Manual Yamaha WR250FM

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  • Yamaha WR250FM - page 1

    LIT-11626-16-48 WR250FR 5UM-28199-10 OWNER’S SERVICE MANUAL ...

  • Yamaha WR250FM - page 2

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  • Yamaha WR250FM - page 3

    WR250FR OWNER’S SERVICE MANUAL ©2002 by Yamaha Motor Corporation, U.S.A. 1st Edition, November 2002 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Corporation U.S.A. is expressly prohibited. Printed in Japan P/N. LIT-11626-16-48 ...

  • Yamaha WR250FM - page 4

    EC020000 INTRODUCTION Congratulations on your purchase of a Yamaha WR series. This model is the culmina- tion of Yamaha’s vast experience in the pro- duction of pacesetting racing machines. It represents the highest grade of craf tsmanship and reliability that have made Yamaha a leader. This manual explains operation, inspection, basic maintenanc ...

  • Yamaha WR250FM - page 5

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  • Yamaha WR250FM - page 6

    IMPORTANT NOTICE THIS MACHINE IS DESIGNED STRICTLY FOR COMPETITION USE, ONLY ON A CLOSED COURSE. It is illegal for this machine to be operated on any public street, road, or highway. Off-road use on public lan ds may also be illegal. Please check local regula- tions before riding. 1. THIS MACHINE IS TO BE OPERATED BY AN EXPERIENCED RIDER ONLY. Do n ...

  • Yamaha WR250FM - page 7

    6. GASOLINE CAN CAUSE INJURY. If you should swallow some gasoline, inhale excess gasoline va pors, or allow any gasoline to get into your eyes, contact a doctor immediatel y. If any gasoline spills onto your skin or clothing, immediately wash skin areas with soap and wate r, and change your clothes. 7. ONLY OPERATE THE MACHINE IN AN AREA WITH ADEQU ...

  • Yamaha WR250FM - page 8

    EC050000 TO THE NEW OWNER This manual will provide you with a good basic understanding of features, operation, and basic maintenance and inspe ction items of this machine. Please read this ma nual carefully and completely before operating your new machine. If you have any questions regarding the operation or maintenance of yo ur machine, please con ...

  • Yamaha WR250FM - page 9

    EC080000 HOW TO USE THIS MANUAL EC081000 PARTICULARLY IMPORTANT INFORMATION The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY IS INVOLVED! Failure to follow WARNING instructions could result in severe injury or death to the machine operator, a bystander, or a person inspecting or repairing the machine. A CAUTION indicates special p ...

  • Yamaha WR250FM - page 10

    EC083000 MANUAL FORMAT All of the procedures in this manual are organized in a sequential, step-by-step fo rmat. The informa- tion has been complied to provide the mechanic with an easy to read, handy reference th at contains comprehensive explanations of all disassembly, repair, assembly, and inspect ion operations. In this revised format, the con ...

  • Yamaha WR250FM - page 11

    ILLUSTRATED SYMBOLS (Refer to the illustration) Illustrated symbols 1 to 7 are designed as thumb tabs to indicate the chapter ’ s number and content. 1 General information 2 Specifications 3 Regular inspectio n and adjustme nts 4 Engine 5 Chassis 6 Electrical 7 Tuning Illustrated symbols 8 to D are used to identify the specifications appearing in ...

  • Yamaha WR250FM - page 12

    MEMO ...

  • Yamaha WR250FM - page 13

    EC090000 INDEX GENERAL INFORMATION 1 SPECIFICATIONS SPEC 2 REGULAR INSPECTION AND ADJUSTMENTS 3 ENGINE ENG 4 CHASSIS CHAS 5 ELECTRICAL ELEC 6 TUNING TUN 7 GEN INFO INSP ADJ – + ...

  • Yamaha WR250FM - page 14

    EC0A0000 CONTENTS CHAPTER 1 GENERAL INFORMATION DESCRIPTION .......................................... 1-1 MACHINE IDENTIFICATION .................... 1-2 IMPORTANT INFORMATION ................... 1-3 CHECKING OF CONNECTION ................ 1-6 SPECIAL TOOLS ...................................... 1-7 CONTROL FUNCTIONS ......................... 1-10 ...

  • Yamaha WR250FM - page 15

    CHAPTER 4 ENGINE SEAT, FUEL TANK AND SIDE COVERS ............................... ........... 4-1 EXHAUST PIPE AND SILENCER ............ 4-3 RADIATOR ............................................... . 4-5 CARBURETOR ......................................... 4-8 CAMSHAFTS ...................... .................... 4-22 CYLINDER HEAD ................. ...

  • Yamaha WR250FM - page 16

    CHAPTER 6 ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ................................... 6-1 MAP-CONTROLLED CDI UNIT ................ 6-2 IGNITION SYSTEM ... ................................ 6-3 ELECTRIC STARTING SYSTEM .............. 6-8 CHARGING SYSTEM ............................. 6-17 THROTTLE POSITION SENSOR SYSTEM ................... ...

  • Yamaha WR250FM - page 17

    GEN INFO 1 - 1 DESCRIPTION EC100000 GENERAL INFORMATION EC110000 DESCRIPTION 1 Clutch lever 2 Hot starter lever 3 Engine stop switch 4 Trip meter 5 Main switch 6 Light switch 7 Start switch 8 Front brake lever 9 Throttle grip 0 Radiator cap A Fuel tank cap B Taillight C Kickstarter crank D Fuel tank E Headlight F Radiator G Coolant drain bolt H Rea ...

  • Yamaha WR250FM - page 18

    1 - 2 GEN INFO MACHINE IDENTIFICATION EC120001 MACHINE IDENTIFICATION There are two significant reasons fo r knowing the serial number of your machine: 1. When ordering parts, you can give the number to your Yamaha dealer for positive identification of the model you own. 2. If your machine is stolen, the auth orities will need the number to search ...

  • Yamaha WR250FM - page 19

    1 - 3 GEN INFO IMPORTANT INFORMATION EC130000 IMPORTANT INFORMATION EC131010 PREPARATION FOR REMOVAL AND DISASSEMBLY 1. Remove all dirt, mud, dust, and foreign material before removal and disassembly. When washing the machine with high pre s- sured water, cover the parts follows. • Silencer exhaust port • Side cover air intake port • Water pu ...

  • Yamaha WR250FM - page 20

    1 - 4 GEN INFO IMPORTANT INFORMATION EC132000 ALL REPLACEMENT PARTS 1. We recommend to use Yamaha genuine parts for all replacements. Use oil an d/or grease recommended by Yamaha for assembly and adjustment. EC133000 GASKETS, OIL SEALS AND O-RINGS 1. All gaskets, oil seals, and O-rings should be replaced when an engine is overhauled. All gasket sur ...

  • Yamaha WR250FM - page 21

    1 - 5 GEN INFO IMPORTANT INFORMATION EC136000 CIRCLIPS 1. All circlips should be inspected carefully before reassembly. Always replace piston pin clips after one use. Replace distorted circlips. When installing a circlip 1 , make sure that the sharp-edged corn er 2 is posi- tioned opposite to the thrust 3 it rece ives. See the sectional view. 4 Sha ...

  • Yamaha WR250FM - page 22

    1 - 6 GEN INFO CHECKING OF CONNECTION EC1C0001 CHECKING OF CONNECTION Dealing with stains, rust, moisture, etc. on the connector. 1. Disconnect: • Connector 2. Dry each terminal with an air blower. 3. Connect and disconnect the connector two or three times. 4. Pull the lead to check that it will not come off. 5. If the terminal comes off, bend up ...

  • Yamaha WR250FM - page 23

    GEN INFO 1 - 7 SPECIAL TOOLS SPECIAL TOOLS The proper special tools are ne cessary for complete and accu rate tune-up and assembly. Using the correct special tool will help prevent damage caused b y the use of improper tools or improvised techniques. The shape a nd part number used f or the special tool differ by country, so t wo types are provided ...

  • Yamaha WR250FM - page 24

    GEN INFO 1 - 8 SPECIAL TOOLS YM-01442, 90890-01442 Fork seal driver This tool is used when install the fork oil seal. YU-3112-C, 90890-03112 Pocket tester Use this tool to inspect the coil resistance, output voltage and amperage. YU-8036-B 90890-03113 Inductive tachometer Engine tachometer This tool is needed for observing engine rpm. YM-33277-A, 9 ...

  • Yamaha WR250FM - page 25

    GEN INFO 1 - 9 SPECIAL TOOLS YM-04141, 90890-04141 Rotor puller This tool is used to remove the flywheel magneto. YM-34487 90890-06754 Dynamic spark tester Ignition checker This instrument is necessary for checking the ignition system components. ACC-QUICK-GS-KT 90890-85505 Quick ga sket  YAMAHA Bond No. 1215 This sealant (Bond) is used for cran ...

  • Yamaha WR250FM - page 26

    1 - 10 GEN INFO CONTROL FUNCTIONS EC150000 CONTROL FUNCTIONS MAIN SWITCH Functions of the respective switch positions are as follows: ON: The engine can be started only at this position. OFF: All electrical circuits are switched off. Main switch indicator light The main switch 1 is equipped with an indica- tor light 2 to avoid forgetting to turn it ...

  • Yamaha WR250FM - page 27

    1 - 11 GEN INFO CONTROL FUNCTIONS EC152000 CLUTCH LEVER The clutch lever 1 is located on the left han- dlebar; it disengage s or engages the clutch. Pull the clutch lever to the handlebar to disen- gage the clutch, and release th e lever to engage the clutch. The lever should be pulled rapidly and released slowly for smooth starts. EC153000 SHIFT P ...

  • Yamaha WR250FM - page 28

    1 - 12 GEN INFO CONTROL FUNCTIONS EC157000 REAR BRAKE PEDAL The rear brake pedal 1 is located on the right side of the machine. Press down on the brake pedal to activate the rear brake . FUEL COCK The fuel cock supplies fuel from the tank to carburetor and also filters the fue l. The fuel cock has three positions: OFF: With the lever in this positi ...

  • Yamaha WR250FM - page 29

    1 - 13 GEN INFO LIGHT SWITCH The light switch 1 is located on the h andlebar. EC15F000 VALVE JOINT This valve joint 1 prevents fuel from flowing out and is installed to the fuel tank breather hose. CAUTION: In this installation, make sure the arrow faces the fuel tank and also downward. SPARK PLUG WRENCH This spark plug wrench 1 is used to remove a ...

  • Yamaha WR250FM - page 30

    1 - 14 GEN INFO FUEL Always use the recommended fuel as stated below. Also, be sure to use new gasoline the day of a race. CAUTION: Use only unleaded gasoline. The use of leaded gasoline will cause s evere damage to the engine internal parts such a s valves, piston rings, and exhaust system , etc. N OTE: If knocking or pinging occurs, use a differe ...

  • Yamaha WR250FM - page 31

    1 - 15 GEN INFO STARTING AND BREAK-IN STARTING AND BREAK-IN W ARNING Never start or run the e ngine in a closed area. The exhaust fumes are poisonous; they can cause loss o f consciousness and death in a very short time. Always operate the machine in a well-ventilated area. CAUTION: • The carburetor on this machine has a built-in accelerator pump ...

  • Yamaha WR250FM - page 32

    1 - 16 GEN INFO STARTING AND BREAK-IN N OTE: If the engine fails to start by pushin g the start switch, release the switch, wait a few seconds, and then try again. Each starting attempt should be as short as possible to preserve the battery. Do not cra nk the engine more t han 10 seconds on any one attempt. If the engine does not start with the sta ...

  • Yamaha WR250FM - page 33

    1 - 17 GEN INFO STARTING AND BREAK-IN STARTING A WARM ENGINE Do not operate the cold starter kno b and throt- tle. Pull the hot starter lever 1 an d start the engine by pushing the start switch or by kick- ing the kickstarter crank forcefully with a firm stroke. As soon as the engine starts, Release the hot starter lever to close th e air passage. ...

  • Yamaha WR250FM - page 34

    1 - 18 GEN INFO BREAK-IN PROCEDURES 1. Before starting the engine, fill the fuel tank with the fuel. 2. Perform the pre-operat ion checks on the machine. 3. Start and warm up the engine. Check the idle speed, and check the ope ration of the controls and the engine stop swit ch. Then, restart the engine and check its operation within no more than 5 ...

  • Yamaha WR250FM - page 35

    GEN INFO 1 - 19 TORQUE-CHECK POINTS TORQUE-CHECK POINTS Frame construct ion Combined seat a nd fuel tank Exhaust system Engine mountin g Steering Steering stem t o handlebar Suspension Front Steering st em to front fork Rear For link type Rear Installa tion of rear shock absorber Rear Installation of swing- arm Wheel Installation of wh eel Front Re ...

  • Yamaha WR250FM - page 36

    1 - 20 GEN INFO CLEANING AND STORAGE EC1B0000 CLEANING AND STORAGE EC1B1000 CLEANING Frequent cleaning of your machine will enhance its appearance, maintain good overall performance, and extend the life of man y com- ponents. 1. Before washing the machine, block off the end of the exhaust pipe to pre vent water from entering. A plastic b ag secured ...

  • Yamaha WR250FM - page 37

    1 - 21 GEN INFO CLEANING AND STORAGE EC1B2001 STORAGE If your machine is to be st ored for 60 days or more, some preventive measures must be taken to avoid deterioration. After cleaning the machine thoroughly, prepare it for storage as follows: 1. Drain the fuel tank, fuel lines, and the car- buretor float bowl. 2. Remove the spark plug , pour a ta ...

  • Yamaha WR250FM - page 38

    SPEC 2 - 1 GENERAL SPECIFICATIONS EC200000 SPECIFICATIONS EC211000 GENERAL SPECIFICATIONS Model name: WR250FR (USA) WR250F (EUROPE) WR250F(R) (CDN, AUS, NZ, ZA) Model code number: 5UM1 (USA) 5UM2 (EUROPE) 5UM4 (CDN, AUS, NZ, ZA) Dimensions: Overall length 2,165 mm (85.2 in) Overall width 827 mm (32.6 in) Overall height 1,303 mm (51.3 in) Seat heigh ...

  • Yamaha WR250FM - page 39

    SPEC 2 - 2 GENERAL SPECIFICATIONS Oil capacity: Engine oil Periodic oil change 1.2 L (1.06 Imp qt, 1.27 US q t) With oil filter replacement 1.3 L (1.14 Imp qt, 1.37 US q t) Total amount 1.4 L (1.23 Imp qt, 1.48 US qt) Coolant capacity (including all routes): 1.3 L (1.14 Imp qt, 1.37 US q t) Air filter: Wet type element Fuel: Type Premium unleaded g ...

  • Yamaha WR250FM - page 40

    SPEC 2 - 3 GENERAL SPECIFICATIONS Brake: Front brake type Single disc brake Operation Right hand operation Rear brake type Single disc brake Operation Right foot operation Suspension: Front suspension Telescopic fork Rear suspension Swingarm (link type monocross suspension) Shock absorber: Front shock absorber Coil spring/oil damper Rear shock abso ...

  • Yamaha WR250FM - page 41

    SPEC 2 - 4 MAINTENANCE SPECIFICATIONS MAINTENANCE SPECIFICATIONS ENGINE Item Standard Limit Cylinder head: Warp limit ---- 0.05 mm (0.002 in) Cylinder: Bore size 77.00 ~ 77.01 mm (3.0315 ~ 3.0319 in) ---- Out of round limit ---- 0.05 mm (0.002 in) Camshaft: Drive method Chain drive (Left) ---- Camshaft cap inside diamete r 22.000 ~ 22.021 mm (0.866 ...

  • Yamaha WR250FM - page 42

    SPEC 2 - 5 MAINTENANCE SPECIFICATIONS Timing chain: Timing chain type/No. of links 92RH2010-114M/114 ---- Timing chain adjustment method Automatic ---- Valve, valve seat, valve guide: Valve clearance (cold) IN 0.10 ~ 0.15 mm (0.0039 ~ 0.0059 in) ---- EX 0.17 ~ 0.22 mm (0.0067 ~ 0.0087 in) ---- Valve dimensions: “ A ” head diameter IN 22.9 ~ 23. ...

  • Yamaha WR250FM - page 43

    SPEC 2 - 6 MAINTENANCE SPECIFICATIONS Stem runout limit ---- 0.01 mm (0.0004 in) Valve seat width IN 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in) 1.6 mm (0.0630 in) EX 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in) 1.6 mm (0.0630 in) Valve spring: Free length IN 37.81 mm (1.49 in) 35.9 mm (1.41 in) EX 37.54 mm (1.48 in) 35.7 mm (1.41 in) Set length (valve closed) IN 29.13 ...

  • Yamaha WR250FM - page 44

    SPEC 2 - 7 MAINTENANCE SPECIFICATIONS Piston pin bore inside diameter 16.002 ~ 16.013 mm (0.6300 ~ 0.6304 in) 16.043 mm (0.6316 in) Piston pin outside diameter 15.991 ~ 16.000 mm (0.6296 ~ 0.6299 in) 15.971 mm (0.6288 in) Piston rings: Top ring: Type Barrel ---- Dimensions (B × T) 0.90 × 2.75 mm (0.04 × 0.11 in) ---- End gap (installed) 0.15 ~ 0 ...

  • Yamaha WR250FM - page 45

    SPEC 2 - 8 MAINTENANCE SPECIFICATIONS Clutch: Friction plate thickness 2.9 ~ 3.1 mm (0.114 ~ 0.122 in) 2.7 mm (0.106 in) Quantity 9 ---- Clutch plate thickness 1.1 ~ 1.3 mm (0.043 ~ 0.051 in) ---- Quantity 8 ---- Warp limit ---- 0.1 mm (0.004 in) Clutch spring free length 37.0 mm (1.46 in) 36.0 mm (1.42 in) Quantity 5 ---- Clutch housing thrust cle ...

  • Yamaha WR250FM - page 46

    SPEC 2 - 9 MAINTENANCE SPECIFICATIONS Lubrication system: Oil filter type Paper type ---- Oil pump type Trochoid type ---- Tip clearance 0.12 mm or less (0.0047 in or less) 0.20 mm (0.008 in) Side clearance 0.09 ~ 0.17 mm (0.0035 ~ 0.0067 in) 0.24 mm (0.009 in) Housing and rotor clearance 0.03 ~ 0.10 mm (0.0012 ~ 0.0039 in) 0.17 mm (0.0067 in) Cool ...

  • Yamaha WR250FM - page 47

    SPEC 2 - 10 MAINTENANCE SPECIFICATIONS Part to be tightened Thread size Q ’ ty Tightening torque Nm m · kg ft · lb Spark plug M10S × 1.0 1 13 1.3 9.4 Camshaft cap M 6 × 1.0 1 0 10 1.0 7.2 Cylinder head blind plug screw M12 × 1.0 1 37 3.7 27 Cylinder head (stud bolt) M6 × 1.0 2 7 0.7 5.1 (stud bolt) M8 × 1.25 1 15 1.5 11 (bolt) M9 × 1.25 4 ...

  • Yamaha WR250FM - page 48

    SPEC 2 - 11 MAINTENANCE SPECIFICATIONS N OTE: - marked portion shall be checked for torque tightening after break-in o r before each race. Silencer M8 × 1.25 2 35 3.5 25 Silencer clamp M8 × 1.25 1 19 1.9 13 Spark arrester (for USA) M6 × 1.0 3 10 1.0 7.2 Silencer end pipe (for USA) M6 × 1.0 1 10 1.0 7.2 Crankcase M6 × 1.0 11 12 1.2 8.7 Crankcas ...

  • Yamaha WR250FM - page 49

    SPEC 2 - 12 MAINTENANCE SPECIFICATIONS CHASSIS Item Standard Limit Steering system: Steering bearing type Taper roller bearing ---- Front suspension: USA, CDN EUROPE AUS, NZ, ZA Front fork travel 300 mm (11.8 in) ←← Fork spring free length 460 mm (18.1 in) ←← Spring rate, STD K = 4.31 N/mm (0.44 kg/mm, 24.6 lb/in) K = 4.12 N/mm (0.42 kg/mm, ...

  • Yamaha WR250FM - page 50

    SPEC 2 - 13 MAINTENANCE SPECIFICATIONS Wheel: USA, CDN, ZA EUROPE, AUS, NZ Front wheel type Spoke wheel ← ---- Rear wheel type Spoke wheel ← ---- Front rim size/material 21 × 1.60/Aluminum ← ---- Rear rim size/material 18 × 1.85/Aluminum 18 × 2.15/Aluminum ---- Rim runout limit: Radial ---- ---- 2.0 mm (0.08 in) Lateral ---- ---- 2.0 mm (0 ...

  • Yamaha WR250FM - page 51

    SPEC 2 - 14 MAINTENANCE SPECIFICATIONS N OTE: 1. First, tighten the steering nut approximately 38 Nm (3.8 m • kg, 27 ft • lb) by using the steering nut wrench, then loosen the steering nut one tu rn. 2. Retighten the steering nut 7 Nm (0.7 m • kg, 5.1 ft • lb). Part to be tightened Thread size Q ’ ty Tightening torque Nm m · kg ft · lb ...

  • Yamaha WR250FM - page 52

    SPEC 2 - 15 MAINTENANCE SPECIFICATIONS Part to be tightened Thread size Q ’ ty Tightening torque Nm m · kg ft · lb Nipple (spoke) — 72 3 0.3 2.2 Rear wheel sprocket M8 × 1.25 6 50 5.0 36 Rear brake disc cover M6 × 1.0 2 7 0.7 5.1 Rear brake caliper protector M6 × 1.0 2 7 0.7 5.1 Drive chain puller adjust bolt and locknut M8 × 1.25 2 16 1. ...

  • Yamaha WR250FM - page 53

    SPEC 2 - 16 MAINTENANCE SPECIFICATIONS N OTE: - marked portion shall be checked for torque tightening after break-in o r before each race. Headlight (left and right) M6 × 1.0 2 10 1.0 7.2 Headlight (lower) M6 × 1.0 1 7 0.7 5.1 Taillight M6 × 1.0 3 4 0.4 2.9 Taillight lead clamp and rear fende r M4 × 1.59 2 0.5 0.05 0.36 Coolant reservoir M6 × ...

  • Yamaha WR250FM - page 54

    SPEC 2 - 17 MAINTENANCE SPECIFICATIONS EC212300 ELECTRICAL Item Standard Limit Ignition system: Advancer type Electrical ---- CDI: Pickup coil resistance (color) 248 ~ 372 Ω at 20 ° C (68 ° F) (White – Red) ---- CDI unit-model/manufacturer 5UM-00/YAMAHA (For USA) ---- 5UM-10/YAMAHA (Except for USA) ---- Ignition coil: Model/manufacturer 5UL-0 ...

  • Yamaha WR250FM - page 55

    SPEC 2 - 18 MAINTENANCE SPECIFICATIONS Starter relay: Model/manufacturer 2768090-A/JIDECO ---- Amperage rating 180 A ---- Coil winding resistance 4.2 ~ 4.6 Ω at 20 °C (68 °F) ---- Starting circuit cut-off relay: Model/manufacturer ACM33221 M06/MATSUSHITA ---- Coil winding resistance 75.69 ~ 92.51 Ω at 20 °C (68 °F) ---- Fuse (amperage × qu ...

  • Yamaha WR250FM - page 56

    SPEC 2 - 19 EC220001 GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasten- ers with standard I.S.O. pitch threads. Torque specifications for special compone nts or assemblies are included in the applicable sec- tions of this book. To avoid warpa ge, tighten multi-fastener assemblies in a crisscross fa sh- ion, in progressiv ...

  • Yamaha WR250FM - page 57

    2 - 20 SPEC CABLE ROUTING DIAGRAM EC240000 CABLE ROUTING DIAGRAM 1 Fuel tank breath er hose 2 Oil tank breather hose 3 Clamp 4 Diode 5 Wire harness 6 Hot starter cable 7 Throttle position sensor lead 8 Neutral switch lead 9 Oil hose 0 Hose guide A AC magneto lead B Cylinder head breather hose C Starter moto r lead D Clutch cable E Radiator hose 1 F ...

  • Yamaha WR250FM - page 58

    2 - 21 SPEC CABLE ROUTING DIAGRAM È Insert the fuel tank breather ho se into the hole in the steering ste m cap. É Pass the oil tank breather hose on t he outside of the AC magneto le ad, neutral switch lead, light switch lead, wire harness, starter motor lea d, neg- ative battery lead and cylinder he ad breather hose. Ê Fasten the diode and rec ...

  • Yamaha WR250FM - page 59

    2 - 22 SPEC Î Fasten the wire harn ess at its white tape. Ï Fasten the wire harne ss, throttle position senso r lead (in the wire harness), starter motor lead and negative batt ery lead. Ð Make sure that the throttle position sensor coupler does not go outside the chassis. Ñ Fasten the throttle po sition sensor lead. Ò Pass the carbur etor bre ...

  • Yamaha WR250FM - page 60

    2 - 23 SPEC CABLE ROUTING DIAGRAM × Pass the cylinder h ead breather hose on the inside of the ra diator hose 1 an d on the outside of the radiator pip e (radiator hose 4). Make sure that the cylinder head breath er hose does not go for- ward of the chassis. Ø Pass the starter mo tor lead in front of the radia tor hose 4. Ù Pass the clutch cable ...

  • Yamaha WR250FM - page 61

    2 - 24 SPEC CABLE ROUTING DIAGRAM 1 Hot starter cable 2 Cable guide 3 Throttle cabl e (return) 4 Throttle cable (pull) 5 Ignition coil 6 Coolant reser voir breather hose 7 Rectifier/regulator 8 Coolant reserv oir hose 9 Rectifier/regulator lead 0 Clamp A CDI unit lead B CDI unit C CDI unit band D CDI unit stay E Rectifier/regulator bracket È Pass ...

  • Yamaha WR250FM - page 62

    2 - 25 SPEC CABLE ROUTING DIAGRAM Ì Fasten the coolant reser voir breather hose and carburetor brea ther hoses togethe r. Í Fasten the CDI unit lead. Î Insert the CDI unit b and over the CDI un it stay as far as possible. Ï Fasten the rectifier/regulator lead to the rectifier/ regulator bracket with a plastic locking tie and cut off the ti e en ...

  • Yamaha WR250FM - page 63

    2 - 26 SPEC CABLE ROUTING DIAGRAM 1 Brake master cylinder 2 Brake hose holder 3 Brake hose È Install the br ake hose s o that its pipe port ion directs as shown an d lightly touches th e projection on the brake caliper. É Pass the brake hose into the brake hose hold ers. Ê If the brake hose contacts the sprin g (rear shock absorber), co rrect it ...

  • Yamaha WR250FM - page 64

    2 - 27 SPEC CABLE ROUTING DIAGRAM 1 Starter moto r lead 2 Negative batte ry lead 3 Wire harness 4 Clamp 5 Taillight lead 6 Coolant reservo ir breather hose 7 Coolant reserv oir hose 8 Positive battery lead 9 Starting circuit c ut-off relay 0 Battery È Position the sta rter motor lead, n egative battery lead and wire harness in the ta nk damper sli ...

  • Yamaha WR250FM - page 65

    2 - 28 SPEC CABLE ROUTING DIAGRAM 1 Throttle cable 2 Brake hose 3 Clamp 4 Light switch lead 5 Hot starter cable 6 Clutch cable 7 Hose guide 8 Clutch switch lead 9 Engine stop switch lead 0 Trip meter cable A Main switch lead B Trip meter C Main switch D Light switch E Start switch lead È Fasten the start switch lead and light switch lead. É Faste ...

  • Yamaha WR250FM - page 66

    3 - 1 INSP ADJ MAINTENANCE INTERVALS EC300000 REGULAR INSPECTION AND ADJUSTMENTS MAINTENANCE INTERVALS The following schedule is intende d as a general guide to maintenance and lubrication. Bear in mind that such factors as weather, terrain, geographical location, and individual usage will alter the required maintenance and lubrication interva ls. ...

  • Yamaha WR250FM - page 67

    3 - 2 INSP ADJ MAINTENANCE INTERVALS SHIFT FORK, SHIFT CAM, GUIDE BAR Inspect Inspect wea r ROTOR NUT Retighten EXHAUST PIPE, SILENCER, PROTECTOR Inspect and retigh ten Clean Replace * Whichever comes first *SPARK ARRESTER Clean (Every six months) CRANK Inspect and clean CARBURETOR Inspect, adju st and clean SPARK PLUG Inspect and clean Replace DRI ...

  • Yamaha WR250FM - page 68

    3 - 3 INSP ADJ MAINTENANCE INTERVALS *marked: For USA FRONT FORKS Inspect and adjust Replace oil Suspension oil “ 01 ” Replace oil seal FRONT FORK OIL SEAL AND DUST SEAL Clean and lube Lithium base grea se REAR SHOCK ABSORBER Inspect and adjust Lube (After rain ride) Molybdenum d isulfide grease Retighten DRIVE CHAIN GUIDE AND ROLLER S Inspect ...

  • Yamaha WR250FM - page 69

    3 - 4 INSP ADJ PRE-OPERATION INSPECTION AND MAINTENANCE EC320000 PRE-OPERATION INSPECTION AND MAINTENANCE Before riding for break-in operation , practice or a race, make sure the machine is in good operating condition. Before using this machine, check the following poin ts. GENERAL INSPECTION AND MAINTENANC E Item Routine Page Coolant Check that co ...

  • Yamaha WR250FM - page 70

    3 - 5 INSP ADJ EC350000 ENGINE COOLANT LEVEL INSPECTION W ARNING Do not remove the radiator cap 1 , drain bolt and hoses when the engine and radia- tor are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury. When the engine has cooled, place a thick towel over the radiator cap, slowl y rotate the cap ...

  • Yamaha WR250FM - page 71

    3 - 6 INSP ADJ COOLANT REPLACEMENT CAUTION: Take care so that coolant does not splash on painted surfaces. If it splashes, wash it away with water. 1. Place a container under the engine. 2. Remove: • Seat Refer to “ SEAT, FUEL TANK AND SIDE COVERS ” section in the CHAPTER 4. 3. Disconnect: • Coolant reservoir hose 1 Drain the coolant comple ...

  • Yamaha WR250FM - page 72

    3 - 7 INSP ADJ COOLANT REPLACEMENT 9. Fill: • Radiator • Engine To specified level. CAUTION: • Do not mix more than one type of ethyl- ene glycol antifreeze containing corro- sion inhibitors for aluminum engine. • Do not use wa ter containing impurities or oil . Recommended coolant: High quality ethylene glycol anti-freeze containing anti-c ...

  • Yamaha WR250FM - page 73

    3 - 8 INSP ADJ RADIATOR CAP INSPECTION/ RADIATOR CAP OPENING PRESS URE INSPECTION 12. Install: • Coolant reservoir cap 13. Start the engine and let it warm up for sev- eral minutes. 14. Turn off the engine and inspect the coolant level. Refer to “ COOLANT LEVEL INSPECTION ” section. N OTE: Before checking the co olant level wait a few minutes ...

  • Yamaha WR250FM - page 74

    3 - 9 INSP ADJ COOLING SYSTEM INSPECTION/ CLUTCH ADJUSTMENT 2. Apply the specified pressure. 3. Inspect: • Pressure Impossible to maintain the specified pre s- sure for 10 seconds → Replace. Radiator cap opening pressure: 110 kPa (1.1 kg/cm 2 , 15.6 psi) COOLING SYSTEM INSPECTION 1. Inspect: • Coolant level 2. Attach: • Radiator cap te ster ...

  • Yamaha WR250FM - page 75

    3 - 10 INSP ADJ THROTTLE CABLE ADJUSTMENT 2. Adjust: • Clutch lever free play N OTE: • Make minute adjustment on the lever side using the adjuster 2 . • After adjustment, check proper operation of clutch lever. Clutch lever free play adjustment steps: • Loosen the locknuts 1 . • Adjust the free play by changing their tight- ening position ...

  • Yamaha WR250FM - page 76

    3 - 11 INSP ADJ THROTTLE LUBRICATION/ HOT STARTER LEVER ADJUSTMENT THROTTLE LUBRICATION 1. Remove: • Cover (throttle cable cap) 1 • Cover (grip cap) 2 • Throttle grip cap 3 2. Apply: • Lithium soap base grease On the throttle cable end a . 3. Install: • Throttle grip cap • Screw (throttle grip cap) • Cover (grip cap) • Cover (thrott ...

  • Yamaha WR250FM - page 77

    3 - 12 INSP ADJ AIR FILTER CLEANING AIR FILTER CLEANING N OTE: Proper air filter maintenance is the biggest key to preventing premature engine wear and damage. CAUTION: Never run the engine without the air filter element in place; this would allow dirt and dust to enter the engine and cause rapid wear and possible engine da mage. 1. Remove: • Air ...

  • Yamaha WR250FM - page 78

    3 - 13 INSP ADJ CAUTION: • Do not twist the element when squeezing the element. • Leaving too much of solvent in the ele- ment may result in poor starting. 5. Inspect: • Air filter element Damage → Replace. 6. Apply: • Foam-air-filter oil or equivalent oil to the element N OTE: • Squeeze out the excess oil. Element should be wet but not ...

  • Yamaha WR250FM - page 79

    3 - 14 INSP ADJ ENGINE OIL LEVEL INSPECTION ENGINE OIL LEVEL INSPECTION 1. Start the engine, warm it up for several minutes, and then turn off the engine and wait for five minutes. 2. Place the machine on a level place and hold it up on upright position by placin g the suitable stand under the engine. 3. Remove: • Oil tank cap 1 1 4. Inspect: • ...

  • Yamaha WR250FM - page 80

    3 - 15 INSP ADJ ENGINE OIL REPLACEMENT (Except for USA and CDN) CAUTION: • Do not add any chemical additives or use oils with a grade of CD a or higher. • Do not use oils labeled “ ENERGY CON- SERVING II ” b or higher. Engine oil also lubricates the clutch and additives could cause clutch slippage. • Do not allow foreign materials to ente ...

  • Yamaha WR250FM - page 81

    3 - 16 INSP ADJ ENGINE OIL REPLACEMENT 4. Remove: • Oil tank cap 1 • Oil filler cap 2 • Frame oil drain bolt 3 • Crankcase oil drain bolt 4 • Oil filter element drain bolt 5 Drain the crankcase and oil tank (frame) of its oil. 5. Remove: • Lower engine bracket • Oil hose clamp 1 • Bolt (oil hose) 2 • Oil hose 3 • Oil strainer (f ...

  • Yamaha WR250FM - page 82

    3 - 17 INSP ADJ 8. Install: • Copper washer 1 • Oil strainer (frame) 2 • Oil hose 3 • Bolt (oil hose) 4 • Oil hose clamp 5 • Lower engine bracket 9. Install: • Copper washer • Oil filter element drain bolt • Crankcase oil drain bolt • Frame oil drain bolt 10. Fill: • Engine oil 11. Check: • Oil leakage 12. Install: • Oil t ...

  • Yamaha WR250FM - page 83

    3 - 18 INSP ADJ OIL PRESSURE INSPECTION 1. Check: • Oil pressure Checking steps: • Slightly loosen the oil pressure check bolt 1 . • Start the engine and keep it idling until oil starts to seep from the oil pressure check bolt. If no oil comes out after one minute, turn the engine off so it will not seize. • Check oil passages and oil pump ...

  • Yamaha WR250FM - page 84

    3 - 19 INSP ADJ ENGINE IDLING SPEED ADJUSTMENT/ VALVE CLEARANCE INSPECTION AND ADJUSTMENT ENGINE IDLING SPEED ADJUSTMENT 1. Start the engine and thoroughly warm it up. 2. Attach: • Inductive tachometer To spark plug lead. 3. Adjust: • Engine idling speed Adjustment steps: • Adjust the pilot screw. Refer to “ PILOT SCREW ADJUSTMENT ” secti ...

  • Yamaha WR250FM - page 85

    3 - 20 INSP ADJ VALVE CLEARANCE INSPECTION AND ADJUSTMENT 3. Remove: • Right radiator Refer to “ RADIA TOR ” section in the CHAPTER 4. • Carburetor Refer to “ CARBURETOR ” section in the CHAPTER 4. • Spark plug • Upper engine bracket • Cylinder head cover Refer to “ CAMSHAFTS ” section in the CHAPTER 4. 4. Remove: • Timing m ...

  • Yamaha WR250FM - page 86

    3 - 21 INSP ADJ VALVE CLEARANCE INSPECTION AND ADJUSTMENT • Measure the valve clearance e using a feeler gauge 1 . N OTE: Record the measured reading if the clear- ance is incorrect. 6. Adjust: • Valve clearance Adjustment steps: • Remove the camshaft (intake and exhau st). Refer to “ CAMSHAFT S ” section in the CHAPTER 4. • Remove the ...

  • Yamaha WR250FM - page 87

    3 - 22 INSP ADJ VALVE CLEARANCE INSPECTION AND ADJUSTMENT N OTE: The thickness a of each pad is indicated in hundreths of millimeters on the pad upper surface. • Round off the last digit o f the installed pad number to the nearest increment. Last digit of pad number Rounded value 0, 1 or 2 0 4, 5 or 6 5 8 or 9 10 EXAMPLE: Installed pad number = 1 ...

  • Yamaha WR250FM - page 88

    3 - 23 INSP ADJ INTAKE EXHAUST MEASURED CLEARA NCE INSTALLED PAD NUMBER 120 125 130 135 140 145 150 155 160 165 17 0 175 180 185 190 195 200 205 210 215 220 225 230 235 240 0.00 ~ 0.04 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 0.05 ~ 0.09 120 125 130 135 140 145 150 15 5 160 165 170 175 180 185 190 ...

  • Yamaha WR250FM - page 89

    3 - 24 INSP ADJ SPARK ARRESTER CLEANING (For USA) W ARNING • Be sure the exhaust pipe and muffler are cool before cleaning the spark arrest er. • Do not start the engine when cleaning the exhaust system. 1. Remove: • Bolt (spark arrester) 1 1 1 2. Remove: • Spark arrester 1 Pull the spark a rrester out of the muffler. 1 3. Clean: • Spark ...

  • Yamaha WR250FM - page 90

    3 - 25 INSP ADJ EC360000 CHASSIS EC361012 BRAKE SYSTEM AIR BLEEDING W ARNING Bleed the brake system if: • The system has been disassembl ed. • A brake hose has been loosened or removed. • The brake fluid is very lo w. • The brake operation is fa ulty. A dangerous loss of braking performance may occur if the brake system is not prop- erly bl ...

  • Yamaha WR250FM - page 91

    3 - 26 INSP ADJ FRONT BRAKE ADJUSTMENT 3. Install: • Protector (rear brake) • Diaphragm • Brake master cylinder cap N OTE: If bleeding is difficult, it may be necessary to let the brake fluid system stabilize for a few hours. Repeat the bleeding procedure when the tiny bubbles in the system have disap- peared. j. Add brake fluid to the le vel ...

  • Yamaha WR250FM - page 92

    3 - 27 INSP ADJ REAR BRAKE ADJUSTMENT/ FRONT BRAKE PAD INSPECTION AND REPLACEMENT EC364002 REAR BRAKE ADJUSTMENT 1. Check: • Brake pedal height a Out of specification → Adjust. Brake pedal height a : 5 mm (0.20 in) 2. Adjust: • Brake pedal height Pedal height adjustment steps: • Loosen the locknut 1 . • Turn the adjusting nut 2 until the ...

  • Yamaha WR250FM - page 93

    3 - 28 INSP ADJ FRONT BRAKE PAD INSPECTION AND REPLACEMENT • Loosen the pad pin 2 . • Remove the brake hose holder 3 and brake caliper 4 from the front fork. • Remove the pad pin and brake pa ds 5 . • Connect the transparent hose 6 to the bleed screw 7 and place the suitable con- tainer under its end. • Loosen the bleed screw a nd push th ...

  • Yamaha WR250FM - page 94

    3 - 29 INSP ADJ REAR BRAKE PAD INSPECTION AND REPLACEMENT 3. Inspect: • Brake fluid level Refer to “ BRAKE FLUID LEVEL INSPEC- TION ” section. • Install the pad pin plug B . T R . . Pad pin plug: 3 Nm (0.3 m • kg, 2.2 ft • lb) 4. Check: • Brake lever operation A softy or spongy feeling → Bleed brake system. Refer to “ BRAKE SYSTEM ...

  • Yamaha WR250FM - page 95

    3 - 30 INSP ADJ REAR BRAKE PAD INSPECTION AND REPLACEMENT • Remove the pad pin 6 and brake pads 7 . • Connect the transparent hose 8 to the bleed screw 9 and place the suitable con- tainer under its end. • Loosen the bleed screw a nd push the brake caliper piston in. CAUTION: Do not reuse the drained brake fluid. • Tighten the bleed screw. ...

  • Yamaha WR250FM - page 96

    3 - 31 INSP ADJ REAR BRAKE PAD INSULATOR INSPECTION/ BRAKE FLUID LEVEL INSPECTION 3. Inspect: • Brake fluid level Refer to “ BRAKE FLUID LEVEL INSPEC- TION ” section. 4. Check: • Brake pedal operation A softy or spongy feeling → Bleed brake system. Refer to “ BRAKE SYSTEM AIR BLEED- ING ” section. EC36b000 REAR BRAKE PAD INSULATOR INS ...

  • Yamaha WR250FM - page 97

    3 - 32 INSP ADJ SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION SPROCKETS INSPECTION 1. Inspect: • Sprocket teeth a Excessive wea r → Replace. N OTE: Replace the drive sprocket, rear wheel sprocket and drive chain as a set. DRIVE CHAIN INSPECTION 1. Remove: • Drive chain 1 N OTE: Remove the drive chain using a drive chain cutter 2 . 2. Clean: • ...

  • Yamaha WR250FM - page 98

    3 - 33 INSP ADJ DRIVE CHAIN INSPECTION 5. Check: • Drive chain stiffness a Clean and oil the dr ive chain and hold as illustrated. Stiff → Replace the drive chain. 6. Install: • Chain joint 1 • O-ring 2 • Drive chain 3 N OTE: When installing the drive chain, ap ply the lith- ium soap base grease on the chain joint and O-rings. New 7. Inst ...

  • Yamaha WR250FM - page 99

    3 - 34 INSP ADJ DRIVE CHAIN SLACK ADJUSTMENT DRIVE CHAIN SLACK ADJUSTMENT 1. Elevate the rear wheel by placing the su it- able stand under the engine. 2. Check: • Drive chain slack a Above the seal guard installat ion bolt. Out of specification → Adjust. N OTE: Before checking and/or adjusting, rotate the rear wheel through several revolutions ...

  • Yamaha WR250FM - page 100

    3 - 35 INSP ADJ FRONT FORK INSPECTION/ FRONT FORK OIL SEAL AND DUST SEAL CLEANING • Tighten the axle nut while pushing down the drive chain. T R . . Axle nut: 125 Nm (12.5 m • kg, 90 ft • lb) • Tighten the locknuts. T R . . Locknut: 16 Nm (1.6 m • kg, 11 ft • lb) EC36C000 FRONT FORK INSPECTION 1. Inspect: • Front fork smooth action Op ...

  • Yamaha WR250FM - page 101

    3 - 36 INSP ADJ FRONT FORK INTERNAL PRESSURE RELIEVING/FRONT FORK REBOUND DAMPING FORCE ADJUSTMENT FRONT FORK INTERNAL PRESSURE RELIEVING N OTE: If the front fork initial movement feels stiff dur- ing a run, relieve the front fork internal pres- sure. 1. Elevate the front wheel by placing a suit- able stand under the engine. 2. Remove the air bleed ...

  • Yamaha WR250FM - page 102

    3 - 37 INSP ADJ FRONT FORK COMPRESSION DAMPING FORCE ADJUSTMENT • STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position. * For EUROPE, AUS, NZ and ZA CAUTION: Do not force the adjuster past the minimum or maximum extent of adjustment. The adjuster may be damaged. W ARNING Always ...

  • Yamaha WR250FM - page 103

    3 - 38 INSP ADJ REAR SHOCK ABSORBER INSPECTION • STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position. * For EUROPE, AUS, NZ and ZA CAUTION: Do not force the adjuster past the minimum or maximum extent of adjustment. The adjuster may be damaged. W ARNING Always adjust each fron ...

  • Yamaha WR250FM - page 104

    3 - 39 INSP ADJ REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT 1. Elevate the rear wheel by placing the su it- able stand under the engine. 2. Remove: • Rear frame 3. Loosen: • Locknut 1 4. Adjust: • Spring preload By turning the adjuster 2 . * For EUROPE N OTE: • Be sure to remove all dirt and m ...

  • Yamaha WR250FM - page 105

    3 - 40 INSP ADJ REAR SHOCK ABSORBER REBOUND DAMPING FORCE ADJUSTMENT EC36N014 REAR SHOCK ABSORBER REBOUND DAMPING FORCE ADJUSTMENT 1. Adjust: • Rebound damping f orce By turning the adjuster 1 . Stiffer a → Increase the rebound damp- ing force. (Turn the adjuster 1 i n.) Softer b → Decrease the rebound damp- ing force. (Turn the adjuster 1 ou ...

  • Yamaha WR250FM - page 106

    3 - 41 INSP ADJ EC36c000 REAR SHOCK ABSORBER LOW COMPRESSION DAMPING FORCE ADJUSTMENT 1. Adjust: • Low compression damping force By turning the adjuster 1 . Stiffer a → Increase the low compres- sion damping force. (Turn the adjuster 1 in.) Softer b → Decrease the low compres- sion damping force. (Turn the adjuster 1 out.) Extent of adjustmen ...

  • Yamaha WR250FM - page 107

    3 - 42 INSP ADJ REAR SHOCK ABSORBER HIGH COMPRESSION DAMPING FORCE ADJUSTMENT EC36d000 REAR SHOCK ABSORBER HIGH COMPRESSION DAMPING FORCE ADJUSTMENT 1. Adjust: • High compression damping force By turning the adjuster 1 . Stiffer a → Increase the high compres- sion damping force. (Turn the adjuster 1 in.) Softer b → Decrease the high compres- ...

  • Yamaha WR250FM - page 108

    3 - 43 INSP ADJ TIRE PRESSURE CHECK/SPOKES INSPECTION AND TIGHTENING/WHEEL INSPECTION EC36Q000 TIRE PRESSURE CHECK 1. Measure: • Tire pressure Out of specification → Adjust. N OTE: • Check the tire while it is co ld. • Loose bead stoppers allow th e tire to slip off its position on the rim when the tire pressure is low. • A tilted tire va ...

  • Yamaha WR250FM - page 109

    3 - 44 INSP ADJ STEERING HEAD INSPECTION AND ADJUSTMENT 2. Inspect: • Bearing free play Exist play → Replace. EC36U013 STEERING HEAD INSPECTION AND ADJUSTMENT 1. Elevate the front wheel by placing a suit- able stand under the engine. 2. Check: • Steer ing stem Grasp the bottom of the forks and gently rock the fork assembly back and forth. Fre ...

  • Yamaha WR250FM - page 110

    3 - 45 INSP ADJ • Tighten the steering ring nut 3 using steering nut wrench 4 . N OTE: Set the torque wrench to the stee ring nut wrench so that they form a right angle. Steering nut wrench: YU-33975/90890-01403 T R . . Steering ring nut (initi al tightening): 38 Nm (3.8 m • kg, 27 ft • lb) • Loosen the steering ring nut on e turn. • Reti ...

  • Yamaha WR250FM - page 111

    3 - 46 INSP ADJ LUBRICATION LUBRICATION To ensure smooth operation of all components, lubricate your machine durin g setup, after break-in, and after every race. 1 All control cable 2 Clutch lever pivot 3 Shift pedal pivot 4 Footrest pivot 5 Throttle-to- handlebar cont act 6 Drive chain 7 Tube guide cable wind ing portion 8 Throttle cable end 9 Clu ...

  • Yamaha WR250FM - page 112

    3 - 47 INSP ADJ ELECTRICAL/SPARK PLUG INSPECTION / IGNITION TIMING CHECK EC370000 ELECTRICAL EC371001 SPARK PLUG INSPECTION 1. Remove: • Spark plug 2. Inspect: • Electrode 1 Wear/damage → Replace. • Insulator color 2 Normal condition is a mediu m to light tan color. Distinctly differen t color → Check the engine condition. N OTE: When the ...

  • Yamaha WR250FM - page 113

    3 - 48 INSP ADJ IGNITION TIMING CHECK 2. Attach: • Timing light • Inductive tachometer To the ignition coil lead (orange le ad 1 ). Timing light: YM-33277-A/90890-03141 Inductive tachometer: YU-8036-B Engine tachometer: 90890-03113 1 3. Check: • Ignition timing 4. Install: • Timing mark accessing screw Checking steps: • Start the engine a ...

  • Yamaha WR250FM - page 114

    3 - 49 INSP ADJ BATTERY INSPECTION AND CHARGING W ARNING Batteries generate explosive hydrogen gas and contain electrolyte which is made of poisonous and highly caustic sulfuric acid. Therefore, always follow these preventive measures: • Wear protective eye gear when handling or working near batteries. • Charge batteries in a well-ventilated ar ...

  • Yamaha WR250FM - page 115

    3 - 50 INSP ADJ BATTERY INSPECTION AND CHARGING N OTE: Since MF batteries are sealed, it is not possi- ble to check the charge state of the battery by measuring the specific gravity of the electro- lyte. Therefore, the charge of the battery has to be checked by measuring the voltage at the battery terminals. 1. Remove: • Seat 2. Disconnect: • B ...

  • Yamaha WR250FM - page 116

    3 - 51 INSP ADJ BATTERY INSPECTION AND CHARGING 4. Measure: • Battery charge È Relationship between the open-circuit voltage and the charging t ime at 20 ° C (68 ° F) (These values var y with the te mperature, th e condition of the batt ery plates, and the elect ro- lyte level.) É Open-circuit voltage Ê Charging time ( hours) Ë Time (minute ...

  • Yamaha WR250FM - page 117

    3 - 52 INSP ADJ BATTERY INSPECTION AND CHARGING 5. Charge: • Battery (refer to the appropriate charging method illustration) W ARNING Do not quick charge a battery. CAUTION: • Never remove the MF battery sealing caps. • Do not use a high-rate battery charger since it forces a high-amperage current into the battery quickly and can cause batter ...

  • Yamaha WR250FM - page 118

    3 - 53 INSP ADJ BATTERY INSPECTION AND CHARGING Charging method using a variable voltage ch arger ...

  • Yamaha WR250FM - page 119

    3 - 54 INSP ADJ BATTERY INSPECTION AND CHARGING Charging method using a constant voltage charger ...

  • Yamaha WR250FM - page 120

    3 - 55 INSP ADJ BATTERY REPLACEMENT/FUSE INSPECTION 6. Install: • Battery • Battery band 7. Connect: • Battery leads (to the battery terminals) CAUTION: First, connect the positive lead 1 , then the negative lead 2 . 8. Check: • Battery terminals Dirt → Clean with a wire b rush. Loose connection → Connect properly. 9. Lubricate: • Bat ...

  • Yamaha WR250FM - page 121

    3 - 56 INSP ADJ FUSE INSPECTION 2. Check: • Continuity 2 Reserve fuse Checking steps: • Remove the fuse 1 . • Connect the pocket tester to the fuse and check the continuity. N OTE: Set the pocket tester selector to “ Ω × 1 ” . Pocket tester: YU-3112-C/90890-03112 • If the pocket tester indicates “ ∞ ” , replace the fuse. 2 1 3. ...

  • Yamaha WR250FM - page 122

    3 - 57 INSP ADJ REPLACING THE HEADLIGHT BULBS/ ADJUSTING THE HEADLIGHT BEAMS REPLACING THE HEADLIGHT BULBS 1. Remove: • Headlight Refer to “ SEAT, FUEL TANK AND SIDE COVERS ” section in the CHAPTER 4. 2. Remove: • Headlight bulb holder cover 1 3. Detach: • Headlight bulb holder 1 4. Remove: • Headlight bulb 2 W ARNING Since the headligh ...

  • Yamaha WR250FM - page 123

    4 - 1 ENG EC400000 ENGINE SEAT, FUEL TANK AND SIDE COVERS Extent of removal: 1 Seat removal 2 Fuel tank removal 3 Side covers removal 4 Headlight removal Extent of removal Order Part name Q ’ ty Remarks SEAT, FUEL TANK AND SIDE COVERS REMOVAL Preparation for removal Turn the fuel cock to “ OFF ” . Disconnect the fuel hose. 1S e a t 1 2 Air sc ...

  • Yamaha WR250FM - page 124

    4 - 2 ENG REMOVAL POINTS Side cover 1. Remove: • Bolt (side cover) • Left side cover 1 • Right side cover 2 N OTE: Draw the side cover down ward to remove it because its claws a are inserted in th e air fil- ter case. SEAT, FUEL TANK AND SIDE COVERS ...

  • Yamaha WR250FM - page 125

    4 - 3 ENG EXHAUST PIPE AND SILENCER EC4S0000 EXHAUST PIPE AND SILENCER È Except for USA Extent of removal: 1 Silencer removal 2 Exhaust pipe removal Extent of removal Order Part name Q ’ ty Remarks EXHAUST PIPE AND SILENCER REMOVAL Preparation for removal Right side cover Refer to “ SEAT, FUEL TANK A ND SIDE COVERS ” section. 1 Bolt (silence ...

  • Yamaha WR250FM - page 126

    4 - 4 ENG EXHAUST PIPE AND SILENCER INSPECTION Silencer and exhaust pipe 1. Inspect: • Gasket 1 Damage → Replace. 1 ASSEMBLY AND INSTALLATION Silencer and exhaust pipe 1. Install: • Gasket • Exhaust pipe 1 • Nut (exhaust pipe ) 2 • Bolt (exhaust pipe) 3 N OTE: First, temporarily tighten the nut (exhaust pipe), then tighten the bolt (exh ...

  • Yamaha WR250FM - page 127

    4 - 5 ENG RADIATOR EC450001 RADIATOR Extent of removal: 1 Radiator removal Extent of removal Order Part name Q ’ ty Remarks RADIATOR REMOVAL Preparation for removal Drain the coolant. Refer to “ COOLANT REPLACEMENT ” section in the CHAPTER 3. Seat, fuel tank and left side cover Refer to “ SE AT, FUEL TANK AND SIDE COVERS ” section. 1 Radi ...

  • Yamaha WR250FM - page 128

    4 - 6 ENG RADIATOR EC456000 HANDLING NOTE W ARNING Do not remove the radiator cap when the engine and radiator are ho t. Scalding hot fluid and steam may be blown o ut under pressure, which could cause serious injury. When the engine has cooled, open the radi- ator cap by the following procedure: Place a thick rag, like a towel, over the radi- ator ...

  • Yamaha WR250FM - page 129

    4 - 7 ENG RADIATOR 3. Install: • Right radiator 1 • Bolt (right radiator) 2 • Radiator hose 3 3 Refer to “ CABLE ROUT ING DIAGRAM ” section in the CHAPTER 2. T R . . 10 Nm (1.0 m · kg, 7.2 ft · lb) 4. Install: • Left radiator 1 • Bolt (left radiator) 2 • Radiator hose 1 3 Refer to “ CABLE ROUT ING DIAGRAM ” section in the CHAP ...

  • Yamaha WR250FM - page 130

    4 - 8 ENG CARBURETOR CARBURETOR 9 7 8 1 T R . . 2 Nm (0.2 m • kg, 1.4 ft • Ib) T R . . 11 Nm (1.1 m • kg, 8.0 ft • Ib) T R . . 4 Nm (0.4 m • kg, 2.9 ft • Ib) 5 1 2 6 6 4 4 3 T R . . 3 Nm (0.3 m • kg, 2.2 ft • Ib) T R . . 3 Nm (0.3 m • kg, 2.2 ft • Ib) T R . . 4 Nm (0.4 m • kg, 2.9 ft • Ib) Extent of removal: 1 Carburetor rem ...

  • Yamaha WR250FM - page 131

    4 - 9 ENG CARBURETOR EC468000 CARBURETOR DISASSEMBLY Extent of removal: 1 Carbure tor disassembly Extent of removal Order Part name Q ’ ty Remarks CARBURETOR DISASSEMBLY 1 Carburetor breather hose 4 2 Valve lever ho using cover 1 3 Screw (throttle shaft) 1 4 Throttle valve 1 5 Needle holder 1 6 Jet needle 1 7 Accelerator pump cover 1 8 Spring 1 9 ...

  • Yamaha WR250FM - page 132

    4 - 10 ENG CARBURETOR Extent of removal Order Part name Q ’ ty Remarks F Float pin 1 G Float 1 H Needle valve 1 I Main jet 1 J Needle jet 1 K Spacer 1 L Pilot jet 1 M Starter jet 1 N Push rod 1 Pull the push rod. O Throttle shaft assembly 1 P Push rod link le ver assembly 1 Q Pilot air jet 1 R Cold starter p lunger 1 1 ...

  • Yamaha WR250FM - page 133

    4 - 11 ENG CARBURETOR HANDLING NOTE CAUTION: Do not loosen the screws (throttle position sensor) 1 except when changing the throt- tle position sensor due to failure because it will cause a drop in engine performance. 1 REMOVAL POINTS Pilot screw 1. Remove: • Pilot screw 1 N OTE: To optimize the fuel flow at a small throt tle opening, each machin ...

  • Yamaha WR250FM - page 134

    4 - 12 ENG CARBURETOR 2. Inspect: • Main jet 1 • Pilot jet 2 • Needle jet 3 • Starter jet 4 • Pilot air jet 5 • Leak jet 6 Damage → Replace. Contamination → Clean. N OTE: • Use a petroleum based solvent for cleaning. Blow out all passages and jets with com- pressed air. • Never use a wire. Needle valve 1. Inspect: • Needle val ...

  • Yamaha WR250FM - page 135

    4 - 13 ENG CARBURETOR Float height 1. Measure: • Float height a Out of specification → Adjust. Float height: 8.0 mm (0.31 in) Measurement and adjustment steps: • Hold the carburetor in an upside down position. N OTE: • Slowly tilt the carburetor in the opposite direction, then take the measurement when the needle valve aligns with the float ...

  • Yamaha WR250FM - page 136

    4 - 14 ENG Starter plunger 1. Inspect: • Cold starter plunger 1 • Hot starter plunger 2 Wear/damage → Replace. Accelerator pump 1. Inspect: • Diaphragm (accelerator pump) 1 • Spring (accelerator pump) 2 • Accelerator pump cover 3 • O-ring 4 • Push rod 5 Tears (diaphragm)/damage → Replace. Dirt → Clean. 2. Inspect: • Throttle s ...

  • Yamaha WR250FM - page 137

    4 - 15 ENG CARBURETOR 2. Install: • Pilot air jet 1 1 3. Install: • Spring 1 1 • Lever 1 2 To lever 2 3 . N OTE: Make sure the spring 1 fits on the stopper a of the lever 2. a 3 1 2 4. Install: • Spring 2 1 To lever 2 2 . 1 2 5. Install: • Push rod link lever assembly 1 N OTE: Make sure the stopper a of the spring 2 fits into the recess b ...

  • Yamaha WR250FM - page 138

    4 - 16 ENG CARBURETOR 7. Install: • Spring 1 To throttle shaft 2 . N OTE: Install the bigger hook a of the sp ring fits on the stopper b of the throttle shaft pulley. 8. Install: • Throttle shaft assembly 1 • Washer (metal) 2 • Washer (resin) 3 • Valve lever 4 N OTE: • Apply the fluorochemical grease on the bear- ings. • Fit the proje ...

  • Yamaha WR250FM - page 139

    4 - 17 ENG CARBURETOR 10. Install: • Starter jet 1 • Pilot jet 2 • Spacer 3 • Needle jet 4 • Main jet 5 11. Install: • Needle valve 1 • Float 2 • Float pin 3 N OTE: • After installing the needle valve to the float, install them to the carburetor. • Check the float for smooth movement. 12. Install: • Pilot screw 1 • Spring 2 ...

  • Yamaha WR250FM - page 140

    4 - 18 ENG CARBURETOR 14. Install: • Diaphragm (air cut valve) 1 • Spring (air cut valve ) 2 • O-ring 3 • Air cut valve cov er 4 • Screw (air cut valve c over) 5 15. Install: • Diaphragm (accelerator pump) 1 • Spring 2 • O-ring 3 • Accelerator pump cover 4 • Hose holder (drain hose) 5 • Screw (accelerator pump cover) 6 N OTE: ...

  • Yamaha WR250FM - page 141

    4 - 19 ENG CARBURETOR 19. Install: • Carburetor breather hose 1 N OTE: Install the carburetor breather hoses to the carburetor so that the hoses do not bend near where they are installed. Accelerator pump timing adjustment Adjustment steps: N OTE: In order for the throttle valve height a to achieve the specified valu e, tuck under the throttle va ...

  • Yamaha WR250FM - page 142

    4 - 20 ENG 3. Install: • Hot starter plunger 1 T R . . 2 Nm (0.2 m · kg, 1.4 ft · lb) 1 4. Tighten: • Screw (air filter joint) 1 • Screw (carburetor joint) 2 T R . . 3 Nm (0.3 m · kg, 2.2 ft · lb) T R . . 3 Nm (0.3 m · kg, 2.2 ft · lb) 5. Install: • Throttle cable (pull) 1 • Throttle cable (return) 2 6. Adjust: • Throttle grip fre ...

  • Yamaha WR250FM - page 143

    4 - 21 ENG 9. Install: • Clamp 1 Refer to “ CABLE ROUT ING DIAGRAM ” section in the CHAPTER 2. 1 CARBURETOR ...

  • Yamaha WR250FM - page 144

    4 - 22 ENG CAMSHAFTS CAMSHAFTS CYLINDER HEAD COVER Extent of removal: 1 Cylinder head cover removal Extent of removal Order Part name Q ’ ty Remarks CYLINDER HEAD COVER REMOVAL Preparation for removal Seat and fuel tank Refer to “ SEAT, FUEL TANK AND SIDE COVERS ” section. Carburet or Refer to “ CARBURETOR ” section. 1 Spark plu g 1 2 Cyl ...

  • Yamaha WR250FM - page 145

    4 - 23 ENG CAMSHAFTS CAMSHAFTS Extent of removal: 1 Camshaft removal Extent of removal Order Part name Q ’ ty Remarks CAMSHAFTS REMOVAL 1 Timing mark accessing screw 1 Refer to “ REMOVAL POINTS ” . 2 Crankshaft end accessing screw 1 3 Timing chain tensioner cap bolt 1 4 Timing chain tensioner 1 5 Camshaft cap 2 6 Clip 2 7 Exhaust camshaft 1 8 ...

  • Yamaha WR250FM - page 146

    4 - 24 ENG CAMSHAFTS REMOVAL POINTS Camshaft 1. Remove: • Timing mark accessing screw 1 • Crankshaft end accessing screw 2 2. Align: • T.D.C. mark With align mark. Checking steps: • Turn the crankshaft count erclockwise with a wrench. • Align the T.D.C. mark a on the rotor with the align mark b on the crankcas e cover when piston is at T. ...

  • Yamaha WR250FM - page 147

    4 - 25 ENG CAMSHAFTS 5. Remove: • Exhaust camshaft 1 • Intake camshaft 2 N OTE: Attach a wire 3 to the timing chain to prevent it from falling into the crankcase. 1 2 3 INSPECTION Camshaft 1. Inspect: • Cam lobe Pitting/scratches/blue discolo ration → Replace. 2. Measure: • Cam lobe length a and b Out of specification → Replace. Cam lob ...

  • Yamaha WR250FM - page 148

    4 - 26 ENG CAMSHAFTS 4. Measure: • Camshaft-to-cap clearance Out of specification → Measure camshaft outside diameter. Camshaft-to-cap clearance: 0.020 ~ 0.054 mm (0.0008 ~ 0.0021 in) <Limit>: 0.08 mm (0.003 in) Measurement steps: • Install the camshaft onto the cylinder head. • Position a strip of Plastigauge ® 1 onto the camshaft. ...

  • Yamaha WR250FM - page 149

    4 - 27 ENG CAMSHAFTS Decompression system 1. Check: • Decompression sy stem Checking steps: • Check that the decompression mecha- nism cam 1 moves smoothly. • Check that the decompression mechanism cam lever pin 2 projects from the camshaft. Timing chain tensioner 1. Check: • While pressing the tensioner rod lightly with fingers, use a thin ...

  • Yamaha WR250FM - page 150

    4 - 28 ENG CAMSHAFTS • Fit the timing chain 3 onto both camshaft sprockets and install the camshafts on the cylinder head. N OTE: The camshafts should be insta lled onto the cylinder head so that the punch mark c on the exhaust camshaft and the punch mark d on the intake camshaft must align with the cylinder head surface , as shown in the illustr ...

  • Yamaha WR250FM - page 151

    4 - 29 ENG 3. Turn: • Crankshaft Counterclockwise several turns. 4. Check: • Rotor T.D.C. mark Align with the crankcase align mark . • Camshaft match marks Align with the cylinder head surf ace. Out of alignment → Adjust. • With the rod fully wound and the chain ten- sioner UP mark a facing upward, install the gasket 1 and the timing chai ...

  • Yamaha WR250FM - page 152

    4 - 30 ENG 6. Install: • Timing chain guide (top side) 1 • Cylinder head cover gasket 2 • Cylinder head cover 3 • Bolt (cylinder head cover) 4 N OTE: Apply the sealant on the cylinder head cover gasket. 7. Install: • Oil tank breather hose • Cylinder head breather hose • Spark plug T R . . 10 Nm (1.0 m · kg, 7.2 ft · lb) Quick gaske ...

  • Yamaha WR250FM - page 153

    4 - 31 ENG CYLINDER HEAD CYLINDER HEAD Extent of removal: 1 Cylinder head removal Extent of removal Order Part name Q ’ ty Remarks CYLINDER HEAD REMOVAL Preparation for removal Seat and fuel tank Refer to “ SEAT, FUEL TANK AND SIDE COVERS ” section. Exhaust pipe and silencer Refer to “ EXHAUST PIPE AND SILENCER ” section. Radiator hose 1 ...

  • Yamaha WR250FM - page 154

    4 - 32 ENG CYLINDER HEAD INSPECTION Cylinder head 1. Eliminate: • Carbon deposits (from the combustion chambe rs) Use a rounded scraper. N OTE: Do not use a sharp instrument to avoid damag- ing or scratching: • Spark plug threads • Valve seats 2. Inspect: • Cylinder head Scratches/damage → Replace. 3. Measure: • Cylinder head warpage Ou ...

  • Yamaha WR250FM - page 155

    4 - 33 ENG CYLINDER HEAD ASSEMBLY AND INSTALLATION Cylinder head 1. Install: • Dowel pin 1 • Cylinder head gasket 2 • Timing chain guide (exhaust side) 3 • Cylinder head 4 N OTE: While pulling up the timing cha in, install the timing chain guide (exhaust side) and cylinder head. 2. Install: • Washer 1 • Cable guide 2 • Bolts [L=145 mm ...

  • Yamaha WR250FM - page 156

    4 - 34 ENG VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS Extent of removal: 1 Valve removal Extent of removal Order Part name Q ’ ty Remarks VALVES AND VALVE SPRINGS REMOVAL Preparation for removal Cylinder head Refer to “ CYLINDER HEAD ” section. 1 Valve lifter 5 Use special tool. Refer to “ REMOVAL POINTS ” . 2 Adjusting pad 5 3 Val ...

  • Yamaha WR250FM - page 157

    4 - 35 ENG VALVES AND VALVE SPRINGS REMOVAL POINTS Valve lifter and valve cotter 1. Remove: • Valve lifter 1 • Pad 2 N OTE: Identify each lifter 1 and pad 2 position very carefully so that they can be reinstalled in their original place. 2. Check: • Valve sealing Leakage at the valve sea t → Inspect the valve face, valve seat and valve seat ...

  • Yamaha WR250FM - page 158

    4 - 36 ENG VALVES AND VALVE SPRINGS INSPECTION Valve 1. Measure: • Stem-to-guide clearance Out of specification → Replace the valve guide. Stem-to-guide clearance = valve guide inside diameter a – valve stem diameter b Clearance (stem to guide): Intake: 0.010 ~ 0.037 mm (0.0004 ~ 0.0015 in) <Limit>: 0.08 mm (0.003 in) Exhaust: 0.025 ~ 0 ...

  • Yamaha WR250FM - page 159

    4 - 37 ENG VALVES AND VALVE SPRINGS Valve guide remover: Intake: 4.0 mm (0.16 in) YM-4111/90890-04111 Exhaust: 4.5 mm (0.18 in) YM-4116/90890-04116 Valve guide installer: Intake: 4.0 mm (0.16 in) YM-4112/90890-04112 Exhaust: 4.5 mm (0.18 in) YM-4117/90890-04117 Valve guide reamer: Intake: 4.0 mm (0.16 in) YM-4113/90890-04113 Exhaust: 4.5 mm (0.18 i ...

  • Yamaha WR250FM - page 160

    4 - 38 ENG VALVES AND VALVE SPRINGS 5. Measure: • Runout (valve stem) Out of specification → Replace. N OTE: • When installing a new valve always replace the guide. • If the valve is removed or replaced always replace the oil seal. 6. Eliminate: • Carbon deposits (from the valve face and valve seat) 7. Inspect: • Valve s eat Pitting/wea ...

  • Yamaha WR250FM - page 161

    4 - 39 ENG VALVES AND VALVE SPRINGS 9. Lap: • Valve face • Valve s eat N OTE: After refacing the valve seat or replacing the valve and valve guide, the valve seat and valve face should be lapped. Lapping steps: • Apply a coarse lapping compound to the valve face. CAUTION: Do not let the compound enter the gap between the valve stem and the gu ...

  • Yamaha WR250FM - page 162

    4 - 40 ENG VALVES AND VALVE SPRINGS Valve spring 1. Measure: • Valve sprin g free length a Out of specification → Replace. 2. Measure: • Compressed spring force a Out of specification → Replace. b Installed length Free length (valve spring): Intake: 37.81 mm (1.49 in) <Limit>: 35.9 mm (1.41 in) Exhaust: 37.54 mm (1.48 in) <Limit> ...

  • Yamaha WR250FM - page 163

    4 - 41 ENG VALVES AND VALVE SPRINGS Combination of cylinder head and valve lifter 1. Combination: For this combination, match the paint color on the cylinder head with that on the valve lifter according to the chart below. N OTE: When you purchase a cylinder hea d, you can- not designate its size. Choose the valve lifter that matches the above char ...

  • Yamaha WR250FM - page 164

    4 - 42 ENG VALVES AND VALVE SPRINGS 3. Install: • Valve cotter N OTE: While compressing the valve spring with a valve spring compressor 1 i nstall the valve cotters. 4. To secure the valve cotters onto the valve stem, lightly tap the valve tip with a piece of wood. CAUTION: Hitting the valve tip with excessive force could damage the valve. Valve ...

  • Yamaha WR250FM - page 165

    4 - 43 ENG CYLINDER AND PISTON CYLINDER AND PISTON Extent of removal: 1 Cylinder removal 2 Piston removal Extent of removal Order Part name Q ’ ty Remarks CYLINDER AND PISTON REMOVAL Preparation for removal Cylinder head Refer to “ CYLINDER HEAD ” section. 1 Bolt (cylinder) 1 2 Cylinder 1 3 Piston pin clip 2 Use special tool. Refer to “ REM ...

  • Yamaha WR250FM - page 166

    4 - 44 ENG CYLINDER AND PISTON REMOVAL POINTS Piston and piston ring 1. Remove: • Piston p in clip 1 • Piston p in 2 • Piston 3 N OTE: • Put identification marks on each piston head for reference during reinstallation. • Before removing each piston pin, d eburr the clip groove and pin hole area. If the piston pin groove is deburred and th ...

  • Yamaha WR250FM - page 167

    4 - 45 ENG CYLINDER AND PISTON Cylinder bore “ C ” 77.00 ~ 77.01 mm (3.0315 ~ 3.0319 in) Taper limit “ T ” 0.05 mm (0.002 in) Out of round “ R ” 0.05 mm (0.002 in) “ C ” = Maximum D “ T ” = (Maximum D 1 or D 2 ) – (Maximum D 5 or D 6 ) “ R ” = (Maximum D 1 , D 3 or D 5 ) – (Minimum D 2 , D 4 or D 6 ) • If out of specif ...

  • Yamaha WR250FM - page 168

    4 - 46 ENG CYLINDER AND PISTON Piston ring 1. Measure: • Ring side clearance Use a feeler gauge 1 . Out of specification → Replace the piston and rings as a set. N OTE: Clean carbon from the piston rin g grooves and rings before measuring th e side clearance. 2. Position: • Piston ring (in cylinder) N OTE: Insert a ring into the cylinder an d ...

  • Yamaha WR250FM - page 169

    4 - 47 ENG CYLINDER AND PISTON Piston pin 1. Inspect: • Piston pin Blue discoloration/grooves → Replace, then inspect the lubrication system. 2. Measure: • Piston pin-to-piston clearance ASSEMBLY AND INSTALLATION Piston ring and piston 1. Install: • Piston ring Onto the piston. N OTE: • Be sure to install the piston rings so that the manu ...

  • Yamaha WR250FM - page 170

    4 - 48 ENG CYLINDER AND PISTON 2. Position: • Top ring • 2nd ring • Oil ring Offset the piston ring end gaps a s shown. a Top ring end b 2nd ring end c Oil ring end (upper) d Oil ring e Oil ring end (lower) 45 ˚ 135 ˚ 135 ˚ a b ce d 3. Install: • Piston 1 • Piston p in 2 • Piston p in clip 3 N OTE: • Apply engine oil onto the pisto ...

  • Yamaha WR250FM - page 171

    4 - 49 ENG 3. Install: • Cylinder gasket 1 • Cylinder 2 N OTE: Install the cylinder with one hand while com- pressing the piston rings wit h the other hand. CAUTION: • Pass the timing chain 3 through the tim- ing chain cavity. • Be careful not to damage the timing chain guide 4 during installation. 4. Install: • Bolt (cylinder) 5 T R . . ...

  • Yamaha WR250FM - page 172

    4 - 50 ENG CLUTCH EC4A0000 CLUTCH Extent of removal: 1 Push rod 1, 2 and push lever shaft removal 2 Push pod 1 disassembly 3 Friction plate and clutch plate removal 4 Primary driven gear removal Extent of removal Order Part name Q ’ ty Remarks CLUTCH REMOVAL Preparation for removal Drain the engine oil. Refer to “ ENGINE OIL REP LACEMENT ” se ...

  • Yamaha WR250FM - page 173

    4 - 51 ENG CLUTCH Extent of removal Order Part name Q ’ ty Remarks 10 Friction plate 9 11 Clutch plate 8 12 Cushion spring 1 13 Seat plate 1 14 Nut (clutch boss) 1 Use special tool. Refer to “ REMOVAL POINTS ” . 15 Look washer 1 16 Clutch boss 1 17 Thrust washer 1 18 Primary driven gear 1 19 Push lever shaft 1 4 1 3 ...

  • Yamaha WR250FM - page 174

    4 - 52 ENG CLUTCH EC4A3000 REMOVAL POINTS Clutch boss 1. Remove: • Nut 1 • Lock washer 2 • Clutch boss 3 N OTE: Straighten the lock washe r tab and use the clutch holding tool 4 to hold the clutch boss. È For USA and CDN É Except for USA and CDN Clutch holding tool: YM-91042/90890-04086 È É EC4A4000 INSPECTION EC484100 Clutch housing and ...

  • Yamaha WR250FM - page 175

    4 - 53 ENG CLUTCH Friction plate 1. Measure: • Friction plate thickness Out of specification → Replace friction plate as a set. Measure at all four points. EC484600 Clutch plate 1. Measure: • Clutch plate warpage Out of specification → Replace clutch plate as a set. Use a surface plate 1 and thickness gauge 2 . Friction plate thickness: 2.9 ...

  • Yamaha WR250FM - page 176

    4 - 54 ENG CLUTCH EC4A5000 ASSEMBLY AND INSTALLATION Push lever shaft 1. Install: • Push lever shaf t 1 • Bolt (push lever shaf t) 2 N OTE: • Apply the lithium soap base grease on the oil seal lip. • Apply the engine oil on the push lever shaft . • Fit the seat plate 3 in t he groove a of the push lever shaft and tighten th e bolt (seat p ...

  • Yamaha WR250FM - page 177

    4 - 55 ENG 3. Bend the lock washer 1 tab. 4. Install: • Seat plate 1 • Cushion spring 2 N OTE: • Install the seat plate with its chamfere d por- tion a facing the clutch boss 3 . • Install the seat plate so that it is not caught on the step b . • Install the cushion spring with the paint c facing out. 1 2 c 3 a b 5. Install: • Friction ...

  • Yamaha WR250FM - page 178

    4 - 56 ENG CLUTCH 7. Install: • Push rod 2 1 • Ball 2 • Push rod 1 3 N OTE: Apply the engine oil on the push rod 1, 2 and ball. 8. Install: • Pressure plate 1 9. Install: • Clutch spring 1 • Bolt (clutch spring) 2 N OTE: Tighten the bolts in stage, using a crisscross pattern. T R . . 8 Nm (0.8 m · kg, 5.8 ft · lb) 10. Install: • Dow ...

  • Yamaha WR250FM - page 179

    4 - 57 ENG OIL FILTER ELEMENT, WATER PUMP AND R IGHT CRANKCASE COVER OIL FILTER ELEMENT, WATER PUMP AND RIGHT CRANKCASE COVER Extent of removal: 1 Oil filter element removal 2 Water pump removal 3 Right crankcase cover removal Extent of removal Order Part name Q ’ ty Remarks OIL FILTER ELEMENT, WATER PUMP AND RIGHT CRANK- CASE COVER REMOVAL Prepa ...

  • Yamaha WR250FM - page 180

    4 - 58 ENG OIL FILTER ELEMENT, WATER PUMP AND R IGHT CRANKCASE COVER Extent of removal Order Part name Q ’ ty Remarks 3 Water pump housing 1 4 Oil delivery pipe 1 5 Bolt (oil hose) 1 6 Kickstarter crank 1 7 Right crankcase cover 1 8 Impeller 1 Refer to “ REMOVAL POINTS ” . 9 Washer 1 10 Impeller shaft 1 11 Oil seal 2 12 Bearing 1 3 2 ...

  • Yamaha WR250FM - page 181

    4 - 59 ENG OIL FILTER ELEMENT, WATER PUMP AND R IGHT CRANKCASE COVER REMOVAL POINTS Impeller shaft 1. Remove: • Impeller 1 • Washer 2 • Impeller shaft 3 N OTE: Hold the impeller shaft on its width across the flats a with spanners, etc. and remove the impeller. EC4G3210 Oil seal N OTE: It is not necessary to disassemble the water pump, unless ...

  • Yamaha WR250FM - page 182

    4 - 60 ENG OIL FILTER ELEMENT, WATER PUMP AND R IGHT CRANKCASE COVER EC444200 Impeller shaft 1. Inspect: • Impeller shaft 1 Bend/wear/damage → Replace . Fur deposits → Clean. EC444300 Impeller shaft gear 1. Inspect: • Gear teeth a Wear/damage → Replace. EC4H4600 Bearing 1. Inspect: • Bearing Rotate inner race with a finger. Rough spot/s ...

  • Yamaha WR250FM - page 183

    4 - 61 ENG OIL FILTER ELEMENT, WATER PUMP AND R IGHT CRANKCASE COVER 2. Install: • Bearing 1 N OTE: Install the bearing by pressing its o uter race parallel. Impeller shaft 1. Install: • Impeller shaft 1 • Washer 2 • Impeller 3 N OTE: • Take care so that the oil seal lip is not dam- aged or the spring does not slip off its posi- tion. • ...

  • Yamaha WR250FM - page 184

    4 - 62 ENG OIL FILTER ELEMENT, WATER PUMP AND R IGHT CRANKCASE COVER 2. Install: • Right crankcase cover 1 • Bolt (right crankcase cover) 2 N OTE: • Apply the engine oil on the impeller shaft end. • Mesh the impeller shaft gear 3 with primary drive gear 4 . • Tighten the bolts in stage, using a crisscross pattern. T R . . 10 Nm (1.0 m · ...

  • Yamaha WR250FM - page 185

    4 - 63 ENG OIL FILTER ELEMENT, WATER PUMP AND R IGHT CRANKCASE COVER Water pump housing 1. Install: • Dowel pin 1 • O-ring 2 N OTE: Apply the lithium soap base grease on the O- ring. New 2. Install: • Water pump housing 1 • Bolt (water pump housing) 2 T R . . 10 Nm (1.0 m · kg, 7.2 ft · lb) Oil filter element 1. Install: • Oil filter el ...

  • Yamaha WR250FM - page 186

    4 - 64 ENG BALANCER BALANCER Extent of removal: 1 Balancer shaft drive gear 2 Balancer shaf t Extent of removal Order Part name Q ’ ty Remarks BALANCER REMOVAL Preparation for removal Primary driven gear Refer to “ CLUTCH ” section. Right crankcase cover Refer to “ OIL FILTER ELEMENT, WATER PUMP AND RIGHT CRANK- CASE COVER ” section. Stat ...

  • Yamaha WR250FM - page 187

    4 - 65 ENG BALANCER REMOVAL POINTS Balancer shaft drive gear and balancer shaft driven gear 1. Straighten the lock washer tab. 2. Loosen: • Nut (primary drive gear) 1 • Nut (balancer shaft driven gear) 2 N OTE: Place an aluminum plate a between the teeth of the balancer shaft drive gear 3 and driven gear 4 . Balancer sha ft 1. Remove: • Balan ...

  • Yamaha WR250FM - page 188

    4 - 66 ENG BALANCER ASSEMBLY AND INSTALLATION Balancer shaft, balancer shaft drive gear and balancer shaft driven gear 1. Install: • Balancer shaft 1 N OTE: • Apply the engine oil on the bearing. • When installing the balancer shaft, align the center a of the balancer shaft weight along the line connecting the centers of the crank- shaft and ...

  • Yamaha WR250FM - page 189

    4 - 67 ENG OIL PUMP OIL PUMP Extent of removal: 1 Oil pump removal 2 Oil pump disassembly Extent of removal Order Part name Q ’ ty Remarks OIL PUMP REMOVAL AND DIS- ASSEMBLY Preparation for removal Primary driven gear Refer to “ CLUTCH ” section. Right crankcase cover Refer to “ OIL FILTER ELEMENT, WATER PUMP AND RIGHT CRANK- CASE COVER ” ...

  • Yamaha WR250FM - page 190

    4 - 68 ENG OIL PUMP Extent of removal Order Part name Q ’ ty Remarks 12 Dowel pin 1 13 Washer 1 14 Oil pump drive shaft 1 15 Rotor housing 1 2 ...

  • Yamaha WR250FM - page 191

    4 - 69 ENG OIL PUMP INSPECTION Oil pump 1. Inspect: • Oil pump drive gear 1 • Oil pump drive shaft 2 • Rotor housing 3 • Oil pump cover 4 Cracks/wear/damage → Replace. 1 3 2 4 2. Measure: • Tip clearance a (between the inner rotor 1 and outer rotor 2 ) • Side clearance b (between the outer rotor 2 and rotor housing 3 ) • Housing and ...

  • Yamaha WR250FM - page 192

    4 - 70 ENG OIL PUMP ASSEMBLY AND INSTALLATION Oil pump 1. Install: • Oil pump drive shaft 1 • Washer 2 • Dowel pin 3 • Inner rotor 1 4 N OTE: • Apply the engine oil on the oil pump drive shaft and inner rotor 1. • Fit the dowel pin into the groove in the inner rotor 1. 2. Install: • Outer rotor 1 1 N OTE: Apply the engine oil on the o ...

  • Yamaha WR250FM - page 193

    4 - 71 ENG 4. Install: • Outer rotor 2 1 • Dowel pin 2 • Oil pump assembly 3 • Bolt (oil pump a ssembly) [L = 25 mm (0.94 in)] 4 • Bolt (oil pump a ssembly) [L = 30 mm (1.18 in)] 5 N OTE: Apply the engine oil on the outer rotor 2 . T R . . 10 Nm (1.0 m · kg, 7.2 ft · lb) T R . . 10 Nm (1.0 m · kg, 7.2 ft · lb) 5. Install: • Oil pump ...

  • Yamaha WR250FM - page 194

    4 - 72 ENG KICK SHAFT AND SHIFT SHAFT KICK SHAFT AND SHIFT SHAFT Extent of removal: 1 Kick shaft removal 2 Kick shaft disassembly 3 Shift shaft removal 4 Se gment removal Extent of removal Order Part name Q ’ ty Remarks KICK SHAFT AND SHIFT SHAFT R EMOVAL Preparation for removal Oil pump Refer to “ OIL PUMP ” section. 1 Kick idle gear 1 2 Kic ...

  • Yamaha WR250FM - page 195

    4 - 73 ENG KICK SHAFT AND SHIFT SHAFT Extent of removal Order Part name Q ’ ty Remarks 12 Torsion spring 1 13 Roller 1 14 Shift guide 1 Refer to “ REMOVAL POINTS ” . 15 Shift lever assembly 1 16 Shift lever 1 17 Pawl 2 18 Pawl pin 2 19 Spring 2 20 Bolt (stopper lever) 1 21 Stopper lever 1 22 Torsion spring 1 23 Segment 1 Refer to “ REMOVAL ...

  • Yamaha WR250FM - page 196

    4 - 74 ENG KICK SHAFT AND SHIFT SHAFT REMOVAL POINTS Kick shaft assembly 1. Remove: • Kick shaft assem bly 1 N OTE: Unhook the torsion spring 2 from the hole a in the crankcase. EC4C3101 Shift guide and shift lever assembly 1. Remove: • Bolt (shift guide) • Shift guide 1 • Shift lever assembly 2 N OTE: The shift lever assembly is disassembl ...

  • Yamaha WR250FM - page 197

    4 - 75 ENG KICK SHAFT AND SHIFT SHAFT EC4B4400 Shift shaft 1. Inspect: • Shift shaft 1 Bend/damage → Replace. • Spring 2 Broken → Replace. EC4C4100 Shift guide and shift lever assembly 1. Inspect: • Shift guide 1 • Shift lever 2 • Pawl 3 • Pawl pin 4 • Spring 5 Wear/damage → Replace. EC4B4500 Stopper lever 1. Inspect: • Stoppe ...

  • Yamaha WR250FM - page 198

    4 - 76 ENG KICK SHAFT AND SHIFT SHAFT EC4B5111 Stopper lever 1. Install: • Torsion spring 1 • Stopper lever 2 • Bolt (stopper lever) 3 N OTE: Align the stopper lever roller with the slot on segment. Shift guide and shift lever assembly 1. Install: • Spring 1 • Pawl pin 2 • Pawl 3 To shift lever 4 . N OTE: Apply the engine oil on the spr ...

  • Yamaha WR250FM - page 199

    4 - 77 ENG KICK SHAFT AND SHIFT SHAFT Shift shaft 1. Install: • Roller 1 • Collar 2 • Torsion spring 3 • Shift shaft 4 N OTE: Apply the engine oil on th e roller and shift shaft. 2. Install: • Shift pedal Refer to “ AC MAGNETO AND STARTER CLUTCH ” section. Kick shaft assembly 1. Install: • Kick gear 1 • Washer 2 • Circlip 3 • ...

  • Yamaha WR250FM - page 200

    4 - 78 ENG KICK SHAFT AND SHIFT SHAFT 3. Install: • Spring gu ide 1 N OTE: Slide the spring guide into the kick shaft, make sure the groove a in the spring guide fits on the stopper of the torsion spring. 4. Install: • Kick shaft assem bly 1 • Washer 2 N OTE: • Apply the molybdenum disulfide grease on the contacting surfaces of the kick sha ...

  • Yamaha WR250FM - page 201

    4 - 79 ENG AC MAGNETO AND STARTER CLUTCH AC MAGNETO AND STARTER CLUTCH Extent of removal: 1 Starter clutch/wheel gear removal 2 Rotor removal 3 Pickup coil/stator removal Extent of removal Order Part name Q’ty Remarks AC MAGNETO AND STATOR REMOVAL Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMEN T” section in the ...

  • Yamaha WR250FM - page 202

    4 - 80 ENG AC MAGNETO AND STARTER CLUTCH Extent of removal Order Part name Q ’ ty Remarks 10 Nut (rotor) 1 11 Rotor 1 Use special tool. Refer to “ REMOVAL POINTS ”. 12 Woodruff key 1 13 Starter clutch 1 14 Starter clutch drive gear 1 15 Bearing 1 16 Plain washer 1 17 Idle gear plate 1 18 Idle gear 2 1 19 Holder 1 20 Pickup coil 1 21 Stator 1 ...

  • Yamaha WR250FM - page 203

    4 - 81 ENG AC MAGNETO AND STARTER CLUTCH EC4L3000 REMOVAL POINTS Rotor 1. Remove: • Nut (rotor) 1 • Plain washer 1 2. Remove: • Rotor 1 Use the rotor puller 2 . Rotor puller: YM-04141/90890-04141 EC4L4000 INSPECTION AC magneto 1. Inspect: • Rotor inner surface a • Stator outer surface b Damage → Inspect the crankshaft runout and cranksh ...

  • Yamaha WR250FM - page 204

    4 - 82 ENG AC MAGNETO AND STARTER CLUTCH 3. Check: • Starter clutch operation • Install the starter clutch drive gear 1 onto the starter clutch 2 and hold the starter clutch. • When turning the starter clutch drive gear counterclockwise É , the starter clutch and the starter clutch drive gear shou ld engage. If the starter clutch drive gear ...

  • Yamaha WR250FM - page 205

    4 - 83 ENG AC MAGNETO AND STARTER CLUTCH 2. Install: • Holder 1 • Bolt 2 CAUTION: Pass the pickup coil lead and charging coil lead under the holder while taking care not to allow these leads to get caught with each other. Also take care to pass the leads so that they do not become loose at the bend of the holder a in order to avoid their con- t ...

  • Yamaha WR250FM - page 206

    4 - 84 ENG AC MAGNETO AND STARTER CLUTCH 5. Install: • Plain washer 1 •B e a r i n g 2 • Starter clutch drive gear 3 • Starter clutch 4 N OTE: Apply the engine oil on the plain washer, bear- ing and starter clutch drive gear inner circum- ference. 1 2 3 4 E 6. Install: • Woodruff key 1 •R o t o r 2 N OTE: • Clean the tapered portions ...

  • Yamaha WR250FM - page 207

    4 - 85 ENG AC MAGNETO AND STARTER CLUTCH 9. Install: • Shaft 1 • Bearing 2 • Idle gear 1 3 N OTE: Apply the engine oil on the shaft, bearing and idle gear inner circumference. 1 2 3 E 10. Install: • Cover (idle gear 1) 1 • Bolt 2 N OTE: Install the cover (idle gear 1) with its mark a facing upward. T R . . 10 Nm (1.0 m · kg, 7.2 ft · lb ...

  • Yamaha WR250FM - page 208

    4 - 86 ENG ENGINE REMOVAL EC4M0000 ENGINE REMOVAL Extent of removal Order Part name Q ’ ty Remarks ENGINE REMO VAL Preparation for removal Hold the machine by placing the suitable stand unde r the frame. W ARNING Support the machine securely so there is no danger of it falling over. Drain the engine oil. Refer to “ ENGINE OIL REPLACEMENT ” se ...

  • Yamaha WR250FM - page 209

    4 - 87 ENG ENGINE REMOVAL Extent of removal: 1 Engine removal Extent of removal Order Part name Q ’ ty Remarks Ignition coil Disconnect the AC magneto lea d. Starter motor lead Disconnect at the starter motor side. Negative battery lead Disconnect at the engine side. Right engine guard 1 Neutral switch 1 2 Drive chain sprocket cover 1 3 Nut (driv ...

  • Yamaha WR250FM - page 210

    4 - 88 ENG ENGINE REMOVAL EC4M3000 REMOVAL POINTS EC4F3100 Drive sprocket 1. Remove: • Nut (drive sprocket) 1 • Lock washer 2 N OTE: • Straighten the lock washer tab. • Loosen the nut while applying the rear brake. 2. Remove: • Drive sprocket 1 • Drive chain 2 N OTE: Remove the drive sprocket together with the drive chain. EC4M3301 Engi ...

  • Yamaha WR250FM - page 211

    4 - 89 ENG ENGINE REMOVAL EC4M5000 ASSEMBLY AND INSTALLATION Engine installation 1. Install: • Engine 1 Install the engine from right side. • Pivot shaft 2 • Engine mounting bolt (lower) 3 • Lower engine bracket 4 • Bolt (engine bracket) 5 • Engine mounting bolt (front) 6 • Upper engine bracket 7 • Engine mounting bolt (upper) 8 • ...

  • Yamaha WR250FM - page 212

    4 - 90 ENG ENGINE REMOVAL Drive sprocket 1. Install: • Drive sprocket 1 • Drive chain 2 N OTE: Install the drive sprocket together with the drive chain. 2. Install: • Lock washer 1 • Nut (drive sprocket) 2 N OTE: Tighten the nut while applying the rear brake. T R . . 75 Nm (7.5 m · kg, 54 ft · lb) New 3. Bend the lock washer tab to lock t ...

  • Yamaha WR250FM - page 213

    4 - 91 ENG ENGINE REMOVAL 2. Install: • Spring 1 • Pin 2 • O-ring 3 • Neutral switch 4 • Screw (neutral switch) 5 N OTE: Apply the lithium soap base grease on the O- ring. T R . . 4 Nm (0.4 m · kg, 2.9 ft · lb) New ...

  • Yamaha WR250FM - page 214

    4 - 92 ENG CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT Extent of removal: 1 Crankcase separation 2 Crankshaft removal Extent of removal Order Part name Q ’ ty Remarks CRANKCASE AND CRANK- SHAFT R EMOVAL Preparation for removal Engine Refer to “ ENGINE REMOVAL ” section. Piston Refer to “ CYLINDER AND PISTON ” sec- tion. Kick shaft a ...

  • Yamaha WR250FM - page 215

    4 - 93 ENG CRANKCASE AND CRANKSHAFT Extent of removal Order Part name Q ’ ty Remarks 4 Bolt [L = 45 mm (1.77 in)] 6 Refer to “ REMOVAL POINTS ” . 5 Bolt [L = 55 mm (2.17 in)] 1 6 Bolt [L = 70 mm (2.76 in)] 4 7 Hose guide 1 8 Clutch ca ble hold er 1 9 Right crankcase 1 10 Left crankcase 1 11 Oil strainer 1 12 Crankshaft 1 Use special tool. Ref ...

  • Yamaha WR250FM - page 216

    4 - 94 ENG CRANKCASE AND CRANKSHAFT CRANKCASE BEARING Extent of removal: 1 Crankcase bearing removal Extent of removal Order Part name Q ’ ty Remarks CRANKCASE BEARING REMOVAL Preparation for removal Transmission Shift cam and shift fork Refer to “ TRANSMISSION, SHIFT CAM AND SHIFT FORK ” section. 1 Oil seal 2 2 Bearing 10 Refer to “ REMOVA ...

  • Yamaha WR250FM - page 217

    4 - 95 ENG CRANKCASE AND CRANKSHAFT REMOVAL POINTS Crankcase 1. Separate: • Right crankcase • Left crankcase Separation steps: • Remove the crankcase bolts 1 , hose guide 2 and clutch cable holder 3 . N OTE: Loosen each bolt 1/4 of a turn at a time and after all the bolts are loosened, remo ve them. • Remove the right crankcase 4 . N OTE: ? ...

  • Yamaha WR250FM - page 218

    4 - 96 ENG CRANKCASE AND CRANKSHAFT Crankshaft 1. Remove: • Crankshaft 1 Use the crankcase separating t ool 2 . CAUTION: Do not use a hammer to drive out the crankshaft. Crankcase bearing 1. Remove: • Bearing 1 N OTE: • Remove the bearing from the cran kcase by pressing its inner race. • Do not use the removed bearing. Crankcase separating ...

  • Yamaha WR250FM - page 219

    4 - 97 ENG CRANKCASE AND CRANKSHAFT EC4N4201 Crankshaft 1. Measure: • Runout limit a • Small end free play limit b • Connecting rod big end side clearance c • Crank width d Out of specification → Replace. Use the dial gauge and a thickness gauge. Dial gauge and stand: YU-3097/90890-01252 Standard <Limit> Runout limit: 0.03 mm (0.001 ...

  • Yamaha WR250FM - page 220

    4 - 98 ENG CRANKCASE AND CRANKSHAFT EC4N5000 ASSEMBLY AND INSTALLATION Crankcase bearing 1. Install: • Bearing • Bearing stopper • Bolt (bearing stop per) • Screw (bearing stopper) • Screw [bearing stopper (crankshaft)] 1 To left and right crankcase. N OTE: • Install the bearing by pressing its outer race parallel. • To prevent the sc ...

  • Yamaha WR250FM - page 221

    4 - 99 ENG CRANKCASE AND CRANKSHAFT 2. Check: • Shifter operation • Transmission operation Unsmooth operatio n → Repair. 3. Install: • Oil strainer 1 • Bolt (oil strainer) 2 T R . . 10 Nm (1.0 m · kg, 7.2 ft · lb) 4. Apply: • Sealant On the right crankcase 1 . N OTE: Clean the contacting surface of left and right crankcase before appl ...

  • Yamaha WR250FM - page 222

    4 - 100 ENG CRANKCASE AND CRANKSHAFT 6. Tighten: • Hose guide 1 • Clutch cable holder 2 • Bolt (crankcase) 3 N OTE: Tighten the crankcase tightening bolts in stage, using a crisscross pattern. T R . . 12 Nm (1.2 m · kg, 8.7 ft · lb) 7. Install: • Oil delivery pipe 2 1 • O-ring 2 • Bolt (oil delivery pipe 2) 3 N OTE: Apply the lithium ...

  • Yamaha WR250FM - page 223

    4 - 101 ENG TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H0000 TRANSMISSION, SHIFT CAM AND SHIFT FORK Extent of removal: 1 Shift fork, shif t cam, main axle and drive axle rem oval Extent of removal Order Part name Q ’ ty Remarks TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVAL Preparation for removal Engine Refer to “ ENGINE REMOVAL ” section. Se ...

  • Yamaha WR250FM - page 224

    4 - 102 ENG TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H3000 REMOVAL POINTS EC4H3230 Transmission 1. Remove: • Main axle 1 • Drive axle 2 • Shift cam • Shift fork 3 • Shift fork 2 • Shift fork 1 N OTE: • Remove assembly with the collar 3 installed to the crankcase. • Remove assembly carefully. Note the posi- tion of each part. Pay pa ...

  • Yamaha WR250FM - page 225

    4 - 103 ENG TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H4810 Shift fork, shift cam and segment 1. Inspect: • Shift fork 1 Wear/damage/scratches → Re place. 2. Inspect: • Shift cam 1 • Segment 2 Wear/damage → Replace. 3. Check: • Shift fork movement Unsmooth operation → Replace shift fork. N OTE: For a malfunctioning shift fork, replace ...

  • Yamaha WR250FM - page 226

    4 - 104 ENG TRANSMISSION, SHIFT CAM AND SHIFT FORK 2. Install: • 2nd wheel gear (28T) 1 • 4th wheel gear (25T) 2 • 3rd wheel gear (28T) 3 • 5th wheel gear (22T) 4 • 1st wheel gear (31T) 5 • O-ring 6 To drive axle 7 . N OTE: • Apply the molybdenum disulfide oil on the 1st, 2nd and 3rd wheel gears inner circu m- ference and on the end s ...

  • Yamaha WR250FM - page 227

    4 - 105 ENG TRANSMISSION, SHIFT CAM AND SHIFT FORK 5. Install: • Shift fork 1 (L) 1 • Shift fork 2 (C) 2 • Shift fork 3 (R) 3 • Shift cam 4 To main axle and drive axle. N OTE: • Apply the molybdenum disulfide oil on the shift fork grooves. • Mesh the shift fork #1 (L) with the 4th wheel gear 5 and #3 (R) with the 5th wheel gear 7 on the ...

  • Yamaha WR250FM - page 228

    5 - 1 CHAS EC500000 CHASSIS EC590000 FRONT WHEEL AND REAR WHEEL EC598000 FRONT WHEEL FRONT WHEEL AND REAR WHEEL Extent of removal: 1 Front wheel removal 2 Whee l bearing removal 3 Brake disc removal Extent of removal Order Part name Q’ty Remarks Preparation for removal FRONT WHEEL REMOVAL Hold the machine by placi ng the suitable stand unde r the ...

  • Yamaha WR250FM - page 229

    5 - 2 CHAS EC598100 REAR WHEEL Extent of removal: 1 Rear wheel removal 2 Wheel bearing removal 3 Brake disc removal Extent of removal Order Part name Q ’ ty Remarks Preparation for removal REAR WHEEL REMOVAL Hold the machine by placi ng the suitable stand unde r the engine . W ARNING Support the machine securely so there is no danger of it fallin ...

  • Yamaha WR250FM - page 230

    5 - 3 CHAS FRONT WHEEL AND REAR WHEEL EC593000 REMOVAL POINTS EC523101 Rear wheel 1. Remove: • Wheel 1 N OTE: Push the wheel forward and remove the drive chain 2 . EC513201 Wheel bearing (if necessary) 1. Remove: • Bearing 1 N OTE: Remove the bearing using a ge neral bearing puller 2 . EC594000 INSPECTION EC514100 Wheel 1. Measure: • Wheel ru ...

  • Yamaha WR250FM - page 231

    5 - 4 CHAS FRONT WHEEL AND REAR WHEEL EC514200 Wheel axle 1. Measure: • Wheel axle bends Out of specification → Replace. Use the dial gauge 1 . N OTE: The bending value is shown by one half o f the dial gauge reading. W ARNING Do not attempt to straighten a bent axle. Wheel axle bending limit: 0.5 mm (0.020 in) EC594200 Brake disc 1. Measure: ? ...

  • Yamaha WR250FM - page 232

    5 - 5 CHAS FRONT WHEEL AND REAR WHEEL EC595000 ASSEMBLY AND INSTALLATION Front wheel 1. Install: • Bearing (left) 1 • Spacer 2 • Bearing (right) 3 • Oil seal 4 N OTE: • Apply the lithium soap base grease on the bearing and oil seal lip when installing. • Use a socket that matches the outside diam- eter of the race of the bearin g. • L ...

  • Yamaha WR250FM - page 233

    5 - 6 CHAS FRONT WHEEL AND REAR WHEEL 5. Install: • Wheel N OTE: • Install the brake disc 1 between the brake pads 2 correctly. • Make sure that the projections a in the t rip meter gear unit fits over the stopper b on the front fork outer tube. 6. Install: • Wheel axle 1 N OTE: Apply the lithium soap base grease on the wheel axle. 7. Insta ...

  • Yamaha WR250FM - page 234

    5 - 7 CHAS FRONT WHEEL AND REAR WHEEL 8. Tighten: • Bolt (axle holder) 1 N OTE: Before tightening the bolt, fit the wheel axle to the axle holder by stroking the front fork se v- eral times with the front brake applied. T R . . 23 Nm (2.3 m · kg, 17 ft · lb) 9. Install: • Brake hose 1 To brake hose holder 2 . N OTE: Before tightening the bolt ...

  • Yamaha WR250FM - page 235

    5 - 8 CHAS 11. Install: • Trip meter cable 1 1 Rear wheel 1. Install: • Bearing (right) 1 • Circlip 2 • Spacer 3 • Bearing (left) 4 • Oil seal 5 N OTE: • Apply the lithium soap base grease on the bearing and oil seal lip when installing. • Install the bearing with seal facing outward. • Use a socket that matches the outside diam- ...

  • Yamaha WR250FM - page 236

    5 - 9 CHAS FRONT WHEEL AND REAR WHEEL 3. Install: • Rear wheel sprocket 1 • Bolt (rear wheel sprocket ) 2 • Washer (rear wheel sprocket) 3 • Nut (rear wheel sprocket) 4 N OTE: Tighten the nuts in stage, using a crisscross pattern. T R . . 50 Nm (5.0 m · kg, 36 ft · lb) 4. Install: • Collar 1 N OTE: Apply the lithium soap base grease on ...

  • Yamaha WR250FM - page 237

    5 - 10 CHAS FRONT WHEEL AND REAR WHEEL 8. Install: • Right drive chain puller 1 • Washer 2 • Nut (wheel axle) 3 N OTE: Temporarily tighten the nut (wheel axle) at this point. 9. Adjust: • Drive chain slack a Refer to “ DRIVE C HAIN SLAC K ADJUST MENT ” section in th e CHAPTER 3. Drive chain slack: 40 ~ 50 mm (1.6 ~ 2.0 in) 10. Tighten: ...

  • Yamaha WR250FM - page 238

    5 - 11 CHAS FRONT BRAKE AND REAR BRAKE EC5A0000 FRONT BRAKE AND REAR BRAKE EC5A8000 FRONT BRAKE Extent of removal: 1 Brake hose removal 2 Brake caliper removal 3 Brake master cylinder removal Extent of removal Order Part name Q ’ ty Remarks Preparation for removal FRONT BRAKE REMOVAL Hold the machine by placi ng the suitable stand unde r the engi ...

  • Yamaha WR250FM - page 239

    5 - 12 CHAS EC5A8100 REAR BRAKE Extent of removal: 1 Brake master cylinder removal 2 Brake hose removal 3 Brake caliper removal Extent of removal Order Part name Q ’ ty Remarks Preparation for removal REAR BRAKE REMOVAL Hold the machine by placi ng the suitable stand unde r the engine . W ARNING Support the machine securely so there is no danger ...

  • Yamaha WR250FM - page 240

    5 - 13 CHAS BRAKE CALIPER DISASSEMBLY È Front É Rear Extent of removal: 1 Front brake caliper disassembly 2 Rear brake caliper disassembly Extent of removal Order Part name Q ’ ty Remarks BRAKE CALIPER DISASSEM- BLY AB 1 Pad pin 1 1 2 Brake pa d 2 2 3 Pad support 1 1 4 Brake caliper piston 2 1 Refer to “ REMOVAL POINTS ” . 5 Dust seal 2 1 6 ...

  • Yamaha WR250FM - page 241

    5 - 14 CHAS FRONT BRAKE AND REAR BRAKE BRAKE MASTER CYLINDER DISASSEMBLY È Front É Rear Extent of removal: 1 Front brak e master cylin der disassemb ly 2 Rear brake master cylinder disasse mbly Extent of removal Order Part name Q ’ ty Remarks BRAKE MASTER CYLINDER DISASSEMBLY 1 Brake master cylinder ca p 1 2 Diaphragm 1 3 Brake master cylinder ...

  • Yamaha WR250FM - page 242

    5 - 15 CHAS FRONT BRAKE AND REAR BRAKE EC5A3000 REMOVAL POINTS Brake fluid 1. Remove: [Front] • Brake master cylinder cap 1 [Rear] • Brake master cylinder cap 1 • Protector N OTE: Do not remove the diaphragm. È Front É Rear 2. Connect the transparent hose 2 to the bleed screw 1 and place a suitable con- tainer under its end. È Front É Rea ...

  • Yamaha WR250FM - page 243

    5 - 16 CHAS FRONT BRAKE AND REAR BRAKE Brake caliper piston seal kit 1. Remove: • Dust seal 1 • Piston seal 2 N OTE: Remove the piston seals and du st seals by pushing them with a finger. CAUTION: Never attempt to pry out piston seals and dust seals. W ARNING Replace the piston seals and dust seals whenever a caliper is disassembled . È Front ...

  • Yamaha WR250FM - page 244

    5 - 17 CHAS Brake caliper 1. Inspect: • Brake caliper cylinder inner surface a Wear/score marks → Replace brake cali- per assembly. È Front É Rear É È 2. Inspect: • Brake caliper piston 1 Wear/score marks → Replace brake cali- per piston assembly. W ARNING Replace the piston seals and dust seals 2 whenever a caliper is disassembled . EC ...

  • Yamaha WR250FM - page 245

    5 - 18 CHAS 2. Install: • Piston seal 1 • Dust seal 2 W ARNING Always use new piston seals and dust seals. N OTE: Fit the piston seals and dust seals onto t he slot on brake caliper correctly. È Front É Rear È New New É 3. Install: • Brake caliper piston 1 N OTE: Apply the brake fluid on the piston wall. CAUTION: • Install the piston wi ...

  • Yamaha WR250FM - page 246

    5 - 19 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: • Copper washer 1 • Union bolt 2 W ARNING Always use new copper washers. CAUTION: Install the brake hose so that its pipe por- tion a directs as shown and lightly touches the projection b on the brake cali- per. T R . . 30 Nm (3.0 m · kg, 22 ft · lb) New 3. Install: • Brake hose holder 1 ? ...

  • Yamaha WR250FM - page 247

    5 - 20 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: • Brake disc cover 1 • Bolt (brake disc cover) 2 T R . . 7 Nm (0.7 m · kg, 5.1 ft · lb) 3. Install: • Brake caliper 1 • Rear wheel 2 Refer to “ FRONT WHEEL AND REAR WHEEL ” section. 4. Tighten: • Pad pin 3 5. Install: • Pad pin plug 4 T R . . 18 Nm (1.8 m · kg, 13 ft · lb) T R . ...

  • Yamaha WR250FM - page 248

    5 - 21 CHAS FRONT BRAKE AND REAR BRAKE 3. Install: • Spring 1 To brake master cylinder piston 2 . N OTE: Install the spring at the smaller dia. sid e. È Front É Rear ÈÉ 4. Install: [Front] • Brake master cylinder kit 1 • Washer 2 • Circlip 3 • Brake master cylinder boot 4 To brake master cylinder 5 . [Rear] • Brake master cylinder k ...

  • Yamaha WR250FM - page 249

    5 - 22 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: • Brake lever 1 • Bolt (brake lever) 2 • Nut (brake lever) 3 N OTE: Apply the lithium soap base grease on the brake lever sliding surface, bolt and contacting surface of the brake master cylinder p iston. Rear brake master cylinder 1. Install: • Copper washer 1 • Brake hose 2 • Union bo ...

  • Yamaha WR250FM - page 250

    5 - 23 CHAS FRONT BRAKE AND REAR BRAKE 4. Install: • Pin 1 • Washer 2 • Cotter pin 3 N OTE: After installing, check the brake pedal height. Refer to “ REAR BRAKE ADJUSTMENT ” sec- tion in the CHAPTER 3. New Front brake hose 1. Install: • Brake hose 1 To brake hose holder 2 . N OTE: Before tightening the bolt (brake hose holder), align t ...

  • Yamaha WR250FM - page 251

    5 - 24 CHAS FRONT BRAKE AND REAR BRAKE 4. Install: • Copper washer 1 • Brake hose 2 • Union bolt 3 W ARNING Always use new copper washers. CAUTION: Install the brake hose so that it contacts the brake master cylinder projection a and that its bent portion b faces downward. T R . . 30 Nm (3.0 m · kg, 22 ft · lb) New Rear brake hose 1. Instal ...

  • Yamaha WR250FM - page 252

    5 - 25 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: • Brake hose holder 1 • Screw (brake hose holder) 2 CAUTION: After installing the brake hose holders, make sure the brake hose does not contact the spring (rear shock absorb er). If it does, correct its twist. T R . . 1 Nm (0.1 m · kg, 0.7 ft · lb) Brake fluid 1. Fill: • Brake fluid Until t ...

  • Yamaha WR250FM - page 253

    5 - 26 CHAS FRONT BRAKE AND REAR BRAKE 2. Air bleed: • Brake system Refer to “ BRAKE SYSTEM AIR BLEED- ING ” section in the CHAPTER 3. 3. Inspect: • Brake fluid level Fluid at lower level → Fill up. Refer to “ BRAKE FLUID LEVEL INSPEC- TION ” section in the CHAPTER 3. 4. Install: [Front] • Diaphragm • Brake master cylinder cap 1 ? ...

  • Yamaha WR250FM - page 254

    5 - 27 CHAS FRONT FORK EC550000 FRONT FORK Extent of removal: 1 Front fork removal Extent of removal Order Part name Q ’ ty Remarks Preparation for removal FRONT FORK REMOVAL Hold the machine by placi ng the suitable stand unde r the engine . W ARNING Support the machine securely so there is no danger of it falling over. Front wheel Refer to “ ...

  • Yamaha WR250FM - page 255

    5 - 28 CHAS FRONT FORK EC558000 FRONT FORK DISASSEMBLY Extent of removal: 1 Oil seal removal 2 Damper rod removal Extent of removal Order Part name Q ’ ty Remarks FRONT FORK DISASSEMBLY 1 Front fork cap bolt 1 Refer to “ REMOVAL POINTS ” . 2 Fork spring 1 Drain the fork oil. 3 Dust seal 1 Refer to “ REMOVAL POINTS ” . 4 Stopper ring 1 5 I ...

  • Yamaha WR250FM - page 256

    5 - 29 CHAS FRONT FORK EC556000 HANDLING NOTE N OTE: The front fork requires careful attention. So it is recommended that the fro nt fork be maintained at the dealers. CAUTION: To prevent an accidental explosion of air, the following instructions should be observed: • The front fork with a built-in pi ston rod has a very sophisticated internal co ...

  • Yamaha WR250FM - page 257

    5 - 30 CHAS FRONT FORK EC553201 Inner tube 1. Remove: • Dust seal 1 • Stopper ring 2 Using slotted-head screwdriver. CAUTION: Take care not to scratch the inner tube. 2. Remove: • Inner tube 1 Oil seal removal steps: • Push in slowly a the inner tube just be fore it bottoms out and then pull it back quickly b . • Repeat this step until th ...

  • Yamaha WR250FM - page 258

    5 - 31 CHAS EC554200 Base valve 1. Inspect: • Valve assembly 1 Wear/damage → Replace. • O-ring 2 Damage → Replace. EC554400 Fork spring 1. Measure: • Fork spring free length a Out of specification → Replace. EC554502 Inner tube 1. Inspect: • Inner tube surface a Score marks → Repair or replace. Use #1,000 grit wet sandpaper. Damaged ...

  • Yamaha WR250FM - page 259

    5 - 32 CHAS Front fork cap bolt 1. Inspect: • Front fork cap bolt 1 • O-ring 2 • Air bleed screw 3 Wear/damage → Replace. EC555000 ASSEMBLY AND INSTALLATION Front fork assembly 1. Wash the all parts in a clean solvent. 2. Install: • Damper rod 1 To inner tube 2 . CAUTION: To install the damper rod into the inner tube, hold the inner tube ...

  • Yamaha WR250FM - page 260

    5 - 33 CHAS 5. Install: • Spring gu ide 1 • Locknut 2 To damper rod 3 . N OTE: • Install the spring guide with its cut a facing upward. • With its thread b facing upward, fully finger tighten the locknut onto the d amper rod. 6. Install: • Dust seal 1 • Stopper ring 2 • Oil seal 3 • Oil seal washer 4 • Slide metal 5 To inner tube ...

  • Yamaha WR250FM - page 261

    5 - 34 CHAS FRONT FORK 9. Install: • Slide metal 1 • Oil seal washer 2 To outer tube slot. N OTE: Press the slide metal into the outer tub e with fork seal driver 3 . Fork seal driver: YM-01442/90890-01442 10. Install: • Oil seal 1 N OTE: Press the oil seal into the outer tube with fo rk seal driver 2 . Fork seal driver: YM-01442/90890-01442 ...

  • Yamaha WR250FM - page 262

    5 - 35 CHAS FRONT FORK 13. Check: • Inner tube smooth movement Tightness/binding/rough spots → Repeat the steps 2 to 12. 14. Compress the front fork fully. 15. Fill: • Front fork oil Until outer tube top surface with reco m- mended fork oil 1 . CAUTION: • Be sure to use recommended fork oil. If other oils are used, they may have an excessiv ...

  • Yamaha WR250FM - page 263

    5 - 36 CHAS FRONT FORK 19. Wait ten minutes until the air bubbles have been removed from the front fork, and the oil has dispense evenly in syste m before setting recommended oil level. N OTE: Fill with the fork oil up to the top end of the outer tube, or the fork oil will not spread over to every part of the front forks, thus making it impossible ...

  • Yamaha WR250FM - page 264

    5 - 37 CHAS FRONT FORK 21. Measure: • Distance a Out of speci fication → Turn into the lock- nut. Distance a : 20 mm (0.79 in) or more Between damper rod 1 top and locknut 2 top. 22. Loosen: • Rebound damping adjuster 1 N OTE: • Loosen the rebound damping a djuster finger tight. • Record the set position of the adju ster (the amount of tu ...

  • Yamaha WR250FM - page 265

    5 - 38 CHAS FRONT FORK 26. Tighten: • Front fork cap bolt (locknut) 1 N OTE: • While compressing the fork spring, set the thin type spanners 2 between the spacer 3 and spring guide 4 . • Hold the locknut 5 and t ighten the front fork cap bolt with specified torque. T R . . 29 Nm (2.9 m · kg, 21 ft · lb) 27. Install: • Front fork cap bolt ...

  • Yamaha WR250FM - page 266

    5 - 39 CHAS FRONT FORK 4. Tighten: • Pinch bolt (upper bracket) 1 • Pinch bolt (lower bracket) 2 CAUTION: Tighten the lower bracket to spec ified torque. If torqued too much, it may cause the front fork to malfunction. 5. Install: • Brake hose holder 1 • Brake caliper 2 • Bolt (brake caliper) 3 N OTE: Fit the brake hose holder cut a over ...

  • Yamaha WR250FM - page 267

    5 - 40 CHAS HANDLEBAR EC5B0000 HANDLEBAR Extent of removal: 1 Handlebar removal Extent of removal Order Part name Q ’ ty Remarks Preparation for removal HANDLEBAR REMOVAL Headlight 1 Hot starter ca ble 1 Discon nect at the lever side. 2 Hot starter l ever holder 1 3 Clutch cable 1 Disconnect at the lever side. 4 Clutch lever ho lder 1 Discon nect ...

  • Yamaha WR250FM - page 268

    5 - 41 CHAS EC5B3000 REMOVAL POINTS Brake master cylinder 1. Remove: • Brake master cylinder bracket 1 • Brake master cylinder 2 CAUTION: • Do not let the brake master cylinder hang on the brake hose. • Keep the brake master cylinder cap side horizontal to prevent air from coming in. EC5B3200 Grip 1. Remove: • Grip 1 N OTE: Blow in air be ...

  • Yamaha WR250FM - page 269

    5 - 42 CHAS EC5B5000 ASSEMBLY AND INSTALLATION Handlebar 1. Install: • Handlebar 1 • Handlebar upper holder 2 • Bolt (handlebar upper holder) 3 N OTE: • The handlebar upper ho lder should be installed with the punched mark a forward. • First tighten the bolts on the front side of the handlebar upper holder, and then tighten the bolts on t ...

  • Yamaha WR250FM - page 270

    5 - 43 CHAS HANDLEBAR 4. Install: • Grip cap cover 1 • Throttle grip 2 N OTE: Apply the lithium soap base grease on the throttle grip sliding surface. 5. Install: • Throttle cables 1 To tube guide 2 . N OTE: Apply the lithium soap base grease on the throttle cable end and tube guide cable wind- ing porti on. 6. Install: • Throttle cable cap ...

  • Yamaha WR250FM - page 271

    5 - 44 CHAS HANDLEBAR 8. Install: • Start switch 1 • Brake master cylinder 2 • Brake master cylinder bracket 3 • Bolt (brake master cy linder bracket) 4 • Clamp 5 N OTE: • The start switch and brake master cylinder bracket should be installed according to the dimensions shown. • Install the bracket so that the arrow mark a faces upwar ...

  • Yamaha WR250FM - page 272

    5 - 45 CHAS HANDLEBAR 11. Install: • Clutch cable 1 • Hot starter cable 2 N OTE: Apply the lithium soap base grease on the clutch cable end and hot starter cable end. 12. Adjust: • Clutch lever free play Refer to “ CLUTCH ADJUSTMENT ” sec- tion in the CHAPTER 3. • Hot starter lever free play Refer to “ HOT STARTER LEVER ADJUST MENT ? ...

  • Yamaha WR250FM - page 273

    5 - 46 CHAS EC560000 STEERING Extent of removal: 1 Lower bracket removal 2 Bearing removal Extent of removal Order Part name Q ’ ty Remarks STEERING REMOVAL W ARNING Support the machine securely so there is no danger of it falling over. Preparation for removal Hold the machine by placing the suitable stand unde r the engine . Headlight Handlebar ...

  • Yamaha WR250FM - page 274

    5 - 47 CHAS STEERING Extent of removal Order Part name Q ’ ty Remarks 10 Ball race cover 1 11 Upper bearing 1 12 Lower bearing 1 Refer to “ REMOVAL POINTS ” . 13 Ball race 2 2 ...

  • Yamaha WR250FM - page 275

    5 - 48 CHAS EC563000 REMOVAL POINTS Steering ring nut 1. Remove: • Steering ring nut 1 Use the steering nut wrench 2 . W ARNING Support the steering stem so that it may not fall down. Steering nut wrench: YU-33975/90890-01403 Lower bearing 1. Remove: • Lower bearing 1 Use the floor chisel 2 . CAUTION: Take care not to damage the steering shaft ...

  • Yamaha WR250FM - page 276

    5 - 49 CHAS EC564101 Bearing and ball race 1. Wash the bearings and ball races with a solvent. 2. Inspect: • Bearing 1 • Ball race Pitting/damage → Replace bearings and ball races as a set. Install the bearing in the ball races. Spin the bearings by hand. If the bearings hang up or are not smooth in their opera- tion in the ball races, replac ...

  • Yamaha WR250FM - page 277

    5 - 50 CHAS STEERING 4. Install: • Washer 1 • Steering ring nut 2 Tighten the steering ring nu t using the steering nut wrench 3 . Refer to “ STEERING HEAD INSPEC- TION AND ADJUSTMENT ” section in the CHAPTER 3. T R . . 7 Nm (0.7 m · kg, 5.1 ft · lb) 5. Check the steering stem by turning it lock to lock. If there is any binding, remove th ...

  • Yamaha WR250FM - page 278

    5 - 51 CHAS 8. Install: • Washer 1 • Steering stem nut 2 T R . . 145 Nm (14.5 m · kg, 105 ft · lb) 9. Install: • Steering stem cap 1 10. After tightening the nut, check the steering for smooth movement. If not, adjust the steering by loosening the steering ring nut little by little. 11. Adjust: • Front fork top end a * For AUS, NZ and ZA ...

  • Yamaha WR250FM - page 279

    5 - 52 CHAS STEERING 13. Install: • Trip meter 1 • Bolt (trip meter) 2 N OTE: Install the trip meter over the coupler bracket 3 . T R . . 7 Nm (0.7 m · kg, 5.1 ft · lb) ...

  • Yamaha WR250FM - page 280

    5 - 53 CHAS SWINGARM EC570000 SWINGARM Extent of removal: 1 Swingarm removal Extent of removal Order Part name Q ’ ty Remarks SWINGARM REMOVAL W ARNING Support the machine securely so there is no danger of it falling over. Preparation for removal Hold the machine by placing the suitable stand unde r the engine . Brake hose holder Rear brake calip ...

  • Yamaha WR250FM - page 281

    5 - 54 CHAS SWINGARM EC578000 SWINGARM DISASSEMBLY Extent of removal: 1 Swingarm disassembly 2 Co nnecting rod removal and disassembly 3 Relay arm removal and disassembly Extent of removal Order Part name Q ’ ty Remarks SWINGARM DISASSEMBLY 1 Cap 2 2 Relay arm 1 3 Connecting rod 1 4 Collar 2 5 Oil seal 2 6 Thrust bearing 2 7 Bushing 2 8 Oil seal ...

  • Yamaha WR250FM - page 282

    5 - 55 CHAS SWINGARM EC573000 REMOVAL POINTS EC573200 Bearing 1. Remove: • Bearing 1 N OTE: Remove the bearing by pressing its outer race. INSPECTION Wash the bearings, bushings, collars, and cov- ers in a solvent. Swingarm 1. Inspect: • Bearing 1 • Bushing 2 Free play exists/unsmooth revolution/rust → Replace bearing and bushing as a set. ...

  • Yamaha WR250FM - page 283

    5 - 56 CHAS SWINGARM EC574310 Connecting rod 1. Inspect: • Bearing (polylube bearing) 1 • Collar 2 Free play exists/unsmooth revolution/rust → Replace bearing and collar as a set. 2. Inspect: • Bearing (polylube bearing) 1 Loss of solid lubrication → Repla ce. • Oil seal 3 Damage → Replace. N OTE: Polylube bearings, with solid lubrica ...

  • Yamaha WR250FM - page 284

    5 - 57 CHAS SWINGARM 2. Install: • Bearing 1 • Oil seal 2 To relay arm. N OTE: • Apply the molybdenum disulfide grease on the bearing when installing. • Install the bearing by pressing it on the side having the manufacture ’ s mark s or numbers. 3. Install: • Bearing 1 • Oil seal 2 To connecting rod. N OTE: • Apply the molybdenum di ...

  • Yamaha WR250FM - page 285

    5 - 58 CHAS SWINGARM 3. Install: • Collar 1 To connecting rod 2 . N OTE: Apply the molybdenum disulfide grease on the collar and oil seal lips. 4. Install: • Connecting rod 1 • Bolt (connecting rod) 2 • Washer 3 • Nut (connecting ro d) 4 To relay arm 5 . N OTE: Apply the molybdenum disulfide grease on the bolt. 5. Install: • Relay arm 1 ...

  • Yamaha WR250FM - page 286

    5 - 59 CHAS SWINGARM 8. Install: • Bolt (connecting rod) 1 • Washer 2 • Nut (connecting ro d) 3 N OTE: • Apply the molybdenum disulfide grease on the bolt. • Do not tighten the nut yet. 9. Install: • Bolt (rear shock absorber-relay arm) 1 • Nut (rear shock absorber-relay arm) 2 N OTE: Apply the molybdenum disulfide grease on the bolt. ...

  • Yamaha WR250FM - page 287

    5 - 60 CHAS SWINGARM 13. Install: • Bolt (lower chain tensioner) 1 • Washer 2 • Collar 3 • Lower chain tensioner 4 • Nut (lower chain tensioner) 5 T R . . 20 Nm (2.0 m · kg, 14 ft · lb) 14. Install: • Drive chain support 1 • Drive chain support cover 2 • Bolt {drive chain support [ = 50 mm (1.97 in)]} 3 • N ut ( drive chain su p ...

  • Yamaha WR250FM - page 288

    5 - 61 CHAS REAR SHOCK ABSORBER EC580000 REAR SHOCK ABSORBER Extent of removal: 1 Rear shoc k absorber removal 2 Rear shock absorber disassembly Extent of removal Order Part name Q ’ ty Remarks REAR SHOCK ABSORBER REMOVAL W ARNING Support the machine securely so there is no danger of it falling over. Preparation for removal Hold the machine by pl ...

  • Yamaha WR250FM - page 289

    5 - 62 CHAS REAR SHOCK ABSORBER Extent of removal Order Part name Q ’ ty Remarks 1 Locking tie 2 2 Taillight coupler 1 3 Starting circuit cut-of f relay coupler 1 4 Plastic band 2 5 Clamp (air filter join t) 1 Only loosen ing. 6 Rear fra me 1 7B o l t (rear shock absorber-relay arm) 1 Hold the swingarm. 8 Bolt (rear shock absorber-frame) 1 9 Rear ...

  • Yamaha WR250FM - page 290

    5 - 63 CHAS HANDLING NOTE W ARNING This rear shock absorber is pro vided with a separate type tank filled with high -pressure nitrogen gas. To prevent the danger of explosion, read and understand the follow- ing information before handling the shock absorber. The manufacturer can not b e held respon- sible for property damage or personal injury tha ...

  • Yamaha WR250FM - page 291

    5 - 64 CHAS EC583000 REMOVAL POINTS EC583320 Bearing 1. Remove: • Stopper ring (upper bearing) 1 N OTE: Press in the bearing while pressing its outer race and remove the stopper rin g. 2. Remove: • Upper bearing 1 N OTE: Remove the bearing by pressing its outer race. 3. Remove: • Lower bearing 1 N OTE: Remove the bearing by pressing its outer ...

  • Yamaha WR250FM - page 292

    5 - 65 CHAS REAR SHOCK ABSORBER EC585000 ASSEMBLY AND INSTALLATION EC585300 Bearing 1. Install: • Upper bearing 1 N OTE: Install the bearing pa rallel until th e stopper ring groove appears by pressing its outer rac e. CAUTION: Do not apply the grease on the bearing outer race because it will wear the rear shock absorber surface o n which the bea ...

  • Yamaha WR250FM - page 293

    5 - 66 CHAS REAR SHOCK ABSORBER 2. Tighten: • Adjuster 1 3. Adjust: • Spring length (installed) a * For EUROPE N OTE: The length of the spring (installed) changes 1.5 mm (0.06 in) per turn of the adjuster. CAUTION: Never attempt to turn the adjuster be yond the maximum or minimum setting. 4. Tighten: • Locknut 1 Rear shock absorber 1. Install ...

  • Yamaha WR250FM - page 294

    5 - 67 CHAS REAR SHOCK ABSORBER 2. Install: • Bushing 1 • Collar 2 • Dust seal 3 N OTE: • Apply the molybdenum disulfide grease on the bearing. • Apply the lithium soap base grease on the bushing, collars and dust sea ls. • Install the dust seals with their lips facing out- ward. 3. Install: • Rear shock absorber 4. Install: • Bolt ...

  • Yamaha WR250FM - page 295

    5 - 68 CHAS REAR SHOCK ABSORBER 8. Install: • Plastic band 1 • Starting circuit cut-o ff relay coupler 2 • Taillight coupler 3 • Locking tie 4 3 2 1 4 ...

  • Yamaha WR250FM - page 296

    6 - 1 – + ELEC ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC600000 ELECTRICAL EC610000 ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC611000 ELECTRICAL COMPONENTS 1 Headlight 2 Engine stop switch 3 Clutch switch 4 Diode 5 Starter relay diode 6 Throttle position sen- sor 7 Starter relay 8 Fuse 9 Starting circuit cut- off relay 0 Taillight A Neutral swit ...

  • Yamaha WR250FM - page 297

    – + ELEC 6 - 2 MAP-CONTROLLED CDI UNIT MAP-CONTROLLED CDI UNIT A map-controlled, CDI ignition syste m is used in the WR250F. The microcomputer in the CDI unit detects t he engine speed and throttle position , thus determining the optimum ignition timing through th e entire operating range. In this way, quick throttle response can be achieved acco ...

  • Yamaha WR250FM - page 298

    –+ ELEC 6 - 3 IGNITION SYSTEM EC620000 IGNITION SYSTEM INSPECTION STEPS Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure and for checking the spark plug which will not spark. *1 marked: Refer to “FUSE INSPECTION” section in t he CHAPTER 3. *2 marked: Refer to “BA ...

  • Yamaha WR250FM - page 299

    6 - 4 – + ELEC IGNITION SYSTEM SPARK GAP TEST 1. Disconnect the ignition coil from spark plug. 2. Remove the ignition coil cap. 3. Connect the dynamic spark tester 1 (igni- tion checker 2 ) as shown. • Ignition coil 3 • Spark plug 4 È For USA and CDN É Except for USA and CDN 4. Kick the kicksta rter crank. 5. Check the ignition sp ark gap. ...

  • Yamaha WR250FM - page 300

    6 - 5 – + ELEC IGNITION SYSTEM 2. Inspect: • Rubber part a Tears/damage → Replace. a MAIN SWITCH INSPECTION 1. Inspect: • Main switch conduct Continuous while the main switch is moved to “ OFF ” → Replace. Not continuous while the main switch is moved to “ ON ” → Replace. Tester (+) lead → Red lead 1 Tester ( – ) lead → Br ...

  • Yamaha WR250FM - page 301

    6 - 6 – + ELEC EC626002 IGNITION COIL INSPECTION 1. Remove the ignition coil cap. 2. Inspect: • Primary coil r esistance Out of specification → Replace. Tester (+) lead → Orange lead 1 Tester ( – ) lead → Black lead 2 Primary coil resistance Tester selector position 0.08 ~ 0.10 Ω at 20 ° C (68 ° F) Ω × 1 3. Inspect: • Secondary ...

  • Yamaha WR250FM - page 302

    6 - 7 – + ELEC IGNITION SYSTEM AC MAGNETO INSPECTION 1. Inspect: • Pickup coil resi stance Out of specification → Replace. Tester (+) lead → Red lead 1 Tester ( – ) lead → White lead 2 Pickup coil resistance Tester selector position 248 ~ 372 Ω at 20 ° C (68 ° F) Ω × 100 RW 1 2 NEUTRAL SWITCH INSPECTION 1. Inspect: • Neutral sw ...

  • Yamaha WR250FM - page 303

    6 - 8 – + ELEC ELECTRIC STARTING SYSTEM STARTING CIRCUIT CUT-OFF SYSTEM OPERATION If the main switch is set to “ ON ” , the starter motor can only operate if at least one of the fol- lowing conditions is met: • The transmission is in neutral (the neutral switch is closed). • The clutch lever is pulled to th e handlebar (the clutch switch ...

  • Yamaha WR250FM - page 304

    – + ELEC 6 - 9 ELECTRIC STARTING SYSTEM INSPECTION STEPS If the starter motor will not operate , use the following inspection step s. *1 marked: Refer to “ FUSE INSPECTION ” section in the CHAPTER 3. *2 marked: Refer to “ BATTERY INSPECTION AND CHAR GING ” section in the CHAPTER 3. *3 marked: Refer to “ MAIN SWITCH INSPECTION ” sectio ...

  • Yamaha WR250FM - page 305

    6 - 10 – + ELEC ELECTRIC STARTING SYSTEM EC624000 COUPLERS AND LEADS C ONNECTION INSPECTION 1. Check: • Couplers and lead s connection Rust/dust/looseness/short-circuit → Repair or replace. STARTER MOTOR OPERATION 1. Connect the positive battery terminal 1 and starter motor lead 2 with a jumper lead 3 . Not operate → Repair or replace the s ...

  • Yamaha WR250FM - page 306

    6 - 11 – + ELEC ELECTRIC STARTING SYSTEM STARTER RELAY INSPECTION 1. Remove: • Starter relay 2. Inspect: • Starter relay conduct Use 12 V battery. Continuous while not connected to the battery → Replace. Not continuous while connected to the battery → Replace. Battery (+) lead → Starter relay terminal 1 Battery ( – ) lead → Starter ...

  • Yamaha WR250FM - page 307

    6 - 12 – + ELEC ELECTRIC STARTING SYSTEM DIODE INSPECTION 1. Remove the diode from wire harne ss. 2. Inspect: • Diode continuity Use pocket tester (tester selection position Ω × 1) Incorrect continuity → Replace. Tester (+) → Blue/Red terminal 1 Tester ( – ) → Sky blue terminal 2 Continuous Tester (+) → Blue/Red terminal 1 Tester ( ...

  • Yamaha WR250FM - page 308

    6 - 13 – + ELEC ELECTRIC STARTING SYSTEM STARTER MOTOR 6 7 8 7 8 3 4 5 3 1 2 New B New New 1 Extent of removal: 1 Starter motor disassembly Extent of removal Order Part name Q ’ ty Remarks STARTER MOTOR REMOVAL Exhaust pipe Refer to “ EXHAUST PIPE AND SILENCER ” section in the CHAPTER 4. Preparation for removal 1 Starter motor 1 STARTER MOT ...

  • Yamaha WR250FM - page 309

    6 - 14 – + ELEC ELECTRIC STARTING SYSTEM INSPECTION AND REPAIR 1. Check: • Commutator Dirt → Clean with 600 gr it sandpaper. 2. Measure: • Commutator diameter a Out of specification → Replace the starter motor. 3. Measure: • Mica undercut a Out of specification → Scrape the mica to the proper measurement with a hacksaw blade which has ...

  • Yamaha WR250FM - page 310

    6 - 15 – + ELEC ELECTRIC STARTING SYSTEM 5. Measure: • Brush length a Out of specification → Replace the brushes as a set. Min. brush length: 3.5 mm (0.14 in) 6. Measure: • Brush spri ng force Out of specification → Replace the brush springs as a set. Brush spring force: 3.92 ~ 5.88 N (400 ~ 600 gf, 14.1 ~ 21.2 oz) ASSEMBLY 1. Install: ? ...

  • Yamaha WR250FM - page 311

    6 - 16 – + ELEC ELECTRIC STARTING SYSTEM 4. Install: • Gasket 1 • Circlip • Plain washer 2 • Washer (starter motor front cover) 3 • Starter motor front cover 4 N OTE: • For installation, align the projections on the washer with the slots in the front cover. • Align the match mark a on the starter motor yoke with the match mark b on ...

  • Yamaha WR250FM - page 312

    – + ELEC 6 - 17 CHARGING SYSTEM EC680000 CHARGING SYSTEM EC681001 INSPECTION STEPS If the battery is not charged, use the following inspection steps. *1 marked: Refer to “ FUSE INSPECTION ” section in the CHAPTER 3. *2 marked: Refer to “ BATTERY INSPECTION AND CHAR GING ” section in the CHAPTER 3. N OTE: • Remove the following parts bef ...

  • Yamaha WR250FM - page 313

    6 - 18 – + ELEC CHARGING SYSTEM EC624000 COUPLERS AND LEADS C ONNECTION INSPECTION 1. Check: • Couplers and lead s connection Rust/dust/looseness/short-circuit → Repair or replace. CHARGING VOLTAGE INSPECTION 1. Start the engine. 2. Inspect: • Charging voltage Out of specification → If no failure is found in checking the source coil resis ...

  • Yamaha WR250FM - page 314

    – + ELEC 6 - 19 THROTTLE POSITION SENSOR SYSTEM THROTTLE POSITION SENSOR SYSTEM INSPECTION STEPS If the throttle position sensor will not operate, use the following inspection steps. N OTE: Use the following special tools in this inspection. Pocket tester: YU-3112-C/90890-03112 Inductive tachometer: YU-8036-B Engine tachometer: 90890-03113 Check ...

  • Yamaha WR250FM - page 315

    6 - 20 – + ELEC THROTTLE POSITION SENSOR SYSTEM HANDLING NOTE CAUTION: Do not loosen the screws (throttle position sensor) 1 except when changing the throt- tle position sensor due to failure because it will cause a drop in engine performance. 1 EC624000 COUPLERS AND LEADS C ONNECTION INSPECTION 1. Check: • Couplers and lead s connection Rust/d ...

  • Yamaha WR250FM - page 316

    6 - 21 – + ELEC THROTTLE POSITION SENSOR SYSTEM 3. Inspect: • Throttle position sensor coil variable resistance Check that the resistance in increased as the throttle grip is moved from t he full close position to the fu ll open position. Out of specification → Replace. Tester (+) lead → Yellow lead 1 Tester ( – ) lead → Black lead 2 Th ...

  • Yamaha WR250FM - page 317

    6 - 22 – + ELEC THROTTLE POSITION SENSOR SYSTEM 4. Adjust: • Engine idling speed Refer to “ ENGINE IDLING SPEED ADJUST MENT ” section in th e CHAPTER 3. 5. Insert the thin electric conductors 2 (lead) into the throttle position sensor coupler 1 , as shown, and connect the tester to them. CAUTION: • Do not insert the electric conductors mo ...

  • Yamaha WR250FM - page 318

    6 - 23 – + ELEC THROTTLE POSITION SENSOR SYSTEM 8. Tighten: • Screw (throttle position sensor) 1 9. Stop the engine. 1 THROTTLE POSITION SENSOR INPUT VOLTAGE INSPECTION 1. Disconnect the throttle position sen sor cou- pler. 2. Start the engine. 3. Inspect: • Throttle position sensor input voltage Out of specification → Replace t he CDI unit ...

  • Yamaha WR250FM - page 319

    – + ELEC 6 - 24 LIGHTING SYSTEM LIGHTING SYSTEM INSPECTION STEPS Refer to the following flow chart wh en inspecting the ignition system for possible p roblems. N OTE: • Replace the bulb and/or bulb socket. 1) Seat 2) Fuel tank • Use the following special tool. Check the bulb and bulb socket. Replace the bulb and/ or bulb socket. Check the lig ...

  • Yamaha WR250FM - page 320

    6 - 25 – + ELEC LIGHTING SYSTEM LIGHT SWITCH INSPECTION 1. Inspect: • Light switch conduct No continuous while being → Replace. Continuous while being OFF → Replace. Tester (+) lead → Yellow lead 1 Tester ( – ) lead → Blue lead 2 Y 1 L 2 Tester sele ctor position Ω × 1 OFF AC MAGNETO INSPECTION 1. Inspect: • Lighting coil resista ...

  • Yamaha WR250FM - page 321

    7 - 1 TUN EC700000 TUNING EC710000 ENGINE Carburetor setting • The air/fuel mixture will vary depending on atmospheric conditions. Therefore, it is nec- essary to take into consideration the a ir pres- sure, ambient temperature, humidity, et c., when adjusting the carburetor. • Perform a test run to check for proper engine performance (e.g., th ...

  • Yamaha WR250FM - page 322

    7 - 2 TUN CAUTION: • The carburetor is extremely sensitive to foreign matter (dirt, sand, water, etc.). During installation, do not allow foreign matter to get into the carburetor. • Always handle the carburetor and its components carefully. Even slight scratches, bends or damage to carburetor parts may prevent the carburetor from functioning c ...

  • Yamaha WR250FM - page 323

    7 - 3 TUN SETTING Effects of the setting parts on the throttle valve opening È Closed É Fully open 1 Pilot screw/pilot jet 2 Throttle valve cutaway 3 Jet needle 4 Main jet 1/2 3/4 1/4 1/8 1 2 3 4 ÈÉ Main system The FLATCR carburetor has a primary ma in jet. This type of main jet is perfect for racing motorcycles since it supplies an even flow o ...

  • Yamaha WR250FM - page 324

    7 - 4 TUN SETTING 1 Jet needle 2 Pilot air jet 3 Needle jet 4 Main jet 5 Pilot jet 6 Pilot screw Main j et ad justm ent The richness of the air-fuel mixture at full throt- tle can be set by changing the main jet 1 . * Except for USA If the air-fuel mixture is too rich or too lean, the engine power will drop, resulting in poor accel- eration. Effect ...

  • Yamaha WR250FM - page 325

    7 - 5 TUN SETTING Pilot screw adjustment The richness of the air-fuel mixtu re with the throttle fully closed to 1/4 open can be set by turning the pilot screw 1 . Turning in the pilot screw will make the mixture lean at low speeds, and turning it ou t will enrich it. * Except for USA N OTE: • If the engine idling speed fluctuates, turn the pilot ...

  • Yamaha WR250FM - page 326

    7 - 6 TUN SETTING Effects of adjusting the pilot jet (reference) È Idle É Fully open 1/4 1/2 3/4 +5% – 5% #42 #38 #40 È É Jet needle groove position adjustment Adjusting the jet needle 1 position affects the acceleration when the throttle is 1/ 8 to 3/4 open. 1. Too rich at intermediate speeds Rough engine operation is felt and the engine wil ...

  • Yamaha WR250FM - page 327

    7 - 7 TUN Jet needle adjustment The jet needle is adjusted by changing it . * Except for USA The tapered sections of all jet needles have the same starting positions, but the needles are available with different straight-portion diameters. Standard jet needle OBDVS * OBELP <Example> OBDVS - 4 Clip position Diameter a of straight por tion Effe ...

  • Yamaha WR250FM - page 328

    7 - 8 TUN Leak jet adjustment (accelerator pump adjustment) The leak jet 1 is a setting part that adjusts the flow of fuel discharged by the accelerator pump. Since the accelerator pump operates only when throttle is open, the leak jet is used to adjust a fuel mixture ratio for quick throttle opening and is therefore different from other setting pa ...

  • Yamaha WR250FM - page 329

    7 - 9 TUN SETTING EC71Q000 Carburetor setting parts * Except for USA Part name Size Part number Main jet Rich (STD) * (STD) Lean #198 #195 #192 #190 #188 #185 #182 #180 #178 #175 #172 #170 #168 #165 #162 #160 4MX-14943-97 4MX-14943-46 4MX-14943-96 4MX-14943-45 4MX-14943-95 4MX-14943-44 4MX-14943-94 4MX-14943-43 4MX-14943-93 4MX-14943-42 4MX-14943-9 ...

  • Yamaha WR250FM - page 330

    7 - 10 TUN Examples of carburet or setting depending on symptom This should be taken simply for an example. It is necessary to set the carbure tor while checking the operating conditions of the eng ine. Symptom Setting Checking At full throttle Hard breathing Shearing noise Whitish spark plug ↓ Lean mixture Increase main jet calibration no . (Gra ...

  • Yamaha WR250FM - page 331

    7 - 11 TUN EC720000 CHASSIS Selection of the seconda ry reduction ratio (Sprocket) <Requirement for selection of secondary gear reduction ratio> • It is generally said that the secondary gear ratio should be reduced for a lo nger straight portion of a speed course and sh ould be increased for a course with ma ny corners. Actually, however, ...

  • Yamaha WR250FM - page 332

    7 - 12 TUN SETTING EC72N000 Drive and rear wheel sprockets setting parts * For AUS and NZ Part name Size Part number Drive sprocket 1 (STD) 13T 9383B-13218 Rear wheel sprocket 2 (STD) * (STD) 48T * 48T * 49T 50T * 50T * 51T 52T * 52T 54T 5GS-25448-50 5NY-25448-00 5NY-25449-00 5GS-25450-50 5NY-25450-00 5NY-25451-00 5GS-25452-50 5NY-25452-00 5PH-2545 ...

  • Yamaha WR250FM - page 333

    7 - 13 TUN SETTING EC722011 Front fork setting The front fork setting should be made depend- ing on the rider ’ s feeling of an actual run and the circuit conditions. The front fork setting includes the follo wing three factors: 1. Setting of air spring ch aracteristics • Change the fork oil level. 2. Setting of spring preload • Change the sp ...

  • Yamaha WR250FM - page 334

    7 - 14 TUN SETTING È Air spring character istics in relation to oil level change É Load Ê Stroke 1 Max. oil level 2 Standard oil level 3 Min. oil level EC727020 Spring preload adjustment The spring preload is adjusted by installing the adjustment washer 1 between the fork spring 2 and damper rod 3 . CAUTION: Do not install three or more adjustme ...

  • Yamaha WR250FM - page 335

    7 - 15 TUN EC72A001 Setting of spring after replacement As the front fork setting can be easily affected by rear suspension, take care so that the machine front and rear are balanced (in posi- tion, etc.) when setting the front fork. 1. Use of soft spring Generally a soft spring gives a soft riding feeling. Rebound damping tends to become stronger ...

  • Yamaha WR250FM - page 336

    7 - 16 TUN EC72P000 Front fork setting parts • Adjustment washer 1 • Front fork spring 2 [Equal pitch spring] * For EUROPE ** For AUS, NZ and ZA [Unequal pitch spring] N OTE: • The unequal pitch spring is softer in initial characteristic than the equal pitch spring and is difficult to bottom out under full compre s- sion. • The I.D. mark (s ...

  • Yamaha WR250FM - page 337

    7 - 17 TUN EC72B000 Rear suspension setting The rear suspension setting should be made depending on the rider ’ s feeling of an actual run and the circuit conditio ns. The rear suspension setting includes the fol- lowing two factors: 1. Setting of spring preload • Change the set length of t he spring. • Change the spring. 2. Setting of dampin ...

  • Yamaha WR250FM - page 338

    7 - 18 TUN SETTING N OTE: • If the machine is new and after it is broken in, the same set length of the spring may change because of the initial fatigue, etc. of the spring. Therefore, be sure to make re- evaluation. • If the standard figure cannot be achieved by adjusting the spring adjuster and changing the spring set length, replace the spri ...

  • Yamaha WR250FM - page 339

    7 - 19 TUN CAUTION: When using a rear shock absorber other than currently installed, use the one whose overall length a does not exceed the stan- dard as it may result in faulty performa nce. Never use one whose overall length is greater than standard. È Coverage of spring by weight É Rider weight 1 Soft 2 Standard 3 Stiff Length a of standard sh ...

  • Yamaha WR250FM - page 340

    7 - 20 TUN SETTING EC72Q000 Rear shock absorber setting parts • Rear shock spring 1 [Equal pitch spring] * For EUROPE ** For AUS, NZ and ZA [Unequal pitch spring] N OTE: • The unequal pitch spring is softer in initial characteristic than the equal pitch spring and is difficult to bottom out under full compre s- sion. • The I.D. color a is mar ...

  • Yamaha WR250FM - page 341

    7 - 21 TUN SETTING EC72H002 Suspension setting • Front fork N OTE: • If any of the following symptoms is experienced with the standard p osition as the base, make resetting by reference to the adjustment procedure given in the same chart. • Before any change, set the rear shock absorber sunken length to the standard figu re 90 ~ 100 mm (3.5 ~ ...

  • Yamaha WR250FM - page 342

    7 - 22 TUN SETTING • Rear shock absorber N OTE: • If any of the following symptoms is experienced with the standard p osition as the base, make resetting by reference to the adjustment procedure given in the same chart. • Adjust the rebound damping in 2-click in crements or decrements. • Adjust the low compression damping in 1-click increme ...

  • Yamaha WR250FM - page 343

    PRINTED IN JAPAN 2002.11-1.8 × 1 CR (E) PRINTED ON RECYCLED PAPER Y AMAHA MO T OR CO . , L TD . 2500 SHINGAI IW A T A SHIZUOKA JAP AN ...

Manufacturer Yamaha Category Bicycle

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