Yamaha YZ250 Owner's Service Manual

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Page 1 Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch, bevor Sie das Fahrzeug in Betrieb nehmen. q Leggere attentamente questo manuale prima di utilizzare questo veicolo. OWNER’S SERVICE MANUAL MANUEL D’ATELIER DU PROPRIETAIRE FAHRER- UND WARTUNGSHANDBUCH MANUALE DI SERVIZIO DEL PROPRIETARIO YZ250 ( Y ) 1P8-28199-34...
Page 2 Read this manual carefully before operating this vehicle. This manual should stay with this vehicle if it is sold. Il convient de lire attentivement ce manuel avant la première utilisation du véhicule. Le manuel doit être remis avec le véhicule en cas de vente de ce dernier. Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch, bevor Sie das Fahrzeug in Betrieb nehmen.
Page 3 2009 2009 Read this manual carefully before operating this vehicle. Read this manual carefully before operating this vehicle. OWNER’S SERVICE MANUAL OWNER’S SERVICE MANUAL YZ250(Y) YZ250(Y) 1P8-28199-34-E0 1P8-28199-34-E0...
Page 5 YZ250 (Y) OWNER'S SERVICE MANUAL ©2008 by Yamaha Motor Co., Ltd. 1st Edition, April 2008 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: Safety Information
• GASOLINE CAN CAUSE INJURY. Congratulations on your purchase of could result in death or serious in- If you should swallow some gaso- a Yamaha YZ series. This model is jury. line, inhale excess gasoline vapors, the culmination of Yamaha's vast ex-...
Page 7: General Information
HOW TO USE THIS MANUAL FINDING THE REQUIRED PAGE 1. This manual consists of seven chapters; "General Information", "Specifications", "Regular inspec- tion and adjustments", "Engine", "Chassis", "Electrical" and "Tun- ing" 2. The table of contents is at the be- ginning of the manual. Look over the general layout of the book be- fore finding then required chapter and item.
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
TABLE OF CONTENTS GENERAL INFORMATION SPECIFICATIONS REGULAR INSPECTION AND ADJUSTMENTS ENGINE CHASSIS ELECTRICAL TUNING...
Page 10: Table Of Contents
CONTENTS CHAPTER 1 CHAPTER 3 CHAPTER 5 GENERAL REGULAR CHASSIS INFORMATION INSPECTION AND ADJUSTMENTS 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 ..1-2 PRE-OPERATION HANDLEBAR....5-24 IMPORTANT...
Page 11: Description
DESCRIPTION GENERAL INFORMATION DESCRIPTION Clutch lever 14. Fuel cock Engine stop switch 15. Starter knob Front brake lever 16. Drive chain Throttle grip 17. Air filter Radiator cap 18. Shift pedal Fuel tank cap 19. Front fork Kickstarter crank Fuel tank Radiator 10.
Page 12: Identification
End of each hose 5. Keep away from fire. ALL REPLACEMENT PARTS VALVE JOINT 1. We recommend to use Yamaha This valve joint "1" prevents fuel from genuine parts for all replace- flowing out and is installed to the fuel ments.
Page 13: Checking Of Connection
CHECKING OF CONNECTION 7. Check for continuity with a tester. assembly and adjustment. CIRCLIPS 1. All circlips should be inspected GASKETS, OIL SEALS AND O- carefully before reassembly. Al- • If there in no continuity, clean the RINGS ways replace piston pin clips after terminals.
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 Ignition checker nents. 90890-06754 Digital tachometer This tool is needed for observing en- YU-39951-B, 90890-06760 gine rpm. YAMAHA Bond No. 1215 (ThreeB- This sealant (Bond) is used for ® No. 1215) crankcase mating surface, etc. 90890-85505...
Page 17: Control Functions
CONTROL FUNCTIONS CONTROL FUNCTIONS KICKSTARTER CRANK FUEL COCK Rotate the kickstarter crank "1" away The fuel cock supplies fuel from the ENGINE STOP SWITCH from the engine. Push the starter tank to carburetor and also filters the The engine stop switch "1" is located down lightly with your foot until the fuel.
Page 18 STARTING AND BREAK-IN ally takes about one or two min- semble the top end. utes. 8. Drain the break-in oil-fuel mixture Never mix two types of oil in the 5. The engine is warmed up when it from the fuel tank and refill with same batch;...
Page 19: 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 20: Cleaning And Storage
CLEANING AND STORAGE CLEANING AND STORAGE STORAGE If your machine is to be stored for 60 CLEANING days or more, some preventive mea- Frequent cleaning of your machine sures must be taken to avoid deterio- will enhance its appearance, maintain ration.
Page 21: General Specifications
GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model name: YZ250Y (USA, CDN, AUS, NZ) YZ250 (EUROPE, ZA) Model code number: 1P8H (USA, CDN) 1P8J (EUROPE) 1P8L (AUS, NZ, ZA) Dimensions: USA, AUS, NZ, ZA EUROPE, CDN Overall length 2,178 mm (85.7 in) 2,184 mm (86.0 in)
Page 22: Maintenance Specifications
MAINTENANCE SPECIFICATIONS Transmission: Primary reduction system Gear Primary reduction ratio 63/21 (3.000) Secondary reduction system Chain drive Secondary reduction ratio 50/14 (3.571) Transmission type Constant mesh, 5-speed Operation Left foot operation Gear ratio: 27/14 (1.929) 23/15 (1.533) 23/18 (1.278) 24/22 (1.091) 20/21 (0.952) Chassis: USA, ZA, AUS, NZ...
Page 23 MAINTENANCE SPECIFICATIONS Item Standard Limit Cylinder: Bore size 66.400–66.414 mm (2.6142–2.6147 in) 66.5 mm (2.1618 in) Taper limit ---- 0.05 mm (0.0020 in) Out of round limit ---- 0.01 mm (0.0004 in) Piston: Piston size/ 66.352–66.367 mm (2.6120–2.6129 in) ---- Measuring point "H"...
Page 24 MAINTENANCE SPECIFICATIONS Item Standard Limit Clutch: Friction plate thickness 2.9–3.1 mm (0.114–0.122 in) 2.8 mm (0.110 Quantity ---- Clutch plate thickness 1.5–1.7 mm (0.059–0.067 in) ---- Quantity ---- Warp limit ---- 0.2 mm (0.008 Clutch spring free length 50.0 mm (1.969 in) 48.0 mm (1.890 in) Quantity...
Page 25 MAINTENANCE SPECIFICATIONS Item Standard Limit Cooling: Radiator core size: ---- Width 107.8 mm (4.24 in) ---- Height 240 mm (9.45 in) ---- Thickness 32 mm (1.26 in) ---- Radiator cap opening pressure 95–125 kPa (0.95–1.25 kg/cm , 13.5–17.8 psi) ---- Radiator capacity (total) 0.63 L (0.55 Imp qt, 0.67 US qt) ----...
Page 26 MAINTENANCE SPECIFICATIONS Item Standard Limit Swingarm: Swingarm free play limit ---- 1.0 mm (0.04 Side clearance ---- 0.2–0.9 mm (0.008–0.035 Wheel: Front wheel type Spoke wheel ---- Rear wheel type Spoke wheel ---- Front rim size/material 21 × 1.60/Aluminum ---- Rear rim size/material 19 ×...
Page 27: Tightening Torques
0.18 mm (0.007 in) ---- Advancer type Electrical ---- CDI: Magneto-model (stator)/Manufacturer 5CU-20/YAMAHA ---- Charging coil 1 resistance (color) 720–1,080 Ωat 20 °C (68 °F) (Black- ---- Black/Red) Charging coil 2 resistance (color) 44–66 Ωat 20 °C (68 °F) (Green/Blue-...
Page 28 TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb Radiator M6 × 1.0 Radiator panel M6 × 1.0 Radiator hose clamp M6 × 1.0 Air filter element M6 × 1.0 Carburetor joint M6 × 1.0 Air filter case M6 ×...
Page 29 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 30 TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb Nipple (spoke) — △ Disc cover and rear brake caliper M6 × 1.0 △ Protector and rear brake caliper M6 × 1.0 △ Drive chain puller adjust bolt and locknut M8 ×...
Page 31 TIGHTENING TORQUES ELECTRICAL Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb Stator M6 × 1.0 Rotor M12 × 1.25 Ignition coil M6 × 1.0 Neutral switch (Except for USA and CDN) M5 × 0.8 2-11...
Page 32 TIGHTENING TORQUES GENERAL TORQUE TORQUE SPECIFI- SPECIFICATIONS CATION This chart specifies torque for stan- (Nut) (Bolt) 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 34: Cable Routing Diagram
CABLE ROUTING DIAGRAM CABLE ROUTING DIAGRAM "ENGINE STOP" button lead Pass the clutch cable on the out- Clamp the "ENGINE STOP" but- Throttle cable side of the throttle cable and ton lead to the frame. Tighten Clutch cable "ENGINE STOP" button lead. the clamp so that the "ENGINE Clamp Align the throttle cable locating...
Page 35 CABLE ROUTING DIAGRAM Clamp the throttle cable and wireharness to the frame. Pass the clutch cable in front of the center of the cylinder head tightening nut. Pass the air vent hose, overflow hose and crankcase breather hose between the frame and connecting rod.
Page 36 CABLE ROUTING DIAGRAM Ignition coil lead Clamp the ignition coil lead to Do not allow the neutral switch Clamp the frame at its locating tape. lead to slacken except over the CDI magneto lead Clamp it in front of the radiator radiator hose.
Page 37 CABLE ROUTING DIAGRAM Pass the radiator breather hose outside the engine bracket and inside the down tube. Then pass the radiator breather hose inside the CDI magneto lead. Clamp the CDI magneto lead, radiator breather hose, YPVS breather hose and neutral switch lead (except for USA and CDN) to the frame.
Page 38 CABLE ROUTING DIAGRAM Clamp Clamp the wireharness protect- Bring the connector cover into Wireharness ing tube to the right engine contact with the coupler. High tension cord bracket. Pass the radiator breather hose CDI unit band Pass the high tension cord to the behind the radiator hose.
Page 39 CABLE ROUTING DIAGRAM Install the brake hose so that its Master cylinder Install the brake hose so that its pipe portion directs as shown Brake hose holder pipe portion directs as shown and lightly touches the projec- Brake hose and lightly touches the projec- tion on the caliper.
Page 40 CABLE ROUTING DIAGRAM Brake hose Install the brake hose so that its Pass the brake hose in front of Master cylinder pipe portion directs as shown the number plate and through "ENGINE STOP" button lead and lightly touches the projec- the cable guide.
Page 41: 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. After...
Page 42 MAINTENANCE INTERVALS After Every Every Every As re- Item break- Remarks race third fifth quired CARBURETOR Inspect, adjust and clean ● ● SPARK PLUG Inspect and clean ● ● Replace ● DRIVE CHAIN Use chain lube. Lubricate, slack, alignment Chain slack: 48–58 mm (1.9–2.3 in) ●...
Page 43 Retighten sprocket bolt ● ● Inspect bearings ● Replace bearings ● Lubricate Lithium base grease ● THROTTLE, CONTROL CABLE Check routing and connection ● ● Lubricate Yamaha cable lube or SAE 10W-30 ● ● motor oil...
Page 44: Inspection And Maintenance
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 45: 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 46 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" 95–125 kPa (0.95–1.25 Out of specification →...
Page 47 ENGINE • Do not twist the element when squeezing the element. • Leaving too much of solvent in the element may result in poor starting. 3. Inspect: 2. Apply: CHECKING THE TRANSMISSION • Air filter element • Lithium soap base grease OIL LEVEL Damage →...
Page 48: Chassis
CHASSIS CHANGING THE TRANSMISSION b. Turn out the pilot air screw by the factory-set number of turns. 1. Start the engine and warm it up for several minutes and wait for To optimize the fuel flow at a smaller five minute. throttle opening, each machine's pilot 2.
Page 49 CHASSIS f. Pull the lever in or push down on Brake lever position adjustment ment, make sure that the rear the pedal. Hold the lever or pedal steps: brake does not drag. in position. a. Loosen the locknut "1". g. Loosen the bleed screw and allow b.
Page 50 CHASSIS d. Remove the pad pin and brake pads "4". Install the pad pin plug "10". b. Loosen the pad pin "3". c. Remove the rear wheel "4" and Pad pin plug: e. Connect the transparent hose "5" brake caliper "5". 3 Nm (0.3 m•kg, 2.2 to the bleed screw "6"...
Page 51: Specifications
CHASSIS this point. PADS" section. 2. Inspect: • Rear brake pad insulator "1" Damage → Replace. CHECKING THE DRIVE CHAIN 1. Measure: Install the brake caliper "12" and • Drive chain length (15 links) "a" rear wheel "13". Out of specification → Replace. Refer to "FRONT WHEEL AND CHECKING THE BRAKE FLUID Drive chain length (15...
Page 52: Adjustments
CHASSIS 4. Check: eral times to find the tightest point. e. Tighten the locknuts. • Drive chain stiffness "a" Check and/or adjust the drive chain Locknut: Clean and oil the drive chain and slack with the rear wheel in this "tight 19 Nm (1.9 m•kg, 13 hold as illustrated.
Page 53 CHASSIS 1. Elevate the front wheel by placing Damage/oil leakage → Replace. a suitable stand under the engine. Always adjust each front fork to 2. Remove the air bleed screw "1" the same setting. Uneven adjust- and release the internal pressure ment can cause poor handling and from the front fork.
Page 54 CHASSIS • Rear frame (lower) ADJUSTING THE REAR SHOCK 4. Adjust: ABSORBER LOW COMPRESSION • Spring preload Rear frame (lower): DAMPING FORCE 29 Nm (2.9 m•kg, 21 1. Adjust: ft•lb) Adjustment steps: • Low compression damping force a. Loosen the locknut "1". ADJUSTING THE REAR SHOCK By turning the adjuster "1".
Page 55 CHASSIS ADJUSTING THE REAR SHOCK Spokes: ABSORBER HIGH COMPRESSION • Check the tire while it is cold. 3 Nm (0.3 m•kg, 2.2 DAMPING FORCE • Loose bead stoppers allow the tire ft•lb) 1. Adjust: to slip off its position on the rim CHECKING THE WHEELS •...
Page 56 CHASSIS 4. Adjust: ing bearings. • Steering ring nut h. Install the washer "5", upper bracket "6", washer "7", steering stem nut "8", handlebar "9", han- Steering ring nut adjustment dlebar upper holder "10" and steps: number plate "11". a. Remove the number plate. b.
Page 57 CHASSIS LUBRICATION To ensure smooth operation of all Use Yamaha cable lube or components, lubricate your machine equivalent on these areas. during setup, after break-in, and after Use SAE 10W-30 motor oil or every race. suitable chain lubricants. Lubricate the following areas...
Page 58: Electrical
ELECTRICAL 7. Adjust: CHECKING THE IGNITION TIMING ELECTRICAL • Ignition timing 1. Remove: CHECKING THE SPARK PLUG • Fuel tank 1. Remove: Refer to "SEAT, FUEL TANK Adjustment steps: • Spark plug AND SIDE COVERS" section in a. Loosen the screws (stator) "1". 2.
Page 59: Seat, Fuel Tank And Side Covers
SEAT, FUEL TANK AND SIDE COVERS ENGINE This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request- ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual.
Page 60 SEAT, FUEL TANK AND SIDE COVERS REMOVING THE SIDE COVER 1. Remove: • Bolt (side cover) • Side cover (left and right) "1" Draw the side cover downward to re- move it because its claws "a" are in- serted in the air filter case. REMOVING THE NUMBER PLATE 1.
Page 61: Exhaust Pipe And Silencer
EXHAUST PIPE AND SILENCER EXHAUST PIPE AND SILENCER REMOVING THE EXHAUST PIPE AND SILENCER 12 Nm (1.2 m kg, 8.7 ft lb) 15 mm (0.59 in) 12 Nm (1.2 m kg, 8.7 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 14.5 mm (0.57 in) 12 Nm (1.2 m kg, 8.7 ft lb)
Page 62 • Fiber "2" 4. Install: • Inner pipe ® Fully apply Quick gasket (Yamaha bond No.1215) or equivalent as shown. Yamaha bond No.1215 ® (Three Bond No.1215): 90890-85505 5. Install: • Bolt (fiber) "1" Bolt (fiber): 10 Nm (1.0 m•kg, 7.2 ft•lb)
Page 63: Radiator
RADIATOR RADIATOR REMOVING THE RADIATOR 2 Nm (0.2 m kg, 1.4 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) Order Part name...
Page 64 RADIATOR HANDLING NOTE • Radiator hose 4 "4" Radiator hose 4: 2 Nm (0.2 m•kg, 1.4 Do not remove the radiator cap ft•lb) when the engine and radiator are hot. Scalding hot fluid and steam Refer to "CABLE ROUTING DIA- may be blown out under pressure, GRAM"...
Page 65: Carburetor And Reed Valve
CARBURETOR AND REED VALVE CARBURETOR AND REED VALVE REMOVING THE CARBURETOR AND REED VALVE 10 Nm (1.0 m kg, 7.2 ft lb) 1 Nm (0.1 m kg, 0.7 ft lb) Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND SIDE Fuel tank COVERS"...
Page 66 CARBURETOR AND REED VALVE DISASSEMBLING THE CARBURETOR 4 Nm (0.4 m kg, 2.9 ft lb) Order Part name Q'ty Remarks Mixing chamber top Throttle valve Refer to removal section. Needle holder Jet needle Float chamber Float pin Float Needle valve Main jet Pilot jet Starter plunger...
Page 67 CARBURETOR AND REED VALVE HANDLING NOTE Contamination → Clean. • Use a petroleum based solvent for Do not loosen the screw (throttle cleaning. Blow out all passages and position sensor) "1" except when jets with compressed air. changing the throttle position sen- •...
Page 68 CARBURETOR AND REED VALVE CHECKING THE REED VALVE MEASURING AND ADJUSTING 1. Measure: THE FLOAT HEIGHT Install the reed valve spacer with its • Reed valve bending "a" 1. Measure: chamfered side "a" to the right. Out of specification → Replace. •...
Page 69 CARBURETOR AND REED VALVE 3. Install: 10. Install: • Pilot air screw "1" • Throttle cable "1" • Throttle stop screw "2" • Locknut "2" Locknut: Note the following installation 4 Nm (0.4 m•kg, 2.9 points: ft•lb) a. Turn in the pilot air screw until it is •...
Page 70 CARBURETOR AND REED VALVE INSTALLING THE CARBURETOR 1. Install: • Carburetor "1" Install the projection between the car- buretor joint slots. 2. Tighten: • Screw (carburetor joint) "1" 3. Tighten: • Screw (air cleaner joint) "1" Place the screw head "a" with its top as shown and secure the clamp in alignment with the horizontal line "b"...
Page 71: Cylinder Head, Cylin Der And Piston
CYLINDER HEAD, CYLINDER AND PISTON CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE CYLINDER HEAD AND CYLINDER 34 Nm (3.4 m kg, 24 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 20 Nm (2.0 m kg, 14 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 25 Nm (2.5 m kg, 18 ft lb) 13 Nm (1.3 m kg, 9.4 ft lb)
Page 72 CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE PISTON AND POWER VALVE 6 Nm (0.6 m kg, 4.3 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) Order Part name...
Page 73 CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE PUSH ROD ure-eight sanding pattern. 1. Remove: • Bolt (push rod) "1" To ensure an even surface rotate the • Push rod "2" cylinder head several times. Insert the set pin "3" included in own- er's tool kit to remove the bolt (push rod).
Page 74 CYLINDER HEAD, CYLINDER AND PISTON 3. Measure: Out of specification → Replace. • Cylinder bore "C" Dis- Use cylinder gauge "1". tance Piston dia. Out of limit → Replace. "b" 17.5 66.352–66.367 Measure the cylinder bore "C" in par- mm (2.6120– allel (A, B, C) to and at right angles to (0.69 in) 2.6129 in)
Page 75 CYLINDER HEAD, CYLINDER AND PISTON 3. Measure: • Cylinder mark "a" • Side clearance When you purchase a cylinder, you Cylinder mark Cylinder size Use a thickness gauge "1". cannot designate its size. Choose the "a" Out of limit → Replace piston and/ piston that matches the above chart.
Page 76 CYLINDER HEAD, CYLINDER AND PISTON INSTALLING THE POWER VALVE 1. Install: • Power valve 1 "1" • Valve holder 2 "2" • Bolt (valve holder 2) "3" Bolt (valve holder 2) 6 Nm (0.6 m•kg, 4.3 ft•lb) 4. Check: 6. Check: •...
Page 77 CYLINDER HEAD, CYLINDER AND PISTON • Before installing the piston pin clip, • Nut (cylinder) "1" cover the crankcase with a clean Nut (cylinder): rag to prevent the piston pin clip 42 Nm (4.2 m•kg, 30 from falling into the crankcase cavi- ft•lb) Tighten the nuts in stage, using a crisscross pattern.
Page 78 CYLINDER HEAD, CYLINDER AND PISTON 6. Install: • O-ring "1" • Dowel pin "2" Apply the lithium soap base grease on the O-rings. 7. Install: • Cylinder head "1" • Copper washer "2" • Nut (cylinder head) "3" Nut (cylinder head): 25 Nm (2.5 m•kg, 18 ft•lb) Tighten the nuts (cylinder head) in...
Page 79: Clutch
CLUTCH CLUTCH REMOVING THE CLUTCH 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty Remarks Refer to "CHANGING THE TRANSMISSION Drain the transmission oil. OIL" section in the CHAPTER 3. Bolt (brake pedal) Shift the brake pedal downward.
Page 80 CLUTCH REMOVING THE CLUTCH BOSS 75 Nm (7.5 m kg, 54 ft lb) 6 Nm (0.6 m kg, 4.3 ft lb) Order Part name Q'ty Remarks Push rod 1 Circlip Washer Bearing Push rod 2 Nut (clutch boss) Refer to removal section. Lock washer Refer to removal section.
Page 81 CLUTCH REMOVING THE CLUTCH BOSS CHECKING THE CLUTCH Wear/Damage → Replace. 1. Remove: SPRINGS • Nut "1" 1. Measure: • Lock washer "2" • Clutch spring free length "a" • Clutch boss "3" Out of specification → Replace springs as a set. Straighten the lock washer tab and Clutch spring free use the clutch holding tool "4"...
Page 82 CLUTCH • Clutch plate "2" • Bolt (clutch spring) "2" Bolt (clutch spring): • Install the clutch plates and friction 10 Nm (1.0 m•kg, 7.2 plates alternately on the clutch ft•lb) boss, starting with a friction plate and ending with a friction plate. Tighten the bolts in stage, using a •...
Page 83: Kick Shaft And Shift Shaft
KICK SHAFT AND SHIFT SHAFT KICK SHAFT AND SHIFT SHAFT REMOVING THE PRIMARY DRIVE GEAR 30 Nm (3.0 m kg, 22 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 55 Nm (5.5 m kg, 40 ft lb) Order Part name Q'ty Remarks...
Page 84 KICK SHAFT AND SHIFT SHAFT REMOVING THE KICK SHAFT AND SHIFT SHAFT 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty...
Page 85 KICK SHAFT AND SHIFT SHAFT REMOVING THE PRIMARY DRIVE Rough spot/Seizure → Replace GEAR the stopper lever. 1. Loosen: • Torsion spring "3" • Bolt (primary drive gear) "1" Broken → Replace. Place an aluminum plate "a" between the teeth of the primary drive gear "2" and driven gear "3".
Page 86 KICK SHAFT AND SHIFT SHAFT INSTALLING THE SHIFT GUIDE INSTALLING THE SHIFT SHAFT 3. Install: AND SHIFT LEVER ASSEMBLY 1. Install: • Spring guide "1" 1. Install: • Roller "1" • Spring "1" • Washer "2" Slide the spring guide into the kick •...
Page 87 KICK SHAFT AND SHIFT SHAFT INSTALLING THE KICK IDLE GEAR Install the kick starter closest to but 1. Install: not contacting the clutch cover • Kick idle gear "1" mounting boss "a". • Washer "2" • Circlip "3" • Apply the transmission oil on the 4.
Page 88: Ypvs Governor
YPVS GOVERNOR YPVS GOVERNOR REMOVING THE YPVS GOVERNOR Order Part name Q'ty Remarks Refer to "KICK SHAFT AND SHIFT SHAFT" Crankcase cover (right) section. Governor assembly Dowel pin Refer to removal section. Retainer Ball Retainer weight Washer Thrust bearing Collar Plate Compression spring Governor gear...
Page 89 YPVS GOVERNOR REMOVING THE GOVERNOR 1. Remove: • Dowel pin "1" While compressing the spring, re- move the dowel pin. CHECKING THE GOVERNOR GROOVE 2. Install: 1. Inspect: • Ball "1" • Washer "1" • Retainer "2" • Collar "2" To governor shaft "3".
Page 90: Water Pump
WATER PUMP WATER PUMP DISASSEMBLING THE WATER PUMP 10 Nm (1.0 m kg, 7.2 ft lb) 14 Nm (1.4 m kg, 10 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty Remarks Refer to "KICK SHAFT AND SHIFT SHAFT" Crankcase cover (right) section.
Page 91 WATER PUMP REMOVING THE IMPELLER • Gear teeth "a" SHAFT Wear/damage → Replace. 1. Remove: • Impeller "1" • Washer "2" • Impeller shaft "3" Hold the impeller shaft on its width INSTALLING THE IMPELLER across the flats "a" with spanners, SHAFT etc.
Page 92 WATER PUMP 4. Install: • Water pump housing cover "1" • Bolt (water pump housing cover) "2" Bolt (water pump hous- ing cover): 10 Nm (1.0 m•kg, 7.2 ft•lb) • Copper washer (coolant drain bolt) "3" • Coolant drain bolt "4" Coolant drain bolt: 10 Nm (1.0 m•kg, 7.2 ft•lb)
Page 93: Cdi Magneto
CDI MAGNETO CDI MAGNETO REMOVING THE CDI MAGNETO 7 Nm (0.7 m kg, 5.1 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 56 Nm (5.6 m kg, 40 ft lb) Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND SIDE Seat and fuel tank COVERS"...
Page 94 CDI MAGNETO REMOVING THE ROTOR INSTALLING THE CDI MAGNETO CHAPTER 3. 1. Remove: 1. Install: Ignition timing (B.T.D.C): • Nut (rotor) "1" • Stator "1" 0.18 mm (0.007 in) • Washer "2" • Screw (stator) "2" Use the rotor holding tool "3". 5.
Page 95: Engine Removal
ENGINE REMOVAL ENGINE REMOVAL REMOVING THE ENGINE 34 Nm (3.4 m kg, 24 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 26 Nm (2.6 m kg, 19 ft lb) 85 Nm (8.5 m kg, 61 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 75 Nm (7.5 m kg, 54 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb)
Page 96 ENGINE REMOVAL 34 Nm (3.4 m kg, 24 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 26 Nm (2.6 m kg, 19 ft lb) 85 Nm (8.5 m kg, 61 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 75 Nm (7.5 m kg, 54 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb)
Page 97 ENGINE REMOVAL HANDLING NOTE • Spring "1" • Brake pedal "2" • O-ring "3" Support the machine securely so • Bolt (brake pedal) "4" there is no danger of it falling over. Bolt (brake pedal): 26 Nm (2.6 m•kg, 19 REMOVING THE DRIVE ft•lb) SPROCKET...
Page 98 ENGINE REMOVAL 4. Install: • Drive chain sprocket guide "1" • Drive chain sprocket cover "2" • Screw (drive chain sprocket cov- er) "3" Screw (drive chain sprocket cover): 5 Nm (0.5 m•kg, 3.6 ft•lb) 5. Connect: (except for USA and CDN) •...
Page 99: Crankcase And Crankshaft
CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT REMOVING THE CRANKSHAFT 14 Nm (1.4 m kg, 10 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 30 Nm (3.0 m kg, 22 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty...
Page 100 CRANKCASE AND CRANKSHAFT 14 Nm (1.4 m kg, 10 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 30 Nm (3.0 m kg, 22 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty Remarks Crankcase (left) Refer to removal section.
Page 101 CRANKCASE AND CRANKSHAFT REMOVING THE SEGMENT 1. Remove: • Bolt (segment) "1" • Segment "2" Turn the segment counterclockwise until it stops and loosen the bolt. REMOVING THE CRANKSHAFT CHECKING THE CRANKCASE 1. Remove: 1. Inspect: If the segment gets an impact, it •...
Page 102 "3": YU-90050/90890-01275 4. Apply: Adapter "4": • Sealant YU-90063/90890-01278 On the right crankcase "1" YAMAHA Bond No.1215 • Hold the connecting rod at top dead ® (ThreeBond No.1215): center with one hand while turning 90890-85505 the nut of the installing tool with the other.
Page 103 CRANKCASE AND CRANKSHAFT 8. Install: • Segment "1" • Bolt (segment) "2" Bolt (segment): 30 Nm (3.0 m•kg, 22 ft•lb) 6. Install: • When installing the segment onto • Holder (except for USA and CDN) the shift cam "3", align the punch "1"...
Page 104: Shift 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 105 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 106 TRANSMISSION, SHIFT CAM AND SHIFT FORK 3. Install: • Washer "1" • Circlip "2" • Be sure the circlip sharp-edged cor- ner "a" is positioned opposite side to the washer and gear "b". • Be sure the circlip end "c" is posi- tioned at axle spline groove "d".
Page 107: Front Wheel And Rear Wheel
FRONT WHEEL AND REAR WHEEL CHASSIS This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request- ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual.
Page 108 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 109 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 110 FRONT WHEEL AND REAR WHEEL 2. Install: • Nut (wheel axle) "1" • Brake disc "1" Nut (wheel axle): Do not strike the inner race of the • Bolt (brake disc) "2" 105 Nm (10.5 m•kg, 75 bearing. Contact should be made Bolt (brake disc): ft•lb) only with the outer race.
Page 111 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 112: 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 113 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 114 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 115 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 116 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 117 FRONT BRAKE AND REAR BRAKE 4. Inspect: HANDLING NOTE • Brake master cylinder piston "1" Apply the brake fluid on the piston • Brake master cylinder cup "2" wall. • All internal parts should be Wear/damage/score marks → Re- cleaned in new brake fluid only. place brake master cylinder kit.
Page 118 FRONT BRAKE AND REAR BRAKE 4. Install: • Pad pin plug "4" • Pad pin plug "4" Pad pin plug: Pad pin plug: 3 Nm (0.3 m•kg, 2.2 3 Nm (0.3 m•kg, 2.2 ft•lb) ft•lb) 4. Install: • Brake master cylinder kit "1" •...
Page 119 FRONT BRAKE AND REAR BRAKE 2. Install: 2. Install: INSTALLING THE FRONT BRAKE • Brake lever "1" • Brake master cylinder "1" HOSE • Bolt (brake lever) "2" • Bolt (brake master cylinder) "2" 1. Install: • Copper washer "1" Bolt (brake lever): Bolt (brake master cylin- •...
Page 120 FRONT BRAKE AND REAR BRAKE 3. Pass the brake hose through the cable guide "1". • Use only the designated quality brake fluid: otherwise, the rubber seals may deteriorate, causing leakage and poor brake performance. • Refill with the same type of brake fluid;...
Page 121 FRONT BRAKE AND REAR BRAKE 4. Install: • Reservoir float (front brake) • Diaphragm • Brake master cylinder cap "1" • Screw (brake master cylinder cap) "2" Screw (bolt) {brake mas- ter cylinder cap}: 2 Nm (0.2 m•kg, 1.4 ft•lb) After installation, while pulling the brake lever in or pushing down on the brake pedal, check whether...
Page 122: Front Fork
FRONT FORK FRONT FORK REMOVING THE FRONT FORK 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 Front wheel WHEEL" section. Refer to "FRONT BRAKE AND REAR Front brake caliper BRAKE"...
Page 123 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 124 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 125 FRONT FORK Use the dial gauge "1". CHECKING THE BASE VALVE 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. they may have an excessively ad- Contamination →...
Page 126 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 127 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 128 FRONT FORK 27. Install: 32. Install: • Push rod "1" • Damper assembly "1" • Copper washer "2" To outer tube. • Adjuster "3" To damper assembly "4". Temporarily tighten the damper as- sembly. • While compressing the inner tube "5", set the cap bolt ring wrench "7"...
Page 129 FRONT FORK 2. Tighten: 5. Install: • Damper assembly "1" • Protector "1" • Bolt (protector) "2" Damper assembly: 30 Nm (3.0 m•kg, 22 Bolt (protector): ft•lb) 5 Nm (0.5 m•kg, 3.6 ft•lb) Use the cap bolt ring wrench "2" to tighten the damper assembly with specified torque.
Page 130: Handlebar
HANDLEBAR HANDLEBAR REMOVING THE HANDLEBAR 1 Nm (0.1 m kg, 0.7 ft lb) 9 Nm (0.9 m kg, 6.5 ft lb) 28 Nm (2.8 m kg, 20 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 40 Nm (4.0 m kg, 29 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) Order...
Page 131 HANDLEBAR DISASSEMBLING THE THROTTLE Order Part name Q'ty Remarks Grip cap (lower) Grip cap (upper) Grip assembly Grip (right) Refer to removal section. Tube guide 5-25...
Page 132 HANDLEBAR REMOVING THE BRAKE MASTER surface "a" with a lacquer thinner. CYLINDER • Align the mating mark "b" on the 1. Remove: grip (right) with the slot "c" in the • Brake master cylinder bracket "1" tube guide. • Brake master cylinder "2" •...
Page 133 HANDLEBAR • Throttle cables "1" To tube guide "2". Apply the lithium soap base grease on the throttle cable end and tube guide cable winding portion. 3. Tighten: 11. Install: • Nut (handlebar lower holder) "1" • Brake master cylinder "1" •...
Page 134 HANDLEBAR 13. Install: • Engine stop switch "1" • Clutch lever holder "2" • Bolt (clutch lever holder) "3" Bolt (clutch lever holder): 4 Nm (0.4 m•kg, 2.9 ft•lb) • Clamp "4" • The engine stop switch, clutch lever holder and clamp should be in- stalled according to the dimensions shown.
Page 135: 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 136 STEERING Order Part name Q'ty Remarks Bearing race Refer to removal section. 5-30...
Page 137 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 138 STEERING 6. Install: • Pinch bolt (upper bracket) "1" • Washer "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): 21 Nm (2.1 m•kg, 15 7. Install: ft•lb) •...
Page 139: 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 140 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. 5-34...
Page 141 SWINGARM HANDLING NOTE 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: CHECKING THE CONNECTING • Bearing "1" Remove with a slotted-head screw- •...
Page 142 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 143 SWINGARM 10. Tighten: • Drive chain support cover "2" • Nut (connecting rod) "1" • Bolt {drive chain support [L = 50 mm (1.97 in)]} "3" Nut (connecting rod): • Nut (drive chain support) "4" 80 Nm (8.0 m•kg, 58 ft•lb) Nut (drive chain sup- port):...
Page 144: Absorber
REAR SHOCK ABSORBER REAR SHOCK ABSORBER REMOVING THE REAR SHOCK ABSORBER 56 Nm (5.6 m kg, 40 ft lb) 32 Nm (3.2 m kg, 23 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 53 Nm (5.3 m kg, 38 ft lb) Order Part name Q'ty...
Page 145: Rear Shock Absorber
REAR SHOCK ABSORBER 56 Nm (5.6 m kg, 40 ft lb) 32 Nm (3.2 m kg, 23 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 53 Nm (5.3 m kg, 38 ft lb) Order Part name Q'ty Remarks Bearing Refer to removal section.
Page 146 To dispose of a damaged or worn- • Stopper ring (upper bearing) "1" ABSORBER out rear shock absorber, take the 1. Inspect: unit to your Yamaha dealer for this • Damper rod "1" disposal procedure. After installing the stopper ring, push Bends/damage → Replace rear back the bearing until it contacts the shock absorber assembly.
Page 147 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 148 REAR SHOCK ABSORBER 6. Install: • Rear frame "1" • Bolt [rear frame (upper)] "2" Bolt [rear frame (upper)]: 32 Nm (3.2 m•kg, 23 ft•lb) • Bolt [rear frame (lower)] "3" Bolt [rear frame (lower)]: 29 Nm (2.9 m•kg, 21 ft•lb) 7.
Page 149 ELECTRICAL This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request- ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to...
Page 150: Nents And Wiring Diagram
ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS CDI unit Solenoid valve Spark plug Engine stop switch Neutral switch (Except for USA Ignition coil and CDN) Throttle position sensor CDI magneto WIRING DIAGRAM CDI unit White/Blue COLOR CODE Engine stop switch White/Red...
Page 151: 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. No spark ↓...
Page 152 IGNITION SYSTEM SPARK GAP TEST Not conductive while it is pushed → 1. Disconnect the spark plug cap Replace. from spark plug. Conductive while it is freed → Re- 2. Connect the dynamic spark tester place. "1" (ignition checker "2") as shown.
Page 153 IGNITION SYSTEM CHECKING THE CDI MAGNETO 1. Inspect: • Pickup coil resistance Out of specification → Replace. Tester (+) lead → White/Red lead "1" Tester (-) lead → White/Blue lead "2" CHECKING THE NEUTRAL SWITCH Tester se- Pickup coil 1. Inspect: lector posi- resistance •...
Page 154: Solenoid Valve System
SOLENOID VALVE SYSTEM SOLENOID VALVE SYSTEM INSPECTION STEPS If the solenoid valve will not operate, use the following inspection steps. Check each couplers and wire connection. No good → Repair or replace. OK ↓ Check solenoid valve. (Check solenoid valve op- No good →...
Page 155 SOLENOID VALVE SYSTEM CHECKING THE COUPLERS AND LEADS CONNECTION 1. Check: • Couplers and leads connection Rust/ Dust/ Looseness/Short-cir- cuit → Repair or replace. CHECKING THE SOLENOID VALVE OPERATION 1. Disconnect the solenoid valve coupler. 2. Connect 12V battery to the sole- noid valve coupler.
Page 156: Throttle Position Sen Sor 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. OK ↓ Check throttle position sensor. (Throttle position No good →...
Page 157: Throttle Position Sensor System
THROTTLE POSITION SENSOR SYSTEM HANDLING NOTE Out of specification → Replace. Tester (+) lead → Yellow lead "2" Tester (-) lead → Black lead "3" Do not loosen the screw (throttle position sensor) "1" except when Tester Throttle position changing the throttle position sen- selec- sensor coil vari- sor due to failure because it will...
Page 158 THROTTLE POSITION SENSOR SYSTEM throttle position sensor and car- buretor. 7. Insert the thin electric conductors 11. Stop the engine. "2" (lead wire) into the throttle po- 12. Remove: sition sensor coupler "1", as • Carburetor shown, and connect the tester to Refer to "CARBURETOR AND them.
Page 159: Tuning
ENGINE TUNING amount of oxygen in the air by so EFFECT OF SETTING PARTS IN much of the water vapor in the RELATION TO THROTTLE VALVE ENGINE same air. OPENING CARBURETOR SETTING • Lower atmospheric pressure (at a • The role of fuel is to cool the engine, high altitude) reduces the density of and in the case of a 2-stroke en- the air.
Page 160 The richness of air-fuel mixture with On the carburetors used in the the throttle fully closed to 1/2 open YZ250, the main nozzle is press-fit- can be set by changing the pilot jet ted, so it can not be replaced. There- "1".
Page 161 ENGINE RELATIONSHIP WITH THROTTLE CARBURETOR SETTING PARTS Part OPENING Jet nee- Size number Main jet Part number The flow of the fuel through the car- dle "3" Size (-14916-) "1" (-14943-) buretor main system is controlled by Rich N8RH 4SR-RH the main jet and then, it is further reg- Rich #190 4MX-45...
Page 162 ENGINE ROAD CONDITION AND EXAMPLES OF CARBURETOR SETTING General condition Sandy condition Under 10°C 15–25°C (59– Over 25°C Under 10°C 15–25°C (59– Over 25°C (50°F) 77°F) (77°F) (50°F) 77°F) (77°F) (Winter) (Spring, Au- (Summer) (Winter) (Spring, Au- (Summer) tumn) tumn) Main jet #178 #178...
Page 163 ENGINE EXAMPLES OF CARBURETOR SETTING DEPENDING ON SYMPTOM Symptom Setting Checking At full throttle Increase main jet calibration no. (Gradual- Discoloration of spark plug → If tan color, it Hard breathing is in good condition. Shearing noise If cannot be corrected: Whitish spark plug Clogged float valve seat Clogged fuel hose...
Page 164 CHASSIS CHANGE OF THE HEAT RANGE a longer straight portion of a speed OF SPARK PLUGS course and should be increased for Judging from the discoloration of a course with many corners. Actual- spark plugs, if they are found improp- ly, however, as the speed depends er, it can be corrected by the following on the ground condition of the day...
Page 165 CHASSIS riding feeling. Rebound damping REAR SUSPENSION SETTING tends to become stronger and the The rear suspension setting should Adjust the oil amount in 5 cm (0.2 front fork may sink deeply over a se- be made depending on the rider's Imp oz, 0.2 US oz) increments or ries of gaps.
Page 166 CHASSIS set length, replace the spring with REAR SHOCK ABSORBER an optional one and make readjust- SETTING PARTS • The unequal-pitch spring is softer in ment. • Rear shock spring "1" initial characteristic than the equal- [Equal-pitch titanium spring] pitch spring and is difficult to bottom out under full compression.
Page 167 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 168 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 170 YAMAHA MOTOR CO., LTD. PRINTED ON RECYCLED PAPER PRINTED IN JAPAN 2500 SHINGAI IWATA SHIZUOKA JAPAN...

Yamaha YZ250 Owner's Service Manual

Chapter 1

Chapter 2 Specifications

Chapter 4 Engine

Chapter 5 Chassis

Chapter 6

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