Manual Yamaha YP250

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Yamaha YP250 - page 1

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Yamaha YP250 - page 2

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Yamaha YP250 - page 3

EB000000 YP250 SERVICE MANUAL  1996 by Y amaha Motor Co., Ltd. 1st Edition, January 1996 All rights reserved. Any reprinting or unauthorized use without the written permission of Y amaha Motor Co., Ltd. is expressly prohibited. ...
Yamaha YP250 - page 4

NOTE: CAUTION: EB001000 NOTICE This manual was produced by the Y amaha Motor Company primarily for use by Y amaha dealers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual, so it is assumed that anyone who uses this book to perform maintenance and repairs on Y amaha scooter has a basic unders ...
Yamaha YP250 - page 5

1 2 4 3 5 6 7 6 8 YP002000 HOW T O USE THIS MANUAL MANUAL ORGANIZA TION This manual consists of chapters for the main categories of subjects. (See “Illustrated symbols”) 1st title 1 : This is the title of the chapter with its symbol on the upper right corner of each page. 2nd title 2 : This title indicates the section of the chapter and only ap ...
Yamaha YP250 - page 6

1 3 5 7 9 11 13 15 18 2 4 8 10 12 14 16 6 21 24 25 17 19 20 22 23 EB003000 ILLUSTRA TED SYMBOLS Illustrated symbols 1 to 9 are designed as thumb tabs to indicate the chapter ’s number and content. 1 General information 2 Specifications 3 Periodic inspection and adjustment 4 Engine 5 Cooling system 6 Carburetion 7 Chassis 8 Electrical 9 T roublesh ...
Yamaha YP250 - page 7

GENERAL INFORMA TION SPECIFICA TIONS PERIODIC INSPECTION AND ADJUSTMENT ENGINE OVERHAUL COOLING SYSTEM CARBURETION CHASSIS ELECTRICAL TROUBLESHOOTING GEN INFO 1 SPEC 2 INSP ADJ 3 ENG 4 COOL 5 CARB 6 CHAS 7 ELEC 8 TRBL SHTG 9 INDEX ...
Yamaha YP250 - page 8

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Yamaha YP250 - page 9

CHAPTER 1 GENERAL INFORMA TION SCOOTER IDENTIFICA TION 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VEHICLE IDENTIFICA TION NUMBER (for E) 1-1 . . . . . . . . . . . . . . . . . . . FRAME SERIAL NUMBER 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ENGINE SERIAL NUMBER 1-1 . . . . . . . . . . ...
Yamaha YP250 - page 10

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Yamaha YP250 - page 11

1-1 SCOOTER IDENTIFICA TION GEN INFO NOTE: NOTE: YP100000 GENERAL INFORMA TION SCOOTER IDENTIFICA TION YP100010 VEHICLE IDENTIFICA TION NUMBER (for E) The vehicle identification number 1 is stamped into the right side of the frame. The vehicle identification number is used to identify your scooter and may be used to regis- ter your scooter with the ...
Yamaha YP250 - page 12

1-2 FEA TURES GEN INFO Engine stop switch Main switch Oil indicator light Fuse Battery Meter Reset button I gnitor unit C.P .U Oil indicator light Reset button NOTE: FEA TURES OIL INDICA TOR LIGHT  Function Pulses (travel distance signals) from the speedometer are counted and cause the oil indicator light to come on at 1,000 km for the first tim ...
Yamaha YP250 - page 13

1-3 FEA TURES GEN INFO Main switch Fuse Battery Thermo switch Auto-choke Igniter unit C.P .U Ignition Main switch Engine stop switch Brake switch Fuse Starter relay Relay Ignitor unit Battery Starter motor Start switch Brake light Sidestand switch AUTO-CHOKE SYSTEM This system is the parallel connection of the ignitor unit circuit and the thermo sw ...
Yamaha YP250 - page 14

1-4 IMPORT ANT INFORMA TION GEN INFO EB101000 IMPORT ANT INFORMA TION PREP ARA TION FOR REMOV AL PROCE- DURES 1. Remove all dirt, mud, dust and foreign ma- terial before removal and disassembly . 2. Use proper tools and cleaning equipment. 3. Refer to the “SPECIAL TOOLS” section. 4. When disassembling the machine, always keep mated parts togeth ...
Yamaha YP250 - page 15

1-5 IMPORT ANT INFORMA TION GEN INFO OR CAUTION: EB101030 LOCK W ASHERS / PLA TES AND COTTER PINS 1. Replace all lock washers / plates and cotter pins after removal. Bend lock tabs along the bolt or nut flats after the bolt or nut has been tightened to specification. EB101040 BEARINGS AND OIL SEALS Install bearings and oil seals so that the manufac ...
Yamaha YP250 - page 16

1-6 IMPORT ANT INFORMA TION GEN INFO NOTE: NOTE: EB801000 CHECKING OF CONNECTIONS Dealing with stains, rust, moisture, etc. on the connector . 1. Disconnect: S Connector 2. Dry each terminal with an air blower . 3. Connect and disconnect the connector two or three. 4. Pull the lead to check that it will not come off. 5. If the terminal comes off, b ...
Yamaha YP250 - page 17

1-7 HOW T O USE THE CONVERSION T ABLE GEN INFO EB201000 HOW TO USE THE CONVERSION T ABLE All specification data in this manual are listed in SI and METRIC UNITS. Use this table to convert METRIC unit data to IMPERIAL unit data. Ex. METRIC MUL TIPLIER IMP **mm  0.03937 = ** in 2 mm  0.03937 = 0.08 in CONVERSION T ABLE METRIC TO IMP Known Multi ...
Yamaha YP250 - page 18

1-8 SPECIAL TOOLS GEN INFO EB102000 SPECIAL TOOLS The following special tools are necessary for complete and accurate tune-up and assembly . Use only the appropriate special tools; this will help prevent damage caused by the use of inappropri- ate tools or improvised techniques. When placing an order , refer to the list provided below to avoid any ...
Yamaha YP250 - page 19

1-9 SPECIAL TOOLS GEN INFO T ool No. T ool name / Usage Illustration 90890-01362 Flywheel puller This tool is used for removing the rotor . 90890-01367 -01368 Fork seal driver weight Fork seal driver attachment (ø33) This tool is used when installing the fork seal. 90890-01384 Oil seal guide This tool is used for protecting the oil seal lip when i ...
Yamaha YP250 - page 20

1-10 SPECIAL TOOLS GEN INFO T ool No. T ool name / Usage Illustration 90890-03141 T iming light This tool is needed for detecting ignition timing. 90890-04101 V alve lapper This tool is used for removing and installing the lifter and for lapping the valve. 90890-04019 -04108 V alve spring compressor Attachment These tools are used when removing or ...
Yamaha YP250 - page 21

CHAPTER 2. SPECIFICA TIONS GENERAL SPECIFICA TIONS 2-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MAINTENANCE SPECIFICA TIONS 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ENGINE 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CHASSIS 2-10 . . . . ...
Yamaha YP250 - page 22

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Yamaha YP250 - page 23

2-1 GENERAL SPECIFICA TIONS SPEC SPECIFICA TIONS GENERAL SPECIFICA TIONS Model YP250 Model code: 4UC 1 (except for CH, A) 4UD1 (for CH, A) Dimensions: Overall length Overall width Overall height Seat height Wheelbase Minimum ground clearance Minimum turning radius 2,1 10 mm , 750 mm 1,330 mm , 700 mm 1,500 mm , 1 15 mm 2,600 mm Basic weight: With o ...
Yamaha YP250 - page 24

2-2 GENERAL SPECIFICA TIONS SPEC Model YP250 Carburetor: T ype / quantity Manufacturer Y28V -1A / 1 TEIKEI Spark plug: T ype Manufacturer Spark plug gap DR8EA NGK 0.6 X 0.7 mm Clutch type: Dry , centrifugal automatic T ransmission: Primary reduction system Primary reduction ratio Secondary reduction sytem Secondary reduction ratio T ransmission typ ...
Yamaha YP250 - page 25

2-3 GENERAL SPECIFICA TIONS SPEC Model YP250 Brake: Front brake type operation Rear brake type operation Single disc brake Right hand operation Drum brake Left hand operation Suspension: Front suspension Rear suspension T elescopic fork Unit swing Shock absorber: Front shock absorber Rear shock absorber Coil spring / Oil damper Coil spring / Oil da ...
Yamaha YP250 - page 26

2-4 MAINTENANCE SPECIFICA TIONS SPEC Face Width Seat Width Margin Thickness MAINTENANCE SPECIFICA TIONS ENGINE Item Standard Limit Cylinder head: W arp limit SSS 0.03 mm Cylinder: Bore size Out of round limit 69.000 X 69.005 mm SSS 69.1 mm 0.03 mm Camshaft: Cam dimensions Intake “A” “B” “C” Exhaust “A” “B” “C” Camshaft runou ...
Yamaha YP250 - page 27

2-5 MAINTENANCE SPECIFICA TIONS SPEC Item Standard Limit Stem-to-guide clearance IN EX Stem runout limit V alve seat width IN EX 0.010 X 0.037 mm 0.025 X 0.052 mm SSS 0.9 X 1.1 mm 0.9 X 1.1 mm 0.08 mm 0.1 mm 0.01 mm 1.6 mm 1.6 mm V alve spring: Free length (Inner) IN / EX Free length (Outer) IN / EX Set length (valve closed) (Inner) IN / EX Set len ...
Yamaha YP250 - page 28

2-6 MAINTENANCE SPECIFICA TIONS SPEC Item Standard Limit Automatic centrifugal clutch: Clutch shoe thickness Clutch housing inside diameter Clutch shoe spring free length Weight outside diameter Clutch – in revolution Clutch – stall revolution 3.0 mm 135 mm 28.1 mm 20 mm 2,100 X 2,700 r / min 3,700 X 4,700 r / min 2.0 mm 135.5 mm SSS 19.5 mm SS ...
Yamaha YP250 - page 29

2-7 MAINTENANCE SPECIFICA TIONS SPEC Item Standard Limit Radiator: T ype Width / height / thickness Radiator cap opening pressure Radiator capacity Reservoir tank capacity Cooling fin with electric fan 140 / 238 / 24 mm 1 10 X 140 kPa (1.1 X 1.4 kg / cm 2 , 1.1 X 1.4 bar) 1.4 L 0.35 L SSS SSS SSS SSS SSS Thermostatic valve: T ype / manufacturer V a ...
Yamaha YP250 - page 30

2-8 MAINTENANCE SPECIFICA TIONS SPEC TIGHTENING TORQUES ENGINE Part to be tightened Part name Thread size Q’ty T ightening torque Remarks g size y Nm m S kg Oil check bolt Exhaust pipe stud bolt Spark plug Cam sprocket cover Cylinder head and cylinder Cylinder head and cylinder (Cam chain side) V alve cover Rotor V alve adjuster locknut Cam shaft ...
Yamaha YP250 - page 31

2-9 MAINTENANCE SPECIFICA TIONS SPEC Part to be tightened Part name Thread size Q’ty T ightening torque Remarks g size y Nm m S kg Cover (oil pump) T iming check plug One way clutch Clutch housing Grease stopper (Primary sheave) Primary fixed sheave Clutch carrier assembly Stator Pick up coil Starter motor Thermo switch Thermo unit Bolt Plug — ...
Yamaha YP250 - page 32

2-10 MAINTENANCE SPECIFICA TIONS SPEC CHASSIS Item Standard Limit Steering system: Steering bearing type Ball bearing SSS Front suspension: Front fork travel Fork spring free length Spring rate (K1) Stroke (K1) Oil capacity Oil level Oil grade Inner tube vend limit 100 mm 265.8 mm 5.7 N / mm (0.57 kg / mm) 0 X 100 mm 0.142 L (142 cm 3 ) 80 mm Fork ...
Yamaha YP250 - page 33

2-1 1 MAINTENANCE SPECIFICA TIONS SPEC Item Standard Limit Rear drum brake: T ype Drum inside diameter Shoe thickness Leading, trailing 160 mm 4 mm SSS 161 mm 2 mm Brake lever: Brake lever free play (front at lever side) Brake lever free play (rear) Throttle cable free play 2 X 5 mm 10 X 20 mm 3 X 5 mm SSS SSS SSS Item Size Bearings and oil seals: ...
Yamaha YP250 - page 34

2-12 MAINTENANCE SPECIFICA TIONS SPEC TIGHTENING TORQUES CHASSIS Part to be tightened Thread size Tightening torque Remarks Nm m S kg Frame and engine bracket Engine bracket, compression rod and engine Compression rod and frame Sidestand (bolt and frame) Sidestand (bolt and nut) Rear footrest bracket Swingarm Rear shock absorber and frame Rear shoc ...
Yamaha YP250 - page 35

2-13 MAINTENANCE SPECIFICA TIONS SPEC NOTE: 1. First, tighten the ring nut (lower) approximately 38 Nm (3.8 m S kg) by using the torque wrench, then loosen the ring nut 1 / 4 turn. 2. Second, tighten the ring nut (lower) approximately 22 Nm (2.2 m S kg) by using the torque wrench, then finger tighten the ring nut (center). Align the slots both ring ...
Yamaha YP250 - page 36

2-14 MAINTENANCE SPECIFICA TIONS SPEC ELECTRICAL Item Standard limit Ignition timing: Ignition timing (B.T .D.C.) Advanced timing (B.T .D.C.) Advanced type 10 _ at 1,500 r / min 32 _ at 5,000 r / min Electrical type SSS SSS SSS T .C.I.: Pickup coil resistance / color T .C.I. unit model / manufacturer 168 X 252 Ω at 20 _ C/ Y ellow – Black J4T06 ...
Yamaha YP250 - page 37

2-15 MAINTENANCE SPECIFICA TIONS SPEC Item Standard limit Starter relay: Model / manufacturer Amperage rating Coil winding resistance 4FL / JIDECO 100 A 4.2 X 4.6 Ω at 20 _ C SSS SSS SSS Horn: Model / manufacturer Maximum amperage YF-12 / NIKKO 2.5 A SSS SSS Flasher relay: T ype Model / manufacturer Flasher frequency Full transistor type 4MY / NI ...
Yamaha YP250 - page 38

2-16 GENERAL T ORQUE SPECIFICA TIONS SPEC GENERAL TORQUE SPECIFICA TIONS This chart specifies torque for standard fasten- ers with standard I.S.O. pitch threads. T orque specifications for special components or as- semblies are included in the applicable sections of this book. T o avoid warpage, tighten multi- fastener assemblies in a crisscross fa ...
Yamaha YP250 - page 39

2-17 LUBRICA TION POINT AND GRADE OF LUBRICANT SPEC LUBRICA TION POINT AND GRADE OF LUBRICANT ENGINE Lubrication Point Symbol Oil seal lips O-ring (Except V -belt drive unit) Cylinder head tightening nut mounting surface Crankshaft pin outside Connecting rod big end thrust surface Rotary filter inner surface Drive gear inner surface Cam chain outsi ...
Yamaha YP250 - page 40

2-18 LUBRICA TION POINT AND GRADE OF LUBRICANT SPEC CHASSIS Lubrication Point Symbol Front wheel oil seal lips (left / right) Swingarm oil seal lips (left / right) Steering head pipe bearing (upper / lower) Steering head pipe dust seal lips (upper / lower) T ube guide (throttle grip) inner surface Brake cable (brake lever) Brake lever and lever hol ...
Yamaha YP250 - page 41

2-19 CABLE ROUTING SPEC 1 Rectifier regulator 2 Fuel sender 3 Fuse (fan) 4 Roll over valve 5 Ignition coil 6 Seat lock cable 7 Handlebar switch 3 lead (right) 8 Front brake switch lead 9 Brake hose 10 Speedometer cable 11 Radiator overflow hose 12 Starter relay / Fuse (main) 13 Battery 14 Battery positive (+) lead 15 Battery negative (–) lead 16 ...
Yamaha YP250 - page 42

2-20 E Pass the overflow hose from the reservoir tank through the clamp inside the frame. F Clamp the mainharness, battery (+) lead and (–) lead to clamp of the frame. G Clamp the fuel sender lead to the pipe. H The mainharness connecting to the taillight assembly to the frame. I Connect the taillight assembly lead to the mainharness over the mud ...
Yamaha YP250 - page 43

2-21 CABLE ROUTING SPEC 1 Seat lock 2 Air filter case 3 Breather hose 4 Fuel hose 5 V acuum hose 6 Sidestand switch lead 7 Thermo switch lead 8 Fan motor lead , 9 Breather hose 10 Overflow hose (fuel tank) 11 Relay 12 Auto choke lead 13 A.C. magneto lead 14 Starter motor lead 15 Engine earth lead 16 Protector (pipe) 17 Seat lock cable A Clamp the m ...
Yamaha YP250 - page 44

2-22 CABLE ROUTING SPEC 1 Front flasher light (right) 2 Front flasher light (left) 3 Handlebar switch (right) lead 4 Front brake switch lead 5 Seat lock cable 6 Throttle cable 7 Brake hose 8 Handlebar switch (left) lead 9 Rear brake switch lead 10 Handlebar under cover 11 Brake cable 2 12 Speedometer cable 13 Stay 1 14 Horn 15 Brake hose stopper 16 ...
Yamaha YP250 - page 45

2-23 CABLE ROUTING SPEC G Pass the brake hose through the hose holder and clamp. H Clamp the headlight lead and horn lead from mainharness to the stay 1. I Install the brake hose with its marking facing to the stopper side. ...
Yamaha YP250 - page 46

2-24 CABLE ROUTING SPEC 1 Fuel overflow hose (filler neck) 2 Throttle cable 1 (nut white) 3 Throttle cable 2 (nut black) 4 Air vent hose (carburetor) 5 Coolant drain hose (carburetor) 6 Fuel drain hose (carburetor) 7 Fuel overflow hose (fuel tank) A Pass the brake cable 2 though the holder and clamp to the crankcase. B Pass the air vent hose, coola ...
Yamaha YP250 - page 47

2-25 CABLE ROUTING SPEC 1 Steering head pipe 2 Brake cable 2 3 Mainharness 4 Downtube 5 Throttle cable 6 Radiator 7 Stay 1 A Pass the brake cable 2 though the clamp on the handlebar holder . B Band the brake cable 2 to the steering head pipe, noting the band direction. (view A) C Band the throttle cable and the right mainharness to the downtube, no ...
Yamaha YP250 - page 48

SPEC ...
Yamaha YP250 - page 49

CHAPTER 3. PERIODIC INSPECTION AND ADJUSTMENT INTRODUCTION 3-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PERIODIC MAINTENANCE / LUBRICA TION INTER V ALS 3-1 . . . . . . . . . . . COVER AND P ANEL 3-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T AIL COVER AND FU ...
Yamaha YP250 - page 50

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Yamaha YP250 - page 51

3-1 INTRODUCTION / PERIODIC MAINTENANCE / LUBRICA TION INTERV ALS INSP ADJ EB300000 PERIODIC INSPECTIONS AND ADJUSTMENTS INTRODUCTION This chapter includes all information necessary to perform recommended inspections and adjust- ments. These preventive maintenance procedures, if followed, will ensure more reliable vehicle opera- tion and a longer s ...
Yamaha YP250 - page 52

3-2 PERIODIC MAINTENANCE / LUBRICA TION INTER V ALS INSP ADJ NOTE: BREAK-IN EVERY NO. ITEM ROUTINE TYPE 1,000 km 6,000 km or 6 months 12,000 km or 12 month 15 Centerstand and sidestand pivot  Check operation and lubricate. Same as engine oil   16 * Sidestand switch  Check and clean or replace if necessary . —    17 * Front fo ...
Yamaha YP250 - page 53

3-3 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 Side panel and seat removal Rear panel Side panel (left) Side panel (right) Rivet Front panel Clip Damper assembly Seat 1 1 1 2 1 2 1 1 Remove the parts in order . Install the damper assembly to the body with its rod side backward and labels up- ward. Reverse the removal procedure for in ...
Yamaha YP250 - page 54

3-4 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 11 T ail cover and fuel tank removal Grab bar Seat lock bracket Screw T ail cover Fuel tank cap Fuel overflow hose Cover Fuel tank cover Coupler (fuel sender lead) Fuel overflow hose Fuel hose 1 1 2 1 1 1 1 1 1 1 1 Remove the parts in order . T ail cover Fuel tank Disconnect the cou ...
Yamaha YP250 - page 55

3-5 COVER AND P ANEL INSP ADJ Order Job name / Part name Q’ty Remarks 12 13 14 V acuum hose Bracket Fuel tank 1 1 1 Reverse the removal procedure for installation. Fuel tank 10 Nm (1.0 m  kg) 7 Nm (0.7 m  kg) 7 Nm (0.7 m  kg) ...
Yamaha YP250 - page 56

3-6 Order Job name / Part name Q’ ty Remarks 1 2 3 4 5 6 7 8 9 10 11 12 13 Footrest board and lower cover removal Mat (footrest board) (left / right) Cover 2 Battery negative (-) lead Battery positive (+) lead Battery Flasher relay Starter relay Reservoir tank Footrest Lid Box Lower cover Footrest board 1/1 1 1 1 1 1 1 1 2 1 1 1 1 Remove the part ...
Yamaha YP250 - page 57

3-7 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 Cowling removal Upper cover Wind screen Inner panel Cowling body Coupler (headlight lead) Coupler (front flasher light lead (left)) Coupler (front flasher light lead (right)) 1 1 1 1 1 1 Remove the parts in order . Reverse the removal procedure for installation. Disconnect the couplers. NO ...
Yamaha YP250 - page 58

3-8 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 Handle cover , meter assembly and legshield removal Handle cover Coupler (meter lead) Meter cable Meter assembly Main switch cover Cover Legshield 1 1 1 2 1 2 1 Remove the parts in order . Disconnect the couplers. Reverse the removal procedure for installation. NOTE: COVER AND P ANEL INSP ...
Yamaha YP250 - page 59

3-9 V AL VE CLEARANCE ADJUSTMENT INSP ADJ NOTE: ***************************************************** ***************************************************** YP303004 ENGINE V AL VE CLEARANCE ADJUSTMENT V alve clearance adjustment should be made with the engine cool, at room temperature. When the valve clearance is to be measured or adjusted, the pis ...
Yamaha YP250 - page 60

3-10 V AL VE CLEARANCE ADJUSTMENT / IDLING SPEED ADJUSTMENT INSP ADJ ***************************************************** ***************************************************** 14 Nm (1.4 m S kg) 10 Nm (1.0 m S kg) 10 Nm (1.0 m S kg) 18 Nm (1.8 m S kg) 7 Nm (0.7 m S kg) 6. Adjust: D V alve clearance Adjustment steps: D Loosen the locknut 1 . D T ur ...
Yamaha YP250 - page 61

3-1 1 IDLING SPEED ADJUSTMENT / THROTTLE CABLE ADJUSTMENT INSP ADJ ***************************************************** ***************************************************** NOTE: ************************************* NOTE: 3. Check:  Engine idling speed Out of specification  Adjust. Engine idling speed: 1,450  1,550 r / min 4. Adjust: ? ...
Yamaha YP250 - page 62

3-12 THROTTLE CABLE ADJUSTMENT / SP ARK PLUG INSPECTION INSP ADJ ***************************************************** CAUTION:  Loosen the locknut 1 on the throttle cable.  T urn the adjuster 2 in or out until specified free play is obtained. T urning in  Free play is increased. T urning out  Free play is decreased.  T ighten the lo ...
Yamaha YP250 - page 63

3-13 SP ARK PLUG INSPECTION / IGNITION TIMING CHECK INSP ADJ 18 Nm (1.8 m S kg) NOTE: NOTE: ***************************************************** ***************************************************** Spark plug gap: 0.6  0.7 mm 6. Install: D Spark plug Before installing a spark plug, clean the gasket surface and plug surface. YP303052 IGNITION T ...
Yamaha YP250 - page 64

3-14 IGNITION TIMING CHECK / COMPRESSION PRESSURE MEASUREMENT INSP ADJ NOTE: NOTE: CAUTION: Ignition timing is not adjustable. 3. Install:  T iming check plug YP303060 COMPRESSION PRESSURE MEASUREMENT Insufficient compression pressure will result in performance loss. 1. Remove:  Side panels Refer to “COVER AND P ANEL” section. 2. Check: ? ...
Yamaha YP250 - page 65

3-15 COMPRESSION PRESSURE MEASUREMENT / ENGINE OIL REPLACEMENT INSP ADJ ***************************************************** ***************************************************** 18 Nm (1.8 m S kg) NOTE: Compression pressure pp (With oil applied into cylinder) Reading Diagnosis Higher than without oil Worn or damaged pistons Same as without oil Po ...
Yamaha YP250 - page 66

3-16 ENGINE OIL LEVEL INSPECTION / ENGINE OIL REPLACEMENT INSP ADJ CAUTION: NOTE: 32 Nm (3.2 m S kg) NOTE: RECOMMENDED ENGINE OIL Refer to the chart for selection of the oils suited to the atomosperic temperature. API ST ANDARD: API SE or higher grade D Do not put in any chemical sdditives or use oils with a grade of CD a or higher . D Be sure not ...
Yamaha YP250 - page 67

3-17 ENGINE OIL REPLACEMENT / ENGINE OIL PRESSURE INSPECTION INSP ADJ ************************************* ***************************************************** NOTE: ***************************************************** 5. Fill:  Crankcase Oil quantity: 1.4L 6. Check:  Engine oil level Refer to “ENGINE OIL LEVEL INSPEC- TION” section. 7 ...
Yamaha YP250 - page 68

3-18 ENGINE OIL PRESSURE INSPECTION / TRANSMISSION OIL REPLACEMENT INSP ADJ 10 Nm (1.0 m S kg) CAUTION: ***************************************************** NOTE: NOTE: 22 Nm (2.2 m S kg) CAUTION: D Start the engine after solving the problem(s), and recheck the oil pressure. D T ighten the oil check bolt to specification. D Start the engine and ch ...
Yamaha YP250 - page 69

3-19 TRANSMISSION OIL REPLACEMENT / EXHAUST SYSTEM INSPECTION / AIR FIL TER CLEANING INSP ADJ 20 Nm (2.0 m S kg) 53 Nm (5.3 m S kg) 20 Nm (2.0 m S kg) CAUTION: 7. Install: D Oil filler cap 1 D O-ring 2 8. Start the engine for several minutes to warm it up and check for the oil leakage. YP***** EXHAUST SYSTEM INSPECTION 1. Remove: D Side panels Refe ...
Yamaha YP250 - page 70

3-20 AIR FIL TER CLEANING / CRANKCASE FIL TER CLEANING INSP ADJ NOTE: CAUTION: 7 Nm (0.7 m S kg) NOTE: 3. Inspect: D Air filter element Damaged  Replace. 4. Clean: D Air filter element 1 Use solvent to clean the element After cleaning, remove the remaining solvent by squeezing the element. Do not twist the element when squeezing the element. 5. ...
Yamaha YP250 - page 71

3-21 CRANKCASE FIL TER CLEANING / COOLANT LEVEL INSPECTION INSP ADJ CAUTION: 7 Nm (0.7 m S kg) NOTE: CAUTION: NOTE: This element is a dry type. Be careful not to stain with grease or water . 3. Clean: D Crankcase filter element 1 Blow out the dust in the element from the outer surface using compressed air . 4. Install: D Crankcase filter element D ...
Yamaha YP250 - page 72

3-22 COOLANT REPLACEMENT INSP ADJ NOTE: YP303180 COOLANT REPLACEMENT 1. Remove:  Side panels  Fuel tank Refer to the “COVERS AND P ANEL” section. 2. Remove:  Hose 1 (reservoir tank) Drain the reservoir tank of its coolant. 3. Remove:  Drain bolt 1  Radiator cap Open the front trunk, remove the cover , slowly loosen to remove the ...
Yamaha YP250 - page 73

3-23 COOLANT REPLACEMENT INSP ADJ 10 Nm (1.0 m S kg) ***************************************************** 5. Install: D Gasket 1 D Drain bolt 2 6. Loosen: D Screw 1 (carburetor bleed) 7. Connect: D Hose (reservoir tank) 8. Fill: D Radiator (to specified level 1 ) Fill the coolant slowly , until the coolant comes out from the carburetor drain pipe. ...
Yamaha YP250 - page 74

3-24 COOLANT REPLACEMENT INSP ADJ ***************************************************** CAUTION: NOTE:  If coolant splashes in your eyes: thoroughly wash your eyes with water and consult a doctor .  If coolant splashes on your clothes: quickly wash it away with water and then with soap and water .  If coolant is swallowed: quickly make the ...
Yamaha YP250 - page 75

3-25 COOLING SYSTEM INSPECTION INSP ADJ YP303190 COOLING SYSTEM INSPECTION 1. Inspect:  Radiator 1  Filler hose (radiator) 2  Outlet hose (radiator) 3  Pipe  Outlet hose (radiator) 4 Cracks / Damage  Replace. Refer to “COOLING SYSTEM” section in chapter 5. ...
Yamaha YP250 - page 76

3-26 FRONT BRAKE ADJUSTMENT INSP ADJ ***** ********************************************** ***************************************************** CAUTION: EB304002 CHASSIS FRONT BRAKE ADJUSTMENT 1. Check:  Brake lever free play a Out of specification  Adjust. Free play (brake lever): 2  5 mm (at brake lever end) 2. Adjust:  Brake lever fr ...
Yamaha YP250 - page 77

3-27 BRAKE FLUID LEVEL INSPECTION INSP ADJ NOTE: NOTE: CAUTION: YP304020 BRAKE FLUID LEVEL INSPECTION 1. Stand the scooter on a level surface. Make sure the scooter is upright when inspect- ing the brake fluid level. 2. Stand the scooter on its centerstand. 3. Inspect:  Brake fluid level Brake fluid level is below the “LOWER” level line a ? ...
Yamaha YP250 - page 78

3-28 BRAKE P AD INSPECTION / AIR BLEEDING (HYDRAULIC BRAKE SYSTEM) INSP ADJ ***************************************************** YP304030 BRAKE P AD INSPECTION 1. Operate the brake lever . 2. Inspect:  Brake pad (front) Wear indicators 1 almost touch the brake disc  Replace the brake pads as a set. Refer to “FRONT AND REAR BRAKE” in CHAP ...
Yamaha YP250 - page 79

3-29 AIR BLEEDING (HYDRAULIC BRAKE SYSTEM) / REAR BRAKE ADJUSTMENT INSP ADJ NOTE: 6 Nm (0.6 m S kg) NOTE: ***************************************************** ***************************************************** When bleeding the brake system, make sure that there is always enough brake fluid in the brake fluid reservoir before applying the brake ...
Yamaha YP250 - page 80

3-30 REAR BRAKE ADJUSTMENT / BRAKE SHOE INSPECTION / STEERING HEAD INSPECTION INSP ADJ CAUTION: ***************************************************** NOTE:  T ighten the locknut (s). Rear wheel side:  T urn the adjuster 3 in or out until the speci- fied free play is obtained. T urning in  Free play is decreased. T urning out  Free play ...
Yamaha YP250 - page 81

3-31 STEERING HEAD INSPECTION INSP ADJ ***************************************************** 38 Nm (3.8 m S kg) NOTE: 22 Nm (2.2 m S kg) 5. Remove: D Handlebar lower holder D Woodruf f key Refer to “STEERING” section in chapter 7. 6. Adjust: D Steering head Adjustment steps: D Remove the ring nut (upper) 1 , lock washer 2 , the ring nut (center ...
Yamaha YP250 - page 82

3-32 STEERING HEAD INSPECTION / FRONT FORK INSPECTION INSP ADJ NOTE: 75 Nm (7.5 m S kg) ***************************************************** D Install the lock washer 1 . Make sure the lock washer tabs sit correctly in the ring nut slots. D Hold the ring nut (under and center), using the exhaust and ring nut wrench, and tighten the ring nut (upper ...
Yamaha YP250 - page 83

3-33 SWINGARM INSPECTION / REAR SHOCK ABSORBER INSPECTION / REAR SHOCK ABSORBER ADJUSTMENT INSP ADJ 40 Nm (4.0 m S kg) 16 Nm (1.6 m S kg) NOTE: YP***** SWINGARM INSPECTION Securely support the scooter so there is no danger of it falling over . 1. Place the scooter on the level place. 2. Check: D Operation Grasp the end of the swingarm and gent- ly ...
Yamaha YP250 - page 84

3-34 REAR SHOCK ABSORBER ADJUSTMENT / TIRE INSPECTION INSP ADJ ***************************************************** b a CAUTION: ***************************************************** Adjustment steps:  T urn the adjuster ring in or out. T urning toward  Spring preload is increased. T urning toward  Spring preload is decreased. Hard Standa ...
Yamaha YP250 - page 85

3-35 TIRE INSPECTION INSP ADJ Basic weight: With oil and full fuel tank 158 kg Maximum load* 197 kg Cold tire pressure Front Rear Up to 90 kg load* 175 kPa (1.75 kg / cm 2 , 1.75 bar) 200 kPa (2.0 kg / cm 2 , 2.0 bar) 90 kg  maximum. load* 200 kPa (2.0 kg / cm 2 , 2.0 bar) 225 kPa (2.25 kg / cm 2 , 2.25 bar) High speed riding 200 kPa (2.0 kg / c ...
Yamaha YP250 - page 86

3-36 TIRE INSPECTION / WHEEL INSPECTION INSP ADJ NOTE: FRONT : Manufacture Size T ype IRC 1 10 / 90-12 64J MB61 CHENG SHIN 1 10 / 90-12 64J C922 REAR: Manufacture Size T ype IRC 130 / 70-12 62L MB61 CHENG SHIN 130 / 70-12 62L C940 After mounting a tire, ride conservatively for a while to give the tire time to seat itself properly in the rim. Failur ...
Yamaha YP250 - page 87

3-37 BA TTER Y INSPECTION INSP ADJ NOTE: CAUTION: YP305000 ELECTRICAL BA TTERY INSPECTION Since the MF battery is a sealed type battery , it is not possible to measure the specific gravity of the electrolyte in order to check the charge state of the battery . Therefore the charge of the bat- tery has to be checked by measuring the volt- age at the ...
Yamaha YP250 - page 88

3-38 V olt meter Relationship between open-circuit voltage and charging time at 20 _ C (68 _ F) *This varies depending on the temperature, the state of charge in battery plates and the electrolyte level. Charging time Hours Open-circuit voltage BA TTER Y INSPECTION INSP ADJ CAUTION: ***************************************************** NOTE: D Batt ...
Yamaha YP250 - page 89

3-39 BA TTER Y INSPECTION INSP ADJ Open-circuit voltage (V) Condition of charge in battery (%) Ambient temperature 20 _ C (68 _ F) Open-circuit voltage (V) Charging Ambient temperature 20 _ C (68 _ F) Check the Open-circuit voltage Time (Minutes) ***************************************************** CAUTION: D Check the condition of the battery usi ...
Yamaha YP250 - page 90

3-40 Measure the open-circuit voltage prior to charging. Connect a charger and AMP meter to the battery , and start charging. Make sure the current is higher than the standard charging current written on the battery . By turning the charging voltage adjust dial, set the charging voltage at 20  25 V . Adjust the voltage so that cur- rent is at st ...
Yamaha YP250 - page 91

3-41 Measure the open-circuit voltage prior to charging. Connect a charger and AMP meter to the battery , and start charging. NOTE: V oltage should be measured 30 min- utes after the machine is stopped. Make sure the current is higher than the standard charging current written on the battery . Charge the battery until the battery’s charging volta ...
Yamaha YP250 - page 92

3-42 BA TTER Y INSPECTION / FUSE INSPECTION INSP ADJ NOTE: CAUTION: CAUTION: ***************************************************** ***************************************************** NOTE: 6. Inspect:  Battery terminals Dirty terminal  Clean with wire brush. Poor connection  Correct. After cleaning the terminals, grease them light- ly . ...
Yamaha YP250 - page 93

3-43 FUSE INSPECTION / HEADLIGHT BEAM ADJUSTMENT INSP ADJ ***************************************************** ***************************************************** 3. Replace:  Blown fuse Replacement steps:  T urn off the main switch.  Install a new fuse with the proper current rat- ing.  T urn on switches to verify operation of relat ...
Yamaha YP250 - page 94

INSP ADJ ...
Yamaha YP250 - page 95

CHAPTER 4. ENGINE ENGINE OVERHAUL 4-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WIREHARNESS AND CABLE 4-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HOSES, AIR FIL TER CASE, ENGINE MOUNTING BOL T AND ENGINE 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
Yamaha YP250 - page 96

OIL PUMP 4-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OIL PUMP INSPECTION 4-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TRANSMISSION 4-44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CRANKCASE AND CRANKSHAF ...
Yamaha YP250 - page 97

4-1 ENGINE REMOV AL ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 Wireharness and cables removal Side panel Footrest board Fuel tank Drain the coolant. Carburetor Spark plug cap Thermo unit lead Startor coil / Pick up coil lead Starting motor lead Earth lead Adjuster Brake cable 1 1 1/1 1 1 1 1 Remove the parts in order . Refer to “ ...
Yamaha YP250 - page 98

4-2 ENGINE REMOV AL ENG Order Job name / Part name Q’ty Remarks 8 9 10 11 Pin Compression spring Cable holder Cable holder 1 1 1 1 Reverse the removal procedure for installation. 7 Nm (0.7 m  kg) 10 Nm (1.0 m  kg) ...
Yamaha YP250 - page 99

4-3 ENGINE REMOV AL ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 Hoses, air filter , engine mounting bolt and engine removal V acuum hose Crankcase breather hose Inlet hose (water pump) Outlet hose (cylinder head) Air filter case assembly Bolt Self locknut / Plane washer Bolt Bolt / Plane washer / Rod assembly Engine 1 1 1 1 1 ...
Yamaha YP250 - page 100

4-4 ENGINE REMOV AL ENG NOTE: 64 Nm (6.4 m  kg) 32 Nm (3.2 m  kg) YP****** ENGINE REMOUNTING When remounting the engine, reverse the re- moval procedure in job instruction chart. Note the following points: 1. Install:  Engine 1  Plane washer 2  Rod 3 T emporarily install the rod and engine, and then tighten the bolts and nuts to spec ...
Yamaha YP250 - page 101

4-5 CYLINDER HEAD ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 Cylinder head removal Drain the coolant. Side panel Footrest board Fuel tank Carburetor Thermo unit lead Plug cap Crankcase breather hose Outlet hose (cylinder head) V acuum hose Breather hose (crankcase) Carburetor joint Joint O-ring 1 1 2 1 1 1 1 1 2 Remove the part ...
Yamaha YP250 - page 102

4-6 Order Job name / Part name Q’ty Remarks 10 11 12 13 14 15 16 17 18 19 20 21 Crankcase filter cover / seal / element Plug / O-ring Cam sprocket cover / O-ring V alve cover (intake side) / O-ring V alve cover (exhaust side) / O-ring T iming chain tensioner assembly T iming chain tensioner gasket Breather plate Cam sprocket / T iming chain Cylin ...
Yamaha YP250 - page 103

4-7 CYLINDER HEAD ENG NOTE: NOTE: NOTE: NOTE: YP401030 CYLINDER HEAD REMOV AL 1. Align: S “I” mark a on the rotor (with stationary pointer b on the crank case cover) T urn the primary sheave counterclockwise with a wrench and align the “I” mark c with the cylin- der head match mark d when the piston is at TDC on the compression stroke. 2. L ...
Yamaha YP250 - page 104

4-8 CYLINDER HEAD ENG ***************************************************** ***************************************************** NOTE: NOTE: 22 Nm (2.2 m S kg) 10 Nm (1.0 m S kg) 2. Inspect: S Cylinder head Scratches / damage  Replace. 3. Measure: S Cylinder head warpage Out of specification  Resurface. Cylinder head warpage: Less than 0.03 ...
Yamaha YP250 - page 105

4-9 CYLINDER HEAD ENG ***************************************************** ***************************************************** NOTE: CAUTION: 3. Install: S Cam sprocket 1 S T iming chain 2 Installing steps: D T urn the primary sheave counterclockwise until the TDC mark a matches the stationary pointer b . D Align the “I” mark c on the cam sp ...
Yamaha YP250 - page 106

4-10 CYLINDER HEAD ENG ***************************************************** ***************************************************** 10 Nm (1.0 m S kg) 8 Nm (0.8 m S kg) 60 Nm (6.0 m S kg) 5. Install: S T iming chain tensioner Installation steps: D Remove the tensioner cap bolt 1 and springs 2 . D Release the timing chain tensioner one-way cam 3 and ...
Yamaha YP250 - page 107

4-1 1 CAMSHAFT AND ROCKER ARMS ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 Camshaft and rocker arms removal Cylinder head Lock washer Plate Rocker arm shaft (intake) Rocker arm shaft (exhaust) Rocker arm Camshaft Locknut Adjuster O-ring 1 1 1 1 2 1 2 2 1 Remove the parts in order . Refer to “CYLINDER HEAD” section. Refer to ...
Yamaha YP250 - page 108

4-12 CAMSHAFT AND ROCKER ARMS ENG NOTE: YP****** ROCKER ARM AND ROCKER ARM SHAFT REMOV AL 1. Remove:  Rocker arm shaft (intake)  Rocker arm shaft (exhaust) Attach a rocker arm shaft puller bolt 1 and weight 2 to the rocker arm shaft and slide out the shaft. Rocker arm shaft puller bolt: 90890-01085 Weight: 90890-01084 YP402052 CAMSHAFT INSPEC ...
Yamaha YP250 - page 109

4-13 CAMSHAFT AND ROCKER ARMS ENG ***************************************************** ***************************************************** YP402060 ROCKER ARMS AND ROCKER ARM SHAFTS INSPECTION 1. Inspect: S Cam lobe contact surface 1 S Adjuster surface 2 Wear / Pitting / Scratches / Blue discolor- ation  Replace. Inspection steps: D Inspect t ...
Yamaha YP250 - page 110

4-14 CAMSHAFT AND ROCKER ARMS ENG 8 Nm (0.8 m  kg) NOTE: NOTE: NOTE: CAUTION: 2. Install:  Plate 1  Look washer 2  Bolt 3 Bend the lock washer tabs along the bolt 3 flats. 3. Apply:  Molybdenum disulfide oil (onto the rocker arm and rocker arm shaft) Molybdenum disulfide oil 4. Install:  Rocker arm 1  Rocker arm shaft 2 (exhaus ...
Yamaha YP250 - page 111

4-15 V AL VES AND V AL VE SPRINGS ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 V alves and valve springs removal Cylinder head Rocker arm, rocker arm shaft V alve cotters Spring retainer V alve spring (inner) V alve spring (outer) V alve (intake) V alve (exhaust) V alve guide Spring seat 4 2 2 2 1 1 2 2 Remove the parts in order . ...
Yamaha YP250 - page 112

4-16 V AL VES AND V AL VE SPRINGS ENG NOTE: CAUTION: YP401 150 V AL VES AND V AL VE SPRINGS REMOV AL 1. Remove:  V alve cotters 1 Attach a valve spring compressor and attach- ment 2 between the valve spring retainer and cylinder head to remove the valve cotters. Do not compress so much as to avoid dam- age to the valve spring. V alve spring comp ...
Yamaha YP250 - page 113

4-17 V AL VES AND V AL VE SPRINGS ENG YP402030 4. Measure: S Spring tilt Out of specification  Replace. Spring tilt limit: 1.7 mm (2.5 _ ) 5. Inspect: S Spring contact face Wear / Pitting / Scratches  Replace. 6. Measure: S V alve guide inside diameter Out of specification  Replace. V alve guide inside diameter: Intake: 6.000  6.012 mm ...
Yamaha YP250 - page 114

4-18 V AL VES AND V AL VE SPRINGS ENG ***************************************************** ***************************************************** NOTE: ***************************************************** CAUTION: 3. Measure: S V alve seat width a Out of specification  Reface the valve seat. V alve seat width: Intake: 0.9  1.1 mm <Limit: ...
Yamaha YP250 - page 115

4-19 V AL VES AND V AL VE SPRINGS ENG NOTE: NOTE: ***************************************************** NOTE: D T urn the valve until the valve face and valve seat are evenly polished, then clean off all compound. For best lapping results, lightly tap the valve seat while rotating the valve back and forth be- tween your hand. D Apply a fine lapping ...
Yamaha YP250 - page 116

4-20 V AL VES AND V AL VE SPRINGS ENG NOTE: CAUTION: 4. Install:  V alve cotters 1 Install the valve cotters while compressing the valve spring with a valve spring compressor and attachment 2 . V alve spring compressor: 90890-04019 Attachment: 90890-04108 5. Secure the valve cotters onto the valve stem by tapping lightly with a piece of wood. Do ...
Yamaha YP250 - page 117

4-21 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 11 12 Cylinder and piston removal Cylinder head Joint O-ring T iming chain guide (exhaust side) Cylinder Dowel pin Cylinder gasket Piston pin circlip Piston pin Piston Piston ring (top) Piston ring (2nd) Side rail / Spacer 1 2 1 1 2 1 2 1 1 1 1 2/1 Remove the parts in order . Refer ...
Yamaha YP250 - page 118

4-22 CYLINDER AND PIST ON ENG NOTE: NOTE: NOTE: YP****** PISTON AND PIST ON RINGS REMOV AL 1. Remove: S Piston pin circlip 1 S Piston pin 2 S Piston 3 Before removing the piston pin circlip, cover the crankcase opening with a clean towel or rag to prevent the circlip from falling into the crank- case cavity . 2. Remove: S T op ring S 2nd ring S Oil ...
Yamaha YP250 - page 119

4-23 CYLINDER AND PIST ON ENG YP****** PISTON AND PIST ON PIN INSPECTION 1. Measure:  Piston skirt diameter Out of specification  Replace. a 5.0 mm from the piston bottom edge Piston skirt diameter: 68.965  68.980 mm Oversize (2) 69.5 mm Oversize (4) 70.0 mm 2. Calculate:  Piston-to-cylinder clearance Piston-to-cylinder clearance = Cyli ...
Yamaha YP250 - page 120

4-24 CYLINDER AND PIST ON ENG NOTE: NOTE: NOTE: YP4021 1 1 PISTON RINGS INSPECTION 1. Measure:  Side clearance Out of specification  Replace the piston and the piston rings as a set. Eliminate the carbon deposits from the piston ring grooves and rings before measuring the side clearance. Side clearance (piston ring): T op ring: 0.04  0.08 ...
Yamaha YP250 - page 121

4-25 CYLINDER AND PIST ON ENG NOTE: NOTE: EB404184 PISTON RINGS, PIST ON AND CYLINDER INST ALLA TION 1. Install: S T op ring 1 S 2nd ring 2 S Side rails (oil ring) 3 S Expander spacer (oil ring) 4 D Make sure to install the piston rings so that the manufactuer ’s marks or numbers are lo- cated on the upper side of the rings. D Lubricate pistons a ...
Yamaha YP250 - page 122

4-26 CYLINDER AND PIST ON ENG NOTE: NOTE: 4. Position: S Piston rings Offset the piston ring end gaps as shown. a T op ring end b Oil ring end (lower) c Oil ring end (upper) d 2nd ring end 5. Lubricate: S Piston outer surface S Piston ring S Cylinder inner surface Engine oil 6. Install: S Cylinder D Install the cylinder with one hand while com- pre ...
Yamaha YP250 - page 123

4-27 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 Crankcase filter cover and crankcase cover (left)removal Side panel Crankcase filter cover Crankcase filter cover seal Crankcase filter element Crankcase cover protector Crankcase cover (left) Crankcase cover gasket 1 1 1 1 1 1 Remove the parts in order . Refer to “COVER AND P ANEL” sec ...
Yamaha YP250 - page 124

4-28 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 V -belt, clutch and secondary / primary sheave removal Nut / Plain washer Primary fixed sheave Nut Clutch housing Clutch assembly V -belt Primary sliding sheave Collar Primary sheave cap 1/1 1 1 1 1 1 1 1 1 Remove the parts in or ...
Yamaha YP250 - page 125

4-29 Order Job name / Part name Q’ty Remarks 10 11 12 13 14 Cam Weight Slider Spacer Oil seal 1 8 4 4 1 Refer to “PRIMARY SHEA VE ASSEMBL Y” section. Reverse the removal procedure for installation. 60 Nm (6.0 m  kg) 60 Nm (6.0 m  kg) 3 Nm (0.3 m  kg) V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG *Shell BT grease No. 3 (9089 ...
Yamaha YP250 - page 126

4-30 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 Secondary sheave disassembly Nut Clutch carrier Clutch shoe spring Compression spring Spring seat Guide pin Secondary sliding sheave O-ring Oil seal Secondary fixed sheave 1 1 3 1 1 4 1 2 2 1 Disassemble the parts in order . R ...
Yamaha YP250 - page 127

4-31 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG NOTE: NOTE: CAUTION: NOTE: YP****** PRIMAR Y SHEA VE REMOV AL 1. Remove:  Nut 1 (primary sheave)  Plate washer  Primary fixed sheave 2 Loosen the nut (primary fixed sheave) while holding the primary fixed sheave with the rotor holder 3 . Rotor holder: 90890-01235 YP****** SECONDA ...
Yamaha YP250 - page 128

4-32 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG NOTE: NOTE: CAUTION: NOTE: 3. Remove: S Clutch assembly 1 S V -belt 2 Remove the V -belt from the primary sheave side with clutch assembly . YP****** SECONDAR Y SHEA VE DISASSEMBL Y 1. Remove: S Nut 1 (secondary sheave) Loosen the nut 1 while attaching the clutch spring compressor 2 and c ...
Yamaha YP250 - page 129

4-33 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG YP****** V -BEL T INSPECTION 1. Inspect:  V -belt 1 Cracks / Wear / Scaling / Chipping  Re- place. Oil / Grease  Check primary sheave and secondary sheave. 2. Measure:  V -belt width 2 Out of specification  Replace V -belt width: 22.6 mm <Limit: 21.0 mm> YP****** WEIG ...
Yamaha YP250 - page 130

4-34 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG NOTE: NOTE: 3 Nm (0.3 m S kg) NOTE: YP****** PRIMAR Y SHEA VE ASSEMBL Y 1. Clean: S Primary sliding sheave face 1 S Primary fixed sheave face 2 S Collar 3 S Weight 4 S Primary sliding sheave cam face 5 Remove any excess grease. 2. Install: S Weight 1 S Collar 2 D Apply Shell BT grease No. ...
Yamaha YP250 - page 131

4-35 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG NOTE: CAUTION: NOTE: CAUTION: 3. Install:  Guide pin 1 4. Apply:  BEL-RA Y assembly lube  (to the guide pin sliding groove 1 , and and oil seal 2 ) 5. Install:  Secondary sheave complete 1  Compression spring  Clutch carrier 2 T emporarily tighten the nut 5 while attachi ...
Yamaha YP250 - page 132

4-36 V -BEL T , CLUTCH AND SECONDAR Y / PRIMAR Y SHEA VE ENG 90 Nm (9.0 m  kg) NOTE: NOTE: NOTE: 7. Install:  Nut 1 (clutch carrier) T ighten the nut (clutch carrier), using the lock- nut wrench 3 while holding the clutch carrier with the rotor holder 2 . Rotor holder: 90890-01235 Locknut wrench: 90890-01348 8. Install:  Clutch housing 1 ? ...
Yamaha YP250 - page 133

4-37 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 Magneto cover and startor coil removal Drain the engine oil. Side panels Couplers (A.C. magneto lead) Exhaust pipe Exhaust pipe gasket Magneto cover Gasket (magneto cover) Dowel pins Startor coil Pick up coil 2 1 1 2 1 2 1 1 Remove the parts in order . NOTE: Refer to “ENGINE OIL REPLA ...
Yamaha YP250 - page 134

4-38 A.C. MAGNETO AND ST ARTER CLUTCH ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 A.C. magneto and starter clutch removal Rotor Shaft (idle gear) Idler gear Starter one way clutch assembly Woodruf f key Starter wheel gear 1 1 1 1 1 1 Remove the parts in order . Refer to “A.C. MAGNETO ROT OR REMOV AL / INST ALLA TION” section. Refe ...
Yamaha YP250 - page 135

4-39 A.C. MAGNETO AND ST ARTER CLUTCH ENG NOTE: NOTE: CAUTION: YP401081 A.C. MAGNETO ROT OR REMOV AL 1. Remove: S Nut 1 (rotor) S Plain washer 2 D Loosen the nut (rotor) 1 while holding the ro- tor with a sheave holder 3 . D Do not allow the sheave holder to touch the projection on the rotor . Sheave holder: 90890-01701 2. Remove: S Rotor 1 S Woodr ...
Yamaha YP250 - page 136

4-40 A.C. MAGNETO AND ST ARTER CLUTCH ENG ***************************************************** ***************************************************** NOTE: NOTE: YP402163 ST ARTER DRIVE GEAR INSPECTION 1. Inspect: S Starter idle gear teeth S Starter drive gear teeth S Starter wheel gear teeth Burrs / chips / roughness / wear  Re- place. 2. Check ...
Yamaha YP250 - page 137

4-41 A.C. MAGNETO AND ST ARTER CLUTCH ENG 80 Nm (8.0 m  kg) NOTE: 3. T ighten:  Nut (rotor) 1 T ighten the nut (rotor) 1 while holding the mag- neto rotor 2 with a sheave holder 3 . Sheave holder: 90890-01701 ...
Yamaha YP250 - page 138

4-42 OIL PUMP ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 Oil pump removal A.C. magneto Cover Pump driven gear Dowel pin Oil pump assembly Gasket Impeller shaft gear Dowel pin Shaft 1 1 1 1 1 1 1 1 Remove the parts in order . Refer to the “A.C. MAGNETO AND ST ARTER CLUTCH” section. Reverse the removal procedure for installatio ...
Yamaha YP250 - page 139

4-43 OIL PUMP ENG EB402140 OIL PUMP INSPECTION 1. Inspect:  Drive gear (oil pump)  Driven gear (oil pump) 1  Pump housing  Pump housing cover Wear / cracks / damage  Replace 2. Measure:  T ip clearance A (between the inner rotor 1 and the outer rotor 2 )  Side clearance B (between the outer rotor 2 and the pump housing 3 ) Out ...
Yamaha YP250 - page 140

4-44 TRANSMISSION ENG Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 T ransmission removal Rear wheel Crankcase cover (left) Drain the transmission oil. T ransmission case cover Gasket (transmission case cover) Dowel pin Primary drive gear Plain washer Plain washer 1st wheel gear 1 1 2 1 1 1 1 Remove the parts in order . Refer to “REAR W ...
Yamaha YP250 - page 141

4-45 Order Job name / Part name Q’ty Remarks 8 9 10 11 Drive axle Main axle Primary driven gear Plain washer 1 1 1 1 Reverse the removal procedure for installation. 16 Nm (1.6 m  kg) TRANSMISSION ENG ...
Yamaha YP250 - page 142

4-46 CRANKCASE AND CRANKSHAFT ENG Order Job name / Part name Q’ty Remarks 1 2 Crankcase and crankshaft removal Engine removal Cylinder head Cylinder , piston V -belt, clutch, secondary / primary sheave A.C. magneto, starter clutch Oil pump W ater pump Rear wheel Bolt O-ring 1 1 Remove the parts in the order . Refer to “ENGINE REMOV AL” sectio ...
Yamaha YP250 - page 143

4-47 Order Job name / Part name Q’ty Remarks 3 4 5 6 7 8 9 T iming chain guide (intake) Crankcase (right) Dowel pin Crankshaft assembly T iming chain Crankcase (left) Oil seal 1 1 2 1 1 1 1 Refer to “CRANKSHAFT INST ALLA TION” section. Refer to “CRANKSHAFT REMOV AL / INST ALLA TION” section. Reverse the removal procedure for installation. ...
Yamaha YP250 - page 144

4-48 CRANKCASE AND CRANKSHAFT ENG NOTE: NOTE: YP****** CRANKSHAFT REMOV AL 1. Remove:  Crankshaft assembly  T iming chain 1  Before removing the crankshaft assembly , remove the timing chain from the crank shaft sprocket.  If the timing chain hooks to the crankshaft sprocket, the crankshaft cannot be removed. YP****** CRANKSHAFT INSPECT ...
Yamaha YP250 - page 145

4-49 CRANKCASE AND CRANKSHAFT ENG NOTE: NOTE: 4. Inspect:  Crankshaft sprocket 1 Wear / Damage  Replace crankshaft.  Bearing 2 Wear / Crack / Damage  Replace crank- shaft.  Pump drive gear 3 Wear / Damage  Replace crankshaft. 5. Inspect:  Crankshaft journal Clogged  Blow out the journal with com- pressed air . YP404073 CRANK ...
Yamaha YP250 - page 146

ENG ...
Yamaha YP250 - page 147

CHAPTER 5. COOLING SYSTEM RADIA TOR 5-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INSPECTION 5-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W A TER PUMP 5-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
Yamaha YP250 - page 148

...
Yamaha YP250 - page 149

5-1 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 Radiator removal Drain the coolant. Fuel tank Footrest board, under cover Cowling body , leg shield Fan motor leads Thermo switch leads Filler hose (radiator) Outlet hose (radiator) Inlet hose (radiator) Radiator 1 2 1 1 1 1 Remove the parts in order . Refer to “COOLANT REPLACEMENT” sect ...
Yamaha YP250 - page 150

5-2 RADIA T OR COOL CAUTION: ***************************************************** ***************************************************** YP500030 INSPECTION 1. Inspect: D Radiator 1 Obstruction  Blow out with com- pressed air through the rear of the radia- tor . Flattened fins  Repair or replace. If flattened over the 20 % of radiator fin, re ...
Yamaha YP250 - page 151

5-3 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 W ater pump removal Drain the coolant. Impeller shaft gear Dowel pin / plain washer Shaft Inlet hose (water pump) Holder Housing cover Housing cover gasket W ater pump housing 1 1/1 1 1 1 1 1 1 Remove the parts in order . Refer to “COOLANT REPLACEMENT” section in CHAPTER 3. Refer to ...
Yamaha YP250 - page 152

5-4 Order Job name / Part name Q’ty Remarks 9 10 11 Impeller shaft O-ring O-ring 1 1 1 Refer to “W A TER PUMP INST ALLA TION” section. Reverse the removal procedure for installation. 10 Nm (1.0 m  kg) 10 Nm (1.0 m  kg) 10 Nm (1.0 m  kg) Oil pump side W A TER PUMP COOL ...
Yamaha YP250 - page 153

5-5 W A TER PUMP COOL NOTE: ***************************************************** ***************************************************** YP****** D It is not necessary to disassemble the water pump, unless there is no abnormality such as excessive change in coolant temperature and / or level, discoloration of coolant, or milky transmission oil. D If ...
Yamaha YP250 - page 154

5-6 W A TER PUMP COOL NOTE: ***************************************************** ***************************************************** NOTE: 10 Nm (1.0 m S kg) 2. Install: D Mechanical seal 1 Apply coolant to the outside of the me- chanical seal before installing. Do not smear any oils grease on to the ring side of the mechanical seal. 3. Inspect: ...
Yamaha YP250 - page 155

5-7 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 Thermostat removal Drain the coolant Side panel Fuel tank Clip Outlet hose (carburetor) Hose clamp Outlet hose (thermostat) Thermostatic cover Thermostatic valve 1 1 1 1 1 1 Remove the parts in order . Refer to “COOLANT REPLACEMENT” section in CHAPTER 3. Refer to “COVER AND P ANEL” s ...
Yamaha YP250 - page 156

5-8 3mm 95 _ C 82”1.5 _ C THERMOST A T COOL ***************************************************** ***************************************************** NOTE: EB502010 INSPECTION 1. Inspect: D Thermostatic valve V alve does not open at 80.5  83.5 _ C  Replace. Inspection steps: D Suspend the thermostatic valve in a vessel. D Place a reliable ...
Yamaha YP250 - page 157

CHAPTER 6. CARBURETION CARBURETION 6-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CARBURETOR DISASSEMBL Y 6-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ASSEMBL Y 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FUEL LEVEL ADJUSTME ...
Yamaha YP250 - page 158

...
Yamaha YP250 - page 159

6-1 Do not bend the air filter joint clamp when installing the carburetor . Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 Carburetor removal Side panel Fuel tank Drain the coolant Auto choke lead coupler Inlet / Outlet hose (carburetor) Fuel hose Throttle cable Air filter joint Nut Carburetor ass’y 1 1/1 1 2 1 2 1 Remove the parts in or ...
Yamaha YP250 - page 160

6-2 Refer to “CARBURETOR ASSEMBL Y” section. Refer to “CARBURETOR ASSEMBL Y” section. Order Job name / Part name Q’ty Remarks Carburetor disassembly Auto choke unit Throttle stop screw set Pilot screw set Cover / Diaphragm spring Piston valve Jet needle ass’y Coasting enricher Accererating pump Float chamber Float pin 1 1 1 1/1 1 1 1 1 ...
Yamaha YP250 - page 161

6-3 Order Job name / Part name Q’ty Remarks Float Needle valve Main jet Pilot jet Main nozzle 1 1 1 1 1 Refer to “CARBURETOR ASSEMBL Y” section. Reverse the disassembly procedure for assembly . 11 12 13 14 15 CARBURET OR CARB ...
Yamaha YP250 - page 162

6-4 CARBURET OR CARB CAUTION: ***************************************************** NOTE: YP600041 ASSEMBL Y Reverse the “DISASSEMBL Y” procedure. Note the following points. D Before assembling, wash all parts in clean petroleum based solvent. D Always use a new gasket. 1. Install: D Main nozzle 1 D Main jet 2 D Pilot jet 3 2. Install: D V alve ...
Yamaha YP250 - page 163

6-5 CARBURET OR CARB ***************************************************** NOTE: ***************************************************** Float height (F .H.): 27 mm Out of specification  Replace. 5. Install: D Diaphragm 1 Align the tab a on the diaphragm with the slot b on the carburetor body . 6. Install: D Compression spring 1 D Cover 2 YP600060 ...
Yamaha YP250 - page 164

6-6 CARBURET OR CARB ***************************************************** ***************************************************** ***************************************************** D Put a garage jack under the engine to ensure that the carburetors are positioned vertically . D Connect the fuel level gauge 1 to the drain pipe 2 . Fuel level gauge ...
Yamaha YP250 - page 165

6-7 CARBURET OR CARB ***************************************************** ***************************************************** YP****** FUEL PUMP INSPECTION 1. Remove: D Side panels Refer to “COVER AND P ANEL” section in CHAPTER 3. 2. Inspect: D Fuel pump Inspection steps: D Place the receptacle under the fuel pipe end. D Start engine, and in ...
Yamaha YP250 - page 166

CARB ...
Yamaha YP250 - page 167

CHAPTER 7. CHASSIS FRONT WHEEL AND BRAKE DISC 7-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FRONT WHEEL AND BRAKE DISC 7-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . FRONT WHEEL DISASSEMBL Y 7-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FRONT WHEEL DISASSEMBL Y 7-3 . . . . . . . . . . . . . . . . . . . . ...
Yamaha YP250 - page 168

...
Yamaha YP250 - page 169

7-1 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 Front wheel and brake disc removal Speedometer cable Axle nut Wheel axle Front wheel assembly Gear unit assembly Collar Brake disc 1 1 1 1 1 1 1 Remove the parts in order . Securely support the scooter so there is no danger of it falling over . Refer to “FRONT WHEEL ASSEMBL Y” section. ...
Yamaha YP250 - page 170

7-2 1 2 3 4 Order Job name / Part name Q’ty Remarks Front wheel disassembly Oil seal Bearing Spacer Bearing 1 1 1 1 Remove the parts in order . Reverse the removal procedure for installation. Refer to “FRONT WHEEL DISASSEMBL Y / ASSEMBL Y” section. FRONT WHEEL AND BRAKE DISC CHAS FRONT WHEEL DISASSEMBL Y ...
Yamaha YP250 - page 171

7-3 FRONT WHEEL AND BRAKE DISC CHAS CAUTION: YP****** FRONT WHEEL DISASSEMBL Y 1. Remove:  Bearing 1  Spacer Remove the bearing using a general bear- ing puller 2 . Handle the wheel with care not to damage the brake disc. If the brake disc is damaged, replace. YP700020 FRONT WHEEL INSPECTION 1. Inspect:  Front wheel axle (by rolling it on ...
Yamaha YP250 - page 172

7-4 FRONT WHEEL AND BRAKE DISC CHAS NOTE: CAUTION: 5. Inspect: S Collar Grooved wear  Replace the collar and the oil seal as a set. YP****** BRAKE DISC INSPECTION 1. Measure: S Brake disc deflection Maximum deflection: 0.15 mm Out of specification  Replace. 2. Measure: S Brake disc thickness Brake disc thickness: 4.0 mm Minimum thickness: 3.5 ...
Yamaha YP250 - page 173

7-5 FRONT WHEEL AND BRAKE DISC CHAS 23 Nm (2.3 m  kg) NOTE: NOTE: NOTE: CAUTION: 2. Install:  Brake disc 1 T ighten the bolts (brake disc) in stage using a crisscross pattern. EB700030 FRONT WHEEL INST ALLA TION Reverse the “REMOV AL” procedure. Note the following points. 1. Lubricate:  Front wheel axle  Bearings  Oil seal (lips) ...
Yamaha YP250 - page 174

7-6 FRONT WHEEL AND BRAKE DISC CHAS NOTE: ***************************************************** ***************************************************** ***************************************************** ***************************************************** NOTE: YP700040 WHEEL ST A TIC BALANCE ADJUSTMENT D After replacing the tire and / or rim, th ...
Yamaha YP250 - page 175

7-7 FRONT WHEEL AND BRAKE DISC CHAS ***************************************************** ***************************************************** 5. Check: S Wheel static balance Checking steps: D T urn the wheel so that it comes to each point as shown. D Check that the wheel is at rest at each point. If not, readjust the front wheel static balance. ...
Yamaha YP250 - page 176

7-8 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 11 Rear wheel and rear brake removal Swingarm Adjuster Brake cable Compression spring Pin Rear wheel assembly Brake lining T ension spring Plate washer Camshaft lever Indicator plate Camshaft 1 1 1 1 1 2 2 1 1 1 1 Remove the part in order . Refer to “REAR SHOCK ABSORBER AND SWINGA ...
Yamaha YP250 - page 177

7-9 REAR WHEEL AND REAR BRAKE CHAS Order Job name / Part name Q’ty Remarks 12 13 Camshaft shim Camshaft seal 1 1 Reverse the removal procedure for installation. 10 Nm (1.0 m  kg) ...
Yamaha YP250 - page 178

7-10 REAR WHEEL AND REAR BRAKE CHAS NOTE: NOTE: EB701020 REAR WHEEL INSPECTION 1. Inspect:  Rear wheel axle  Rear wheel  Rear wheel bearings  Oil seals Refer to “FRONT WHEEL”. 2. Measure:  Rear wheel runout Refer to “FRONT WHEEL”. EB701021 REAR BRAKE INSPECTION 1. Inspect:  Brake lining surface Glazed areas  Polish. Use ...
Yamaha YP250 - page 179

7-1 1 REAR WHEEL AND REAR BRAKE CHAS ***************************************************** ***************************************************** 4. Inspect: S Brake drum inner surface S Oil / scratches  Repair . S Oil Use a rag soaked in lacquer thinner or sol- vent. S Scratches Use an emery cloth (lightly and evenly polishing) 5. Inspect: S Cam ...
Yamaha YP250 - page 180

7-12 FRONT BRAKE CHAS Order Job name / Part name Q’ty Remarks 1 2 3 Brake pad removal Caliper support bolt Brake pad Pad support 1 2 1 Remove the parts in order . Refer to “BRAKE P AD REPLACEMENT” section. Reverse the removal procedure for installation. 23 Nm (2.3 m  kg) FRONT BRAKE BRAKE P AD ...
Yamaha YP250 - page 181

7-13 FRONT BRAKE CHAS NOTE: NOTE: CAUTION: 23 Nm (2.3 m S kg) YP702010 BRAKE P AD REPLACEMENT It is not necessary to disassemble the brake cal- iper and brake hose to replace the brake pads. 1. Remove: S Bolt (caliper support bolt) 1 Move the direction brake caliper to the ar- row mark. 2. Remove: S Brake pads D Install new brake pad springs when t ...
Yamaha YP250 - page 182

7-14 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 Master cylinder removal Drain the brake fluid Rear view mirror (right) Brake lever / compression spring Brake switch Union bolt Plain washer Brake hose Master cylinder bracket Master cylinder 1 1/1 1 1 2 1 1 1 Remove the parts in order . Refer to “BRAKE FLUID REPLACE- MENT” section ...
Yamaha YP250 - page 183

7-15 Order Job name / Part name Q’ty Remarks 1 2 3 4 Master cylinder disassembly Master cylinder boot Circlip Master cylinder assembly Spring 1 1 1 1 Remove the parts in order . Refer to “MASTER CYLINDER ASSEMBL Y” section. Reverse the disassembly procedure for assembly . FRONT BRAKE CHAS MASTER CYLINDER DISASSEMBL Y ...
Yamaha YP250 - page 184

7-16 FRONT BRAKE CHAS YP702040 MASTER CYLINDER INSPECTION 1. Inspect: S Master cylinder 1 Wear / scratches  Replace the master cylinder assembly . S Master cylinder cup 2 S Cracks / damage  Replace. 2. Inspect: S Master cylinder S Scratches / wear / damage  Replace the master cylinder assembly . 3. Inspect: S Diaphragm Wear / damage  Re ...
Yamaha YP250 - page 185

7-17 FRONT BRAKE CHAS 10 Nm (1.0 m  kg) CAUTION: 26 Nm (2.6 m  kg) CAUTION: 2. Install:  Spring 1 Install the spring with its smaller diameter to the master cylinder piston.  Master cylinder kit 2 3. Install:  Circlip 1 Install the circlip securely into the master cylinder groove.  Master cylinder boot 2 YP****** MASTER CYLINDER I ...
Yamaha YP250 - page 186

7-18 FRONT BRAKE CHAS 3. Air bleed: S Brake system Refer to “AIR BLEEDING” section in CHAPTER 3. D Use only designated quality brake fluid: Otherwise, the rubber seals may deterio- rate, causing leakage and poor brake per- formance. D Refill with the same type of brake fluid: mixing fluids may result in a harmful chemical reaction and lead to p ...
Yamaha YP250 - page 187

7-19 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 Caliper removal Drain the brake fluid Brake hose holder Union bolt Plain washer Brake hose Caliper support bolt Caliper assembly 1 1 2 1 1 1 Remove the parts in order . Refer to “BRAKE FLUID REPLACE- MENT” section in CHAPTER 3. Refer to “CALIPER INST ALLA TION” section. Reverse the ...
Yamaha YP250 - page 188

7-20 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 Caliper disassembly Brake pad Pad support Caliper piston Dust seal Piston seal Bleed screw / Cap 2 1 2 2 2 1/1 Remove the parts in order . Refer to “BRAKE CALIPER DIS- ASSEMBL Y / ASSEMBL Y” section. Reverse the disassembly procedure for assembly . 6 Nm (0.6 m  kg) FRONT BRAKE CHAS C ...
Yamaha YP250 - page 189

7-21 FRONT BRAKE CHAS NOTE: ***************************************************** ***************************************************** CAUTION: CAUTION: YP702020 BRAKE CALIPER DISASSEMBL Y Before disassembling either brake caliper , drain the brake fluid from the brake hose, mas- ter cylinder , brake caliper and reservoir tank. 1. Remove: S Brake ...
Yamaha YP250 - page 190

7-22 FRONT BRAKE CHAS CAUTION: 23 Nm (2.3 m S kg) 26 Nm (2.6 m S kg) CAUTION: EB702050 BRAKE CALIPER ASSEMBL Y D All internal brake components should be cleaned and lubricated with new brake fluid only before installation. Recommended brake fluid: DOT #4 D Replace the caliper piston seals whenev- er a brake caliper is disassembled. 1. Install: S Pi ...
Yamaha YP250 - page 191

7-23 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 Front fork removal Front wheel Caliper assembly Front fender Inner fender Bolt (under bracket upper) Cap bolt / O-ring Bolt (under bracket lower) Front fork (left / right) 1 1 1 2 2/2 2 1/1 Remove the parts in order . Refer to “FRONT WHEEL” section. Refer to “FRONT FORK REMOV AL / I ...
Yamaha YP250 - page 192

7-24 FRONT FORK CHAS Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 11 Front fork disassembly Cap bolt O-ring Fork spring Dust seal Retaining clip Oil seal Bolt (Damper rod) / Gasket Inner tube Oil lock piece Damper rod Rebound spring 1 1 1 1 1 1 1/1 1 1 1 1 Remove the parts in order . Refer to “FRONT FORK REMOV AL / INST ALLA TIO ...
Yamaha YP250 - page 193

7-25 FRONT FORK CHAS NOTE: NOTE: YP****** FRONT FORK REMOV AL D Securely support the scooter so there is no danger of it falling over . D Stand the scooter on a level surface. D Stand the scooter on its centerstand. 1. Loosen: S Bolt (lower bracket upper) 1 Loosen only the upper bolt. 2. Remove: S Cap bolt 1 Use 17 mm width hexagonal wrench for rem ...
Yamaha YP250 - page 194

7-26 FRONT FORK CHAS CAUTION: 2. Remove:  Inner tube  Oil lock pice 3. Remove:  Oil seal 1 Never reuse the oil seal. 2 Rag YP703030 FRONT FORK INSPECTION 1. Inspect:  Inner tube bending Inner tube bending limit: 0.2 mm Scratches / bends / damage  Replace. Do not attempt to straighten a bent inner tube as this may dangerously weaken t ...
Yamaha YP250 - page 195

7-27 FRONT FORK CHAS 23 Nm (2.3 m S kg) NOTE: NOTE: CAUTION: 2. Install: S Inner tube 1 Into outer tube 2 . 3. Install: S Plain washer 1 S Bolt (damper rod) 2 4. T ighten: S Bolt (damper rod) 1 T ighten damper rod bolt 1 while holding the damper rod with a T -handle 2 and a damper rod holder 3 . Damper rod holder: 90890-04084 T -handle 90890-01326 ...
Yamaha YP250 - page 196

7-28 FRONT FORK CHAS NOTE: NOTE: 7. Inspect: S Inner tube operation Unsmooth operation  Disassembly and recheck. 8. Fill: S Fork oil Oil quantity: 0.142 L Recommended oil: Fork oil 15 WT or equivalent 9. After filling up, slowly pump the fork up and down to distribute the fork oil. 10. Measure: S Oil level a Out of specification  Adjust. Oil ...
Yamaha YP250 - page 197

7-29 FRONT FORK CHAS NOTE: 45 Nm (4.5 m  kg) 23 Nm (2.3 m  kg) EB703050 FRONT FORK INST ALLA TION Reverse the “REMOV AL“ procedure. Note the following points. 1. Install:  Front fork 1 T emporary tighten the pinch bolts. Pull up the inner tube until its end flushes the top of the under bracket 2 , then temporarily tighten the bolt (und ...
Yamaha YP250 - page 198

7-30 HANDLEBAR CHAS Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 Handlebar removal Handlebar upper cover Rear view mirror (right) Rear view mirror (left) Master cylinder bracket Master cylinder Grip end (right) Handlebar switch (right) Throttle cable Grip assembly Brake cable Lever holder (left) 1 1 1 1 1 1 2 1 1 1 Remove the part ...
Yamaha YP250 - page 199

7-31 HANDLEBAR CHAS Order Job name / Part name Q’ty Remarks 11 12 13 14 15 Handlebar switch (left) Grip end (left) Grip Upper handlebar holder Handlebar 1 1 1 2 1 Refer to “HANDLEBAR INST ALLA TION” section. Refer to “HANDLEBAR REMOV AL” section. Refer to “HANDLEBAR INST ALLA TION” section. Reverse the removal procedure for installati ...
Yamaha YP250 - page 200

7-32 HANDLEBAR CHAS ***************************************************** ***************************************************** NOTE: 23 Nm (2.3 m S kg) NOTE: NOTE: YP****** HANDLEBAR REMOV AL 1. Remove: S Grip (Left) Removal steps: D Remove the grip end (left). D Blow with compressed air between the han- dlebar and adhesive side of the grip to re- ...
Yamaha YP250 - page 201

7-33 HANDLEBAR CHAS NOTE: NOTE: NOTE: ***************************************************** ***************************************************** 4. Install: S Handlebar switch (left) 1 Align the handlebar switch mating surface with the punched mark a on the handlebar . 5. Install: S Lever holder (left) 1 Align the lever holder mating surface with ...
Yamaha YP250 - page 202

7-34 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 10 11 Steering removal Handlebar upper cover Front fork Handlebar Nut Handlebar lower holder Woodruf f key Ring nut (upper) Lock washer Ring nut (center) Rubber washer Ring nut (lower) Ball race cover Ball race 1 Lower bracket 1 1 1 1 1 1 1 1 1 1 1 Remove the parts in order . Refer to ...
Yamaha YP250 - page 203

7-35 STEERING CHAS Order Job name / Part name Q’ty Remarks 12 13 14 15 Ball bearing Ball bearing Ball race 1 Ball race 2 22 19 1 1 Refer to “STEERING INST ALLA TION” section. Reverse the removal procedure for installation. 139 Nm (13.9 m  kg) 75 Nm (7.5 m  kg) 1st step: 38 Nm (3.8 m  kg) 2nd step: Loosen the ring nut 1 / 4 turn. 3rd ...
Yamaha YP250 - page 204

7-36 STEERING CHAS NOTE: NOTE: YP704010 STEERING REMOV AL D Securely support the scooter so that there is no danger of it falling over . D Stand the scooter on a level surface. 1. Remove: S Handlebar lower holder 1 S Woodruf f key 2 Remove the handlebar lower holder by loosen- ing the ring nut (upper) 3 gradually . 2. Remove: S Ring nut (upper) S L ...
Yamaha YP250 - page 205

7-37 STEERING CHAS ***************************************************** ***************************************************** NOTE: CAUTION: 139 Nm (13.9 m S kg) NOTE: Bearing race replacement steps: D Remove the bearing races on the head pipe using long rod 1 and the hammer as shown. D Remove the bearing race on the under brack- et using the floo ...
Yamaha YP250 - page 206

7-38 Order Job name / Part name Q’ty Remarks 1 2 3 4 5 6 7 8 9 Rear shock absorber and swingarm removal Side panels Box Nut Muffler assembly Axle nut Rear shock absorber Swingarm Collar Oil seal Bearing 1 2 1 1 1 1 1 1 1 Remove the parts in order . Refer to “COVER AND P ANEL” section in CHAPTER 3. Loosen. Remove with the rear brake applied. R ...
Yamaha YP250 - page 207

CHAPTER 8. ELECTRICAL ELECTRICAL COMPONENTS 8-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CIRCUIT DIAGRAM 8-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CHECKING SWITCHES 8-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CHECKING STEPS 8-4 . . . . . . ...
Yamaha YP250 - page 208

...
Yamaha YP250 - page 209

8-1 ELECTRICAL COMPONENTS ELEC 1 Main switch 2 Ignition coil 3 Spark plug cap 4 Fuel sender 5 Rectifier / Regulator 6 Starting circuit cut-off relay 7 Wireharness 8 Thermo unit 9 Ignitor unit 10 Sidestand switch 11 Battery 12 Starter relay 13 Flasher relay 14 Horn EB800000 ELECTRICAL ELECTRICAL COMPONENTS ...
Yamaha YP250 - page 210

8-2 CIRCUIT DIAGRAM ELEC CIRCUIT DIAGRAM ...
Yamaha YP250 - page 211

8-3 CIRCUIT DIAGRAM ELEC 1 A.C. magneto 2 Rectifier regulator 3 Main switch 4 Battery 5 Main fuse 6 Starter relay 7 Starter motor 8 Thermo switch (auto choke) 9 Auto choke 10 Ignitor unit 11 Ignition coil 12 Spark plug 13 Pickup coil 14 Sidestand switch 15 Starting circuit cut-off relay 16 Lights switch 17 Starter switch 18 Engine stop switch 19 Ha ...
Yamaha YP250 - page 212

8-4 CHECKING SWITCHES ELEC NOTE: YP-N CHECKING SWITCHES CHECKING STEPS Using pocket tester , check switches for continu- ity between their terminals to determine wheth- er they are correctly connected. Repalce the switch component if any of the combinations does not produce the correct reading. Pocket tester: 90890-031 12  T urn the switch to th ...
Yamaha YP250 - page 213

8-5 Before checking a switch refer to the checking switches as shown in the left page and check for the correct terminal connections (closed circuit) according to the color combinations shown in the chart. Poor connection, fault  Repair or replace. * Indicates coupler positions. CHECKING SWITCHES ELEC YP****** SWITCH POSITION AND TERMINAL CONNEC ...
Yamaha YP250 - page 214

8-6 IGNITION SYSTEM ELEC 3 Main switch 4 Battery 5 Main fuse 10 Ignitor unit 11 Ignition coil 12 Spark plug 13 Pickup coil 14 Sidestand switch 18 Engine stop switch EB802000 IGNITION SYSTEM CIRCUIT DIAGRAM ...
Yamaha YP250 - page 215

8-7 IGNITION SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section in CHAPTER 8. Replace the fuse. NO CONTINUITY CONTINUITY YP****** 2. Battery  Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3.  Clean battery terminals.  Recharge or replace the battery . INCORRECT CORRECT YP****** ...
Yamaha YP250 - page 216

8-8 IGNITION SYSTEM ELEC YP****** 4. Ignition spark gap S Disconnect the spark plug cap from the spark plug. S Connect the ignition checker as shown. Spark plug S T urn the main switch to “ON”. S Check the ignition spark gap . S Check the spark by pushing the starter switch, and increase the spark gap until a misfire occurs. MEETS SPECIFICA TIO ...
Yamaha YP250 - page 217

8-9 IGNITION SYSTEM ELEC YP****** 6. Ignition coil resistance S Disconnect the ignition coil connector from the wireharness. S Connect the pocket tester ( Ω 1) to the ignition coil. S Check if the primary coil has the specified re- sistance. S Connect the pocket tester ( Ω 1 k) to the ignition coil. S Check the secondary has the specified re- s ...
Yamaha YP250 - page 218

8-10 IGNITION SYSTEM ELEC YP****** 7. Pickup coil resistance S Disconnect the pickup coil coupler from the wireharness. S Connect the pocket tester ( Ω 100) to the pickup coil coupler . : Pickup coil resistance: 168 X 252 Ω (20 _ C) YP****** 8. Main switch Refer to “CHECKING SWITCHES” section in the CHAPTER 8. NO CONTINUITY Replace the main ...
Yamaha YP250 - page 219

8-1 1 CHARGING SYSTEM ELEC 1 A.C. magneto 2 Rectifier regulator 4 Battery 5 Main fuse YP804000 CHARGING SYSTEM CIRCUIT DIAGRAM ...
Yamaha YP250 - page 220

8-12 CHARGING SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section. Replace the fuse. NO CONTINUITY CONTINUITY YP****** 2. Battery S Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3. S Clean battery terminals. S Recharge or replace the battery . INCORRECT CORRECT : YP804010 TROUBLESHOOTING ...
Yamaha YP250 - page 221

8-13 YP****** 3. Charging voltage S Connect the engine tachometer to the spark plug lead . S Connect the pocket tester (DC20 V) to the battery . S Measure the battery terminal voltage. S Start the engine and accelerate to about 5,000 r / min. S Check the terminal voltage. OUT OF SPECIFICA TION The charging circuit is not faulty . Replace the batter ...
Yamaha YP250 - page 222

8-14 CHARGING SYSTEM ELEC YP****** 4. Starter coil resistance S Remove the A.C. magneto coupler from wireharness. S Connect the pocket tester ( Ω 1) to the sta- tor coil. S Measure the stator coil resistance. Replace the stator coil. OUT OF SPECIFICA TION T ester (+) lead  white terminal T ester (–) lead  White terminal : Stator coil resi ...
Yamaha YP250 - page 223

8-15 ELECTRIC ST ARTING SYSTEM ELEC 3 Main switch 4 Battery 5 Main fuse 6 Starter relay 7 Starter motor 14 Sidestand switch 15 Starting circuit cut-off relay 17 Starter switch 18 Engine stop switch 23 Rear brake switch 24 Front brake switch EB80300 ELECTRIC ST ARTING SYSTEM CIRCUIT DIAGRAM ...
Yamaha YP250 - page 224

8-16 ELECTRICAL ST ARTING SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section in CHAPTER 8. Replace the fuse. NO CONTINUITY CONTINUITY YP****** 2. Battery S Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3. S Clean the battery terminals. S Recharge or replace battery . INCORRECT CORRECT : ...
Yamaha YP250 - page 225

8-17 ELECTRICAL ST ARTING SYSTEM ELEC YP****** 3. Starter motor S Connect the battery positive terminal and starter motor cable using a jumper lead. S Check the starter motor operation. CONTINUITY Repair or replace the starter motor . DOES NOT MOVE : : YP****** 4. Starter relay S Disconnect the relay unit coupler from the wireharness. S Connect the ...
Yamaha YP250 - page 226

8-18 : YP****** 6. Main switch Refer to “CHECKING SWITCHES” section. NO CONTINUITY Replace the main switch. CONTINUITY YP****** 7. Engine stop switch Refer to “CHECKING SWITCHES” section. NO CONTINUITY Replace the right handlebar switch. CONTINUITY YP****** 8. Sidestand switch Refer to “CHECKING SWITCHES” section. NO CONTINUITY Replace ...
Yamaha YP250 - page 227

8-19 ELECTRICAL ST ARTING SYSTEM ELEC Order Job name / Part name Q’ty Remarks 1 Starter motor removal Air cleaner case Starter motor 1 Remove the parts in order . Refer to “ENGINE REMOV AL AND INST ALLA TION” section in CHAPTER 4. Reverse the removal procedure for instal- lation. 7 Nm (0.7 m S kg) 7 Nm (0.7 m S kg) 10 Nm (1.0 m S kg) 5 Nm (0. ...
Yamaha YP250 - page 228

8-20 ELECTRICAL ST ARTING SYSTEM ELEC NOTE: Good condition Bad condition A B f  f  f   f YP803034 Inspection and repair 1. Inspect: S Commutator Dirt  Clean it with #600 grit sandpaper . 2. Measure: S Commutator diameter a Commutator wear limit: 27 mm Out of specification  Replace the starter motor 3. Measure: S Mica undercut a Mi ...
Yamaha YP250 - page 229

8-21 ELECTRICAL ST ARTING SYSTEM ELEC NOTE: 5 Nm (0.5 m  kg) NOTE: Brush spring force: 570 X 920 g 7. Inspect:  Bearing  Oil seal Wear / damage  Repalce. YP****** Assembly Reverse the “Removal” procedure. Note the following points. 1. Install:  Brush holder 1 Align the projection a on the brush seat with the slot b on the housing ...
Yamaha YP250 - page 230

8-22 3 Main switch 4 Battery 5 Main fuse 16 Lights switch 29 Dimmer switch 30 Pass switch 32 T ail / Brake light 33 Licence light 36 Head light 39 Auxiliary light 40 Meter lights LIGHTING SYSTEM ELEC EB804000 LIGHTING SYSTEM CIRCUIT DIAGRAM ...
Yamaha YP250 - page 231

8-23 LIGHTING SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section. Repalce the fuse. NO CONTINUITY CONTINUITY : YP****** 2. Battery S Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3. S Clean battery terminals. S Recharge or replace battery . INCORRECT CORRECT YP****** 3. Main switch Refer ...
Yamaha YP250 - page 232

8-24 YP****** 5. Dimmer switch / Pass switch Refer to “CHECKING SWITCHES” section. Replace the left handlebar switch. NO CONTINUITY : YP****** 6. Wiring connection S Check the connections of the entire lighting system. Refer to “WIRING DIAGRAM”. Correct. POOR CONNECTIONS Check the condition of each of the lighting system’s circuits. Refer ...
Yamaha YP250 - page 233

8-25 LIGHTING SYSTEM ELEC YP805021 1. Bulb and bulb socket Refer to “CHECKING SWITCHES” section. Replace the bulb and / or bulb socket. NO CONTINUITY : 2. V oltage S Connect the pocket tester (DC20 V) to the bulb socket coupler . T ester (+) lead  Blue terminal T ester (–) lead  Black terminal S T urn the main switch to on. S T urn the ...
Yamaha YP250 - page 234

8-26 LIGHTING SYSTEM ELEC 1. Bulb and bulb socket Refer to “CHECKING SWITCHES” section. Replace the bulb and / or bulb socket. NO CONTINUITY 2. V oltage S Connect the pocket tester (DC20 V) to the bulb socket connector . T ester (+) lead  Blue terminal T ester (–) lead  Black terminal S T urn the main switch to on. S T urn the lights sw ...
Yamaha YP250 - page 235

8-27 LIGHTING SYSTEM ELEC 1. Bulb and bulb socket Refer to “CHECKING SWITCHES” section. Replace the bulb and / or bulb socket. NO CONTINUITY 2. V oltage S Connect the pocket tester (DC20 V) to the bulb socket connector . T ester (+) lead  Blue terminal T ester (–) lead  Black terminal S T urn the main switch to on. S T urn the lights sw ...
Yamaha YP250 - page 236

8-28 SIGNAL SYSTEM ELEC 3 Main switch 4 Battery 5 Main fuse 23 Rear brake switch 24 Front brake switch 25 Flasher relay 26 Horn 27 T urn switch 28 Horn switch 33 T ail / Brake light 34 Rear flasher lights 35 Front flasher lights 38 T urn indicator lights 43 Fuel gauge 49 Fuel sender EB806000 SIGNAL SYSTEM CIRCUIT DIAGRAM ...
Yamaha YP250 - page 237

8-29 SIGNAL SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section. Replace the fuse. NO CONTINUITY CONTINUITY : YP****** 2. Battery S Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3. S Clean battery terminals. S Recharge or replace battery . INCORRECT CORRECT YP****** 3. Main switch Refer t ...
Yamaha YP250 - page 238

8-30 SIGNAL SYSTEM ELEC YP****** 4. Wireharness S Check the connections of the entire signal system. Refer to “CIRCUIT SYSTEM WIRING DIA- GRAM” section. Correct. POOR CONNECTION : Check condition of each of the signal sys- tem’s circuits. Refer to “SIGNAL SYSTEM CHECK” section. CONTINUITY ...
Yamaha YP250 - page 239

8-31 SIGNAL SYSTEM ELEC 1. HORN switch Refer to “CHECKING SWITCHES” section. CONTINUITY Replace the left handlebar switch. NO CONTINUITY 2. V oltage S Connect the pocket tester (DC20 V) to the horn lead. T ester (+) lead  Brown terminal . T ester (–) lead  Frame ground 1 MEETS SPECIFICA TION S T urn the main switch to on. S Check for vo ...
Yamaha YP250 - page 240

8-32 1. Bulb and bulb socket Refer to “CHECKING SWITCHES” section. Replace the bulb and / or bulb socket. NO CONTINUITY 3. V oltage S Connect the pocket tester (DC20 V) to the bulb socket connector . T ester (+) lead  Blue terminal T ester (–) lead  Black terminal S T urn the main switch to on. S The brake lever is pulled in. S Check fo ...
Yamaha YP250 - page 241

8-33 1. Bulb and bulb socket Refer to “CHECKING SWITCHES” section. MEETS SPECIFICA TION Replace the bulb and / or bulb socket. NO CONTINUITY 3. V oltage S Connect the pocket tester (DC20 V) to the flasher relay coupler . T ester (+) lead  Brown terminal . T ester (–) lead  Frame ground 1 MEETS SPECIFICA TION S T urn the main switch to o ...
Yamaha YP250 - page 242

8-34 6. Wiring connection S Wiring circuit from the turn switch to bulb socket connector is fault. Repair . Refer to “CIRCUIT DIAGRAM”. 5. V oltage S Connect the pocket tester (DC20 V) to the bulb socket connector . At flasher light (left) T ester (+) lead  Chocolate lead T ester (–) lead  Black terminal S T urn the main switch to on. S ...
Yamaha YP250 - page 243

8-35 SIGNAL SYSTEM ELEC Float position Specificated resistance UP 4 X 10 Ω 90 X 100 Ω DOWN 1. Fuel sender S Remove the fuel sender from the fuel tank. S Disconnect the fuel sender coupler from the wireharness. Connect the pocket tester ( Ω 10) to the fuel sender coupler lead. 2. V oltage S Connect the pocket tester (DC20 V) to the fuel gauge ...
Yamaha YP250 - page 244

8-36 Float “UP” “F” “E” Float “DOWN” 3. Fuel gauge S Connect the fuel sender to wireharness. S Move the float to “UP” or “DOWN” . 1 S T urn the main switch to “ON”. S Check the fuel gauge needle moves “F” or “E”. Replace the fuel gauge. DOES NOT MOVE 2 MOVES : Float position Needle moves This circuit is not fault ...
Yamaha YP250 - page 245

8-37 3 Main switch 4 Battery 5 Main fuse 20 Fuse (fan) 21 Thermo switch 22 Fan motor 46 Thermo meter 50 Thermo unit COOLING SYSTEM ELEC YP80700 COOLING SYSTEM CIRCUIT DIAGRAM ...
Yamaha YP250 - page 246

8-38 COOLING SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section. Replace the fuse. NO CONTINUITY CONTINUITY : YP****** 2. Battery S Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3. S Clean battery terminals. S Recharge or replace battery . INCORRET CORRECT YP****** 3. Main switch Refer t ...
Yamaha YP250 - page 247

8-39 COOLING SYSTEM ELEC 4. Fan motor (inspection 1)  Disconnect the fan motor couplers.  Cconnect the battery as shown. Battery (+) lead  Blue terminal Battery (–) lead  Black terminal 1 MOVES  Check the fan motor operation. Replace fan motor . DOES NOT MOVE 5. Fan motor (inspection 2)  T urn the main switch to on.  Remove t ...
Yamaha YP250 - page 248

8-40 COOLING SYSTEM ELEC S Handle the thermo switch with special care. Never subject it to strong shocks or allow it to be dropped. Should it be dropped, it must be replaced. S Do not touch the thermo switch to the bottom of the heated vessel. 7. Wiring connection S Check the connection of the entire cooling system. Refer to “CIRCUIT DIAGRAM” s ...
Yamaha YP250 - page 249

8-41 COOLING SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section. Replace the fuse. NO CONTINUITY CONTINUITY : YP****** 2. Battery S Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3. S Clean battery terminals. S Recharge or replace battery . INCORRET CORRECT YP****** 3. Main switch Refer t ...
Yamaha YP250 - page 250

8-42 D Handle the thermo unit with special care. Never subject it to strong shocks or al- low it to be dropped. Should it be dropped, it must be replaced. D Do not touch the thermo unit to the bot- tom of the heated vessel. 80 _ C 47.5 X 56.8 Ω 26.2 X 29.3 Ω 100 _ C 4. Thermo unit S Drain the coolant, and remove the thermo unit from the radiato ...
Yamaha YP250 - page 251

8-43 YP****** 6. Wiring connection S Check the connections of the entire cooling system. Refer to “CIRCUIT DIAGRAM” section. Correct. POOR CONNECTION : Replace the temperature gauge. CORRECT COOLING SYSTEM ELEC ...
Yamaha YP250 - page 252

8-44 3 Main switch 4 Battery 5 Main fuse 8 Thermo switch (auto choke) 9 Auto choke 10 Ignitor unit 18 Engine stop switch AUT O CHOKE SYSTEM ELEC YP****** AUT O CHOKE SYSTEM CIRCUIT DIAGRAM ...
Yamaha YP250 - page 253

8-45 AUT O CHOKE SYSTEM ELEC NOTE: YP****** 1. Fuse Refer to “CHECKING SWITCHES” section. Repalce the fuse. NO CONTINUITY CONTINUITY : YP****** 2. Battery S Check the battery condition. Refer to “BA TTERY INSPECTION” section in CHAPTER 3. S Clean battery terminals. S Recharge or replace battery . INCORRECT CORRECT YP****** 3. Main switch Re ...
Yamaha YP250 - page 254

8-46 AUT O CHOKE SYSTEM ELEC S Disconnect the thermo switch from the ra- diator . S Connect the pocket tester ( Ω 1) to the thermo switch . S Immerse the thermo switch in the coolant . S Check the thermo switch for continuity . Note temperatures while heating the water with the temperature gauge . S Handle the thermo switch with special care. Nev ...
Yamaha YP250 - page 255

8-47 YP****** 6. Auto choke unit resistance S Disconnect the auto choke unit coupler from the wireharness. S Connect the pocket tester ( Ω 1) to the auto choke unit coupler lead. : Auto choke unit resistance: 16 X 24 Ω (20 _ C) T ester (+) lead  Black terminal T ester (–) lead  Black terminal 1 2 Replace the auto choke unit. OUT OF SPEC ...
Yamaha YP250 - page 256

ELEC ...
Yamaha YP250 - page 257

CHAPTER 9. TROUBLESHOOTING ST ARTING F AILURE / HARD ST ARTING 9-1 . . . . . . . . . . . . . . . . . . . . . . . . . . FUEL SYSTEM 9-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COMPRESSION SYSTEM 9-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IGNITION SYSTEM 9-2 . . . . . . ...
Yamaha YP250 - page 258

...
Yamaha YP250 - page 259

9-1 ST ARTING F AILURE / HARD ST ARTING TRBL SHTG NOTE: EB90000 TROUBLESHOOTING The following troubleshooting does not cover all the possible causes of trouble. It should be helpful, however , as a guide to troubleshooting. Refer to the relative procedure in this manual for inspection, adjustment and replacement of parts. YP90000 ST ARTING F AILURE ...
Yamaha YP250 - page 260

9-2 POOR IDLE SPEED PERFORMANCE TRBL SHTG IGNITION SYSTEM Battery  Improperly charged battery  Faulty battery Fuse  Burnt out, improper connection Spark plug  Improper plug gap  Worn electrodes  Wire between terminals broken  Improper heat range  Worn electrodes  Faulty spark plug cap Ignition coil  Broken or shorted p ...
Yamaha YP250 - page 261

9-3 POOR MEDIUM AND HIGH SPEED PERFORMANCE TRBL SHTG EB902000 POOR MEDIUM AND HIGH SPEED PERFORMANCE POOR MEDIUM AND HIGH SPEED PERFORMANCE Refer to “ST ARTING F AILURE / HARD ST AR TING” section. (Fuel system, electrical system, compres- sion system and valve train) Carburetor  Improperly adjusted fuel level  Clogged main nozzle  Clog ...
Yamaha YP250 - page 262

9-4 F AUL TY CLUTCH TRBL SHTG YP****** F AUL TY CLUTCH WHEN ENGINE IS RUN, SCOOTER DOES NOT RUN V belt  Worn / bent / slipping Cam, slider  Worn / damaged Compression spring  Damage Gears  Damage YP904000 CLUTCH SLIPPING Clutch weight spring  Worn / loose Clutch shoe  Worn / damaged Primary sliding sheave  Seized YP****** POOR ...
Yamaha YP250 - page 263

9-5 OVERHEA TING OR OVER COOLING TRBL SHTG YP905000 OVERHEA TING OR OVER COOLING OVERHEA TING Ignition system  Improper spark plug gap  Improper spark plug heat range  Faulty ignitor unit Fuel system  Improper carburetor setting  Improper fuel level adjustment  Clogged air cleaner element Compression system  Heavy carbon deposi ...
Yamaha YP250 - page 264

9-6 F AUL TY BRAKE / FRONT FORK MALFUNCTION TRBL SHTG YP906000 F AUL TY BRAKE POOR BRAKING EFFECT Front brake  Worn brake pad  Worn brake disc  Air in brake fluid  Leaking brake fluid  Faulty master cylinder kit  Faulty caliper seal kit  Loose union bolt  Broken brake hose  Oily or greasy brake pad  Oily or greasy brak ...
Yamaha YP250 - page 265

9-7 INST ABLE HANDLING / ST ARTER MOTOR DOES NOT OPERA TE TRBL SHTG YP908000 INST ABLE HANDLING INST ABLE HANDLING Handlebars  Loose handlebar tightening bolt Steering  Loose or overtightening steering nut  Bent under bracket  Damaged bearing or ball race Front forks  Uneven oil levels on both sides  Broken front fork spring  T ...
Yamaha YP250 - page 266

9-8 F AUL TY SIGNAL AND LIGHTING SYSTEM TRBL SHTG YP909000 F AUL TY SIGNAL AND LIGHTING SYSTEM HEADLIGHT DARK  Improper bulb  T oo many electric accesories  Hard charging  Faulty rectifier / regulator  Faulty battery  Improperly connected coupler , connector , wireharness  Improperly grounded  Faulty main switch or Lights (d ...
Yamaha YP250 - page 267

1. A.C. magneto 2. Rectifier / regulator 3. Main switch 4. Main fuse 5. Battery 6. Starter relay 7 Starter motor 8 Thermo switch (auto choke) 9. Auto choke 10. Ignitor unit 1 1. Ignition coil 12. Spark plug 13. Pickup coil 14. Sidestand switch 15. Starting circuit cut-off relay 16. Lights switch 17. Starter switch 18. Engine stop switch 19. Handleb ...

Manufacturer Yamaha Category Mobility Scooter

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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 YP250.

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A complete manual for the device Yamaha YP250, 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 YP250 by users. Manuals are usually written by a technical writer, but in a language understandable to all users of Yamaha YP250.

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 YP250 - 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 YP250, 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 YP250, that we can find in the current document
3. Tips how to use the basic functions of the device Yamaha YP250 - which should help us in our first steps of using Yamaha YP250
4. Troubleshooting - systematic sequence of activities that will help us diagnose and subsequently solve the most important problems with Yamaha YP250
5. FAQ - Frequently Asked Questions
6. Contact detailsInformation about where to look for contact to the manufacturer/service of Yamaha YP250 in a specific country, if it was not possible to solve the problem on our own.

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