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Yamaha YZ250F 2008 Owner's Service Manual

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2008
OWNER'S SERVICE MANUAL
MANUEL D'ATELIER DU
PROPRIETAIRE
FAHRER- UND
WARTUNGSHANDBUCH
MANUALE DI SERVIZIO DEL
PROPRIETARIO
YZ250F(X)
5XC-28199-34

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Summary of Contents for Yamaha YZ250F 2008

  • Page 1 2008 OWNER’S SERVICE MANUAL MANUEL D’ATELIER DU PROPRIETAIRE FAHRER- UND WARTUNGSHANDBUCH MANUALE DI SERVIZIO DEL PROPRIETARIO YZ250F(X) 5XC-28199-34...
  • Page 3 2008 OWNER’S SERVICE MANUAL YZ250F(X) 5XC-28199-34-E0...
  • Page 5 YZ250F(X) OWNER'S SERVICE MANUAL ©2007 by Yamaha Motor Co., Ltd. 1st Edition, April 2007 All rights reserved.Any reprinting or unauthorized use without the written permission of Yamaha Motor Co., Ltd. is expressly prohibited. Printed in Japan...

  • Page 6: Important Notice

    FOREWARD 5. GASOLINE IS HIGHLY FLAM- A CAUTION indicates special pre- MABLE. INTRODUCTION cautions that must be taken to avoid Always turn off the engine Congratulations on your purchase of damage to the machine. while refueling. Take care to a Yamaha YZ series. This model is not spill any gasoline on the the culmination of Yamaha's vast ex- engine or exhaust system.

  • Page 7: General Information

    and item. 10. PROPERLY SECURE THE Bend the book at its edge, as MACHINE BEFORE TRANS- shown, to find the required fore PORTING IT. edge symbol mark and go to a When transporting the ma- page for required item and de- chine in another vehicle, al- scription.
  • Page 8 der of the jobs in the exploded di- 4. A job instruction chart "4" accom- HOW TO READ DESCRIPTIONS agram. A number that is enclosed panies the exploded diagram, To help identify parts and clarify pro- by a circle indicates a disassem- providing the order of jobs, names cedure steps, there are exploded dia- bly step.
  • Page 9 TABLE OF CONTENTS GENERAL INFORMATION SPECIFICATIONS REGULAR INSPECTION AND ADJUSTMENTS ENGINE CHASSIS ELECTRICAL TUNING...
  • Page 10 CONTENTS CHAPTER 1 CHAPTER 3 CHAPTER 5 GENERAL INFOR- REGULAR INSPEC- CHASSIS MATION TION AND AD- JUSTMENTS FRONT WHEEL AND REAR WHEEL ....5-1 DESCRIPTION ....1-1 FRONT BRAKE AND MACHINE MAINTENANCE REAR BRAKE ....5-6 IDENTIFICATION ..... 1-2 INTERVALS...... 3-1 FRONT FORK....5-16 INCLUDED PARTS ..

  • Page 11: Description

    DESCRIPTION GENERAL INFORMATION DESCRIPTION Clutch lever 14. Fuel cock Hot starter lever 15. Cold starter knob Front brake lever 16. Drive chain Throttle grip 17. Air filter Radiator cap 18. Oil level check window Fuel tank cap 19. Shift pedal Engine stop switch 20.

  • Page 12: Machine Identification

    MACHINE IDENTIFICATION MACHINE IDENTIFICATION IMPORTANT INFORMATION There are two significant reasons for PREPARATION FOR REMOVAL knowing the serial number of your AND DISASSEMBLY machine: 1. Remove all dirt, mud, dust, and 1. When ordering parts, you can foreign material before removal give the number to your Yamaha and disassembly.

  • Page 13: Checking Of Connection

    CHECKING OF CONNECTION age to the bearing surfaces. 4. During the machine disassembly, clean all parts and place them in trays in the order of disassembly. This will speed up assembly time and help assure that all parts are correctly reinstalled. 6.

  • Page 14: Special Tools

    SPECIAL TOOLS SPECIAL TOOLS The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or improvised techniques. The shape and part number used for the special tool differ by country, so two types are provided.
  • Page 15 SPECIAL TOOLS Tool name/Part number How to use Illustration Radiator cap tester These tools are used for checking YU-24460-01, 90890-01325 the cooling system. Radiator cap tester adapter YU-33984, 90890-01352 Steering nut wrench This tool is used when tighten the YU-33975, 90890-01403 steering ring nut to specification.
  • Page 16 SPECIAL TOOLS Tool name/Part number How to use Illustration Timing light This tool is necessary for checking YM-33277-A, 90890-03141 ignition timing. Valve spring compressor This tool is needed to remove and YM-4019, 90890-04019 install the valve assemblies. Clutch holding tool This tool is used to hold the clutch YM-91042, 90890-04086 when removing or installing the...
  • Page 17 SPECIAL TOOLS Tool name/Part number How to use Illustration Dynamic spark tester This instrument is necessary for YM-34487 checking the ignition system compo- Ignition checker nents. 90890-06754 YAMAHA Bond No. 1215 (ThreeB- This sealant (Bond) is used for ® No. 1215) crankcase mating surface, etc.

  • Page 18: Control Functions

    CONTROL FUNCTIONS CONTROL FUNCTIONS ENGINE STOP SWITCH The engine stop switch "1" is located on the left handlebar. Continue push- ing the engine stop switch till the en- gine comes to a stop. THROTTLE GRIP COLD STARTER KNOB The throttle grip "1" is located on the When cold, the engine requires a right handlebar;...
  • Page 19 STARTING AND BREAK-IN 6. Return the cold starter knob to its The engine fails to start original position and run the en- Pull the hot starter lever all the way If knocking or pinging occurs, use a gine at 3,000–5,000 r/min for 1 or out and while holding the lever, kick different brand of gasoline or higher 2 minutes.
  • Page 20 STARTING AND BREAK-IN BREAK-IN PROCEDURES 1. Before starting the engine, fill the fuel tank with the fuel. 2. Perform the pre-operation checks on the machine. 3. Start and warm up the engine. Check the idle speed, and check the operation of the controls and the engine stop switch.

  • Page 21: Torque-Check Points

    TORQUE-CHECK POINTS TORQUE-CHECK POINTS Frame construction Frame to rear frame Combined seat and fuel tank Fuel tank to frame Exhaust system Silencer to rear frame Engine mounting Frame to engine Engine bracket to engine Engine bracket to frame Steering Steering stem to handlebar Steering stem to frame Steering stem to upper bracket Upper bracket to handlebar...

  • Page 22: Cleaning And Storage

    CLEANING AND STORAGE CLEANING AND STORAGE the carburetor float bowl. 2. Remove the spark plug, pour a ta- CLEANING blespoon of SAE 10W-30 motor Frequent cleaning of your machine oil in the spark plug hole, and re- will enhance its appearance, maintain install the plug.

  • Page 23: General Specifications

    GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model name: YZ250FX (USA, CDN, AUS, NZ) YZ250F (EUROPE, ZA) Model code number: 5XCL (USA,CDN) 5XCM (EUROPE) 5XCP (AUS, NZ, ZA) Dimensions: USA, CDN, ZA, AUS, NZ EUROPE Overall length 2,162 mm (85.12 in) 2,165 mm (85.24 in) ←...

  • Page 24: Chassis

    GENERAL SPECIFICATIONS Fuel: Type Premium unleaded gasoline only with a research octane number of 95 or higher. Tank capacity 7.0 L (1.54 Imp gal, 1.85 US gal) Carburetor: Type FCR-MX37 Manufacturer KEIHIN Spark plug: Type/manufacturer CR8E/NGK (resistance type) 0.7–0.8 mm (0.028–0.031 in) Clutch type: Wet, multiple-disc Transmission:...

  • Page 25: Maintenance Specifications

    MAINTENANCE SPECIFICATIONS Rear wheel travel 306 mm (12.0 in) Electrical: Ignition system CDI magneto MAINTENANCE SPECIFICATIONS ENGINE Item Standard Limit Cylinder head: Warp limit ---- 0.05 mm (0.002 Cylinder: Bore size 77.00–77.01 mm (3.0315–3.0319 in) ---- Out of round limit ---- 0.05 mm (0.002 Camshaft:...
  • Page 26 MAINTENANCE SPECIFICATIONS Item Standard Limit Valve, valve seat, valve guide: Valve clearance (cold) 0.10–0.15 mm (0.0039–0.0059 in) ---- 0.17–0.22 mm (0.0067–0.0087 in) ---- Valve dimensions: "A" head diameter (IN) 22.9–23.1 mm (0.9016–0.9094 in) ---- "A" head diameter (EX) 24.4–24.6 mm (0.9606–0.9685 in) ---- "B"...
  • Page 27 MAINTENANCE SPECIFICATIONS Item Standard Limit 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 Valve seat width (EX) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630 Valve spring: Free length (IN) 37.81 mm (1.49 in) 36.81 mm (1.45 Free length (EX)
  • Page 28 MAINTENANCE SPECIFICATIONS Item Standard Limit 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) 0.15–0.25 mm (0.006–0.010 in) 0.50 mm (0.020 Side clearance (installed)
  • Page 29 MAINTENANCE SPECIFICATIONS Item Standard Limit Quantity ---- Warp limit ---- 0.1 mm (0.004 Clutch spring free length 35.7 mm (1.41 in) 34.7 mm (1.37 Quantity ---- Clutch housing thrust clearance 0.10–0.35 mm (0.0039–0.0138 in) ---- Clutch housing radial clearance 0.010–0.044 mm (0.0004–0.0017 in) ---- Clutch release method Inner push, cam push...
  • Page 30 MAINTENANCE SPECIFICATIONS Item Standard Limit Height 240 mm (9.4 in) ---- Thickness 22 mm (0.9 in) ---- Radiator cap opening pressure 110 kPa (1.1 kg/cm , 15.6 psi) ---- Radiator capacity (total) 0.58 L (0.51 Imp qt, 0.61 US qt) ---- Water pump Type...
  • Page 31 MAINTENANCE SPECIFICATIONS Item Standard Limit Rear wheel type Spoke wheel ---- Front rim size/material 21 × 1.60/Aluminum ---- Rear rim size/material 19 × 1.85/Aluminum ---- Rim runout limit: Radial ---- 2.0 mm (0.08 Lateral ---- 2.0 mm (0.08 Drive chain: Type/manufacturer DID520DMA2 SDH/DAIDO ----...

  • Page 32: Tightening Torques

    TIGHTENING TORQUES Item Standard Limit Ω Pickup coil resistance (color) 248–372 at 20 °C (68 °F) (White–Red) ---- CDI unit-model/manufacturer 5XC-L0/YAMAHA (For USA and CDN) ---- 5XC-M0/YAMAHA (For EUROPE, AUS, ---- NZ and ZA) Ignition coil: Model/manufacturer 5UL-10/DENSO ---- Minimum spark gap 6 mm (0.24 in) ---- Ω...
  • Page 33 TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb Oil tank drain bolt M8 × 1.25 Oil tank (upper) M6 × 1.0 Oil tank and frame M6 × 1.0 Carburetor joint clamp M4 × 0.7 Air filter joint clamp M6 ×...
  • Page 34 TIGHTENING TORQUES CHASSIS △ - marked portion shall be checked for torque tightening after break-in or before each race. Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb △ Upper bracket and outer tube M8 × 1.25 △ Lower bracket and outer tube M8 ×...
  • Page 35 TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb △ Rear brake disc cover M6 × 1.0 △ Rear brake caliper protector M6 × 1.0 Drive chain puller adjust bolt and locknut M8 × 1.25 Engine mounting: △...
  • Page 36 TIGHTENING TORQUES 1. First, tighten the steering ring nut approximately 38 Nm (3.8 m•kg, 27 ft•lb) by using the steering nut wrench, then loosen the steering ring nut one turn. 2. Retighten the steering ring nut 7 Nm (0.7 m•kg, 5.1 ft•lb). ELECTRICAL Tightening torque Part to be tightened...
  • Page 37 TIGHTENING TORQUES GENERAL TORQUE TORQUE SPECIFI- SPECIFICATIONS CATION (Bolt This chart specifies torque for stan- (Nut) dard fasteners with standard I.S.O. m•kg ft•lb pitch threads. Torque specifications 6 mm for special components or assem- blies are included in the applicable sections of this book.

  • Page 38: Lubrication Diagrams

    LUBRICATION DIAGRAMS LUBRICATION DIAGRAMS Oil filter element Oil pump Drive axle Main axle Intake camshaft Exhaust camshaft Oil tank Oil delivery pipe To oil tank 2-16...
  • Page 39 LUBRICATION DIAGRAMS Crankshaft Oil filter element Oil tank Oil hose From oil pump 2-17...

  • Page 40: Cable Routing Diagram

    CABLE ROUTING DIAGRAM CABLE ROUTING DIAGRAM Fuel tank breather hose 10. Hot starter cable Aligh the paint mark on the cylin- Radiator hose 1 11. Fuel hose der head breather hose with the Connector cover 12. Carburetor overflow hose front end of the hose guide. Cylinder head breather hose Insert the end of the fuel tank Pass the cylinder head breather...
  • Page 41 CABLE ROUTING DIAGRAM Pass the clutch cable in front of the radiator mounting boss. Pass the fuel hose between the hot starter cable and throttle po- sition sensor lead. Pass the carburetor breater hos- es so that they are not pinched between the upper engine bracket and carburetor.
  • Page 42 CABLE ROUTING DIAGRAM Hot starter cable 12. Radiator breather hose Fasten the throttle position sen- Radiator hose 2 13. Engine stop switch lead sor lead behind the hump of the Clamp 14. Sub-wire harness frame. Ignition coil lead 15. CDI unit bracket Fasten the neutral switch lead Throttle position sensor lead 16.
  • Page 43 CABLE ROUTING DIAGRAM Fasten the neutral switch lead, CDI magneto lead, radiator breather hose and clutch cable over the radiator mounting boss. Pass the radiator breather hose in front of the radiator, on the left of the chassis, and then be- tween the frame and radiator hose 4.
  • Page 44 CABLE ROUTING DIAGRAM Throttle cable (pull) Pass the cylinder head breather Throttle cable (return) hose so that it does not contact Radiator hose 2 the ignition coil. Ignition coil Fasten the throttle cables with Cylinder head breather hose the clamp so that the cables are Clamp not bent, and pass them under Rear arm bracket...
  • Page 45 CABLE ROUTING DIAGRAM Brake master cylinder If the brake hose contacts the Brake hose holder spring (rear shock absorber), Brake hose correct its twist. Install the brake hose so that its Install the brake hose so that its pipe portion directs as shown pipe portion directs as shown and lightly touches the projec- and lightly touches the projec-...
  • Page 46 CABLE ROUTING DIAGRAM Throttle cable Pass the clutch cable and hot Clamp starter cable through the cable Hot starter cable guide. Clutch cable Pass the brake hose in front of Engine stop switch lead the number plate. Cable guide Pass the throttle cables through Brake hose the cable guide.

  • Page 47: Regular Inspection And

    MAINTENANCE INTERVALS REGULAR INSPECTION AND ADJUSTMENTS MAINTENANCE INTERVALS The following schedule is intended 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 intervals. If you are a doubt as to what intervals to follow in maintaining and lubricating your machine, consult your Yamaha dealer.

  • Page 48: Maintenance Intervals

    MAINTENANCE INTERVALS Every Every After third fifth (or Every As re- Item break- Remarks race (or 500 1,000 quired CYLINDER ● Inspect and clean Inspect score marks. ● Replace Inspect wear. CLUTCH ● ● Inspect and adjust Inspect housing, friction plate, clutch plate and spring.
  • Page 49 MAINTENANCE INTERVALS Every Every After third fifth (or Every As re- Item break- Remarks race (or 500 1,000 quired OIL STRAINER ● Clean FRAME ● ● Clean and inspect FUEL TANK, COCK ● ● Clean and inspect BRAKES ● ● Adjust lever position and pedal height ●...
  • Page 50 MAINTENANCE INTERVALS Every Every After third fifth (or Every As re- Item break- Remarks race (or 500 1,000 quired TIRE, WHEELS ● ● Inspect air pressure, wheel run- out, tire wear and spoke loose- ness ● ● Retighten sprocket bolt ●...
  • Page 51 PRE-OPERATION INSPECTION AND MAINTENANCE 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 points. GENERAL INSPECTION AND MAINTENANCE Item Routine Page Check that coolant is filled up to the radiator cap.

  • Page 52: Engine

    ENGINE ENGINE gine. 2. Remove: CHECKING THE COOLANT LEVEL • When coolant splashes to your • Coolant drain bolt "1" eye. Thoroughly wash your eye with Do not remove the radiator cap water and see your doctor. "1", drain bolt and hoses when the •...
  • Page 53 ENGINE 2. Apply the specified pressure. ADJUSTING THE CLUTCH CABLE ADJUSTING THE THROTTLE FREE PLAY CABLE FREE PLAY Radiator cap opening 1. Check: 1. Check: pressure: • Clutch lever free play "a" • Throttle grip free play "a" 110 kPa (1.1 kg/cm →...
  • Page 54 ENGINE 5. Install: • Air filter guide "1" CLEANING THE AIR FILTER ELEMENT Align the projection "a" on filter guide with the hole "b" in air filter element. Proper air filter maintenance is the biggest key to preventing premature engine wear and damage. 2.
  • Page 55 ENGINE (For USA and CDN) 5. Remove: • Oil hose clamp "1" Recommended oil: • Bolt (oil hose) Yamalube 4, • Oil hose "2" SAE10W30 or • Oil strainer "3" SAE20W40 Yamalube 4-R, SAE10W50 API service SG type or 4. Install: higher, JASO standard •...
  • Page 56 ENGINE • Oil hose clamp • Bolt (oil tank) Oil hose clamp: Bolt (oil tank): 2 Nm (0.2 m•kg, 1.4 7 Nm (0.7 m•kg, 5.1 ft•lb) ft•lb) 13. Check: • Engine oil level CHECKING THE OIL PRESSURE 1. Check: • Oil pressure ADJUSTING THE ENGINE IDLING SPEED 1.
  • Page 57 ENGINE ADJUSTING THE VALVE CLEARANCE In order to be sure that the piston is at Top Dead Center, the punch mark "c" • The valve clearance should be ad- on the exhaust camshaft and the justed when the engine is cool to punch mark "d"...
  • Page 58 ENGINE Use the new pad number only as a guide when verifying the valve clear- ance adjustment. f. Install the new pads "3" and the valve lifters "4". • Apply the engine oil on the valve lift- ers. • Apply the molybdenum disulfide oil on the valve stem ends.
  • Page 59 ENGINE INTAKE EXHAUST 3-13...
  • Page 60 CHASSIS CHASSIS reached; then release the lever or pedal. BLEEDING THE HYDRAULIC BRAKE SYSTEM Bleed screw: 6 Nm (0.6 m•kg, 4.3 ft•lb) Bleed the brake system if: Repeat steps (e) to (h) until of the • The system has been disassem- air bubbles have been removed bled.
  • Page 61 CHASSIS e. Connect the transparent hose "5" Install the pad pin plug "10". to the bleed screw "6" and place Pad pin plug: the suitable container under its 3 Nm (0.3 m•kg, 2.2 end. ft•lb) CHECKING AND REPLACING THE FRONT BRAKE PADS 1.
  • Page 62 CHASSIS this point. PADS" section. 2. Inspect: • Rear brake pad insulator "1" → Damage Replace. b. Loosen the pad pin "3". c. Remove the rear wheel "4" and Install the brake caliper "12" and brake caliper "5". rear wheel "13". Refer to "FRONT WHEEL AND Refer to "FRONT WHEEL AND REAR WHEEL"...
  • Page 63 CHASSIS hold as illustrated. chain" position. → Stiff Replace the drive chain. CHECKING THE DRIVE CHAIN 1. Measure: 3. Adjust: • Drive chain length (15 links) "a" 5. Install: • Drive chain slack → Out of specification Replace. • Drive chain "1" •...
  • Page 64 CHASSIS CHECKING THE FRONT FORK • Air bleed screw ADJUSTING THE FRONT FORK 1. Inspect: COMPRESSION DAMPING FORCE Air bleed screw: • Front fork smooth action 1. Adjust: 1 Nm (0.1 m•kg, 0.7 Operate the front brake and • Compression damping force ft•lb) stroke the front fork.
  • Page 65 CHASSIS of the adjuster. Extent of adjustment: • The I.D. mark "b" is marked at the end of the spring. • The standard length and extent of Maximum Minimum adjustment vary according to the 20 clicks out Fully turned in quantity of I.D.
  • Page 66 CHASSIS This is the position which is back • Spokes by the specific number of turns Spokes: from the fully turned-in position. 3 Nm (0.3 m•kg, 2.2 (Which align the punch mark "a" ft•lb) on the adjuster with the punch mark "b"...
  • Page 67 CHASSIS 3. Check: • Steering smooth action Avoid over-tightening. Turn the handlebar lock to lock. → Unsmooth action Adjust steer- Steering ring nut (final ing ring nut. tightening): 7 Nm (0.7 m•kg, 5.1 ft•lb) g. Check the steering stem by turn- ing it lock to lock.
  • Page 68 CHASSIS LUBRICATION To ensure smooth operation of all Tube guide cable winding por- Lubricate the following areas components, lubricate your machine tion with high quality, lightweight lith- during setup, after break-in, and after Throttle cable end ium-soap base grease. every race. Clutch cable end All control cable 10.

  • Page 69: Electrical

    ELECTRICAL ELECTRICAL CHECKING THE SPARK PLUG 1. Remove: • Spark plug 2. Inspect: • Electrode "1" → Wear/damage Replace. • Insulator color "2" 2. Attach: Normal condition is a medium to • Timing light light tan color. • Inductive tachometer →...

  • Page 70: Seat, Fuel Tank And Side Covers

    SEAT, FUEL TANK AND SIDE COVERS ENGINE SEAT, FUEL TANK AND SIDE COVERS REMOVING THE SEAT, FUEL TANK AND SIDE COVERS Order Part name Q'ty Remarks Turn the fuel cock to "OFF". Disconnect the fuel hose. Seat Air scoop (left and right) Bolt (fuel tank) Fuel tank Left side cover...
  • Page 71 SEAT, FUEL TANK AND SIDE COVERS REMOVING THE SIDE COVER 1. Remove: Put the portion "a" of the flap of the air • Bolt (side cover) filter case on the inside of the air • Left side cover "1" scoop. •...

  • Page 72: Exhaust Pipe And Silencer

    EXHAUST PIPE AND SILENCER EXHAUST PIPE AND SILENCER REMOVING THE EXHAUST PIPE AND SILENCER Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND SIDE Right side cover COVERS" section. Bolt (silencer clamp) Only loosening. Bolt [silencer (front)] Bolt [silencer (rear)] Collar Silencer Silencer clamp...
  • Page 73 EXHAUST PIPE AND SILENCER CHECKING THE SILENCER AND EXHAUST PIPE • Install the gasket with its meshed 1. Inspect: area "a" toward the exhaust pipe • Gasket "1" side. → Damage Replace. • The gasket should be installed ac- cording to the dimension shown. CHANGING THE SILENCER FIBER 1.

  • Page 74: Radiator

    RADIATOR RADIATOR REMOVING THE RADIATOR Order Part name Q'ty Remarks Refer to "CHANGING THE COOLANT" sec- Drain the coolant. tion in the CHAPTER 3. Refer to "SEAT, FUEL TANK AND SIDE Seat and fuel tank COVERS" section. Radiator guard Radiator hose clamp Only loosening.
  • Page 75 RADIATOR HANDLING NOTE Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury. When the engine has cooled, open 3. Install: the radiator cap by the following •...

  • Page 76: Carburetor

    CARBURETOR CARBURETOR REMOVING THE CARBURETOR 4 Nm (0.4 m kg, 2.9 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 11 Nm (1.1 m kg, 8.0 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 3 Nm (0.3 m kg, 2.2 ft lb) 3 Nm (0.3 m kg, 2.2 ft lb) Order...
  • Page 77 CARBURETOR DISASSEMBLING THE CARBURETOR Order Part name Q'ty Remarks Carburetor breather hose Valve lever housing cover Screw (throttle shaft) Throttle valve Needle holder Jet needle Accelerator pump cover Spring Diaphragm (accelerator pump) Float chamber Leak jet Pilot screw Refer to removal section. Float pin Float Needle valve...
  • Page 78 CARBURETOR Order Part name Q'ty Remarks Spacer Pilot jet Starter jet Push rod Pull the push rod. Throttle shaft assembly Push rod link lever assembly Pilot air jet Cold starter plunger...
  • Page 79 CARBURETOR → HANDLING NOTE Damage Replace. → Contamination Clean. Do not loosen the screw (throttle • Use a petroleum based solvent for position sensor) "1" except when cleaning. Blow out all passages and changing the throttle position sen- jets with compressed air. sor due to failure because it will •...
  • Page 80 CARBURETOR • Spring 2 "6" 5. Install: → Dirt Clean. • Push rod link lever assembly "1" Make sure the stopper "a" of the spring 2 fits into the recess "b" in the carburetor. f. Recheck the float height. ASSEMBLING THE CARBURETOR CHECKING THE FLOAT 1.
  • Page 81 CARBURETOR Install the diaphragm (accelerator pump) with its mark "a" facing the spring. 12. Install: • Pilot screw "1" • Spring "2" • Washer "3" • O-ring "4" 15. Install: • Jet needle "1" Note the following installation • Collar "2" points: •...
  • Page 82 CARBURETOR 18. Install: • Throttle cable (return) "2" • Carburetor breather hose "1" Throttle cable (return): 11 Nm (1.1 m•kg, 8.0 Install the carburetor breather hoses ft•lb) to the carburetor so that the hoses do not bend near where they are in- stalled.

  • Page 83: Camshafts

    CAMSHAFTS CAMSHAFTS REMOVING THE CYLINDER HEAD COVER Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND SIDE Seat and fuel tank COVERS" section. Spark plug Cylinder head breather hose Bolt (cylinder head cover) Cylinder head cover Cylinder head cover gasket Timing chain guide (top side) 4-14...
  • Page 84 CAMSHAFTS REMOVING THE CAMSHAFTS Order Part name Q'ty Remarks Timing mark accessing screw Refer to removal section. Crankshaft end accessing screw Refer to removal section. Timing chain tensioner cap bolt Refer to removal section. Timing chain tensioner Refer to removal section. Camshaft cap Refer to removal section.
  • Page 85 CAMSHAFTS → REMOVING THE CAMSHAFT Out of specification Replace. 1. Remove: Cam lobes length: • Timing mark accessing screw "1" Intake "a": • Crankshaft end accessing screw 30.246–30.346 mm "2" (1.1908–1.1947 in) <Limit>: 30.146 mm (1.1869 in) Intake "b": 4. Remove: 22.45–22.55 mm •...
  • Page 86 CAMSHAFTS 4. Measure: • Camshaft-to-cap clearance → Out of specification Measure camshaft outside diameter. Camshaft-to-cap clear- ance: 0.028–0.062 mm (0.0011–0.0024 in) CHECKING THE CAMSHAFT <Limit>:0.08 mm (0.003 SPROCKET 1. Inspect: • Camshaft sprocket "1" → Wear/damage Replace the Measurement steps: camshaft assembly and timing a.
  • Page 87 CAMSHAFTS c. Fit the timing chain "3" onto both 5. Install: camshaft sprockets and install the • Timing mark accessing screw "1" Installation steps: camshafts on the cylinder head. • Crankshaft end accessing screw a. While pressing the tensioner rod "2"...

  • Page 88: Cylinder Head

    CYLINDER HEAD CYLINDER HEAD REMOVING THE CYLINDER HEAD Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND SIDE Seat and fuel tank COVERS" section. Refer to "EXHAUST PIPE AND SILENCER" Exhaust pipe and silencer section. Radiator hose 1 Disconnect at cylinder head side.
  • Page 89 CYLINDER HEAD CHECKING THE CYLINDER HEAD INSTALLING THE CYLINDER 1. Eliminate: HEAD • Carbon deposits (from the com- 1. Install: bustion chambers) • Dowel pin "1" Use a rounded scraper. • Cylinder head gasket "2" • Timing chain guide (exhaust side) "3"...

  • Page 90: Valves And Valve Springs

    VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS REMOVING THE VALVES AND VALVE SPRINGS Order Part name Q'ty Remarks Cylinder head Refer to "CYLINDER HEAD" section. Valve lifter Refer to removal section. Adjusting pad Refer to removal section. Valve cotter Refer to removal section.
  • Page 91 VALVES AND VALVE SPRINGS REMOVING THE VALVE LIFTER AND VALVE COTTER 1. Remove: • Valve lifter "1" • Pad "2" Identify each lifter "1" and pad "2" po- sition very carefully so that they can CHECKING THE VALVE b. Install the new valve guide using a be reinstalled in their original place.
  • Page 92 VALVES AND VALVE SPRINGS 4. Measure: • Margin thickness "a" → Out of specification Replace. Margin thickness: Intake: 0.8 mm (0.0315 in) Exhaust: 0.7 mm (0.0276 in) c. Install the valve into the cylinder head. Measurement steps: d. Turn the valve until the valve face a.
  • Page 93 VALVES AND VALVE SPRINGS INSTALLING THE VALVES 1. Apply: Hitting the valve tip with excessive • Molybdenum disulfide oil force could damage the valve. Onto the valve stem and valve stem seal. 2. Install: • Valve "1" • Valve spring seat "2" 2.

  • Page 94: Cylinder And Piston

    CYLINDER AND PISTON CYLINDER AND PISTON REMOVING THE CYLINDER AND PISTON Order Part name Q'ty Remarks Cylinder head Refer to "CYLINDER HEAD" section. Bolt (cylinder) Cylinder Piston pin clip Refer to removal section. Piston pin Refer to removal section. Piston Refer to removal section.
  • Page 95 CYLINDER AND PISTON REMOVING THE PISTON AND • Piston-to-cylinder clearance Piston-to-cylinder clear- PISTON RING ance: 1. Remove: 0.030–0.055 mm Measurement steps: • Piston pin clip "1" (0.0012–0.0022 in) a. Measure the cylinder bore "C" • Piston pin "2" <Limit>:0.1 mm (0.004 with a cylinder bore gauge.
  • Page 96 CYLINDER AND PISTON 3. Measure: Oil ring end (upper) • Ring end gap Oil ring → Out of specification Replace. Oil ring end (lower) 3. Install: • Piston "1" You cannot measure the end gap on • Piston pin "2" the expander spacer of the oil control •...
  • Page 97 CYLINDER AND PISTON Install the cylinder with one hand while compressing the piston rings with the other hand. • Pass the timing chain "3" through the timing chain cavity. • Be careful not to damage the tim- ing chain guide "4" during instal- lation.

  • Page 98: Clutch

    CLUTCH CLUTCH REMOVING THE CLUTCH Order Part name Q'ty Remarks Refer to "CHANGING THE ENGINE OIL" Drain the engine oil. section in the CHAPTER 3. Brake pedal Refer to "ENGINE REMOVAL" section. Clutch cable Disconnect at engine side. Clutch cover Clutch spring Pressure plate Push rod 1...
  • Page 99 CLUTCH Order Part name Q'ty Remarks Nut (clutch boss) Refer to removal section. Lock washer Refer to removal section. Clutch boss Refer to removal section. Thrust washer Primary driven gear Push lever shaft 4-30...
  • Page 100 CLUTCH REMOVING THE CLUTCH BOSS CHECKING THE CLUTCH CHECKING THE PUSH LEVER 1. Remove: SPRINGS SHAFT • Nut "1" 1. Measure: 1. Inspect: • Lock washer "2" • Clutch spring free length "a" • Push lever shaft "1" → → •...
  • Page 101 CLUTCH INSTALLING THE CLUTCH 4. Install: 7. Install: 1. Install: • Seat plate "1" • Push rod 2 "1" • Primary driven gear "1" • Cushion spring "2" • Ball "2" • Thrust washer "2" • Push rod 1 "3" •...
  • Page 102 CLUTCH 11. Install: • Clutch cover "1" • Bolt (clutch cover) Bolt (clutch cover): 10 Nm (1.0 m•kg, 7.2 ft•lb) Tighten the bolts in stage, using a crisscross pattern. 4-33...

  • Page 103: Oil Filter Element And Water Pump

    OIL FILTER ELEMENT AND WATER PUMP OIL FILTER ELEMENT AND WATER PUMP REMOVING THE OIL FILTER ELEMENT AND WATER PUMP Order Part name Q'ty Remarks Refer to "CHANGING THE ENGINE OIL" Drain the engine oil. section in the CHAPTER 3. Refer to "CHANGING THE COOLANT"...
  • Page 104 OIL FILTER ELEMENT AND WATER PUMP Order Part name Q'ty Remarks Washer Refer to removal section. Impeller shaft Refer to removal section. Oil seal Refer to removal section. Bearing Refer to removal section. 4-35...
  • Page 105 OIL FILTER ELEMENT AND WATER PUMP REMOVING THE IMPELLER SHAFT • Apply the lithium soap base grease 1. Remove: on the oil seal lip. • Impeller "1" • Install the oil seal with its manufac- • Washer "2" ture's marks or numbers facing the •...
  • Page 106 OIL FILTER ELEMENT AND WATER PUMP • Washer • Bolt (kickstarter crank) Apply the lithium soap base grease on the O-ring. Bolt (kickstarter crank): 33 Nm (3.3 m•kg, 24 ft•lb) Install so that there is a clearance "a" INSTALLING THE RIGHT of 5 mm (0.20 in) or more between CRANKCASE COVER the kickstarter and frame and that the...

  • Page 107: Balancer

    BALANCER BALANCER REMOVING THE BALANCER Order Part name Q'ty Remarks Primary driven gear Refer to "CLUTCH" section. Refer to "OIL FILTER ELEMENT AND WA- Right crankcase cover TER PUMP" section. Stator Refer to "CDI MAGNETO" section. Nut (primary drive gear) Refer to removal section.
  • Page 108 BALANCER REMOVING THE BALANCER CHECKING THE BALANCER 1. Straighten the lock washer tab. SHAFT 2. Loosen: 1. Inspect: • Nut (primary drive gear) "1" • Balancer shaft → • Nut (balancer shaft driven gear) Cracks/damage Replace. "2" Place an aluminum plate "a" between 4.

  • Page 109: Oil Pump

    OIL PUMP OIL PUMP REMOVING THE OIL PUMP Order Part name Q'ty Remarks Primary driven gear Refer to "CLUTCH" section. Refer to "OIL FILTER ELEMENT AND WA- Right crankcase cover TER PUMP" section. Circlip Washer Oil pump drive gear Oil pump assembly Outer rotor 2 Circlip Inner rotor 2...
  • Page 110 OIL PUMP Order Part name Q'ty Remarks Rotor housing 4-41...
  • Page 111 OIL PUMP REMOVING THE OIL TANK Order Part name Q'ty Remarks Refer to "CHANGING THE ENGINE OIL" Drain the engine oil. section in the CHAPTER 3. Oil hose 2 Oil hose 1 Dowel pin Oil tank breather hose Oil tank Oil strainer 4-42...
  • Page 112 OIL PUMP CHECKING THE 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. INSTALLING THE OIL PUMP 4. Install: 1. Install: •...

  • Page 113: Kick Shaft And Shift Shaft

    KICK SHAFT AND SHIFT SHAFT KICK SHAFT AND SHIFT SHAFT REMOVING THE KICK SHAFT AND SHIFT SHAFT Order Part name Q'ty Remarks Oil pump Refer to "OIL PUMP" section. Kick idle gear Kick shaft assembly Refer to removal section. Spring guide Torsion spring Ratchet wheel Kick gear...
  • Page 114 KICK SHAFT AND SHIFT SHAFT Order Part name Q'ty Remarks Pawl Pawl pin Spring Bolt (stopper lever) Stopper lever Torsion spring Segment Refer to removal section. 4-45...

  • Page 115: Kick Shaft And Shift Shaft

    KICK SHAFT AND SHIFT SHAFT REMOVING THE KICK SHAFT • Kick shaft "2" • Stopper lever "1" → → ASSEMBLY Wear/damage Replace. Wear/damage Replace. 1. Remove: • Spring "3" • Torsion spring "2" → → • Kick shaft assembly "1" Broken Replace.
  • Page 116 KICK SHAFT AND SHIFT SHAFT INSTALLING THE SHIFT GUIDE INSTALLING THE SHIFT SHAFT AND SHIFT LEVER ASSEMBLY 1. Install: 1. Install: • Roller "1" • Spring "1" • Collar "2" • Pawl pin "2" • Torsion spring "3" • Pawl "3" •...
  • Page 117 KICK SHAFT AND SHIFT SHAFT 5. Hook: • Torsion spring "1" Turn the torsion spring clockwise and hook into the proper hole "a" in the crankcase. INSTALLING THE KICK IDLE GEAR 1. Install: • Kick idle gear "1" • Washer "2" •...

  • Page 118: Cdi Magneto

    CDI MAGNETO CDI MAGNETO REMOVING THE CDI MAGNETO Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND SIDE Seat and fuel tank COVERS" section. Disconnect the CDI magneto lead. Refer to "KICK SHAFT AND SHIFT SHAFT" Shift pedal section.
  • Page 119 CDI MAGNETO REMOVING THE ROTOR INSTALLING THE CDI MAGNETO 1. Remove: 1. Install: • Nut (rotor) "1" • Stator "1" • Washer "2" • Screw (stator) "2" Use the rotor holding tool "3". Screw (stator): Rotor holding tool: 10 Nm (1.0 m•kg, YU-1235/90890-01235 7.2ft•lb) 4.

  • Page 120: Engine Removal

    ENGINE REMOVAL ENGINE REMOVAL REMOVING THE ENGINE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand Refer to "HANDLING NOTE". under the frame. Refer to "SEAT, FUEL TANK AND SIDE Seat and fuel tank COVERS" section. Carburetor Refer to "CARBURETOR"...
  • Page 121 ENGINE REMOVAL Order Part name Q'ty Remarks Lower engine guard Neutral switch Drive chain sprocket cover Nut (drive sprocket) Refer to removal section. Lock washer Refer to removal section. Drive sprocket Refer to removal section. Clip Bolt (brake pedal) Brake pedal Upper engine bracket Lower engine bracket Engine mounting bolt...
  • Page 122 ENGINE REMOVAL HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE DRIVE SPROCKET 1. Remove: INSTALLING THE ENGINE • Nut (drive sprocket) "1" 1. Install: • Lock washer "2" • Engine "1" Install the engine from right side.
  • Page 123 ENGINE REMOVAL 2. Install: 2. Install: • Lock washer "1" • Hose guide (cylinder head breath- • Nut (drive sprocket) "2" er hose) "1" • Bolt (hose guide) "2" Nut (drive sprocket): 75 Nm (7.5 m•kg, 54 Bolt (hose guide): ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb)

  • Page 124: Crankcase And Crankshaft

    CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT REMOVING THE CRANKSHAFT Order Part name Q'ty Remarks Engine Refer to "ENGINE REMOVAL" section. Piston Refer to "CYLINDER AND PISTON" section. Refer to "KICK SHAFT AND SHIFT SHAFT" Kick shaft assembly section. Refer to "KICK SHAFT AND SHIFT SHAFT" Segment section.
  • Page 125 CRANKCASE AND CRANKSHAFT Order Part name Q'ty Remarks Left crankcase Refer to removal section. Oil strainer Crankshaft Refer to removal section. 4-56...
  • Page 126 CRANKCASE AND CRANKSHAFT REMOVING THE CRANKCASE BEARING Order Part name Q'ty Remarks Refer to "TRANSMISSION, SHIFT CAM AND Transmission SHIFT FORK" section. Refer to "TRANSMISSION, SHIFT CAM AND Shift cam and shift fork SHIFT FORK" section. Oil seal Bearing Refer to removal section. 4-57...
  • Page 127 CRANKCASE AND CRANKSHAFT DISASSEMBLING THE Crankcase separating CRANKCASE tool: 1. Separate: YU-1135-A/90890- • Right crankcase 01135 • Left crankcase Separation steps: Do not use a hammer to drive out a. Remove the crankcase bolts "1", the crankshaft. 2. Inspect: hose guide "2" and clutch cable •...
  • Page 128 CRANKCASE AND CRANKSHAFT Screw [bearing stopper (crankshaft)]: 14 Nm (1.4 m•kg, 10 ft•lb) To left and right crankcase. • Install the bearing by pressing its outer race parallel. • To prevent the screw [bearing stop- per (crankshaft)] from becoming loose, crush the screw head periph- ery "a"...
  • Page 129 CRANKCASE AND CRANKSHAFT Apply the lithium soap base grease on the Orings. 5. Install: • Dowel pin "1" • O-ring "2" • Right crankcase 8. Install: To left crankcase. • Timing chain "1" • Timing chain guide (intake side) • Apply the lithium soap base grease "2"...

  • Page 130: Cam And Shift Fork

    TRANSMISSION, SHIFT CAM AND SHIFT FORK TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION, SHIFT CAM AND SHIFT FORK Order Part name Q'ty Remarks Engine Refer to "ENGINE REMOVAL" section. Refer to "CRANKCASE AND CRANK- Separate the crankcase. SHAFT" section. Main axle Refer to removal section.
  • Page 131 TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION idler gear and on the inner surface of 1. Remove: the sliding gear, then install. • Main axle "1" • Drive axle "2" • Shift cam • Shift fork 3 • Shift fork 2 •...
  • Page 132 TRANSMISSION, SHIFT CAM AND SHIFT FORK 4. Install: 6. Install: • Collar "1" • Transmission assembly "1" To left crankcase "2". • Apply the lithium soap base grease on the oil seal lip. Apply the engine oil on the bearings •...

  • Page 133: Front Wheel And Rear Wheel

    FRONT WHEEL AND REAR WHEEL CHASSIS FRONT WHEEL AND REAR WHEEL REMOVING THE FRONT WHEEL Order Part name Q'ty Remarks Hold the machine by placing the suitable stand Refer to "HANDLING NOTE". under the engine. Bolt (axle holder) Only loosening. Nut (front wheel axle) Front wheel axle Front wheel...
  • Page 134 FRONT WHEEL AND REAR WHEEL REMOVING THE REAR WHEEL Order Part name Q'ty Remarks Hold the machine by placing the suitable stand Refer to "HANDLING NOTE". under the engine. Nut (rear wheel axle) Rear wheel axle Drive chain puller Rear wheel Refer to removal section.

  • Page 135: Front Wheel And Rear Wheel

    FRONT WHEEL AND REAR WHEEL HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE REAR WHEEL 1. Remove: • Wheel "1" CHECKING THE WHEEL AXLE 1. Measure: Push the wheel forward and remove •...
  • Page 136 FRONT WHEEL AND REAR WHEEL • Bolt (brake disc) "2" Nut (wheel axle): Bolt (brake disc): Do not strike the inner race of the 105 Nm (10.5 m•kg, 75 12 Nm (1.2 m•kg, 8.7 bearing. Contact should be made ft•lb) ft•lb) only with the outer race.
  • Page 137 FRONT WHEEL AND REAR WHEEL 4. Install: • Collar "1" Temporarily tighten the nut (wheel axle) at this point. Apply the lithium soap base grease on the oil seal lip. 9. Adjust: • Drive chain slack "a" 5. Install: Drive chain slack: •...

  • Page 138: Front Brake And Rear Brake

    FRONT BRAKE AND REAR BRAKE FRONT BRAKE AND REAR BRAKE REMOVING THE FRONT BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand Refer to "HANDLING NOTE". under the engine. Drain the brake fluid. Refer to removal section. Brake hose holder (protector) Union bolt Brake hose...
  • Page 139 FRONT BRAKE AND REAR BRAKE REMOVING THE REAR BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand Refer to "HANDLING NOTE". under the engine. Refer to "FRONT WHEEL AND REAR Rear wheel WHEEL" section. Drain the brake fluid. Refer to removal section.
  • Page 140 FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE CALIPER Order Part name Q'ty Remarks Front Rear Pad pin Brake pad Pad support Brake caliper piston Refer to removal section. Brake caliper piston dust seal Refer to removal section. Brake caliper piston seal Refer to removal section.
  • Page 141 FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE MASTER CYLINDER Order Part name Q'ty Remarks Front Rear Brake master cylinder cap Diaphragm Reservoir float Push rod (Front) Brake master cylinder boot Circlip Use a long nose circlip pliers. Washer Push rod (Rear) Brake master cylinder kit...
  • Page 142 FRONT BRAKE AND REAR BRAKE HANDLING NOTE • Cover piston with rag and use ex- Support the machine securely so treme caution when expelling there is no danger of it falling over. piston from cylinder. • Never attempt to pry out piston. DRAINING THE BRAKE FLUID 1.
  • Page 143 FRONT BRAKE AND REAR BRAKE seals and brake caliper piston dust seals whenever a caliper is disassembled. INSTALLING THE BRAKE CALIPER PISTON 1. Clean: • Brake caliper • Brake caliper piston seal CHECKING THE BRAKE CALIPER • Brake caliper piston dust seal 1.
  • Page 144 FRONT BRAKE AND REAR BRAKE 4. Install: • Brake master cylinder kit "1" • Washer (front brake) "2" • Push rod (rear brake) "2" • Circlip "3" • Brake master cylinder boot "4" • Push rod (front brake) "5" To brake master cylinder. INSTALLING THE REAR BRAKE INSTALLING THE BRAKE CALIPER...
  • Page 145 FRONT BRAKE AND REAR BRAKE 2. Install: • Bolt (brake master cylinder) "2" • Union bolt "3" • Brake lever "1" Bolt (brake master cylin- Union bolt: • Bolt (brake lever) "2" der): 30 Nm (3.0 m•kg, 22 Bolt (brake lever): 10 Nm (1.0 m•kg, 7.2 ft•lb) 6 Nm (0.6 m•kg, 4.3...
  • Page 146 FRONT BRAKE AND REAR BRAKE 4. Install: lower the boiling point of the flu- • Copper washer "1" id and may result in vapor lock. • Brake hose "2" • Union bolt "3" Brake fluid may erode painted sur- Union bolt: faces or plastic parts.
  • Page 147 FRONT BRAKE AND REAR BRAKE A. Front B. Rear 5. Install: (rear brake only) • Protector "1" • Bolt (protector) "2" Bolt (protector): 7 Nm (0.7 m•kg, 5.1 ft•lb) 5-15...

  • Page 148: Front Fork

    FRONT FORK FRONT FORK REMOVING THE FRONT FORK 21 Nm (2.1 m kg, 15 ft lb) 21 Nm (2.1 m kg, 15 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) Order Part name...
  • Page 149 FRONT FORK DISASSEMBLING THE FRONT FORK 30 Nm (3.0 m kg, 22 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 1 Nm (0.1 m kg, 0.7 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 55 Nm (5.5 m kg, 40 ft lb) Order Part name Q'ty...
  • Page 150 FRONT FORK HANDLING NOTE Support the machine securely so there is no danger of it falling over. The front fork requires careful atten- tion. So it is recommended that the 3. Remove: front fork be maintained at the deal- • Adjuster "1" ers.
  • Page 151 FRONT FORK CHECKING THE BASE VALVE Use the dial gauge "1". 1. Inspect: Inner tube bending limit: • Be sure to use recommended • Base valve "1" 0.2 mm (0.008 in) fork oil. If other oils are used, → Wear/damage Replace.
  • Page 152 FRONT FORK 6. Tighten: base valve with specified torque. • Locknut "1" Cap bolt wrench: Fully finger tighten the locknut onto YM-01500/90890-01500 the damper assembly. Cap bolt ring wrench: YM-01501/90890-01501 15. Install: • Dust seal "1" • Stopper ring "2" •...
  • Page 153 FRONT FORK 17. Install: • Outer tube "1" To inner tube "2". 21. Install: 25. Install: • Dust seal "1" • Damper assembly "1" To inner tube "2". 18. Install: Apply the lithium soap base grease • Slide metal "1" on the inner tube.
  • Page 154 FRONT FORK 31. Fill: • Front fork oil "1" From outer tube top. Recommended oil: Suspension oil "S1" Standard oil amount: 330 cm (11.6 Imp oz, 11.2 US oz) 28. Inspect: INSTALLING THE FRONT FORK Extent of adjustment: • Gap "a" between the adjuster "1" 1.
  • Page 155 FRONT FORK 4. Tighten: 7. Adjust: • Pinch bolt (upper bracket) "1" • Compression damping force Pinch bolt (upper brack- Turn in the damping adjuster "1" fin- et): ger-tight and then turn out to the orig- 21 Nm (2.1 m•kg, 15 inally set position.

  • Page 156: Handlebar

    HANDLEBAR HANDLEBAR REMOVING THE HANDLEBAR Order Part name Q'ty Remarks Number plate Remove the band only. Hot starter cable Disconnect at the lever side. Hot starter lever holder Clutch cable Disconnect at the lever side. Clutch lever holder Engine stop switch Brake master cylinder Refer to removal section.
  • Page 157 HANDLEBAR REMOVING THE BRAKE MASTER tance "a" from the mounting bolt CYLINDER center facing forward. 1. Remove: • Apply the lithium soap base grease • Brake master cylinder bracket "1" on the thread of the handlebar low- • Brake master cylinder "2" er holder.
  • Page 158 HANDLEBAR 5. Install: 8. Install: • Right grip "1" • Throttle cable cap "1" • Collar "2" • Screw (throttle cable cap) "2" Apply the adhesive on the tube Screw (throttle cable guide "3". cap): 4 Nm (0.4 m•kg, 2.9 •...
  • Page 159 HANDLEBAR 13. Adjust: • Clutch lever free play Refer to "ADJUSTING THE CLUTCH CABLE FREE PLAY" section in the CHAPTER 3. • Hot starter lever free play Refer to "ADJUSTING THE HOT STARTER LEVER FREE PLAY" section in the CHAPTER 3. 5-27...

  • Page 160: Steering

    STEERING STEERING REMOVING THE STEERING Order Part name Q'ty Remarks TIGHTENING STEPS: Tighten ring nut. 38 Nm (3.8 m•kg, 27 ft•lb) Loosen it one turn. Retighten it. 7 Nm (0.7 m•kg, 5.1 ft•lb) Hold the machine by placing the suitable stand Refer to "HANDLING NOTE".
  • Page 161 STEERING Order Part name Q'ty Remarks Bearing race Refer to removal section. 5-29...
  • Page 162 STEERING HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE STEERING RING 1. Remove: CHECKING THE BEARING AND 3. Install: • Steering ring nut "1" BEARING RACE • Lower bracket "1" Use the steering nut wrench "2". 1.
  • Page 163 STEERING 6. Install: 11. Tighten: • Washer "1" • Pinch bolt (upper bracket) "1" Pinch bolt (upper brack- et): 21 Nm (2.1 m•kg, 15 ft•lb) • Pinch bolt (lower bracket) "2" Pinch bolt (lower brack- et): 7. Install: 21 Nm (2.1 m•kg, 15 •...

  • Page 164: Swingarm

    SWINGARM SWINGARM REMOVING THE SWINGARM Order Part name Q'ty Remarks Hold the machine by placing the suitable stand Refer to "HANDLING NOTE". under the engine. Refer to "FRONT BRAKE AND REAR Brake hose holder BRAKE" section. Refer to "FRONT BRAKE AND REAR Rear brake caliper BRAKE"...
  • Page 165 SWINGARM DISASSEMBLING THE SWINGARM Order Part name Q'ty Remarks Refer to removal section. Relay arm Connecting rod Collar Oil seal Thrust bearing Bushing Oil seal Bearing Refer to removal section. 5-33...
  • Page 166 SWINGARM HANDLING NOTE 2. Inspect: • Oil seal "3" → Damage Replace. Support the machine securely so there is no danger of it falling over. REMOVING THE CAP 1. Remove: • Left cap "1" 2. Install: • Bearing "1" Remove with a slotted-head screw- •...
  • Page 167 SWINGARM • Washer "3" • Swingarm up and down move- • Nut (connecting rod) "4" ment "b" Unsmooth movement/binding/ Nut (connecting rod): → rough spots Grease or replace 80 Nm (8.0 m•kg, 58 bearings, bushings and collars. ft•lb) To relay arm "5". INSTALLING THE SWINGARM Apply the molybdenum disulfide 1.
  • Page 168 SWINGARM • Nut (drive chain support) "4" Nut (drive chain sup- port): 7 Nm (0.7 m•kg, 5.1 ft•lb) • Bolt {drive chain support cover [L = 10 mm (0.39 in)]} "5" 11. Tighten: Bolt (drive chain support • Nut (relay arm) "1" cover): 7 Nm (0.7 m•kg, 5.1 Nut (relay arm):...

  • Page 169: Rear Shock Absorber

    REAR SHOCK ABSORBER REAR SHOCK ABSORBER REMOVING THE REAR SHOCK ABSORBER Order Part name Q'ty Remarks Hold the machine by placing the suitable stand Refer to "HANDLING NOTE". under the engine. Refer to "SEAT, FUEL TANK AND SIDE Seat COVERS" section in the CHAPTER 4. Refer to "EXHAUST PIPE AND SILENCER"...
  • Page 170 REAR SHOCK ABSORBER Order Part name Q'ty Remarks Bearing Refer to removal section. 5-38...
  • Page 171 REAR SHOCK ABSORBER HANDLING NOTE • Spring "3" → Damage Replace spring. → Fatigue Replace spring. • Support the machine securely so Move spring up and down. there is no danger of it falling • Spring guide "4" over. → Wear/damage Replace spring •...
  • Page 172 REAR SHOCK ABSORBER 3. Install: 4. Adjust: 3. Install: • Lower bearing "1" • Spring length (installed) • Rear shock absorber Refer to "ADJUSTING THE 4. Install: REAR SHOCK ABSORBER • Bolt (rear shock absorber-frame) Install the bearing by pressing it on SPRING PRELOAD"...
  • Page 173 REAR SHOCK ABSORBER • Bolt [rear frame (lower)] "3" Bolt [rear frame (lower)]: 32 Nm (3.2 m•kg, 23 ft•lb) 7. Tighten: • Bolt (air filter joint) "1" Bolt (air filter joint): 3 Nm (0.3 m•kg, 2.2 ft•lb) 5-41...

  • Page 174: Electrical Components And Wiring Diagram

    ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS Engine stop switch CDI magneto CDI unit Throttle position sensor Ignition coil Neutral switch Spark plug WIRING DIAGRAM Engine stop switch Yellow COLOR CODE Throttle position sensor Black/Blue Black Neutral switch...

  • Page 175: Ignition System

    IGNITION SYSTEM 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. → Spark gap test Spark *Clean or replace spark plug. ↓...
  • Page 176 IGNITION SYSTEM SPARK GAP TEST Result 1. Disconnect the ignition coil from Conductive (while the spark plug. engine stop switch is 2. Remove the ignition coil cap. pushed) 3. Connect the dynamic spark tester → Not conductive while it is pushed "1"...
  • Page 177 IGNITION SYSTEM 3. Inspect: • Charging coil 2 resistance → Out of specification Replace. → Tester (+) lead Pink lead "1" → Tester (-) lead Black lead "2" Charging Tester se- coil 2 resis- lector posi- tance tion Ω 44-66 Ω...

  • Page 178: Throttle Position Sensor System

    THROTTLE POSITION SENSOR SYSTEM THROTTLE POSITION SENSOR SYSTEM INSPECTION STEPS If the throttle position sensor will not operate, use the following inspection steps. → Check entire ignition system for connection. No good Repair or replace. ↓ → Check throttle position sensor. (Throttle position No good Replace.
  • Page 179 THROTTLE POSITION SENSOR SYSTEM HANDLING NOTE 3. Inspect: 4. Install: • Throttle position sensor coil vari- • Throttle position sensor "1" able resistance • Screw (throttle position sensor) Do not loosen the screw (throttle Check that the resistance in in- "2"...
  • Page 180 THROTTLE POSITION SENSOR SYSTEM the CDI unit. → Measure the output voltage accurate- Tester (+) lead Blue lead "1" → ly with a digital electronic voltmeter Tester (-) lead Black/Blue lead that gives an easy reading of a small "2" voltage.

  • Page 181: Tuning

    ENGINE TUNING correctly and opens and closes CONSTRUCTION OF smoothly. CARBURETOR AND SETTING ENGINE PARTS ATMOSPHERIC CONDITIONS AND CARBURETOR SETTING The FLATCR carburetor has a prima- CARBURETOR SETTINGS • The air/fuel mixture will vary de- ry main jet. This type of main jet is pending on atmospheric conditions.
  • Page 182 ENGINE ADJUSTING THE PILOT SCREW A. Idle The richness of the air-fuel mixture B. Fully open 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 ADJUSTING THE JET NEEDLE speeds, and turning it out will enrich GROOVE POSITION...
  • Page 183 ENGINE 2. When rough engine operation is CARBURETOR SETTING PARTS felt in quick throttle opening, se- lect a leak jet having higher cali- Main jet Size Part number brating No. than standard to lean Rich #188 4MX-14943-95 out the mixture. <Example> #70 →...
  • Page 184 ENGINE SPECIFICATIONS OF JET NEEDLE Diameter of straight portion Rich Lean Rich 1 richer NFPN-6 NFPP-6 NFPQ-6 NFPR-6 NFPS-6 NFPT-6 NFPU-6 0.5 richer NFLN-6 NFLP-6 NFLQ-6 NFLR-6 NFLS-6 NFLT-6 NFLU-6 NFPN-5 NFPP-5 NFPQ-5 NFPR-5 NFPS-5 NFPT-5 NFPU-5 0.5 leaner NFLN-5 NFLP-5 NFLQ-5 NFLR-5...
  • Page 185 ENGINE * This should be taken simply for an example. It is necessary to set the carburetor while checking the operating conditions of the engine.
  • Page 186 CHASSIS CHASSIS DRIVE AND REAR WHEEL The front fork setting includes the fol- SPROCKETS SETTING PARTS lowing three factors: SELECTION OF THE SECONDARY 1. Setting of air spring characteris- REDUCTION RATIO (SPROCKET) Part name Size Part number tics • Change the fork oil amount. Secondary reduction ratio = Drive 2.
  • Page 187 CHASSIS C. Stroke the end of the spring. 3. Loosen the locknut "1" and make Max. oil amount adjustment by turning the spring Standard oil amount adjuster "2" to achieve the stan- Min. oil amount dard figure from the subtraction of the length "b"...
  • Page 188 CHASSIS [Unequal-pitch steel spring] [Titanium spring] SPRING SPRI When using a rear shock absorber EXTENT OF AD- SPRING FREE other than currently installed, use JUSTMENT "b" PART I.D. LENGTH the one whose overall length "a" NUM- MARK/ does not exceed the standard as it One I.D.
  • Page 189 CHASSIS SUSPENSION SETTING (FRONT FORK) • If any of the following symptoms is experienced with the standard position 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 figure 90–100 mm (3.5–3.9 in). Section Medi- Symptom...
  • Page 190 CHASSIS SUSPENSION SETTING (REAR SHOCK ABSORBER) • If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure given in the same chart. • Adjust the rebound damping in 2-click increments or decrements. •...
  • Page 192 YAMAHA MOTOR CO., LTD. PRINTED ON RECYCLED PAPER PRINTED IN JAPAN 2500 SHINGAI IWATA SHIZUOKA JAPAN...

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Yz250f(x)Yz250f z 2010Yz250f 2010Yzf250Yz250z 20102008 yz250fx

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