS00031 LUBRICA TION POINTS AND LUBRICANT TYPES ENGINE M 4 4 Oil seal lips Bearings O-rings (except V -belt dr ive unit) O-rings (fuel injector) Cylinder head tightening nut mounting surface Cylinder head stud bolt thread Cylinder head nut ...

  • Yamaha YW125Y_ - page 44

    2-24 SPEC BEL-RA Y asembly lube ® BEL-RA Y asembly lube ® Y amaha bond NO .1215 Lubrication P oint Lubricant LUBRICA TION POINTS AND LUBRICANT TYPES G G Main and drive axle serration (sprocket) Drive axle taper rollor bearing T ransmission bearing Secondary fixed sheave inner surface Secondary sliding sheave torque cam ditch Crankcase mating surf ...

  • Yamaha YW125Y_ - page 45

    2-25 SPEC LUBRICA TION POINTS AND LUBRICANT TYPES Lubrication P oint Lubricant LS LS LS LS LS LS LS EAS00032 CHASSIS LS Engine mounting bolt Steering bearing and bearing races (upper and lower) Throttle grip inner surface and throttle cables Rear brak e lev er pivoting point and metal-to-metal moving parts Rear brake cable and brake lock lever (cab ...

  • Yamaha YW125Y_ - page 46

    2-26 SPEC CABLE ROUTING EAS00035 CABLE ROUTING 1 Connector cover 2 Horn 3 F ront brac ket 4 Star ting circuit cut-off relay 5 T ur n signal relay 6 Headlight relay 7 ECU lead 8 T ur n signal rela y lead 9 Main switch 0 Horn lead q Main switch lead w Rectifier/regulator lead e Wire harness r Throttle cable assembly t Seat lock cable y O 2 sensor lea ...

  • Yamaha YW125Y_ - page 47

    2-27 SPEC CABLE ROUTING E Headlight relay lead passes by the right side of inner f ender r ib . F Star t relay sub lead to f orward. G Orientation: white tape. H T otally cover the terminal after locking. I T orque: 4Nm (0.4m • kgf , 2.9ft • lbf). J Star ter relay inser ts into holder cer tainly . K After connecting, press lead of tail/brake li ...

  • Yamaha YW125Y_ - page 48

    2-28 SPEC CABLE ROUTING 1 Rectifier/regulator 2 Body ear th lead 3 Horn 4 ECU 5 Headlight lead 6 T ur n signal relay 7 Horn lead 8 Rectifier/regulator lead 9 Brake hose holder 3 0 Brake hose holder 1 q Fuel hose w Pipe 3 e Roll over valve r Pipe 4 t Rear brake cable y Sidestand switch A Rear brake cable passes through the wire guide of front bracke ...

  • Yamaha YW125Y_ - page 49

    2-29 SPEC CABLE ROUTING 1 Plain washer 2 Lean angle cut-off switch 3 Lean angle cut-off switch lead 4 FI diagnostic tool 5 Hight tension cord 6 Fuel pump lead 7 Engine temperature sensor lead 8 Fuel injector lead 9 Clamp (90464-13800) 0 Star ter motor positive lead q Star ter motor negative lead w Star ter motor e Pipe 4 r Roll over valve t Pipe 3 ...

  • Yamaha YW125Y_ - page 50

    2-30 SPEC CABLE ROUTING F Ignition coil lead passes under the cross tube. G P ass the throttle cable assemb ly through wire guide. H Locate the white tape of wire harness in the holder . I Clamp (90464-10800) the O 2 sensor lead. J Clamp (90464-25803) the star ter motor lead, AC magneto lead, ISC (idle speed control) valve lead, sensor module (MAQS ...

  • Yamaha YW125Y_ - page 51

    2-31 SPEC CABLE ROUTING 1 Rear brake cable 2 Speedometer 3 F ront master cylinder 4 Brush guard (right) 5 T ur n signal light (r ight) 6 Throttle cable assembly 7 Speedometer cable 8 T ur n signal light (left) 9 Brush guard (left) 0 Handlebar bracket q Clamp (90464-12812) w Bracket e T ur n signal light lead (right) r Right handlebar switch lead t ...

  • Yamaha YW125Y_ - page 52

    3-59 CHK ADJ CHAPTER 3 PERIODIC CHECKS AND ADJUSTMENTS INTRODUCTION ....................................................................................... 3 - 1 PERIODIC MAINTENANCE AND ADJUSTMENT ................................. 3 - 1 P er iodic maintenance char t f or the emission control system ........... 3 - 1 Genela maintenance and lub lica ...

  • Yamaha YW125Y_ - page 53

    3-60 CHK ADJ CHECKING THE TIRES .................................................................. 3-43 CHECKING THE WHEELS .............................................................. 3-46 CHECKING AND LUBRICA TING THE CAB LES ............................ 3-46 LUBRICA TING THE LEVERS ......................................................... 3-47 ...

  • Yamaha YW125Y_ - page 54

    3-1 CHK ADJ EAS00036 PERIODIC CHECKS AND ADJUSTMENTS INTRODUCTION This chapter includes all information necessary to perform recommended checks and adjustments. If followed, these preventive maintenance procedures will ensure more reliable vehicle operation, a longer ser vice lif e and reduce the need for costly o verhaul work. This inf ormation ap ...

  • Yamaha YW125Y_ - page 55

    3-2 CHK ADJ PERIODIC MAINTENANCE AND ADJUSTMENT NO. ITEM ROUTINE INITIAL ODOMETER READING 1000 km (600 mi) or 1 month 4000 km (2000 mi) or 6 months 7000 km (4000 mi) or 12 months 10000 km (6000 mi) or 18 months 13000 km (8000 mi) or 24 months 16,000 km (10,000 mi) or 30 months 1 Air filter element •R e p l a c e .   2 V-belt case air fil ...

  • Yamaha YW125Y_ - page 56

    3-3 CHK ADJ EAUT2710 TIP 8 Air filter and V -belt filter • This model’ s air filter is equipped with a disposable oil-coated paper element, which must not be cleaned with compressed air to avoid damaging it. • The air filter element needs to be replaced and V -belt filter needs to be ser viced more fre- quently when riding in unusually wet or ...

  • Yamaha YW125Y_ - page 57

    3-4 CHK ADJ EAS00038 CO VER AND P ANEL SEA T AND TRUNK Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 1 1 1 1 1 1 1 Remov e the par ts in the order listed. For installation, reverse the removal pro- cedure. CO VER AND P ANEL Removing the seat and trunk Seat Fuel tank cap cover Seat hinge Upper cover T r unk Side cover (left) Side cover (right) 7 2 7 ...

  • Yamaha YW125Y_ - page 58

    3-5 CHK ADJ CO VER AND P ANEL FOO TREST BO ARD Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 1 1 1 1 1 4 Remov e the par ts in the order listed. NO TICE First, disconnect the negative battery lead, and then the positive battery lead. After installing the battery be sure to turn the main switch fr om “ON” to “OFF” three times in 3 seconds in ...

  • Yamaha YW125Y_ - page 59

    3-6 CHK ADJ CO VER AND P ANEL Remarks Order Job/P ar t Q’ty TIP While installing, the fuse box should be installed to the correct position. For installation, reverse the removal pro- cedure. 8 Footrest board 1 1 5 4 6 3 7 2 8 7Nm (0.7 m•kgf , 5.1 ft•lbf) www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 60

    3-7 CHK ADJ 1 23Nm (2.3 m•kgf , 16.6 ft•lbf) 4 5 2 3 9Nm (0.9 m•kgf , 6.5 ft•lbf) 14Nm (1.4 m•kgf , 10.1 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) LEG SHIELD 1 ASSEMBL Y AND LEG SHIELD 2 Remarks Order Job/P ar t Q’ty CO VER AND P ANEL Removing the leg shield 1 assembly and leg shield 2 Footrest board Sa ...

  • Yamaha YW125Y_ - page 61

    3-8 CHK ADJ CO VER AND P ANEL Remarks Order Job/P ar t Q’ty Disassembling the leg shield 1 as- sembly P anel Headlight cover Headlight assembly P anel (leg shield 1) Leg shield 1 1 2 3 4 5 1 1 1 1 1 Remov e the par ts in the order listed. F or assembly , re verse the disassembly procedure. 5 4 7Nm (0.7 m•kgf , 5.1 ft•lbf) 1 2 3 www.ScooterTi ...

  • Yamaha YW125Y_ - page 62

    3-9 CHK ADJ ADJUSTING THE V AL VE CLEARANCE EAS00049 ENGINE ADJUSTING THE V AL VE CLEARANCE The following procedure applies to all of the valves. TIP 8 V alve clearance adjustment should be made on a cold engine, at room temperature. 8 When the valve clearance is to be measured or adjusted, the piston must be at top dead center (TDC) on the compres ...

  • Yamaha YW125Y_ - page 63

    3-10 CHK ADJ 3 2 1 ADJUSTING THE V AL VE CLEARANCE c . Align the TDC mark c on the AC magneto rotor with the stationary pointer d on the crankcase. d. Measure the valve clearance with a thick- ness gauge. Out of specification J Adjust. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ 4. Adjust: 8 valve clearance ▼▼▼▼▼ ...

  • Yamaha YW125Y_ - page 64

    3-11 CHK ADJ ADJUSTING THE V AL VE CLEARANCE e. Measure the valve clearance again. f. If the valve clearance is still out of specifi- cation, repeat all of the valve clearance ad- justment steps until the specified clearance is obtained. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ 5. Install: 8 breather 7Nm (0.7m • kgf, ...

  • Yamaha YW125Y_ - page 65

    3-12 CHK ADJ 1 CHECKING THE ENGINE IDLING SPEED EAS00054 CHECKING THE ENGINE IDLING SPEED TIP Prior to checking the engine idling speed, the air filter element should be clean, and the engine should have adequate compression. 1. Star t the engine and let it war m up f or se v- eral minutes. 2. Remove: 8 battery box cover 8 front cover Ref er to “ ...

  • Yamaha YW125Y_ - page 66

    3-13 CHK ADJ a 1 2 b a ADJUSTING THE TH RO TTLE CABLE FREE PLA Y EAS00056 ADJUSTING THE THRO TTLE CABLE FREE PLA Y TIP Prior to adjusting the throttle cable free pla y , the engine idling speed should be chec ked properly . 1 . Check: 8 throttle cable free play a Out of specification J Adjust. Throttle cable free play (at the flange of the throttle ...

  • Yamaha YW125Y_ - page 67

    3-14 CHK ADJ 1 a b ADJUSTING THE SEA T SPRING FORCE ADJUSTING THE SEA T SPRING FORCE TIP When open the seat and seat will not fold up automatically , adjust the spring force . 1. Remove: 8 seat 8 upper cover 2. Adjust: 8 screw 1 Direction a Spring force is increased. Direction b Spring force is decreased. 3. Install: 8 upper cover 8 seat www.Scoot ...

  • Yamaha YW125Y_ - page 68

    3-15 CHK ADJ CHECKING THE SP ARK PLUG EAS00060 CHECKING THE SP ARK PLUG 1. Remove: 8 battery box cover 8 front cover Ref er to “CO VER AND P ANEL ”. 2 . Disconnect: 8 spark plug cap W ARNING Remove the spark plug cap, the engine is extremely hot. 3. Remove: 8 spark plug NO TICE Before removing the spark plug, blow away any dirt accumulated in t ...

  • Yamaha YW125Y_ - page 69

    3-16 CHK ADJ CHECKING THE SP ARK PLUG 8. Install: 8 spark plug 13Nm(1.3m • kgf, 9.4ft • lbf) TIP Before installing the spark plug, clean the spark plug and gasket surface. 9. Connect: 8 spark plug cap 10. Install: 8 front cover 8 battery box cover Ref er to “CO VER AND P ANEL ”. T R . . www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 70

    3-17 CHK ADJ 2 1 CHECKING THE IGNITION TIMING EAS00062 CHECKING THE IGNITION TIMING TIP Prior to checking the ignition timing, check the wiring connections of the entire ignition system. Make sure all connections are tight and free of corrosion. 1. Remove: 8 battery box cover 8 front cover Ref er to “CO VER AND P ANEL ”. 2 . Attach: 8 digital t ...

  • Yamaha YW125Y_ - page 71

    3-18 CHK ADJ CHECKING THE IGNITION TIMING Engine idling speed 1700 ~ 1900r/min b . Check that the mark a on the AC magneto rotor is within the firing range b on the crankcase. Incorrect firing range J Check the ignition system. TIP The ignition timing is not adjustable. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ 4 . Remov ...

  • Yamaha YW125Y_ - page 72

    3-19 CHK ADJ 1 MEASURING THE COMPRESSION PRESSURE EAS00067 MEASURING THE COMPRESSION PRES- SURE TIP Insufficient compression pressure will result in a loss of performance. 1. Measure: 8 valve clearance Out of specification J Adjust Ref er to “ADJUSTING THE V AL VE CLEARANCE”. 2. Star t the engine, warm it up f or se veral min- utes, and then tu ...

  • Yamaha YW125Y_ - page 73

    3-20 CHK ADJ MEASURING THE COMPRESSION PRESSURE Compression pressure (with oil applied into the cylinder) Reading Higher than without oil Same as without oil Diagnosis Piston ring(s) wear or damage J Repair . Piston, valves, cylinder head gasket or piston possibly defective J Repair . 7. Measure: 8 compression pressure Out of specification J Refer ...

  • Yamaha YW125Y_ - page 74

    3-21 CHK ADJ MEASURING THE COMPRESSION PRESSURE T R . . 8. Remove: 8 compression gauge 9. Install: 8 spark plug 13Nm(1.3m • kgf, 9.4ft • lbf) 10 . Connect: 8 spark plug cap 11. Install: 8 front cover 8 battery box cover Ref er to “CO VER AND P ANEL ”. www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 75

    3-22 CHK ADJ 3 . Check: 8 engine oil level The engine oil level should be between the minimum level mark a and maximum le vel mark b . Below the minimum level mark J Add the recommended engine oil to the proper level. Recommended engine oil type SAE20W -40 or SAE10W -30 Recommended engine oil grade API service SG type or higher JASO standard MA NO ...

  • Yamaha YW125Y_ - page 76

    3-23 CHK ADJ 1 2 1 43 2 1 CHANGING THE ENGINE OIL T R . . T R . . EAS00076 CHANGING THE ENGINE OIL 1. Star t the engine, warm it up f or se veral min- utes, and then turn it off. 2. Place a container under the engine oil drain bolt. 3. Remove: 8 engine oil filler cap 1 8 engine oil drain bolt 2 (along with the gasket) 4. Drain: 8 engine oil (comple ...

  • Yamaha YW125Y_ - page 77

    3-24 CHK ADJ 1 CHANGING THE ENGINE OIL Quantity T otal amount 0. 8 5 ~ 0.95L (0.9 ~ 1.0 US qt, 0.75 ~ 0. 8 4 Imp. qt) Periodic oil change 0. 8 0 ~ 0.90L (0. 8 7 ~ 0.9 8 US qt, 0.74 ~ 0. 8 3 Imp. qt) 8. Install: 8 engine oil filler cap 9. Star t the engine, warm it up f or se veral min- utes, and then turn it off. 1 0.Check: 8 engine (for engine oil ...

  • Yamaha YW125Y_ - page 78

    3-25 CHK ADJ 1 2 1 CHANGING THE TRANSMISSION OIL T R . . CHANGING THE TRANSMISSION OIL 1. Stand the scooter on a level surface. TIP 8 Stand the scooter on a suitable stand. 8 Make sure that the scooter upright. 2. Star t the engine, warm it up f or se veral min- utes, and then turn it off. 3. Place a container under the transmission oil drain bolt. ...

  • Yamaha YW125Y_ - page 79

    3-26 CHK ADJ MEASURING THE ENGINE OIL PRESSURE EAS00077 MEASURING THE ENGINE OIL PRESSURE 1 . Check: 8 engine oil level Below the minimum level mark J Add the recommended engine oil to the proper level. Ref er to”CHECKING THE ENGINE OIL LEVEL ”. 2. Star t the engine, warm it up f or se veral min- utes, and then turn it off. NO TICE When the eng ...

  • Yamaha YW125Y_ - page 80

    3-27 CHK ADJ MEASURING THE ENGINE OIL PRESSURE T R . . c . Star t the engine after solving the problem(s) and check the engine oil pressure again. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ 7. Tighten: 8 engine temperature sensor 18Nm(1.8m • kgf, 13.0ft • lbf) 8. Connect: 8 engine temperature sensor coupler 9. Install ...

  • Yamaha YW125Y_ - page 81

    3-28 CHK ADJ 1 2 1 CLEANING THE AIR FIL TER ELEMENT EAS00086 CLEANING THE AIR FIL TER ELEMENT 1. Remove: 8 air filter case cover 1 8 air filter element 2 2. Clean: 8 air filter element 1 Apply compressed air to the outer sur- face of the air filter element. 3 . Check: 8 air filter element Damage J Replace. TIP 8 Replace the air filter element every ...

  • Yamaha YW125Y_ - page 82

    3-29 CHK ADJ 1 2 EAS00090 CLEANING THE V -BEL T CASE AIR FIL TER ELEMENT 1. Remove: 8 V -belt case cove r 8 V -belt case air filter guide 1 8 V -belt case air filter element 2 2. Clean: 8 V -belt case air filter element (with solvent) TIP After cleaning, carefully pat the V -belt case air filter element on a clean cloth to remove the ex- cess solve ...

  • Yamaha YW125Y_ - page 83

    3-30 CHK ADJ 2 1 CHECKING THE THRO TTLE BOD Y JOINT AND INT AKE MANIFOLD/CHECKING THE FUEL HOSE EAS00094 CHECKING THE THRO TTLE BOD Y JOINT AND INT AKE MANIFOLD 1. Remove: 8 seat 8 trunk 8 battery box cover 8 front cover Ref er to “CO VER AND P ANEL ”. 2. Remove: 8 fuel tank Ref er to “REMO VING THE FUEL T ANK” in chapter 6. EAS00096 CHECKI ...

  • Yamaha YW125Y_ - page 84

    3-31 CHK ADJ 1 1 2 EAS00098 CHECKING THE BREA THER HOSES 1. Remove: 8 seat 8 trunk 8 battery box cover 8 front cover Ref er to “CO VER AND P ANEL ”. 2 . Check: 8 crankcase breather hose 1 8 transmission case breather hose 2 Cracks/damage J Replace. Loose connection J Connect properly . NO TICE Make sure the breather hoses are routed correctly . ...

  • Yamaha YW125Y_ - page 85

    3-32 CHK ADJ 2 1 3 4 5 CHECKING THE EXHA UST SYSTEM EAS00099 CHECKING THE EXHA UST SYSTEM The following procedure applies to all of the muffler and gasket. 1. Remove: 8 O 2 sensor coupler 8 muffler Refer to “REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM” in chapter 4. 2 . Check: 8 muffler 1 Crack/damage J Replace. 8 gasket 2 Exhaust gas leak J Re ...

  • Yamaha YW125Y_ - page 86

    3-33 CHK ADJ 1 2 1 1 CHECKING THE CANISTER AND ROLL O VER V AL VE CHECKING THE CANISTER AND R OLL O VER V AL VE The following procedure applies to all of the can- ister and roll over valve. 1. Remove: 8 seat 8 trunk Ref er to “CO VER AND P ANEL ”. 2 . Check: 8 hose (to throttle body) 1 8 hose (to roll over valve) 2 Cracks/damage J Replace. Loos ...

  • Yamaha YW125Y_ - page 87

    3-34 CHK ADJ CHECKING THE CANISTER AND ROLL O VER V AL VE 7 . Check: 8 roll over valve ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Remove the roll over valve. b . Put roll ov er valv e with the ver tical angle. c . Connect the hose to direction a and blow air in the hose. Unobstructed J Normal. Obstruction J Replace. d. ...

  • Yamaha YW125Y_ - page 88

    3-35 CHK ADJ 1 CHECKING THE FR ONT BRAKE/ADJUSTING THE REAR BRAKE EAS00114 ADJUSTING THE REAR BRAKE 1 . Check: 8 brake lever free play a Out of specification J Adjust. Brake lever free play 10 ~ 20mm (0.39 ~ 0.79in) EAS00108 CHASSIS CHECKING THE FRONT BRAKE TIP The brake lever free play is not adjustable. W ARNING A soft or spongy feeling in the br ...

  • Yamaha YW125Y_ - page 89

    3-36 CHK ADJ EAS00116 CHECKING THE BRAKE FLUID LEVEL 1. Stand the scooter on a level surface. TIP 8 Place the scooter on a suitable stand. 8 Make sure the scooter is upright. CHECKING THE BRAKE FLUID LEVEL 2 . Check: 8 brake fluid level Below the minimum level mark a J Add the recommended brake fluid to the proper level. Recommended brake fluid DO ...

  • Yamaha YW125Y_ - page 90

    3-37 CHK ADJ 1 1 1 2 CHECKING THE FR ONT BRAKE P ADS/CHECKING THE REAR BRAKE SHOES/CHECKING THE FRONT BRAKE HOSE EAS00117 CHECKING THE FR ONT BRAKE P ADS The following procedure applies to all of the brake pads. 1. Operate the brake. 2 . Check: 8 front brake pad Wear indicators 1 almost touch the brake disc J Replace the brake pads as a set. Ref er ...

  • Yamaha YW125Y_ - page 91

    3-38 CHK ADJ 1 2 EAS00133 BLEEDING THE HYDRA ULIC BRAKE SYS- TEM W ARNING Bleed the hydraulic brake system whenever: 8 8 8 8 8 the system is disassembled. 8 8 8 8 8 a brake hose is loosened, disconnected or replaced. 8 8 8 8 8 the brake fluid level is very low . 8 8 8 8 8 brake operation is faulty . 1. Remove: 8 brake master cylinder reservoir cap ...

  • Yamaha YW125Y_ - page 92

    3-39 CHK ADJ BLEEDING THE HYDRA ULIC BRAKE SYSTEM TIP Loosening the bleed screw will release the pres- sure and cause the brake lever to contact the throttle grip . h. Tighten the bleed screw and then release the brak e lev er . i. Repeat steps (e) to (h) until all of the air bubbles have disappeared from the brake fluid in the plastic hose. j. Tig ...

  • Yamaha YW125Y_ - page 93

    3-40 CHK ADJ 5 CHECKING AND ADJUSTING THE STEERING HEAD EAS00148 CHECKING AND ADJUSTING THE STEER- ING HEAD 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . TIP Place the scooter on a suitable stand so that the front wheel is elevated. 2 . Check: 8 steering head Grasp the ...

  • Yamaha YW125Y_ - page 94

    3-41 CHK ADJ 6 CHECKING AND ADJUSTING THE STEERING HEAD T R . . Lower ring nut (initial tightening torque) 3 8 Nm (3. 8 m • kgf, 27.5ft • lbf) c . Losen the lower ring nut completely and then tighten it to specification with a steering nut wrench. W ARNING Do not over tighten the lower ring nut. Lower ring nut (final tightening torque) 14Nm (1. ...

  • Yamaha YW125Y_ - page 95

    3-42 CHK ADJ CHECKING THE FRONT FORK EAS00151 CHECKING THE FRONT FORK 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . 2 . Check: 8 inner tube Damage/scratches J Replace. 8 oil seal Oil leakage J Replace. 3. Hold the scooter upright and apply the front brake. 4 . Check: 8 ...

  • Yamaha YW125Y_ - page 96

    3-43 CHK ADJ CHECKING THE TIRES EAS00163 CHECKING THE TIRES The following procedure applies to both of the tires. 1 . Check: 8 tire pressure Out of specification J Regulate. W ARNING 8 8 8 8 8 The tire pressure should only be checked and regulated when the tire temperature equals the ambient air tem- perature. 8 8 8 8 8 The tire pressure and the su ...

  • Yamaha YW125Y_ - page 97

    3-44 CHK ADJ CHECKING THE TIRES 2 . Check: 8 tire surfaces Damage/wear J Replace the tire. Minimum tire tread depth 0. 8 mm (0.03in) 1 Tire tread depth 2 Sidewall 3 Wear indicator W ARNING 8 8 8 8 8 Do not use a tubeless tire on a wheel designed only for tube tires to avoid tire failure and personal injury from sudden deflation. 8 8 8 8 8 When usin ...

  • Yamaha YW125Y_ - page 98

    3-45 CHK ADJ CHECKING THE TIRES Front tire Manufacturer Model Size KEND A K761 120/70-12 51L Rear tire Manufacturer Model Size KEND A K761 130/70-12 56L W ARNING New tires have a relatively low grip on the road surface until they have been slightly w orn. Therefore, appro ximately 100 km should be traveled at normal speed before any high-speed ridi ...

  • Yamaha YW125Y_ - page 99

    3-46 CHK ADJ EAS00170 CHECKING AND LUBRICA TING THE CABLES The following procedure applies to all of the in- ner and outer cables. W ARNING Damaged outer cable may cause the cable to corrode and interfere with its movement. Replace damaged outer cable and inner cables as soon as possible. 1 . Check: 8 outer cable Damage J Replace. 2 . Check: 8 cabl ...

  • Yamaha YW125Y_ - page 100

    3-47 CHK ADJ LUBRICA TING THE LEVERS/LUBRICA TING THE SIDEST AND/ LUBRICA TING THE CENTERST AND/LUBRICA TING THE REAR SUSPENSION EAS00171 LUBRICA TING THE LEVERS Lubricate the pivoting point and metal-to-metal moving par ts of the le vers. Recommended lubricant Lithium-soap-based grease EAS00172 LUBRICA TING THE SIDEST AND Lubricate the pivoting po ...

  • Yamaha YW125Y_ - page 101

    3-48 CHK ADJ CHECKING AND CHARGING THE BA TTER Y EAS00179 ELECTRICAL SYSTEM CHECKING AND CHARGING THE B A TTERY W ARNING Batteries generate explosive hydrogen gas and contain electrolyte which is made of poisonous and highly caustic sulfuric acid. Therefore, always follow these preventive measures: 8 8 8 8 8 W ear protective e ye gear when handling ...

  • Yamaha YW125Y_ - page 102

    3-49 CHK ADJ 2 1 CHECKING AND CHARGING THE BA TTER Y TIP Since MF batteries are sealed, it is not possible to check the charge state of the battery by mea- suring the specific gravity of the electrolyte. Therefore, the charge of the battery has to be checked by measuring the voltage at the bat- tery terminals. 2 . Disconnect: 8 battery leads (from ...

  • Yamaha YW125Y_ - page 103

    3-50 CHK ADJ CHECKING AND CHARGING THE BA TTER Y 8 No charging is necessary when the open- circuit voltage equals or e xceeds 12.8 V . b . Check the charge of the battery , as shown in the char ts and the follo wing e xample. Example c . Open-circuit v oltage = 12.0 V d. Charging time = 6.5 hours e. Charge of the battery = 20 ~ 30% ▲▲▲▲▲? ...

  • Yamaha YW125Y_ - page 104

    3-51 CHK ADJ CHECKING AND CHARGING THE BA TTER Y 8 8 8 8 8 Before removing the battery charger lead clips from the battery terminals, be sure to turn off the battery charger . 8 8 8 8 8 Make sure the battery charger lead clips are in full contact with the battery termi- nal and that they are not shorted. A cor- roded battery charger lead clip may g ...

  • Yamaha YW125Y_ - page 105

    3-52 CHK ADJ Charger Ammeter Measure the open-circuit v oltage pr ior to charging. Connect a charger and am- meter to the batter y and star t charging. Is the amperage higher than the standard charging am- perage written on the bat- ter y? Charging method using a v ariable-current (v oltage) charger TIP Leav e the batter y unused for more than 30 m ...

  • Yamaha YW125Y_ - page 106

    3-53 CHK ADJ This type of batter y charger cannot charge an MF batter y . A va r iable voltage charger is recom- mended. YES NO Charging method using a constant v oltage charger Measure the open-circuit voltage prior to charging. Connect a charger and am- meter to the batter y and star t charging. Is the amperage higher than the standard charging a ...

  • Yamaha YW125Y_ - page 107

    3-54 CHK ADJ 1 2 CHECKING AND CHARGING THE BA TTER Y 6. Install: 8 battery 8 band 7. Connect: 8 battery leads (to the battery terminals) NO TICE First, connect the positive battery lead 1 1 1 1 1 , and then the negative battery lead 2 2 2 2 2 . 8 . Check: 8 battery terminals Dir t J Clean with a wire brush. Loose connection J Connect properly . 9. ...

  • Yamaha YW125Y_ - page 108

    3-55 CHK ADJ EAS00181 CHECKING THE FUSES The following procedure applies to all of the fuses. NO TICE T o av oid a shor t cir cuit, al ways set the main switch to “OFF” when c hecking or replacing a fuse. 1. Remove: 8 battery box cover Ref er to “CO VER AND P ANEL ”. CHECKING THE FUSES 2 . Check: 8 fuse ▼▼▼▼▼▼▼▼▼▼▼▼? ...

  • Yamaha YW125Y_ - page 109

    3-56 CHK ADJ CHECKING THE FUSES Fuses Main Headlight Signaling system Ignition Fuel injection sys- tem Reserve Q’ty 1 1 1 1 1 1 1 1 Amperage rating 20A 10A 15A 10A 10A 20A 15A 10A W ARNING Never use a fuse with an amperage rating other than that specified. Improvising or using a fuse with the wrong amperage rating may cause extensive damage to th ...

  • Yamaha YW125Y_ - page 110

    3-57 CHK ADJ 1 2 REPLA CING THE HEADLIGHT BULBS EAS00183 REPLA CING THE HEADLIGHT BULBS The following procedure applies to both of the headlight bulbs. 1. Remove: 8 safeguard 8 leg shield 1 Ref er to “CO VER AND P ANEL ”. 2 . Disconnect: 8 headlight coupler 3. Remove: 8 dust boot 8 headlight bulb holder 1 8 headlight bulb 2 W ARNING Since the h ...

  • Yamaha YW125Y_ - page 111

    3-58 CHK ADJ 1 b a c d 2 b 1 a c d 2 ADJUSTING THE HEADLIGHT BEAMS EAS00185 ADJUSTING THE HEADLIGHT BEAMS The following procedure applies to both of the headlights. 1. Adjust: 8 headlight beam (ve r tically) ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. T ur n the low beam light adjusting scre w 1 in direction a or b . Di ...

  • Yamaha YW125Y_ - page 112

    CHAS 4-66 CHAPTER 4 CHASSIS FR ONT WHEEL AND BRAKE DISC ....................................................... 4 - 1 FR ONT WHEEL ................................................................................. 4 - 2 REMO VING THE FRONT WHEEL .................................................... 4 - 3 CHECKING THE FRONT WHEEL ..................... ...

  • Yamaha YW125Y_ - page 113

    CHAS 4-67 HANDLEB AR .......................................................................................... 4-49 REMO VING THE HANDLEBAR ...................................................... 4-51 CHECKING THE HANDLEBAR ...................................................... 4-52 INST ALLING THE HANDLEBAR ........................................ ...

  • Yamaha YW125Y_ - page 114

    CHAS 4-1 Remarks Order Job/P ar t Q’ty FR ONT WHEEL AND BRAKE DISC Removing the front wheel and brake disc Speedometer cable Wheel axle nut Wheel axle F ront wheel Collar Speedometer gear unit F ront brake disc 1 2 3 4 5 6 7 1 1 1 1 1 1 1 Remov e the par ts in the order listed. TIP Place the scooter on a suitable stand so that the front wheel is ...

  • Yamaha YW125Y_ - page 115

    CHAS 4-2 Remarks Order Job/P ar t Q’ty 1 1 1 1 EAS00518 FRONT WHEEL FR ONT WHEEL AND BRAKE DISK Disassembling the fr ont wheel Oil seal Bearing Spacer Bearing 1 2 3 4 Remov e the par ts in the order listed. F or assembly , re verse the disassembly procedure. 2 1 4 3 www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 116

    CHAS 4-3 FR ONT WHEEL AND BRAKE DISK EAS00520 REMO VING THE FRONT WHEEL 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . TIP Place the scooter on a suitable stand so that the front wheel is elevated. 2. Remove: 8 speedometer cable 8 front wheel axle nut 8 front wheel axle ...

  • Yamaha YW125Y_ - page 117

    CHAS 4-4 2 . Check: 8 tire 8 front wheel Damage/wear  Replace. Ref er to “CHECKING THE TIRES” and “CHECKING THE WHEELS” in chapter 3. FR ONT WHEEL AND BRAKE DISK EAS00525 CHECKING THE FRONT WHEEL 1. Check: 8 wheel axle Roll the wheel axle on a flat surf ace. Bends  Replace. Wheel axle bending limit 0.25mm (0.01in) W ARNING Do not atte ...

  • Yamaha YW125Y_ - page 118

    CHAS 4-5 1 2 4 3 5. Replace: 8 wheel bearings New 8 oil seal New ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Clean the outside of the front wheel hub . b . Remove the oil seal 1 with a flat-head scre wdr ive r . TIP T o pre vent damaging the wheel, place a rag 2 between the screwdriver and the wheel surface. c . Remove ...

  • Yamaha YW125Y_ - page 119

    CHAS 4-6 FR ONT WHEEL AND BRAKE DISK EAS00528 CHECKING THE BRAKE DISC 1 . Check: 8 brake disc Damage/galling  Replace. 2. Measure: 8 brake disc deflection a Out of specification  Correct the brake disc deflection or replace the brake disc. Brake disc deflection limit (maxi- mum) 0.15mm (0.006in) ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼? ...

  • Yamaha YW125Y_ - page 120

    CHAS 4-7 FR ONT WHEEL AND BRAKE DISK TIP Tighten the brake disc bolts in stages and in a crisscross pattern. Brake disc bolt 23Nm (2.3m • kgf, 16.6ft • lbf) LOCTITE ® d. Measure the brake disc deflection. e. If out of specification, repeat the adjustment steps until the brake disc deflection is within specification. f . If the brake disc defle ...

  • Yamaha YW125Y_ - page 121

    CHAS 4-8 1 2 3 1 2 FR ONT WHEEL AND BRAKE DISK EAS00542 INST ALLING THE FRONT WHEEL 1. Lubricate: 8 wheel axle 8 wheel bearings 8 oil seal lip 8 speedometer gear unit Recommended lubricant Lithium-soap-based grease 2. Install: 8 speedometer gear unit 1 TIP Make sure the speedometer gear unit and the wheel hub are installed with the two projections ...

  • Yamaha YW125Y_ - page 122

    CHAS 4-9 FR ONT WHEEL AND BRAKE DISK EAS00548 ADJUSTING THE FRONT WHEEL ST A TIC BALANCE TIP 8 After replacing the tire, wheel or both, the front wheel static balance should be ad- justed. 8 Adjust the front wheel static balance with the brak e disc installed. 1. Remo ve: 8 balancing weight(s) 2. Find: 8 front wheel’ s heavy spot TIP Place the fr ...

  • Yamaha YW125Y_ - page 123

    CHAS 4-10 FR ONT WHEEL AND BRAKE DISK 3. Adjust: 8 front wheel static balance ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Install a balancing weight 1 onto the rim e xactly opposite the heavy spot “X”. TIP Star t with the lightest weight. b . T ur n the front wheel 90° so that the heavy spot is positioned as shown. ...

  • Yamaha YW125Y_ - page 124

    CHAS 4-11 2 3 1 9 10 4 6 5 8 12 12 11 7 10Nm (1.0 m•kgf , 7.2 ft•lbf) Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 10 11 1 1 1 1 1 1 2 1 1 1 1/2 Removing the rear wheel and rear brake O 2 sensor coupler Muffler Swingarm Brake adjuster Brake cable Compression spring Pin Rear wheel Brake shoe kit T ension spr ing Plate washer Camshaft lever ...

  • Yamaha YW125Y_ - page 125

    CHAS 4-12 Remarks Order Job/P ar t Q’ty For installation, reverse the removal pro- cedure. REAR WHEEL AND REAR BRAKE 2 3 1 9 10 4 6 5 8 12 12 11 7 10Nm (1.0 m•kgf , 7.2 ft•lbf) 12 Collar 1 www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 126

    CHAS 4-13 1 EAS00564 REMO VING THE REAR WHEEL 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . TIP Place the scooter on a suitable stand so that the rear wheel is elevated. 2 . Disconnect: 8 O 2 sensor coupler 3. Remove: 8 muffler 8 wheel axle nut 1 8 swingarm Refer to ? ...

  • Yamaha YW125Y_ - page 127

    CHAS 4-14 REAR WHEEL AND REAR BRAKE EAS00567 CHECKING THE REAR WHEEL DRIVE HUB 1 . Check: 8 rear wheel drive hub Cracks/damage  Replace the rear wheel. EAS00569 CHECKING THE BRAKE The f ollowing procedure applies to all of the brak e shoes. 1. Check: 8 brak e shoe lining Glazed areas  Repair . Sand the glazed areas with course sand- paper . T ...

  • Yamaha YW125Y_ - page 128

    CHAS 4-15 2 1 a a a a 2. Measure: 8 brak e shoe lining thickness a Out of specification  Replace. Brake shoe lining thickness limit (minimum) 1.0mm (0.04in) W ARNING Do not allow oil or grease to contact the brake shoes. TIP Replace the brake shoes as a set, if either is worn to the wear limit. REAR WHEEL AND REAR BRAKE 3. Measure: 8 brak e dr u ...

  • Yamaha YW125Y_ - page 129

    CHAS 4-16 1 T R . . REAR WHEEL AND REAR BRAKE TIP Lubricate the brake camshaft and O-rings with lithium-soap-based grease. W ARNING After installing the brake camshaft and O- rings, remove any excess grease. ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Install the brake camshaft so its punch mark a is positioned as shown ...

  • Yamaha YW125Y_ - page 130

    CHAS 4-17 REAR WHEEL AND REAR BRAKE EAS00574 INST ALLING THE REAR WHEEL 1. Lubricate: 8 wheel axle Recommended lubricant Lithium-soap-based grease 2. Install: 8 rear wheel 3. Install: 8 swingarm 8 wheel axle nut 1 8 muffler Refer to “REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM”. 1 4. Connect: 8 O 2 sensor coupler 5. Adjust: 8 brake lever free p ...

  • Yamaha YW125Y_ - page 131

    CHAS 4-18 EAS00575 ADJUSTING THE REAR WHEEL ST A TIC BALANCE TIP 8 After replacing the tire, wheel or both, the rear wheel static balance should be ad- justed. 8 Adjust the rear wheel static balance with the rear wheel drive hub installed. 1. Adjust: 8 rear wheel static balance Ref er to “ADJUSTING THE FRONT WHEEL ST A TIC BALANCE”. REAR WHEEL ...

  • Yamaha YW125Y_ - page 132

    CHAS 4-19 Remarks Order Job/P ar t Q’ty 1 2 3 4 5 1 1 1 2 2 Removing the front brake pads Brake caliper Circlip Brake pad retaining bolt Brake pad Brake pad spring Remov e the par ts in the order listed. Disconnect. For installation, reverse the removal pro- cedure. FRONT BRAKE EAS00576 FRONT BRAKE FR ONT BRAKE P ADS Refer to “REPLACING THE FRO ...

  • Yamaha YW125Y_ - page 133

    CHAS 4-20 FRONT BRAKE EAS00579 NO TICE Disc brake components rarely require disassembly . Therefore, always follow these preventive measures: 8 8 8 8 8 Never disassemble brake components unless absolutely necessary . 8 8 8 8 8 If any connection on the hydraulic brake system is disconnected, the entire brake system must be disassembled, drained, cle ...

  • Yamaha YW125Y_ - page 134

    CHAS 4-21 1 2 FRONT BRAKE EAS00581 REPLA CING THE FRONT BRAKE P ADS TIP When replacing the brake pads, it is not neces- sary to disconnect the brake hose or disas- semble the br ake caliper . 1. Loosen: 8 brake pad retaining bolt 1 2 . Remove: 8 brake caliper 2 3 . Remove: 8 circlip 8 brake pad retaining bolt 8 brake pads 8 brake pad springs 4. Mea ...

  • Yamaha YW125Y_ - page 135

    CHAS 4-22 FRONT BRAKE 6. Lubricate: 8 brake pad retaining bolt Recommended lubricant Silicone grease NO TICE 8 8 8 8 8 Do not allow grease to contact the brake pads. 8 8 8 8 8 Remove any excess grease. 7. Install: 8 brake pad retaining bolt 13Nm (1.3m • kgf, 9.4ft • lbf) 8 circlip 8 brake caliper 49Nm (4.9m • kgf, 35.4ft • lbf) T R . . T R ...

  • Yamaha YW125Y_ - page 136

    CHAS 4-23 1 2 3 9 4 7 8 7 6 10 5 1.6Nm (0.16 m•kgf , 1.5 ft•lbf) 26Nm (2.6 m•kgf , 18.8 ft•lbf) 9Nm (0.9 m•kgf , 6.5 ft•lbf) FRONT BRAKE EAS00584 FRONT BRAKE MASTER CYLINDER Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 10 1 1 1 1/1 1 1 2 1 1 1 Removing the front brake master cyl- inder Brush guard (right) Brake fluid Brake master r ...

  • Yamaha YW125Y_ - page 137

    CHAS 4-24 FRONT BRAKE Remarks Order Job/P ar t Q’ty 1 2 3 4 5 1 1 1 1 1 Disassembling the front brake mas- ter cylinder Dust boot Circlip W asher Brake master cylinder kit Brake master cylinder body Remov e the par ts in the order listed. F or assembly , re verse the disassembly procedure. EAS00585 1 2 3 4 5 www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 138

    CHAS 4-25 1 3 2 FRONT BRAKE EAS00588 DISASSEMBLING THE FR ONT BRAKE MAS- TER CYLINDER TIP Before disassembling the front brake master cylinder , drain the brak e fluid from the entire brake system. 1. Remove: 8 brush guard (right) Refer to “HANDLEBAR”. 2. Remove: 8 brake lever/compress spring 8 front brake light switch 8 union bolt 1 8 copper w ...

  • Yamaha YW125Y_ - page 139

    CHAS 4-26 1 1 1 FRONT BRAKE EAS00590 CHECKING THE FR ONT BRAKE MASTER CYLINDER 1 . Check: 8 brake master cylinder 1 Damage/scratches/wear  Replace. 8 brake fluid delivery passages (brake master cylinder body) Obstruction  Blow out with compressed air . 2 . Check: 8 brake master cylinder kit 1 Damage/scratches/wear  Replace. 3 . Check: 8 br ...

  • Yamaha YW125Y_ - page 140

    CHAS 4-27 2 1 a FRONT BRAKE EAS00597 ASSEMBLING AND INST ALLING THE FRONT BRAKE MASTER CYLINDER W ARNING 8 8 8 8 8 Before installation, all internal brake components should be cleaned and lu- bricated with clean or new brake fluid. 8 8 8 8 8 Never use solvents on internal brake components. Recommended brake fluid DO T 4 1. Install: 8 brake master c ...

  • Yamaha YW125Y_ - page 141

    CHAS 4-28 2 1 3 FRONT BRAKE 3. Install: 8 copper washers 1 Ne w 8 brake hose 2 8 union bolt 3 26Nm (2.6m • kgf, 18.8ft • lbf) NO TICE When installing the brake hose onto the brake master cylinder , make sure the brake hose touch the projection a a a a a on the brake master cylinder . W ARNING Proper brake hose routing is essential to insure saf ...

  • Yamaha YW125Y_ - page 142

    CHAS 4-29 FRONT BRAKE NO TICE Brake fluid may damage painted surfaces and plastic parts. Therefore, alw ays clean up any spilt brake fluid immediatel y . 5. Bleed: 8 brake system Ref er to “BLEEDING THE HYDRA ULIC BRAKE SYSTEM” in chapter 3. 6 . Check: 8 brake fluid level Below the minimum level mark a  Add the recommended brake fluid to the ...

  • Yamaha YW125Y_ - page 143

    CHAS 4-30 Remarks Order Job/P ar t Q’ty 1 2 3 4 5 1 1 2 1 1 Removing the front brake caliper Brake fluid Brake hose holder 1 Union bolt Copper washer Brake hose Brake caliper Remov e the par ts in the order listed. Drain. Disconnect. For installation, reverse the removal pro- cedure. EAS00612 FRONT BRAKE CALIPER FRONT BRAKE 1 2 3 3 4 5 26Nm (2.6 ...

  • Yamaha YW125Y_ - page 144

    CHAS 4-31 FRONT BRAKE Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 1 1 1 1 1 1 1/1 1 Disassembling the front brake cali- per Brake pad Brake pad spring Brake caliper bracket Brake caliper piston Brake caliper dust seal Brake caliper piston seal Spring Spring seat Bleed screw/cap Brake caliper body Remov e the par ts in the order listed. Refer to ...

  • Yamaha YW125Y_ - page 145

    CHAS 4-32 2 1 3 a FRONT BRAKE EAS00619 DISASSEMBLING THE FR ONT BRAKE CALIPER TIP Bef ore disassembling the brak e caliper , drain the brake fluid from the entire brake system. 1. Remove: 8 union bolt 1 8 copper washers 2 8 brake hose 3 TIP Put the end of the brake hose into a container and pump out the brak e fluid carefully . 2. Remove: 8 brake c ...

  • Yamaha YW125Y_ - page 146

    CHAS 4-33 1 2 3 FRONT BRAKE EAS00631 CHECKING THE FR ONT BRAKE CALIPER Recommended brake component replacement schedule Brake pads Piston seal Brake hose Brake fluid If necessary Every two years Every four years Every two years and whenever the brake is disassembled 1 . Check: 8 brake caliper piston 1 Rust/scratches/wear  Replace the brake calip ...

  • Yamaha YW125Y_ - page 147

    CHAS 4-34 2 1 3 FRONT BRAKE EAS00637 ASSEMBLING AND INST ALLING THE FRONT BRAKE CALIPER W ARNING 8 8 8 8 8 Before installation, all internal brake components should be cleaned and lu- bricated with clean or new brake fluid. 8 8 8 8 8 Never use solvents on internal brake components as they will cause the pis- ton seal to swell and distort. 8 8 8 8 8 ...

  • Yamaha YW125Y_ - page 148

    CHAS 4-35 3 2 4 1 1 FRONT BRAKE 5. Install: 8 brake caliper 1 (temporarily) 8 copper washers 2 Ne w 8 brake hose 3 8 union bolt 4 26Nm (2.6m • kgf, 18.8ft • lbf) 8 brake hose holder 1 7Nm (0.7m • kgf, 5.1ft • lbf) W ARNING Proper brake hose routing is essential to insure safe scooter operation. Refer to “CABLE ROUTING” in chapter 2. T R ...

  • Yamaha YW125Y_ - page 149

    CHAS 4-36 FRONT BRAKE 8. Fill: 8 brake fluid reservoir (with the specified amount of the recom- mended brake fluid) Recommended brake fluid DO T 4 W ARNING 8 8 8 8 8 Use only the designated brake fluid. Other brake fluids may cause the rub- ber seals to deteriorate, causing leakage and poor brake performance. 8 8 8 8 8 Refill with the same type of ...

  • Yamaha YW125Y_ - page 150

    CHAS 4-37 FRONT BRAKE 1 1. Check: 8 brake lever operation Soft or spongy feeling  Bleed the brake system. Ref er to “BLEEDING THE HYDRA ULIC BRAKE SYSTEM” in chapter 3. www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 151

    CHAS 4-38 FRONT FORK Remarks Order Job/P ar t Q’ty 1 2 3 4 1 2 1 1 Removing the front fork legs Leg shield 1 F ront wheel Brake hose holder 1 Brake caliper F ront f ender Lower bracket pinch bolt Stopper ring F ront fork leg Remov e the par ts in the order listed. The following procedure applies to both of the front fork legs. Refer to “CO VER ...

  • Yamaha YW125Y_ - page 152

    CHAS 4-39 FRONT FORK Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 0 q w 1/1 1 1 1/1 1 1/1 1 1 1 1 1 1 Disassembling the front fork legs Clamp/boot Cap Stopper ring Collar/O-ring Fork spring Damper rod bolt/copper washer Damper rod Rebound spring Inner tube Oil seal clip Oil seal Outer tube Remov e the par ts in the order listed. The following ...

  • Yamaha YW125Y_ - page 153

    CHAS 4-40 FRONT FORK Remarks Order Job/P ar t Q’ty F or assembly , re verse the disassembly procedure. 2 3 4 5 7 8 9 1 6 6 q 0 4 w 20Nm (2.0 m•kgf , 14.5 ft•lbf) www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 154

    CHAS 4-41 2 1 FRONT FORK EAS00651 REMO VING THE FRONT FORK LEGS The following procedure applies to both of the front fork legs. 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . TIP Place the scooter on a suitable stand so that the front wheel is elevated. 2. Remove: 8 leg ...

  • Yamaha YW125Y_ - page 155

    CHAS 4-42 FRONT FORK EAS00653 DISASSEMBLING THE FRONT FORK LEGS The following procedure applies to both of the front fork legs. 1. Remove: 8 clamp/boot 2. Remove: 8 cap 8 stopper ring 8 collar/O-ring 8 fork spring 1 NO TICE The collar/O-ring and fork spring jump out after removing stopper ring. 3. Drain: 8 fork oil TIP Stoke the outer tube several ...

  • Yamaha YW125Y_ - page 156

    CHAS 4-43 FRONT FORK 5. Remove: 8 damper rod 1 8 rebound spring 8 inner tube 2 6. Remove: 8 oil seal clip 1 (with a flat-head screwdriver) NO TICE Do not scratch the inner tube. 7. Remove: 8 oil seal 1 NO TICE Never reuse the oil seal. 8 Rag 2 1 2 1 1 2 Damper rod holder 90890-01294 (YM-01300-1) T -handle 90890-01326 (YM-01326) www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 157

    CHAS 4-44 FRONT FORK EAS00656 CHECKING THE FRONT FORK LEGS The following procedure applies to both of the front fork legs. 1 . Check: 8 inner tube 1 8 outer tube 2 Bends/damage/scratches  Replace. W ARNING Do not attempt to straighten a bent inner tube as this may dangerously weaken it. 2. Measure: 8 spring free length a Out of specification  ...

  • Yamaha YW125Y_ - page 158

    CHAS 4-45 FR ONT FORK 1 2 3 EAS00658 ASSEMBLING THE FR ONT FORK LEGS The following procedure applies to both of the front fork legs. W ARNING 8 8 8 8 8 Make sure the oil levels in both front fork legs are equal. 8 8 8 8 8 Uneven oil levels can result in poor han- dling and a loss of stability . TIP 8 When assembling the front fork leg, be sure to r ...

  • Yamaha YW125Y_ - page 159

    CHAS 4-46 FR ONT FORK TIP While holding the damper rod assembly with the damper rod holder 2 and T -handle 3 , tighten the damper rod assembly bolt. Damper rod holder 90890-01294 (YM-01300-1) T -handle 90890-01326 (YM-01326) 4. Install: 8 oil seal 1 Ne w (with the fork seal driver weight 2 and adapter 3 ) Fork seal driver weight 90890-01367 (YM-A94 ...

  • Yamaha YW125Y_ - page 160

    CHAS 4-47 5. Install: 8 oil seal clip 1 TIP Adjust the oil seal clip so that it fits into the outer tube’ s groove . FR ONT FORK 6. Fill: 8 front fork leg (with the specified amount of the recom- mended fork oil) Quantity (each front fork leg) 0.104L (0.11 US qt, 0.09 Imp. qt) Recommended oil Fork oil 10W or equivalent TIP 8 While filling the fro ...

  • Yamaha YW125Y_ - page 161

    CHAS 4-48 1 2 FR ONT FORK T R . . TIP 8 Install the spring with the smaller pitch fac- ing down. 8 Bef ore installing the collar , lubr icate its O- ring with grease. 8 Press down the collar/O-ring, adjust the stopper ring so that it fits into the inner tube’ s groove. 8. Install: 8 clamp/boot EAS00663 INST ALLING THE FR ONT FORK LEGS The followi ...

  • Yamaha YW125Y_ - page 162

    CHAS 4-49 28Nm (2.8 m•kgf , 20.3 ft•lbf) 1 8 12 10 2 11 9 3 14 3 13 5 7 1 4 2 6 5Nm (0.5 m•kgf , 3.6 ft•lbf) Remov e the par ts in the order listed. Refer to “CO VER AND P ANEL ” in chap- ter 3. Disconnect. Refer to “FRONT BRAKE”. Cut. Disconnect. Disconnect. Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 10 11 12 1/1 1/1 2 1 1 1 ...

  • Yamaha YW125Y_ - page 163

    CHAS 4-50 28Nm (2.8 m•kgf , 20.3 ft•lbf) 1 8 12 10 2 11 9 3 14 3 13 5 7 1 4 2 6 5Nm (0.5 m•kgf , 3.6 ft•lbf) HANDLEB AR Remarks Order Job/P ar t Q’ty 13 14 Upper handlebar holder Handlebar 2 1 For installation, reverse the removal pro- cedure. www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 164

    CHAS 4-51 1 3 2 HANDLEB AR 1 EAS00666 REMO VING THE HANDLEBAR 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . 2. Remove: 8 leg shield 1 8 leg shield 2 Ref er to “CO VER AND P ANEL ” in chap- ter 3. 8 rear view mirror (left and right) 8 brush guard (left and right) 8 ...

  • Yamaha YW125Y_ - page 165

    CHAS 4-52 EAS00668 CHECKING THE HANDLEBAR 1 . Check: 8 handlebar 1 Bends/cracks/damage  Replace. W ARNING Do not attempt to straighten a bent handlebar as this may dangerously weaken it. HANDLEB AR 1 www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 166

    CHAS 4-53 1 2 1 HANDLEB AR T R . . EAS00673 INST ALLING THE HANDLEBAR 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . 2. Install: 8 handlebar 1 8 upper handlebar holders 2 28Nm(2.8m • kgf, 20.3ft • lbf) NO TICE First, tighten the bolts on the front side of the handle ...

  • Yamaha YW125Y_ - page 167

    CHAS 4-54 1 2 3 a b HANDLEB AR 5. Install: 8 throttle grip assembly 1 8 throttle cable assembly 2 8 right handlebar switch 3 TIP 8 Lubricate the inside of the throttle grip as- sembly with a thin coat of lithium-soap- based grease and install it onto the handle- bar 4 . 8 Align the projection a on the right handle- bar switch with the hole b in the ...

  • Yamaha YW125Y_ - page 168

    CHAS 4-55 8 16Nm (1.6 m•kgf , 11.6 ft•lbf) 4 6 3 1 2 13 12 10 9 5 11 7 4Nm (0.4 m•kgf , 2.9 ft•lbf) 4Nm (0.4 m•kgf , 2.9 ft•lbf) 48Nm (4.8 m•kgf , 34.7 ft•lbf) 60Nm (6.0 m•kgf , 43.4 ft•lbf) 4Nm (0.4 m•kgf , 2.9 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 9Nm (0.9 m•kgf , 6.5 ft•lbf) Remarks Order Job/P ar t Q’ty STEERING ...

  • Yamaha YW125Y_ - page 169

    CHAS 4-56 Remarks Order Job/P ar t Q’ty LO WER BRACKET STEERING HEAD Removing the lower bracket Leg shield 1 Leg shield 2 F ront wheel Brake caliper F ront f or k legs Handlebar Handlebar bracket Brake hose holder 2 Upper ring nut Lock washer Center ring nut Rubber washer Lower ring nut Bearing race cover Upper bearing inner race Lower bracket Up ...

  • Yamaha YW125Y_ - page 170

    CHAS 4-57 Remarks Order Job/P ar t Q’ty STEERING HEAD 11 12 13 14 15 Lower bearing Upper bearing outer race Lower bearing outer race Lower bearing inner race Dust seal 1 1 1 1 1 For installation, reverse the removal pro- cedure. 7Nm (0.7 m•kgf , 5.1 ft•lbf) 2 9 3 4 5 6 10 12 7 8 13 11 14 15 1 75Nm (7.5 m•kgf , 54.2 ft•lbf) 1st 38Nm (3.8 m ...

  • Yamaha YW125Y_ - page 171

    CHAS 4-58 1 2 1 2 2 1 STEERING HEAD EAS00678 REMO VING THE LO WER BRA CKET 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . 2 . Remove: 8 brake hose holder 2 8 handlebar bracket 1 TIP Remove the handlebar bracket by loosening the ring nut 2 gradually . 3. Remove: 8 upper ...

  • Yamaha YW125Y_ - page 172

    CHAS 4-59 1 STEERING HEAD EAS00682 CHECKING THE STEERING HEAD 1. W ash: 8 bearings 8 bearing races Recommended cleaning solvent Kerosene 2 . Check: 8 bearings 1 8 bearing races 2 Damage/pitting  Replace. 3. Replace: 8 bearings 8 bearing races 8 dust seal ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Remove the bearing ...

  • Yamaha YW125Y_ - page 173

    CHAS 4-60 1 4 2 5 3 1 3 2 STEERING HEAD EAS00684 INST ALLING THE STEERING HEAD 1. Lubricate: 8 bearings 1 8 bearing races Recommended lubricant Lithium-soap-based grease 2. Install: 8 lower ring nut 1 8 rubber washer 2 8 center ring nut 3 8 lock washer 4 8 upper ring nut 5 Ref er to “CHECKING THE STEERING HEAD” in chapter 3. 1 LS T R . . 3. Ins ...

  • Yamaha YW125Y_ - page 174

    CHAS 4-61 11 9 10 8 4 7 6 5 2 2 1 3 44Nm (4.4 m•kgf , 31.8 ft•lbf) 31Nm (3.1 m•kgf , 22.4 ft•lbf) 53Nm (5.3 m•kgf , 38.3 ft•lbf) 105Nm (10.5 m•kgf , 75.9 ft•lbf) 18Nm (1.8 m•kgf , 13.0 ft•lbf) 30Nm (3.0 m•kgf , 21.7 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 13Nm (1.3 m•kgf , 9.4 ft•lbf) 31Nm (3.1 m•kgf , 22.4 ft•lbf) ...

  • Yamaha YW125Y_ - page 175

    CHAS 4-62 1 EAS00693 REMO VING THE REAR SHOCK ABSORBER ASSEMBLIES 1. Stand the scooter on a level surface. W ARNING Securely support the scooter so that there is no danger of it falling over . TIP Place the scooter on a suitable stand so that the rear wheel is elevated. EAS00695 CHECKING THE REAR SHOCK ABSORBER ASSEMBL Y The following procedure app ...

  • Yamaha YW125Y_ - page 176

    CHAS 4-63 2 1 1 2 T R . . T R . . EAS00699 INST ALLING THE REAR SHOCK AB- SORBER ASSEMBLIES 1. Install: 8 rear shock absorber assembly upper nuts 1 30Nm (3.0m • kgf, 21.7ft • lbf) 8 rear shock absorber assembly lower bolts 2 18Nm (1.8m • kgf, 13.0ft • lbf) REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM EAS00702 REMO VING THE SWINGARM 1. Stand ...

  • Yamaha YW125Y_ - page 177

    CHAS 4-64 2 4 3 1 3 1 2 EAS00708 CHECKING THE SWINGARM 1 . Check: 8 swingarm Bends/cracks/damage  Replace. 2 . Check: 8 spacer 1 8 collar 2 8 oil seals 3 8 bearing 4 Damage/wear  Replace. REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM EAS00711 INST ALLING THE SWINGARM 1. Lubricate: 8 bearing 8 oil seal lips 8 rear wheel axle splines Recommended ...

  • Yamaha YW125Y_ - page 178

    CHAS 4-65 REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM 4. Tighten: 8 exhaust pipe nut 13Nm (1.3m • kgf, 9.4ft • lbf) 8 muffler and swingarm bolt 31Nm (3.1m • kgf, 22.4ft • lbf) 8 muffler and swingarm bolt 53Nm (5.3m • kgf, 38.3ft • lbf) 5. Connect: 8 O 2 sensor coupler T R . . T R . . T R . . www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 179

    ENG 5-71 CHAPTER 5 ENGINE ENGINE REMO V AL .................................................................................. 5 - 1 LEADS AND HOSES ......................................................................... 5- 1 ENGINE .............................................................................................. 5 - 3 INST ALLING THE ...

  • Yamaha YW125Y_ - page 180

    ENG 5-72 CHECKING THE V -BEL T ................................................................. 5-45 CHECKING THE PRIMAR Y SHEA VE ............................................ 5-46 CHECKING THE PRIMAR Y SHEA VE WEIGHTS .......................... 5-46 CHECKING THE SLIDER ................................................................ 5-47 CHECKING ...

  • Yamaha YW125Y_ - page 181

    5-1 ENG 7Nm (0.7 m•kgf , 5.1 ft•lbf) 1 4 4 3 2 3Nm (0.3 m•kgf , 2.2 ft•lbf) Remarks Order Job/P ar t Q’ty EAS00188 ENGINE ENGINE REMO V AL LEADS AND HOSES ENGINE REMO V AL Removing the leads and hoses Seat/trunk Battery box cover/front cover Side cover (left and right) Battery/footrest board Rear brake cable/adjuster/spring/pin O 2 sensor ...

  • Yamaha YW125Y_ - page 182

    5-2 ENG 7Nm (0.7 m•kgf , 5.1 ft•lbf) 1 4 4 3 2 3Nm (0.3 m•kgf , 2.2 ft•lbf) ENGINE REMO V AL Remarks Order Job/P ar t Q’ty 1 2 3 4 Rear brake cable holder Spark plug cap Engine temperature sensor coupler Air filter/breather hose 1 1 1 1/1 TEM” in chapter 7. Disconnect. Disconnect. For installation, reverse the removal pro- cedure. www. ...

  • Yamaha YW125Y_ - page 183

    5-3 ENG 1 7 18Nm (1.8 m•kgf , 13.0 ft•lbf) 5 3 7 4 6 2 32Nm (3.2 m•kgf , 23.1 ft•lbf) Remarks Order Job/P ar t Q’ty EAS00191 ENGINE ENGINE REMO V AL Removing the engine Rear fender Rear shock absorber assembly lower bolt Engine mounting nut/washer Engine mounting bolt Engine W asher Collar 1 2 3 4 5 6 7 1 2 1/1 1 1 1 2 Remov e the par ts ...

  • Yamaha YW125Y_ - page 184

    ENG 5-4 ENGINE REMO V AL T R . . T R . . EAS00192 INST ALLING THE ENGINE 1. Install: 8 engine 1 8 engine mounting bolt 2 8 engine mounting nut 3 TIP 8 Apply lithium-soap-based grease to the unthreaded por tion of the engine mounting bolt shaft. 8 Do not fully tighten the engine mounting bolt.. 2. Install: 8 rear shock absorber assembly lower bolts ...

  • Yamaha YW125Y_ - page 185

    5-5 ENG 6 1 2 3 3 2 13 4 7 12 11 5 5 14 15 8 9 10 6 10Nm (1.0 m•kgf , 7.2 ft•lbf) 8Nm (0.8 m•kgf , 5.8 ft•lbf) 9Nm (0.9 m•kgf , 6.5 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 13Nm (1.3 m•kgf , 9.4 ft•lbf) 18Nm (1.8 m•kgf , 13.0 ft•lbf) 22Nm (2.2 m•kgf , 15.9 ft•lbf) 12Nm (1.2 m•kgf , 8.7 ft•lbf) 30Nm (3.0 m•kgf , 21.7 ft ...

  • Yamaha YW125Y_ - page 186

    5-6 ENG 6 1 2 3 3 2 13 4 7 12 11 5 5 14 15 8 9 10 6 10Nm (1.0 m•kgf , 7.2 ft•lbf) 8Nm (0.8 m•kgf , 5.8 ft•lbf) 9Nm (0.9 m•kgf , 6.5 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 13Nm (1.3 m•kgf , 9.4 ft•lbf) 18Nm (1.8 m•kgf , 13.0 ft•lbf) 22Nm (2.2 m•kgf , 15.9 ft•lbf) 12Nm (1.2 m•kgf , 8.7 ft•lbf) 30Nm (3.0 m•kgf , 21.7 ft ...

  • Yamaha YW125Y_ - page 187

    ENG 5-7 CYLINDER HEAD EAS00225 REMO VING THE CYLINDER HEAD 1. Remove : 8 air guide 8 air shroud cylinder 3 Ref er to “ST AR TER CLUTCH AND AC MA GNET O”. 8 V -belt case Ref er to “BEL T DRIVE”. 8 muffler Refer to “REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM” in chapter 4. 2. Remove : 8 breather/O-ring 8 valve cover (intake)/O-ring 8 val ...

  • Yamaha YW125Y_ - page 188

    ENG 5-8 1 2 1 2 3 6 5 4 CYLINDER HEAD 6. Remove: 8 timing chain tensioner (along with the gasket) 8 camshaft sprocket bolt 1 8 camshaft sprocket plate 2 8 camshaft sprocket 3 8 timing chain 4 TIP T o prev ent the timing chain from f alling into the crankcase, fasten it with a wire. 7. Remove: 8 cylinder head TIP 8 Loosen the nuts in the proper sequ ...

  • Yamaha YW125Y_ - page 189

    ENG 5-9 1 2 CYLINDER HEAD EAS00227 CHECKING THE CYLINDER HEAD 1. Eliminate: 8 combustion chamber carbon deposits (with a rounded scraper) TIP Do not use a sharp instrument to avoid damag- ing or scratching: 8 spark plug bore thread 8 valve seats 2 . Check: 8 cylinder head Damage/scratches J Replace. 3. Measure: 8 cylinder head warpage Out of specif ...

  • Yamaha YW125Y_ - page 190

    ENG 5-10 6 1 4 3 2 5 EAS00231 INST ALLING THE CYLINDER HEAD 1. Install: 8 gasket New 8 dowel pins 2. Install: 8 cylinder head 3. Tighten: 8 cylinder head nuts 22 Nm (2.2 m • kgf, 15.9 ft • lbf) 8 cylinder head bolts 12 Nm (1.2 m • kgf, 8.7 ft • lbf) TIP 8 Lubricate the cylinder head nuts with en- gine oil. 8 Tighten the cylinder head nuts a ...

  • Yamaha YW125Y_ - page 191

    ENG 5-11 1 2 3 4 5 TIP 8 When installing the camshaft sprock et, be sure to keep the timing chain as tight as possible on the e xhaust side. 8 Align the slot on the camshaft with the tab in the camshaft sprocket. NO TICE Do not turn the crankshaft when installing the camshaft to avoid damage or improper valve timing. e. Remove the wire from the tim ...

  • Yamaha YW125Y_ - page 192

    ENG 5-12 8 . Check: 8 “I” mark a Align the “I” mark on the AC magneto ro- tor with the stationary pointer b on the crankcase. 8 “I” mark c Align the “I” mark on the camshaft sprocket with the stationary pointer d on the cylinder head. Out of alignment J Correct. Refer to the installation steps above. 9. Tighten: 8 camshaft sproc ket ...

  • Yamaha YW125Y_ - page 193

    5-13 ENG 5 2 3 3 4 1 8 6 3 3 2 7 7Nm (0.7 m•kgf , 5.1 ft•lbf) 12Nm (1.2 m•kgf , 8.7 ft•lbf) Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 THE ROCKER ARMS AND CAMSHAFT 1 4 4 1 1 1 1 1 Remov e the par ts in the order listed. Refer to “CYLINDER HEAD”. Ref er to “REMO VING THE ROCKER ARMS AND CAMSHAFT” and “INST ALL- ING THE CAMSHAF ...

  • Yamaha YW125Y_ - page 194

    ENG 5-14 1 2 1 2 THE R OCKER ARMS AND CAMSHAFT EAS00202 REMO VING THE ROCKER ARMS AND CAM- SHAFT 1. Remove: 8 locknut 1 8 stopper plate 2 2. Remove: 8 intake rocker arm shaft 8 exhaust rocker arm shaft 8 intake rocker arm 8 exhaust rocker arm TIP Remove the rocker arm shafts with the slide hammer bolt 1 and weight 2 . Slide hammer bolt 90890-01085 ...

  • Yamaha YW125Y_ - page 195

    ENG 5-15 THE R OCKER ARMS AND CAMSHAFT EAS00205 CHECKING THE CAMSHAFT 1 . Check: 8 camshaft lobes Blue discoloration/pitting/scratches J Replace the camshaft. 2. Measure: 8 camshaft lobe dimensions a and b Out of specification J Replace the cam- shaft. Camshaft lobe dimension limit Intake a a a a a 25.267 ~ 25.367mm (0.995 ~0.999in) <Limit>:2 ...

  • Yamaha YW125Y_ - page 196

    ENG 5-16 THE R OCKER ARMS AND CAMSHAFT EAS00206 CHECKING THE ROCKER ARMS AND ROCKER ARM SHAFTS The following procedure applies to all of the rocker arms and rocker arm shafts. 1 . Check: 8 rocker arm (camshaft touch surface) 1 8 rocker arm (valve touch surface) 2 Damage/wear J Replace. 2 . Check: 8 rocker arm shaft Blue discoloration/excessive wear ...

  • Yamaha YW125Y_ - page 197

    ENG 5-17 THE ROCKER ARMS AND CAMSHAFT Above 0.034mm (0.0013in) J Replace the de- f ective par t(s). Rocker-arm-to-rocker-arm-shaft clearance 0.009 ~ 0.034mm (0.0004 ~ 0.0013in) EAS00207 CHECKING THE TIMING CHAIN, CAMSHAFT SPROCKET AND TIMING CHAIN GUIDES The following procedure applies to all of the cam- shaft sprocket and timing chain guides. 1 . ...

  • Yamaha YW125Y_ - page 198

    ENG 5-18 THE R OCKER ARMS AND CAMSHAFT EAS00210 CHECKING THE TIMING CHAIN TENSIONER 1 . Check: 8 timing chain tensioner Cracks/damage J Replace. 2 . Check: 8 one-way cam operation Rough movement J Replace the timing chain tensioner . 3 . Check: 8 cap bolt 8 O-ring New 8 spring 8 one-way cam 8 gasket New 8 timing chain tensioner rod Damage/wear J Re ...

  • Yamaha YW125Y_ - page 199

    ENG 5-19 1 1 2 1 2 EAS00220 INST ALLING THE CAMSHAFT AND ROCKER ARMS 1. Lubricate: 8 camshaft 1 Recommended lubricant Camshaft Engine oil Camshaft bearing Engine oil 2. Lubricate: 8 rocker arms 8 rocker arm shafts Recommended lubricant Molybdenum disulfide oil THE R OCKER ARMS AND CAMSHAFT 3. Install: 8 exhaust rocker arm 1 8 exhaust rocker arm sha ...

  • Yamaha YW125Y_ - page 200

    ENG 5-20 THE R OCKER ARMS AND CAMSHAFT 5. Install: 8 stopper plate 1 8 locknut 2 12Nm (1.2m • kgf, 8.7ft • lbf) T R . . www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 201

    5-21 ENG Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 8 4 4 2 2 4 4 8 EAS00236 V AL VES AND V AL VE SPRINGS Removing the valves and valve springs Cylinder head Rocker arms Rocker arm shafts Camshaft V alve cotter V alve spring retainer V alve spring V alve (intak e) V alve (e xhaust) V alve stem seal V alve stem seat/v alve guide O-ring Remov e ...

  • Yamaha YW125Y_ - page 202

    5-22 ENG V AL VES AND V AL VE SPRINGS Remarks Order Job/P ar t Q’ty For installation, reverse the removal pro- cedure. 1 2 3 6 8 7 8 1 2 8 3 6 8 7 4 5 www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 203

    ENG 5-23 1 2 3 V AL VES AND V AL VE SPRINGS EAS00237 REMO VING THE V AL VES The following procedure applies to all of the valves and related components. TIP Bef ore removing the inter nal par ts of the cylin- der head (e.g., valves, valve springs, valve seats), make sure the valves properly seal. 2 . Remove: 8 valve cotters 1 TIP Remove the valve c ...

  • Yamaha YW125Y_ - page 204

    ENG 5-24 V AL VES AND V AL VE SPRINGS 3 . Remove: 8 valve spring retainer 1 8 valve spring 2 8 valve stem seal 3 8 valve 4 TIP Identify the position of each par t very carefully so that it can be reinstalled in its original place. EAS00239 CHECKING THE V AL VES AND V AL VE GUIDES The f ollowing procedure applies to all of the v alves and v alve gui ...

  • Yamaha YW125Y_ - page 205

    ENG 5-25 V AL VES AND V AL VE SPRINGS 2. Replace: 8 valve guide TIP T o ease valv e guide removal and installation, and to maintain the correct fit, heat the cylinder head to 100°C (212°F) in an oven. ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a . Remove the valve guide with the valve guide remover 1 . b . Install the n ...

  • Yamaha YW125Y_ - page 206

    ENG 5-26 5. Measure: 8 valve margin thickness a Out of specification J Replace the valve. V alve margin thickness (intake) 0.7mm (0.028in) V alve margin thickness (exhaust) 1.0mm (0.039in) V AL VES AND V AL VE SPRINGS 6. Measure: 8 valve stem runout Out of specification J Replace the valve. TIP 8 When installing a new valve, always replace the valv ...

  • Yamaha YW125Y_ - page 207

    ENG 5-27 EAS00240 CHECKING THE V AL VE SEA TS The f ollowing procedure applies to all of the v alves and v alve seats. 1. Eliminate: 8 carbon deposits (from the v alve f ace and valv e seat) 2. Check: 8 v alve seat Pitting/wear J Replace the cylinder head. 3. Measure: 8 v alve seat width a Out of specification J Replace the cylin- der head. V alve ...

  • Yamaha YW125Y_ - page 208

    ENG 5-28 ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Apply a coarse lapping compound a to the valve face. NO TICE Do not let the lapping compound enter the gap between the valve stem and the v alve guide. b . Apply molybdenum disulfide oil onto the v alve stem. c. Install the v alve into the cylinder head. d. T ur n the ...

  • Yamaha YW125Y_ - page 209

    ENG 5-29 a EAS00241 CHECKING THE V AL VE SPRINGS The f ollowing procedure applies to all of the valv e springs. 1. Measure: 8 valve spring free length a Out of specification J Replace the valve spring. V alve spring free length 41.88mm (1.649in) <Limit>: 39.786mm (1.566in) V AL VES AND V AL VE SPRINGS 2. Measure: 8 compressed valve spring for ...

  • Yamaha YW125Y_ - page 210

    ENG 5-30 1 2 3 EAS00245 INST ALLING THE V AL VES The f ollowing procedure applies to all of the valves and related components. 1. Deburr: 8 valve stem end (with an oil stone) 2. Lubricate: 8 valve stem 1 8 valve stem seal 2 (with the recommended lubricant) Recommended lubricant Molybdenum disulfide oil V AL VES AND V AL VE SPRINGS b a 1 2 3. Instal ...

  • Yamaha YW125Y_ - page 211

    ENG 5-31 V alve spring compressor 90890-04019 (YM-04019) V alve spring compressor attach- ment 90890-04108 (YM-04108) V AL VES AND V AL VE SPRINGS 5. T o secure the valv e cotters onto the valv e stem, lightly tap the valve tip with a soft- f ace hammer . NO TICE Hitting the valve tip with e xcessive forc e could damage the valve. www.ScooterTime. ...

  • Yamaha YW125Y_ - page 212

    5-32 ENG Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 EAS00251 CYLINDER AND PIST ON Removing the cylinder and piston Cylinder head Timing chain guide (exhaust side) Cylinder Dowel pin Cylinder gasket Piston pin clip Piston pin Piston Piston ring set Remov e the par ts in the order listed. Refer to “CYLINDER HEAD”. Ref er to “REMO VING THE ...

  • Yamaha YW125Y_ - page 213

    ENG 5-33 3 2 1 EAS00253 REMO VING THE CYLINDER AND PIST ON 1. Remo ve: 8 piston pin clip 1 8 piston pin 2 8 piston 3 NO TICE Do not use a hammer to drive the piston pin out. TIP 8 Bef ore removing the piston pin clip , cover the crankcase opening with a clean rag to prevent the piston pin clip from falling into the crankcase. 8 Before removing the ...

  • Yamaha YW125Y_ - page 214

    ENG 5-34 CYLINDER AND PIST ON EAS00255 CHECKING THE CYLINDER AND PIST ON 1 . Check: 8 piston wall 8 cylinder wall V er tical scratches J Rebore or replace the cylinder , and replace the piston and piston rings as a set. 2. Measure: 8 piston-to-cylinder clearance ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Measure cylind ...

  • Yamaha YW125Y_ - page 215

    ENG 5-35 e. Calculate the piston-to-cylinder clearance with the following formula. Piston-to-cylinder clearance = Cylinder bore “C” - Piston skir t diameter “P” Piston-to-cylinder clearance 0.010 ~ 0.035mm (0.0004 ~0.0014in) <Limit>: 0.15mm (0.0059in) f. If out of specification, rebore or replace the cylinder , and replace the piston ...

  • Yamaha YW125Y_ - page 216

    ENG 5-36 EAS00263 CHECKING THE PIST ON RINGS 1. Measure: 8 piston ring side clearance Out of specification J Replace the pis- ton and piston rings as a set. TIP Bef ore measuring the piston r ing side clearance, eliminate any carbon deposits from the piston ring groov es and piston r ings. Piston ring side clearance T op ring 0.02 ~ 0.08mm (0.0008 ...

  • Yamaha YW125Y_ - page 217

    ENG 5-37 4. Calculate: 8 piston-pin-to-piston-pin-bore clearance Out of specification J Replace the pis- ton pin and piston as a set. Piston-pin-to-piston-pin-bore clearance = Piston pin bore diameter b - Piston pin outside diameter a Piston-pin-to-piston clearance 0.002 ~ 0.018mm (0.00008 ~ 0.0007in) 3. Measure: 8 piston pin bore diameter b Out of ...

  • Yamaha YW125Y_ - page 218

    ENG 5-38 2 3 1 CYLINDER AND PIST ON EAS00267 INST ALLING THE PIST ON AND CYLINDER 1. Install: 8 oil ring expander 8 oil ring rail 8 2nd ring 8 top ring TIP Be sure to install the piston rings so that the manuf acturer’ s marks or numbers a face up . CHECKING THE TIMING CHAIN GUIDE (EX- HA UST SIDE) 1 . Check: 8 timing chain guide (exhaust side) D ...

  • Yamaha YW125Y_ - page 219

    ENG 5-39 1 a b A c d CYLINDER AND PIST ON 3. Install: 8 gasket New 8 dowel pins 4. Lubricate: 8 piston 8 piston rings 8 cylinder (with the recommended lubricant) Recommended lubricant Engine oil 5 . Offset: 8 piston ring end gaps a Top ring b Lower oil ring rail c Upper oil ring rail d 2nd ring A Exhaust side 6. Install: 8 cylinder 1 TIP 8 While co ...

  • Yamaha YW125Y_ - page 220

    5-40 ENG Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 1 1 1 1 1 1 1 1 1 EAS00316 BEL T DRIVE V -BEL T CASE Removing the V -belt case Air duct V -belt case cove r V -belt case filter guide V -belt case filter element O-ring Gasket (V -belt case) Plate Gasket (plate) V -belt case Remov e the par ts in the order listed. For installation, reverse ...

  • Yamaha YW125Y_ - page 221

    5-41 ENG Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 10 11 12 1/1 1 1 1 1 1 1 1 1/3 6 2 1 Remov e the par ts in the order listed. Ref er to “V -BEL T CASE”. Ref er to “REMO VING THE PRIMAR Y SHEA VE” and “INST ALLING THE SEC- OND AR Y SHEA VE, V -BEL T AND PRI- MAR Y SHEA VE”. Ref er to “REMO VING THE SECOND- AR Y SHEA VE AND V ...

  • Yamaha YW125Y_ - page 222

    5-42 ENG 8 2 4 3 5 6 7 1 e 0 q w e 9 r 90Nm (9.0 m•kgf , 7.2 ft•lbf) Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 0 q w e r 1 3 1 3 3 3 1 1 1 3 1 2 2 1 Disassemble the parts in the order listed. F or assembly , re verse the disassembly procedure. Disassembling the secondary sheave Clutch carrier nut Clip Plate Clutch shoe spring Clutch sho ...

  • Yamaha YW125Y_ - page 223

    ENG 5-43 2 1 3 1 2 3 1 2 3 BEL T DRIVE EAS00318 REMO VING THE SECOND AR Y SHEA VE AND V -BEL T 1. Remo ve: 8 secondar y sheav e nut 1 8 clutch housing 2 TIP While holding the clutch housing with the sheave holder 3 , loosen the secondar y sheav e nut. Sheave holder 90890-01701 (YS-01880-A) EAS00317 REMO VING THE PRIMAR Y SHEA VE 1. Remove: 8 V -bel ...

  • Yamaha YW125Y_ - page 224

    ENG 5-44 1 2 BEL T DRIVE TIP While holding the clutch carrier with the rotor holding tool 2 , loosen the clutch carrier nut one full turn with the locknut wrench 3 . Rotor holding tool 90890-01235 (YU-01235) Locknut wrench 90890-01348 (YM-01348) 3. Remove: 8 secondary sheave 1 8 V -belt 2 TIP Remov e the V -belt and secondar y sheav e from the prim ...

  • Yamaha YW125Y_ - page 225

    ENG 5-45 2. Measure: 8 clutch shoe thickness Out of specification J Replace the clutch shoes and springs as a set. Clutch shoe thickness 3.2 ~ 3.5mm (0.13 ~ 0.14in) <Limit>: 2.0mm (0.079in) TIP 8 Inspect clutch shoes a . 8 After removing the clutch shoe spring, do not use them again. 8 Replace the all three as a set. TIP After sanding the gla ...

  • Yamaha YW125Y_ - page 226

    ENG 5-46 2 1 BEL T DRIVE CHECKING THE PRIMAR Y SHEA VE 1 . Check: 8 primary sliding sheave 1 8 primary fixed sheave 2 Cracks/damage/wear J Replace the pri- mary sliding sheave, primary fixed sheav e and V -belt. 2 . Check: 8 free movement Stick or excessive play J Replace the primary sliding sheave, collar or both. TIP Inser t the collar 2 into the ...

  • Yamaha YW125Y_ - page 227

    ENG 5-47 BEL T DRIVE CHECKING THE SLIDER 1 . Check: 8 slider 1 Damage/wear J Replace EAS00322 CHECKING THE SECOND AR Y SHEA VE 1. Check: 8 secondar y fixed shea ve 8 secondar y sliding sheav e Crac ks/damage/wear J Replace the sec- ondary fixed and sliding sheaves as a set. 2 . Check: 8 torque cam groov e 1 Damage/wear J Replace the secondar y fix ...

  • Yamaha YW125Y_ - page 228

    ENG 5-48 1 2 3 4 4 5 BEL T DRIVE EAS00323 ASSEMBLING THE PRIMAR Y SHEA VE 1. Clean: 8 primar y fixed shea ve 1 8 primar y sliding sheave 2 8 collar 3 8 primar y sheave weights 4 TIP Use thinner to clean up grease , dir t on the pr i- mar y sliding sheav e cam side 5 . 2. Install: 8 primary sheave weights 1 8 collar 2 3. Install: 8 sliders 1 8 cam 2 ...

  • Yamaha YW125Y_ - page 229

    ENG 5-49 2 1 3 EAS00324 ASSEMBLING THE SECOND AR Y SHEA VE 1. Lubricate: 8 secondary fixed shea ve’ s inner surf ace 1 8 secondar y sliding sheav e’ s inner surface 2 8 oil seals 8 bearings (with the recommended lubricant) Recommended lubricant BEL-RA Y assembl y lube ® 2. Install: 8 secondar y sliding sheav e 1 TIP Install the secondary slidi ...

  • Yamaha YW125Y_ - page 230

    ENG 5-50 2 1 3 2 1 5. Install: 8 secondar y sheav e 1 8 spring 8 clutch carrier 2 TIP Attach the clutch spring holder 3 and clutch spring holder ar m 4 onto the secondar y sheav e as shown. Then, compress the spring, and tighten the clutch carrier nut 5 . Clutch spring holder 90890-01337 (YM-33285) BEL T DRIVE T R . . EAS00325 INST ALLING THE SECON ...

  • Yamaha YW125Y_ - page 231

    ENG 5-51 2 1 3 2 1 3 BEL T DRIVE Rotor holding tool 90890-01235 (YU-01235) Locknut wrench 90890-01348 (YM-01348) 3. Install: 8 clutch housing 1 8 secondary sheave nut 2 60Nm(6.0m • kgf, 43.4ft • lbf) TIP Tighten the secondary sheave nut with the sheave holder 3 . Sheave holder 90890-01701 (YS-01880-A) T R . . T R . . 4. Install: 8 primary fixed ...

  • Yamaha YW125Y_ - page 232

    ENG 5-52 1 2 3 BEL T DRIVE 5. P osition: 8 V -belt 1 TIP P osition the V -belt in the pr imar y shea ve 2 (when the pulley is at its widest position) and in the secondary sheave 3 (when the pulley is at its narrowest position), and mak e sure the V - belt is tight. 6. Install: 8 V -belt case Ref er to “V -BEL T CASE”. www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 233

    5-53 ENG 9 1 2 3 4 5 6 7 8 7Nm (0.7 m•kgf , 5.1 ft•lbf) 10Nm (1.0 m•kgf , 7.2 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 70Nm (7.0 m•kgf , 50.6 ft•lbf) 9Nm (0.9 m•kgf , 6.5 ft•lbf) Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 1 1 1/1 1 1 1 1 1 1 Remov e the par ts in the order listed. Disconnect. For installation, reverse the rem ...

  • Yamaha YW125Y_ - page 234

    5-54 ENG 7 6 5 4 2 3 2 1 10Nm (1.0 m•kgf , 7.2 ft•lbf) 10Nm (1.0 m•kgf , 7.2 ft•lbf) Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 1 2 1 1 1 1 1 EAS00342 ST ARTER CLUTCH Removing the starter clutch V -belt case Primary fixed sheave Primary sliding sheave Idle gear plate Plate washer Idle gear Star ter clutch Star ter wheel gear holder Star ...

  • Yamaha YW125Y_ - page 235

    ENG 5-55 1 2 3 1 2 EAS00347 REMO VING THE A C MA GNET O 1. Remove: 8 air guide 8 air shroud cylinder 3 2. Remove: 8 fan 8 AC magneto rotor nut 1 8 washer TIP While holding the AC magneto rotor 3 with the rotor holding tool 2 , loosen the AC magneto ro- tor nut. Rotor holding tool 90890-01235 (YU-01235) 3. Remove: 8 AC magneto rotor 1 (with the flyw ...

  • Yamaha YW125Y_ - page 236

    ENG 5-56 EAS00351 CHECKING THE ST ARTER CLUTCH 1 . Check: 8 star ter clutch roller Damage/wear J Replace. 2 . Check: 8 star ter clutch idle gear 8 star ter wheel gear Burrs/chips/roughness/wear J Replace the def ective par t(s). 3 . Check: 8 star ter wheel gear’ s contacting surf aces Damage/pitting/wear J Replace the star ter wheel gear . 4 . Ch ...

  • Yamaha YW125Y_ - page 237

    ENG 5-57 2 3 1 ST ARTER CLUTCH AND A C MA GNET O EAS00354 INST ALLING THE A C MA GNET O 1. Install: 8 stator coil assembly 8 crankshaft position sensor 8 woodruff key 8 AC magneto rotor 8 washer 8 AC magneto rotor nut TIP 8 Clean the tapered por tion of the crankshaft and the A C magneto rotor hub . 8 When installing the A C magneto rotor , make su ...

  • Yamaha YW125Y_ - page 238

    5-58 ENG 1 2 3 4 5 7 6 8 9 1 13Nm (1.3 m•kgf , 9.4 ft•lbf) 13Nm (1.3 m•kgf , 9.4 ft•lbf) 4Nm (0.4 m•kgf , 2.9 ft•lbf) EAS00360 OIL PUMP Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 7 8 9 1/1 1 1 1 1/1 1 1 1 1 Removing the oil pump AC magneto rotor Stator coil assembly Cover/O-ring Gasket Oil seal Dowel pin Circlip/plate washer Oil pump d ...

  • Yamaha YW125Y_ - page 239

    ENG 5-59 EAS00364 CHECKING THE OIL PUMP 1 . Check: 8 oil pump drive gear 8 oil pump driven gear 1 8 oil pump housing 8 oil pump housing cover Cracks/damage/wear J Replace the def ective par t(s). 2. Measure: 8 inner-rotor-to-outer-rotor-tip clearance a 8 outer-rotor-to-oil-pump-housing clearance b . Out of specification J Replace the oil pump . 1 I ...

  • Yamaha YW125Y_ - page 240

    ENG 5-60 1 2 3 4 5 6 1 OIL PUMP EAS00375 ASSEMBLING THE OIL PUMP 1. Lubricate: 8 inner rotor 8 outer rotor 8 oil pump shaft (with the recommended lubricant) Recommended lubricant Engine oil EAS00376 INST ALLING THE OIL PUMP 1 . Install: 8 gasket New 8 oil pump 1 4 Nm (0.4 m • kgf, 2.9 ft • lbf) NO TICE After tightening the bolts, make sure the ...

  • Yamaha YW125Y_ - page 241

    5-61 ENG Remarks Order Job/P ar t Q’ty 1 2 3 4 5 6 1 1 2 1 1 1 Removing the transmission T ransmission oil Muffler Swingarm Rear wheel V -belt case V -belt Secondary sheave Right crankcase cover Right crankcase cover gasket Dowel pin Primary drive gear shaft Main axle Drive axle Remov e the par ts in the order listed. Drain. Refer to “REAR SHOC ...

  • Yamaha YW125Y_ - page 242

    ENG 5-62 TRANSMISSION EAS00425 CHECKING THE TRANSMISSION 1. Measure: 8 main axle runout (with a centering device and dial gauge ) Out of specification J Replace the main axle. Main axle runout limit 0.04mm (0.002in) 2. Measure: 8 drive axle runout (with a centering device and dial gauge ) Out of specification J Replace the drive axle. Drive axle ru ...

  • Yamaha YW125Y_ - page 243

    5-63 ENG (x7) (x2) 1 2 3 3 3 4 4 10 5 6 7 8 9 12 12 13 11 20Nm (2.0 m•kgf , 14.5 ft•lbf) 23Nm (2.3 m•kgf , 16.6 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 13Nm (1.3 m•kgf , 9.4 ft•lbf) Remarks Order Job/P ar t Q’ty 1 2 3 4 2 1 1/2 1/1 Remov e the par ts in the order listed. Refer to “ENGINE REMOVEL ” ...

  • Yamaha YW125Y_ - page 244

    5-64 ENG (x7) (x2) 1 2 3 3 3 4 4 10 5 6 7 8 9 12 12 13 11 20Nm (2.0 m•kgf , 14.5 ft•lbf) 23Nm (2.3 m•kgf , 16.6 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) 13Nm (1.3 m•kgf , 9.4 ft•lbf) CRANKSHAFT Remarks Order Job/P ar t Q’ty 5 6 7 8 9 10 11 12 13 Timing chain guide (intake side) Crankcase (right) Oil se ...

  • Yamaha YW125Y_ - page 245

    ENG 5-65 1 1 2 EAS00385 DISASSEMBLING THE CRANKCASE 1. Remove: 8 centerstand 2. Remove: 8 crankcase bolts 1 TIP Loosen each bolt 1/4 of a turn at a time, in stages and in a crisscross pattern. After all of the bolts are fully loosened, remove them. 3. Remove: 8 right crankcase 1 NO TICE T ap on one side of the crankcase with a soft- face hammer 2 2 ...

  • Yamaha YW125Y_ - page 246

    ENG 5-66 1 2 CRANKSHAFT EAS00389 REMO VING THE CRANKSHAFT ASSEMBL Y 1. Remove: 8 crankshaft assembly 1 8 timing chain 2 TIP 8 Bef ore removing the crankshaft assembly , remove the timing chain from the crankshaft sprocket. 8 The crankshaft assembly cannot be re- moved if the timing chain is attached onto the crankshaft sprocket. EAS00394 CHECKING T ...

  • Yamaha YW125Y_ - page 247

    ENG 5-67 3. Measure: 8 crankshaft width Out of specification J Replace the crank- shaft. Crankshaft width 45.45 ~ 45.50mm (1.789 ~ 1.791in) 4 . Check: 8 crankshaft sprocket 1 Damage/wear J Replace the crankshaft. 8 bearing 2 Cracks/damage/wear J Replace the crankshaft. 8 oil pump drive gear 3 Damage/wear J Replace the crankshaft. EAS00399 CHECKING ...

  • Yamaha YW125Y_ - page 248

    ENG 5-68 EAS00207 CHECKING THE TIMING CHAIN AND TIMING CHAIN GUIDE(INT AKE SIDE) 1 . Check: 8 timing chain Damage/stiffness J Replace the timing chain and camshaft sprocket as a set. 2 . Check: 8 timing chain guide (intake side) Damage/wear J Replace. EAS00401 CHECKING THE BEARINGS AND OIL SEALS 1 . Check: 8 bearings Clean and lubricate the bearing ...

  • Yamaha YW125Y_ - page 249

    ENG 5-69 1 2 CRANKSHAFT EAS00418 ASSEMBLING THE CRANKCASE 1. Thoroughly clean all the gasket mating sur- faces and crankcase mating surfaces. 2. Apply: 8 sealant (onto the crankcase mating surfaces) Y amaha bond No. 1215 90890-85505 (A CC-11001-05-01) TIP Do not allow any sealant to come into contact with the oil galler y . EAS00408 INST ALLING THE ...

  • Yamaha YW125Y_ - page 250

    ENG 5-70 1 CRANKSHAFT 3. Install: 8 dowel pins 8 right crankcase 1 TIP T ap lightly on the r ight crankcase with a soft- f ace hammer . T R . . 4. Tighten: 8 crankcase bolts 13Nm(1.3m • kgf, 9.4ft • lbf) TIP Tighten the crankcase bolts in stages and in a crisscross pattern. 5. Apply: 8 engine oil (onto the crankshaft pin, bearing and oil delive ...

  • Yamaha YW125Y_ - page 251

    6-37 FI CHAPTER 6 FUEL INJECTION SYSTEM FUEL INJECTION SYSTEM .................................................................... 6 - 1 WIRING DIA GRAM ............................................................................ 6- 2 ECU’S SELF-DIA GNOSTIC FUNCTION .......................................... 6 - 4 CHECKING FOR A DEFECTIVE ENGINE ...

  • Yamaha YW125Y_ - page 252

    6-1 FI EAS00894 FUEL INJECTION SYSTEM FUEL INJECTION SYSTEM 1 ECU 2 Engine trouble warning light 3 Lean angle cut-off switch 4 Fuel hose 5 Ignition coil 6 Fuel injector 7 Intake air pressure sensor 8 ISC (idle speed control) valve 9 Intake air temperature sensor 0 Battery q Air filter case w Catalytic conv er ter e Crankshaft position sensor r Engi ...

  • Yamaha YW125Y_ - page 253

    6-2 FI WIRING DIA GRAM FUEL INJECTION SYSTEM L/Y B/L R W/R B/L W/R W/L W W W WW W W/R B/L W W W W W W W W W R B B R R R R R B R R R B L/W R/W L/W R/W L/W R/W (BLACK) (BLACK) B R B Br Br Br R/B Br Br/L R Br B/W (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A R R W/R R R/W Or R/B R/B Or Or/B Or/B R/B R/B G L/ ...

  • Yamaha YW125Y_ - page 254

    6-3 FI FUEL INJECTION SYSTEM 1 Crankshaft position sensor 4 Main fuse 5 Fuel injection system fuse 6 Battery q Main switch w Sidestand switch t Engine stop switch y Ignition fuse u Signaling system fuse s Engine trouble warning light d Speed sensor , Ignition coil . Spark plug / Fuel injector ! Fuel pump @ ECU # Lean angle cut-off switch $ Engine t ...

  • Yamaha YW125Y_ - page 255

    6-4 FI ECU’S SELF-DIA GNOSTIC FUNCTION The ECU is equipped with a self-diagnostic function in order to ensure that the engine control sys- tem is operating normally . If this function detects a malfunction in the system, it immediately operates the engine under substitute characteristics and illuminates the engine trouble warning light to aler t ...

  • Yamaha YW125Y_ - page 256

    6-5 FI EAS00902 SELF-DIA GNOSTIC F ANCTION T ABLE If the ECU detects an abnormal signal from a sensorwhile the vehicle is being driven, the ECU illuminates the engine trouble warning light and provides the engine with alternate operating instruc- tions that are appropriate for the type of malfunction. When an abnor mal signal is receiv ed from a se ...

  • Yamaha YW125Y_ - page 257

    6-6 FI F ault code No . Item Symptom Engine star tability V ehicle driveability 39 30 41 42 43 44 46 50 61 _ Fuel injector Lean angle cut-off switch (latch up detected) (open or shor t circuit) Speed sensor Fuel system voltage (moni- toring voltage) Error in reading from or writ- ing on EEPROM V ehicle system pow er sup- ply (monitoring voltage) EC ...

  • Yamaha YW125Y_ - page 258

    6-7 FI FUEL INJECTION SYSTEM EAS00904 TR OUBLESHOO TING CHART Erasing the malfunction history:* The malfunction histor y is stored e v en if the main s witch is tur ned OFF . The malfunction history must be erased in the diagnostic mode. Ref er to “Diagnostic mode table (Diagnostic code No .62)”. * Operated when the engine trouble warning light ...

  • Yamaha YW125Y_ - page 259

    6-8 FI EAS00905 DIA GNOSTIC MODE It is possible to monitor the sensor output data or check the activation of actuators with con- necting the Fl diagnostic tool to the normal mode or the diagnostic monitoring mode. Fl diagnostic tool 90890-03182 (YU-03182) Setting the normal mode TIP The engine speed, engine temperature, and fault code, if detected, ...

  • Yamaha YW125Y_ - page 260

    6-9 FI Setting the diagnostic mode 1. T ur n the main switch to “OFF”. 2. Disconnect the self diag signal connector 1 , and then connect the Fl diagnostic-tool 2 as shown. 3 . While press the “MODE” button, turn the main switch to “ON”. TIP 8 ”DIAG” appears on the LCD of the Fl diag- nostic tool. 8 ”POWER” LED (Green) comes on. ...

  • Yamaha YW125Y_ - page 261

    6-10 FI F ault codeNo. Symptom Diagnostic code 12 13 14 15 16 19 22 24 28 30 33 37 39 41 42 43 44 46 50 61 No normal signals are received from the crankshaft position sensor . Intake air pressure sensor-open or short circuit detected. F aulty intake air pressure sensor system Throttle position sensor-open or short circuit detected. A stuck throttle ...

  • Yamaha YW125Y_ - page 262

    6-11 FI Diag- nostic code Item Data displayed on FI diagnostic tool (reference value) Description of action EAS00907 Diagnostic mode table TIP 8 Check the intake air temperature and engine temprature as close as possible to the intake air temperature sensor and the engine temperature sensor respectiv ely . 8 If it is not possible to check the intak ...

  • Yamaha YW125Y_ - page 263

    6-12 FI FUEL INJECTION SYSTEM LCD Display Probable cause of malfunction Sympton Communication error with the FI diagnostic tool EAS00908 TROUBLESHOO TING DET AILS This section describes the countermeasures per fault code number displayed on the Fl diagnostic tool. Check and service the items or components that are the probable cause of the malfunct ...

  • Yamaha YW125Y_ - page 264

    6-13 FI No nor mal signals are received from the cr ankshaft position sensor . 1 2 3 4 Installed condition of sensor . Connected condition of con- nector . Inspect the coupler for any pins that may have pulled out. Check that the coupler is connected securely . TIP Set the main switch to OFF before connecting or discon- necting the connector . Open ...

  • Yamaha YW125Y_ - page 265

    6-14 FI FUEL INJECTION SYSTEM Intake air pressure sensor-open or short circuit detected. 1 2 3 Connected condition of con- nector Inspect the coupler for any pins that may have pulled out. Check the locking condition of the coupler . TIP Set the main switch to OFF before connecting or discon- necting the connector . Open or shor t circuit in wir in ...

  • Yamaha YW125Y_ - page 266

    6-15 FI Intake air pressure- sensor hose system malfunction (clogged or de- tached hose). 1 2 Connected state of connector Intake air pressure sensor cou- pler Main wirring harness ECU cou- pler Defective intake air pressure sensor . Check the coupler for any pins that may have pulled out. Chec k that the coupler is connected securely . If there is ...

  • Yamaha YW125Y_ - page 267

    6-16 FI Stuck throttle position sensor detected. 1 2 3 F ault code No . 1 6 Symptom Used diagnostic code No . D01 (throttle position sensor) Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method FUEL INJECTION SYSTEM Reinstated by star t- ing the engine, oper- ating it at idle, and then racing it. ...

  • Yamaha YW125Y_ - page 268

    6-17 FI 1 2 B/L Y L P/W Br/W FUEL INJECTION SYSTEM Intake air temper ature sensor open or shor t circuit is detected. 1 2 3 4 F ault code No . 2 2 Symptom Used diagnostic code No . D05 (intake air temperature sensor) Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by turn- ing the ...

  • Yamaha YW125Y_ - page 269

    6-18 FI Engine temperature sensor open or short circuit is detected. 1 2 3 4 F ault code No . 2 8 Symptom Used diagnostic code No . D11 (engine temperature sensor) Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by turn- ing the main switch ON. Installed condition of sensor Connec ...

  • Yamaha YW125Y_ - page 270

    6-19 FI 2 1 L Y/G B/L 45˚ 45˚ B/R The vehicle has o ver tur ned. 1 2 3 4 F ault code No . 3 0 Symptom Used diagnostic code No . D08 (lean angle cut-off switch) Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by turn- ing the main switch ON (howe ver , the engine cannot be restar ...

  • Yamaha YW125Y_ - page 271

    6-20 FI FUEL INJECTION SYSTEM Open circuit detected in the primary lead of the ignition coil. 1 2 3 F ault codeNo . 3 3 Symptom Used diagnostic code No . D30 Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by star t- ing the engine and operating it at idle. Connected condition of ...

  • Yamaha YW125Y_ - page 272

    6-21 FI FUEL INJECTION SYSTEM Fuel injector open or shor t circuit is detected. 1 2 3 F ault code No . 3 9 Symptom Used diagnostic code No . D36 (fuel injector) Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by star t- ing the engine. Connected condition of con- nector Inspect th ...

  • Yamaha YW125Y_ - page 273

    6-22 FI FUEL INJECTION SYSTEM No normal signals are received from the speed sensor . 1 2 3 4 F ault code No . 4 2 Symptom Used diagnostic code No . D07 (speed sensor) Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by input- ting the vehicle speed signals by turning the front whee ...

  • Yamaha YW125Y_ - page 274

    6-23 FI FUEL INJECTION SYSTEM An error is delected while reading from or writing on EEPROM (CO adjustment value, code re-registering key code, and throttle valve fully closed notification value). 1 F ault code No . 4 4 Symptom Used diagnostic code No . D60 (EEPROM improper cylinder indication) Order Inspection operation item and probable cause Oper ...

  • Yamaha YW125Y_ - page 275

    6-24 FI FUEL INJECTION SYSTEM 1 Used diagnostic code No . -- Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by turn- ing the main switch ON. Malfunction in ECU Replace the ECU . F aulty ECU memory . (when this malfunction is detected in the ECU , the f ault code number might not ...

  • Yamaha YW125Y_ - page 276

    6-25 FI ISC (idle speed control) valv e open or shor t circuit is detected. 1 2 3 F ault code No . 6 1 Symptom Used diagnostic code No . D54 (ISC (idle speed control)v alve) Order Inspection operation item and probable cause Operation item and countermeasure Reinstatement method Reinstated by set- ting the main switch to ON, The ISC (idle speed con ...

  • Yamaha YW125Y_ - page 277

    6-26 FI 3 7 4 5 6 1 2 10Nm (1.0 m•kgf , 7.2 ft•lbf) 4Nm (0.4 m•kgf , 2.9 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) Remarks Order Job/P ar t Q’ty EAS00909 THR O TTLE BOD Y AND FUEL INJECT OR FUEL T ANK THR O TTLE BOD Y AND FUEL INJECT OR Removing the fuel tank Seat/trunk Battery box cover/front cover Side cover (left and right) Fuel Fuel pu ...

  • Yamaha YW125Y_ - page 278

    6-27 FI 3 7 4 5 6 1 2 10Nm (1.0 m•kgf , 7.2 ft•lbf) 4Nm (0.4 m•kgf , 2.9 ft•lbf) 7Nm (0.7 m•kgf , 5.1 ft•lbf) Remarks Order Job/P ar t Q’ty THR O TTLE BOD Y AND FUEL INJECT OR 6 7 Fuel pump Fuel tank 1 1 Ref er to “REMO VING THE FUEL PUMP” and “INST ALLING THE FUEL PUMP”. Refer to “REMOVING THE FUEL T ANK” and “INST ALLI ...

  • Yamaha YW125Y_ - page 279

    6-28 FI Remarks Order Job/P ar t Q’ty FUEL INJECT OR AND FUEL HOSE THR O TTLE BOD Y AND FUEL INJECT OR Removing the fuel injector and fuel hose Fuel tank Fuel hose holder (to frame) Fuel hose holder (to intake manifold) Clamp Fuel injector coupler Fuel injector and fuel hose 1 2 3 4 5 Remov e the par ts in the order listed. Ref er to “REMO VING ...

  • Yamaha YW125Y_ - page 280

    6-29 FI THR O TTLE BOD Y AND FUEL INJECT OR Remarks Order Job/P ar t Q’ty THR OTTLE BOD Y Removing the throttle body Air filter/breather hose Fuel tank Fuel pipe (to throttle body) Throttle body clamp screw Sensor module coupler ISC (idle speed control) valve coupler Throttle cable assembly Throttle body 1 2 3 4 5 6 1 1 1 1 1 1 Remov e the par ts ...

  • Yamaha YW125Y_ - page 281

    6-30 FI 1 THR O TTLE BOD Y AND FUEL INJECT OR REMO VING THE FUEL T ANK 1. Extract the fuel in the fuel tank through the fuel tank cap with a pump . 2. Remove : 8 fuel return hose 8 fuel hose 1 NO TICE 8 8 8 8 8 Be sure to disconnect the fuel hose by hand. Do not forcefully disconnect the hose with tools. 8 8 8 8 8 Although the fuel has been removed ...

  • Yamaha YW125Y_ - page 282

    6-31 FI THR O TTLE BOD Y AND FUEL INJECT OR REMO VING THE FUEL PUMP 1. Remove: 8 fuel tank Ref er to “REMO VING THE FUEL T ANK”. 2. Remove: 8 fuel pump NO TICE 8 8 8 8 8 Do not drop the fuel pump or give it a strong shock. 8 8 8 8 8 Do not touch the base section of the fuel sender . EAS00911 NO TICE The fuel pump should not be disassembled. ww ...

  • Yamaha YW125Y_ - page 283

    6-32 FI EAS00912 CHECKING THE FUEL INJECT OR 1 . Check: 8 fuel injector Damage J Replace. EAS00913 CHECKING THE THRO TTLE BOD Y 1 . Check: 8 throttle body Cracks/damage J Replace the throttle body . 2 . Check: 8 butterfly valve Damage/scratches/wear J Replace. NO TICE 8 8 8 8 8 Do not adjust the stop screw 1 1 1 1 1 . 8 8 8 8 8 Do not clean the thr ...

  • Yamaha YW125Y_ - page 284

    6-33 FI 1 THR O TTLE BOD Y AND FUEL INJECT OR INST ALLING THE FUEL PUMP 1. Install : 8 fuel pump 4Nm (0.4m • kgf, 2.9ft • lbf) TIP 8 Do not damage the installion surface of the fuel tank when installing the fuel pump . 8 Always use a new fuel pump gasket. 8 Align the projection a on the fuel pump with the alignment mark b on the fuel tank. 8 Ti ...

  • Yamaha YW125Y_ - page 285

    6-34 FI 1 2 3 EAS00915 CHECKING THE FUEL PUMP AND PRES- SURE REGULA T OR OPERA TION 1 . Check: 8 pressure regulator operation ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a . Remove the battery box cover and front cov e r . Ref er to “CO VER AND P ANEL ” in chapter 3. b . Remove the fuel hose 1 from the fuel pump . NO T ...

  • Yamaha YW125Y_ - page 286

    6-35 FI THR O TTLE BOD Y AND FUEL INJECT OR 3 2 1 B/L Y L P/W Br/W EAS0091 6 CHECKING THE THR O TTLE POSITION SEN- SOR 1 . Check: 8 throttle position sensor ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Connect the digital circuit tester to the ter- minals of the throttle position sensor . P ositive tester probe J J J J J ...

  • Yamaha YW125Y_ - page 287

    6-36 FI EAS00916 CHECKING THE ISC (IDLE SPEED CON- TR OL) V AL VE TIP Do not remove the ISC (idle speed control) valve unit completely from the throttle body assembly . 1 . Check: 8 ISC (idle speed control) valve ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a . Disconnect the ISC (idle speed control) valve coupler from the ...

  • Yamaha YW125Y_ - page 288

    7-43 -+ ELEC CHAPTER 7 ELECTRICAL SYSTEM ELECTRICAL COMPONENTS ................................................................ 7 - 1 WIRING DIA GRAM ................................................................................... 7 - 2 CHECKING SWITCH CONTINUITY ........................................................ 7 - 4 CHECKING THE SWITCHE ...

  • Yamaha YW125Y_ - page 289

    7-1 -+ ELEC EAS00729 ELECTRICAL SYSTEM ELECTRICAL COMPONENTS 1 Main switch 2 F ront brak e light switch 3 Rectifier/regulator 4 Rear brake light switch 5 Sidestand switch 6 Battery 7 Main fuse 8 ECU 9 Fuse box 0 Ignition coil q Spark plug cap w Fuel pump e Star ter rela y r Horn t T ur n signal relay y Star ting circuit cut-off relay u Headlight re ...

  • Yamaha YW125Y_ - page 290

    7-2 -+ ELEC WIRING DIA GRAM WIRING DIA GRAM L/Y B/L R W/R B/L W/R W/L W W W WW W W/R B/L W W W W W W W W W R B B R R R R R B R R R B L/W R/W L/W R/W L/W R/W (BLACK) (BLACK) B R B Br Br Br R/B Br Br/L R Br B/W (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A R R W/R R R/W Or R/B R/B Or Or/B Or/B R/B R/B G L/B ...

  • Yamaha YW125Y_ - page 291

    7-3 -+ ELEC WIRING DIA GRAM 1 AC magneto 2 Rectifier/regulator 3 Body ear th 4 Main fuse 5 Fuel injection system fuse 6 Battery 7 Wire lead 8 Star ter rela y 9 Star ter motor 0 Star ting circuit cut-off relay q Main switch w Sidestand switch e Headlight relay r Star t switch t Engine stop switch y Ignition fuse u Signaling system fuse i Headlight f ...

  • Yamaha YW125Y_ - page 292

    7-4 -+ ELEC EAS00730 CHECKING SWITCH CONTINUITY Check each s witch f or continuity with the pock et tester . If the continuity reading is incorrect, check the wiring connections and if necessar y , replace the switch. NO TICE Never insert the tester probes into the coupler terminal slots a a a a a . Always insert the pr obes from the opposite end o ...

  • Yamaha YW125Y_ - page 293

    7-5 -+ ELEC EAS00731 CHECKING THE SWITCHES Check each s witch for damage or wear , proper connections, and also f or continuity between the terminals. Refer to “CHECKING SWITCH CONTINUITY”. Damage/wear J Repair or replace. Improperly connected J Proper ly connect. Incorrect continuity reading J Replace the s witch. CHECKING THE SWITCHES 1 Rear ...

  • Yamaha YW125Y_ - page 294

    7-6 -+ ELEC EAS00733 CHECKING THE BULBS AND B ULB SOCKETS Check each b ulb and bulb soc ket for damage or wear , proper connections, and also f or contin u- ity between the terminals. Damage/w ear J Repair or replace the bulb , bulb sock et or both. Improperly connected J Properly con- nect. No continuity J Repair or replace the bulb , bulb soc ket ...

  • Yamaha YW125Y_ - page 295

    7-7 -+ ELEC NO TICE 8 8 8 8 8 Be sure to hold the socket firmly when removing the b ulb. Ne ver pull the lead, otherwise it may be pulled out of the ter - minal in the coupler . 8 8 8 8 8 A v oid touching the glass par t of the headlight bulb to keep it free fr om oil, otherwise the transparency of the glass, the life of the b ulb, and the luminous ...

  • Yamaha YW125Y_ - page 296

    7-8 -+ ELEC P ocket tester 90890-03112 (YU-03112-C) TIP Check each bulb socket for continuity in the same manner as described in the bulb section; how ev er , note the f ollowing. ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Install a good bulb into the b ulb sock et. b . Connect the pock et tester probes to the re- spec ...

  • Yamaha YW125Y_ - page 297

    7-9 -+ ELEC EAS00734 IGNITION SYSTEM CIRCUIT DIA GRAM IGNITION SYSTEM L/Y B/L R W/R B/L W/R W/L W W W WW W W/R B/L W W W W W W W W W R B B R R R R R B R R R B L/W R/W L/W R/W L/W R/W (BLACK) (BLACK) B R B Br Br Br R/B Br Br/L R Br B/W (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A R R W/R R R/W Or R/B R/B ...

  • Yamaha YW125Y_ - page 298

    7-10 -+ ELEC EAS00736 TR OUBLESHOO TING The ignition system fails to operate (no spark or intermittent spark). Check: 1. main and ignition fuses 2. battery 3. spark plug 4. ignition spark gap 5. spark plug cap resistance 6. ignition coil resistance 7. crankshaft position sensor resistance 8. main switch 9. engine stop switch 1 0 . sidestand switch ...

  • Yamaha YW125Y_ - page 299

    7-11 -+ ELEC EAS00742 4. Ignition spark gap 8 Disconnect the spark plug cap from the spark plug. 8 Connect the ignition checker 1 as shown. 2 Spark plug cap 8 Set the main switch to “ON”. 8 Measure the ignition spark gap a . 8 Crank the engine by pushing the star ter switch and gradually increase the spark gap until a misfire occurs. Minimum ig ...

  • Yamaha YW125Y_ - page 300

    7-12 -+ ELEC 8 Measure the primary coil resistance. Primary coil resistance 2.16 ~ 2.64 Ω Ω Ω Ω Ω at 20°C (68°F) 8 Connect the pocket tester ( Ω × 1k) to the ignition coil as shown. Negative tester probe J J J J J orange 2 2 2 2 2 P ositive tester probe J J J J J spark plug lead 1 1 1 1 1 8 Measure the secondary coil resistance. Secondary ...

  • Yamaha YW125Y_ - page 301

    7-13 -+ ELEC IGNITION SYSTEM EAS00749 8 . Main switch 8 Check the main s witch for continuity . Ref er to “CHECKING THE SWITCHES”. 8 Is the main switch OK? YES N O Replace the main switch. EAS00750 9. Engine stop switch 8 Check the engine stop s witch for continuity . Ref er to “CHECKING THE SWITCHES”. 8 Is the engine stop switch OK? YES N ...

  • Yamaha YW125Y_ - page 302

    7-14 -+ ELEC IGNITION SYSTEM EAS00754 12. Wiring 8 Check the entire ignition system’ s wir ing. Refer to “CIRCUIT DIAGRAM”. 8 Is the ignition system’ s wiring proper ly con- nected and without defects? YES N O Properly connect or repair the ignition system’ s wir ing. Replace the ECU . www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 303

    7-15 -+ ELEC EAS00755 ELECTRIC ST AR TING SYSTEM CIRCUIT DIA GRAM ELECTRIC ST ARTING SYSTEM L/Y B/L R W/R B/L W/R W/L W W W WW W W/R B/L W W W W W W W W W R B B R R R R R B R R R B L/W R/W L/W R/W L/W R/W (BLACK) (BLACK) B R B Br Br Br R/B Br Br/L R Br B/W (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A R R ...

  • Yamaha YW125Y_ - page 304

    7-16 -+ ELEC EAS00756 ST ARTING CIRCUIT CUT -OFF SYSTEM OP- ERA TION If the engine stop switch is set to “ # ” and the main switch is set to “ON” (both switches are closed), the star ter motor can only operate if at least one of the following conditions is met: 8 The brake lever (front or rear) is pulled to the handlebar (the brake light sw ...

  • Yamaha YW125Y_ - page 305

    7-17 -+ ELEC EAS00757 TR OUBLESHOO TING The starter motor fails to turn. Check: 1. main, signal and ignition fuses 2. battery 3. star ter motor 4. star ting circuit cut-off rela y 5. star ter relay 6. main switch 7. engine stop switch 8. brake light switch (front and rear) 9. sidestand switch 10 . star t switch 11 . wiring connections (of the entir ...

  • Yamaha YW125Y_ - page 306

    7-18 -+ ELEC EAS00758 3 . Star ter motor 8 Connect the positive battery terminal 1 and star ter motor lead 2 with a jumper lead 3 . W ARNING 8 8 8 8 8 A wire that is used as a jumper lead must have at least the same capacity or more as that of the battery lead, otherwise the jumper lead may burn. 8 8 8 8 8 This check is likely to produce sparks, th ...

  • Yamaha YW125Y_ - page 307

    7-19 -+ ELEC ELECTRIC ST ARTING SYSTEM EAS00761 5. Star ter relay 8 Disconnect the star ter rela y coupler from the coupler . 8 Connect the pocket tester ( Ω × 1) and bat- ter y (12 V) to the star ter relay coupler as shown. P ositive battery terminal J J J J J red/white 1 1 1 1 1 Negative battery terminal J J J J J blue/white 2 2 2 2 2 P ositive ...

  • Yamaha YW125Y_ - page 308

    7-20 -+ ELEC EAS00764 1 0 . Star t switch 8 Check the star t s witch f or continuity . Ref er to “CHECKING THE SWITCHES”. 8 Is the star t s witch OK? YES N O Replace the right handlebar switch. EAS00766 11. Wiring 8 Check the entire star ting system’ s wir ing. Refer to “CIRCUIT DIAGRAM”. 8 Is the star ting system’ s wiring properly con ...

  • Yamaha YW125Y_ - page 309

    7-21 -+ ELEC EAS00767 ST ARTER MO T OR Remarks Order Job/P ar t Q’ty Removing the starter motor Seat/trunk Air filter/breather hose Star ter motor lead/ear th lead Star ter motor Disassembling the starter motor O-ring Star ter motor front cov er O-ring Brush Brush Spring Circlip Armature Stator O-ring Star ter motor rear cov er 1 2 1 2 3 4 5 6 7 ...

  • Yamaha YW125Y_ - page 310

    7-22 -+ ELEC ELECTRIC ST ARTING SYSTEM Remarks Order Job/P ar t Q’ty F or assembly , re verse the disassembly procedure. 1 2 7Nm (0.7 m•kgf , 5.1 ft•lbf) 4Nm (0.4 m•kgf , 2.9 ft•lbf) www.ScooterTime.net ...

  • Yamaha YW125Y_ - page 311

    7-23 -+ ELEC 1 2 EAS00769 CHECKING THE ST ARTER MO T OR 1. Check: 8 commutator Dir t J Clean with 600-grit sandpaper . 2. Measure: 8 commutator diameter a Out of specification J Replace the starter motor . Commutator wear limit 21 mm (0.83in) 3. Measure: 8 mica undercut b Out of specification J Scrape the mica to the proper measurement with a hack- ...

  • Yamaha YW125Y_ - page 312

    7-24 -+ ELEC 5. Measure: 8 brush length a Out of specification J Replace the brushes as a set. Brush length wear limit 3.5 mm (0.14in) 6. Measure: 8 brush spr ing force Out of specification J Replace the brush springs as a set. Brush spring for ce 5.52 ~ 8.28 N/mm (0.56 ~ 0.84kgf/ mm, 1.24 ~ 1.86lbf/in) 7. Check: 8 gear teeth Damage/wear J Replace ...

  • Yamaha YW125Y_ - page 313

    7-25 -+ ELEC ELECTRIC ST ARTING SYSTEM 3. Install: 8 O-rings New 8 bolts 1 4Nm (0.4m • kgf, 2.9ft • lbf) TIP Align the match marks a on the stator with the match marks b on the front and star ter motor rear covers. EAS00772 ASSEMBLING THE ST ARTER MOT OR 1. Install: 8 brush spring 8 brush 1 2. Install: 8 armature 8 star ter motor front cover 1 ...

  • Yamaha YW125Y_ - page 314

    7-26 -+ ELEC EAS00773 CHARGING SYSTEM CIRCUIT DIA GRAM CHARGING SYSTEM L/Y B/L R W/R B/L W/R W/L W W W WW W W/R B/L W W W W W W W W W R B B R R R R R B R R R B L/W R/W L/W R/W L/W R/W (BLACK) (BLACK) B R B Br Br Br R/B Br Br/L R Br B/W (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A R R W/R R R/W Or R/B R/B ...

  • Yamaha YW125Y_ - page 315

    7-27 -+ ELEC EAS00774 TROUBLESHOO TING The battery is not being charged. Check: 1. main fuse 2. battery 3. charging voltage 4. stator coil resistance 5. wiring connections (of the entire charging system) TIP 8 Before troubleshooting, remove the follow- ing par t(s): 1. battery box cover 2. front cover 3. leg shield 1 8 T roubleshoot with the f ollo ...

  • Yamaha YW125Y_ - page 316

    7-28 -+ ELEC The charging circuit is OK. EAS00776 4. Stator coil resistance 8 Disconnect the star ter coil coupler from the wire harness. 8 Connect the pocket tester ( Ω × 1) to the sta- tor coil as shown. P ositive tester probe J J J J J white 1 1 1 1 1 Negative tester probe J J J J J white 2 2 2 2 2 P ositive tester probe J J J J J white 1 1 1 ...

  • Yamaha YW125Y_ - page 317

    7-29 -+ ELEC EAS00780 LIGHTING SYSTEM CIRCUIT DIA GRAM LIGHTING SYSTEM R R B R L/Y B/L R W/R B/L W/R W/L W W W WW W W/R B/L W W W W W W W W W R B B R R R R R B R R R B L/W R/W L/W R/W L/W R/W (BLACK) (BLACK) B R B Br Br Br R/B Br Br/L R Br B/W (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A R R W/R R R/W Or ...

  • Yamaha YW125Y_ - page 318

    7-30 -+ ELEC EAS00781 TR OUBLESHOO TING Any of the following fail to light: headlight, high beam indicator light, taillight or meter light. Check: 1. main and headlight fuses 2. battery 3. main switch 4. dimmer switch 5 headlight relay 6 wiring connections (of the entire lighting system) TIP 8 Before troubleshooting, remove the follow- ing par t(s) ...

  • Yamaha YW125Y_ - page 319

    7-31 -+ ELEC EAS00787 6. Wiring 8 Check the entire lighting system’ s wir ing. Refer to “CIRCUIT DIAGRAM”. 8 Is the lighting system’ s wiring proper ly con- nected and without defects? YES N O Properly connect or repair the lighting system’ s wir ing. Check the condition of each of the lighting system’ s circuits. Refer to “CHECKING T ...

  • Yamaha YW125Y_ - page 320

    7-32 -+ ELEC The wiring circuit from the main switch to the headlight coupler or meter assembly cou- pler is faulty and must be repaired. Refer to “CIRCUIT DIAGRAM”. This circuit is OK. YES N O LIGHTING SYSTEM 3. V oltage 8 Connect the pock et tester (DC 20 V) to the headlight and high beam indicator light cou- plers as shown. A When the dimmer ...

  • Yamaha YW125Y_ - page 321

    7-33 -+ ELEC LIGHTING SYSTEM 2. V oltage 8 Connect the pock et tester (DC 20 V) to the meter light coupler (wire harness side) as shown. P ositive tester probe J J J J J blue 1 1 1 1 1 Negative tester probe J J J J J black 2 2 2 2 2 8 Set the main switch to “ON”. 8 Measure the voltage (DC 12 V) of b lue 1 on the meter light coupler (wire harnes ...

  • Yamaha YW125Y_ - page 322

    7-34 -+ ELEC EAS00790 3. The tail/brake light fails to come on. 1. T ail/brake light b ulb and socket 8 Check the tail/brake light bulb and socket for continuity . Ref er to “CHECKING THE BULBS AND BULB SOCKETS” 8 Are the tail/brake light bulb and socket OK? YES N O Replace the tail/brake light bulb , sock et or both. LIGHTING SYSTEM 2. V oltag ...

  • Yamaha YW125Y_ - page 323

    7-35 -+ ELEC EAS00793 SIGNALING SYSTEM CIRCUIT DIA GRAM SIGNALING SYSTEM R R B R L/Y B/L R W/R B/L W/R W/L W W W WW W W/R B/L W W W W W W W W W R B B R R R R R B R R R B L/W R/W L/W R/W L/W R/W (BLACK) (BLACK) B R B Br Br Br R/B Br Br/L R Br B/W (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A R R W/R R R/W ...

  • Yamaha YW125Y_ - page 324

    7-36 -+ ELEC EAS00794 TROUBLESHOO TING 8 8 8 8 8 Any of the following fail to light: turn sig- nal light, brake light or an indicator light. 8 8 8 8 8 The horn fails to sound. Check: 1. main and signaling fuses 2. battery 3. main switch 4. wiring connections (of the entire signaling system) TIP 8 Before troubleshooting, remove the follow- ing par t ...

  • Yamaha YW125Y_ - page 325

    7-37 -+ ELEC 4. V oltage 8 Connect the pock et tester (DC 20 V) to the horn connector at the pink terminal as shown. P ositive tester probe J J J J J pink 1 1 1 1 1 Negative tester probe J J J J J ground 8 Set the main switch to “ON”. 8 Measure the voltage (DC 12 V) of pink 1 at the horn terminal. 8 Is the voltage within specification? YES N O ...

  • Yamaha YW125Y_ - page 326

    7-38 -+ ELEC 2. Brake light switches 8 Check the brake light switches for continu- ity . Ref er to “CHECKING THE SWITCHES”. 8 Is the brake light switch OK? YES N O Replace the brake light switch. SIGNALING SYSTEM EAS00798 2. The tail/brake light fails to come on. 1. T ail/brake light b ulb and socket 8 Check the tail/brake light bulb and socket ...

  • Yamaha YW125Y_ - page 327

    7-39 -+ ELEC EAS00799 3. The turn signal light, turn signal indicator light or both fail to blink. 1. T ur n signal indicator light bulb and soc k et 8 Check the turn signal indicator light bulb and sock et for contin uity . Ref er to “CHECKING THE BULBS AND BULB SOCKETS” 8 Are the turn signal indicator light bulb and socket OK? YES N O Replace ...

  • Yamaha YW125Y_ - page 328

    7-40 -+ ELEC 5. V oltage 8 Connect the pock et tester (DC 20 V) to the turn signal relay coupler (wire harness side) as shown. P ositive tester probe J J J J J bro wn/white 1 1 1 1 1 Negative tester probe J J J J J ground 8 Set the main switch to “ON”. 8 Measure the v oltage (DC 12 V) on brown/ white 1 at the turn signal relay coupler (wire har ...

  • Yamaha YW125Y_ - page 329

    7-41 -+ ELEC EAS00804 4. The fuel le v el gauge f ails to oper ate . 1. Fuel sender 8 Remove the fuel pump from the fuel tank. 8 Connect the pocket tester ( Ω × 1) to the fuel sender coupler (wire harness side) as shown. P ositive tester probe J J J J J green 1 1 1 1 1 Negative tester probe J J J J J black 2 2 2 2 2 8 Measure the fuel sender resi ...

  • Yamaha YW125Y_ - page 330

    7-42 -+ ELEC 3. Fuel level gauge 8 Set the main switch to “ON”. 8 Move the float up 1 or down 2 . 8 Check that the fuel level gauge needle moves to “F” or “E”. TIP Before reading the fuel level gauge, leave the float in one position (either up or down) for at least three minutes. 8 Does the fuel level gauge needle move ap- propriately? ...

  • Yamaha YW125Y_ - page 331

    8-6 TRBL SHTG CHAPTER 8 TROUBLE SHOO TING ST ARTING F AILURE/HARD ST ARTING ................................................. 8 - 1 ENGINE .............................................................................................. 8 - 1 FUEL SYSTEM .................................................................................. 8 - 1 ELECTRICA ...

  • Yamaha YW125Y_ - page 332

    8-1 TRBL SHTG EAS00844 TR OUBLESHOO TING TIP The following guide for troubleshooting does not cover all the possible causes of trouble. It should be helpful, howe ver , as a guide to basic troubleshooting. Ref er to the relativ e procedure in this manual f or checks, adjustments , and replacement of par ts. ST ARTING F AILURE/HARD ST AR TING ST AR ...

  • Yamaha YW125Y_ - page 333

    8-2 TRBL SHTG INCORRECT ENGINE IDLING SPEED/POOR MEDIUM- AND-HIGH-SPEED PERFORMANCE EAS00847 INCORRECT ENGINE IDLING SPEED ENGINE Cylinder and cylinder head 8 Incorrect valve clearance 8 Damaged valve train components Air filter 8 Clogged air filter element FUEL SYSTEM Throttle body 8 Damaged or loose throttle body joint 8 Improperly ISC (idle spee ...

  • Yamaha YW125Y_ - page 334

    8-3 TRBL SHTG F A UL TY CLUTCH/O VERHEA TING EAS00853 F A UL TY CLUTCH ENGINE OPERA TES BUT SCOO TER WILL NO T MO VE V -belt 8 Bent, damaged or worn V -belt 8 Slipping V -belt Primary pulley cam and primary pulley slider 8 Damaged or worn primary pulley cam 8 Damaged or worn primary pulley slider Clutch spring(s) 8 Damaged clutch spring T ransmissi ...

  • Yamaha YW125Y_ - page 335

    8-4 TRBL SHTG POOR BRAKING PERFORMANCE/F A UL TY FR ONT FORK LEGS/UNST ABLE HANDLING EAS00859 POOR BRAKING PERFORMANCE Disc brake 8 Worn brake pad 8 Worn brake disc 8 Air in hydraulic brake system 8 Leaking brake fluid 8 F aulty brake caliper kit 8 F aulty brake caliper seal 8 Loose union bolt 8 Damaged brake hose 8 Oil or grease on the brake disc ...

  • Yamaha YW125Y_ - page 336

    8-5 TRBL SHTG F A UL TY LIGHTING OR SIGNALING SYSTEM EAS00866 F A UL TY LIGHTING OR SIGNALING SYSTEM HEADLIGHT DOES NO T COME ON 8 Wrong headlight bulb 8 T oo many electrical accessories 8 Hard charging 8 Incorrect connection 8 Improperly grounded circuit 8 P oor contacts (main s witch) 8 Burnt-out headlight bulb 8 F aulty headlight rela y HEADLIGH ...

  • Yamaha YW125Y_ - page 337

    (BLACK) (BLACK) (RED) (RED) 10A 15A 10A MAIN LOCK OFF ON 20A OFF PUSH HORN HI LO L N R DIMMER FLASHER 10A (BLACK) (BLACK) OFF ON OFF RUN ST ART E/G ST OP B (BROWN) (BROWN) (GREEN) (GREEN) (BLACK) (BLACK) (BLACK) (BLACK) (BLACK) (BLACK) (BLACK) (BLACK) (BLACK) (BLACK) (BLACK) 4 6 78 9 q r t y u i # $ % ^ & * @ , . / ) j k h g l ; z p a s d f x c ...

  • Yamaha YW125Y_ - page 338

    Y amaha Motor Canada Ltd. 480 Gordon Baker Road T oronto , ON M2H 3B4 www.ScooterTime.net ...

Manufacturer Yamaha Category Utility Trailer

Documents that we receive from a manufacturer of a Yamaha YW125Y_ can be divided into several groups. They are, among others:
- Yamaha technical drawings
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- Yamaha product data sheets
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All of them are important, but the most important information from the point of view of use of the device are in the user manual Yamaha YW125Y_.

A group of documents referred to as user manuals is also divided into more specific types, such as: Installation manuals Yamaha YW125Y_, service manual, brief instructions and user manuals Yamaha YW125Y_. Depending on your needs, you should look for the document you need. In our website you can view the most popular manual of the product Yamaha YW125Y_.

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A complete manual for the device Yamaha YW125Y_, how should it look like?
A manual, also referred to as a user manual, or simply "instructions" is a technical document designed to assist in the use Yamaha YW125Y_ by users. Manuals are usually written by a technical writer, but in a language understandable to all users of Yamaha YW125Y_.

A complete Yamaha manual, should contain several basic components. Some of them are less important, such as: cover / title page or copyright page. However, the remaining part should provide us with information that is important from the point of view of the user.

1. Preface and tips on how to use the manual Yamaha YW125Y_ - At the beginning of each manual we should find clues about how to use the guidelines. It should include information about the location of the Contents of the Yamaha YW125Y_, FAQ or common problems, i.e. places that are most often searched by users in each manual
2. Contents - index of all tips concerning the Yamaha YW125Y_, that we can find in the current document
3. Tips how to use the basic functions of the device Yamaha YW125Y_ - which should help us in our first steps of using Yamaha YW125Y_
4. Troubleshooting - systematic sequence of activities that will help us diagnose and subsequently solve the most important problems with Yamaha YW125Y_
5. FAQ - Frequently Asked Questions
6. Contact detailsInformation about where to look for contact to the manufacturer/service of Yamaha YW125Y_ in a specific country, if it was not possible to solve the problem on our own.

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