Page 1 2021 OWNER’S SERVICE MANUAL YZ250 YZ250X Read this manual carefully before operating this vehicle. YZ250 YZ250M YZ250XM BF1-2819U-50-E0...
Page 2 If you believe that your vehicle has a defect which could cause a crash or could cause injury or death, you should immediately inform Transport Canada in addition to notifying Yamaha Motor Canada Ltd, Canada. If Transport Canada receives similar complaints, it may open an investigation, and if it finds that a safety defect exists in a group of vehicles, it may order a recall and remedy campaign.
Page 3 EAM20080 YZ250, YZ250M, YZ250XM OWNER’S SERVICE MANUAL ©2021 by Yamaha Motor Co., Ltd. First edition, April 2020 All rights reserved. Any reproduction or unauthorized use without the written permission of Yamaha Motor Co., Ltd. is expressly prohibited.
Page 4: Important Manual Information
EAM20180 IMPORTANT Congratulations on your purchase of a Yamaha YZ series. This model is the culmination of Yamaha’s vast experience in the production of pacesetting racing machines. It represents the highest grade of craftsmanship and reliability that have made Yamaha a leader.
Page 5: How To Use This Manual
EAM20082 HOW TO USE THIS MANUAL In this manual, descriptions of installation, removal, disassembly, assembly, check, and adjustment procedures are laid out with the individual steps in sequential order. • The manual is divided into chapters and each chapter is divided into sections. The current section title “1”...
Page 6 EAM20083 SYMBOLS The following symbols are used in this manual for easier understanding. The following symbols are not relevant to every vehicle. SYMBOL DEFINITION SYMBOL DEFINITION Serviceable with engine mounted Gear oil Filling fluid Molybdenum disulfide oil Lubricant Brake fluid Special tool Wheel bearing grease Tightening torque...
Page 7: General Information
TABLE OF CONTENTS EAM10003 GENERAL INFORMATION SPECIFICATIONS PERIODIC CHECKS AND ADJUSTMENTS CHASSIS ENGINE COOLING SYSTEM FUEL SYSTEM ELECTRICAL SYSTEM TROUBLESHOOTING TUNING...
Page 9: Table Of Contents
GENERAL INFORMATION SAFETY INFORMATION..................1-1 FOR SAFETY, BE SURE TO OBEY THE FOLLOWING: ......1-1 LOCATION OF IMPORTANT LABELS ............1-4 DESCRIPTION....................1-7 IDENTIFICATION....................1-8 VEHICLE IDENTIFICATION NUMBER ............1-8 ENGINE SERIAL NUMBER ...............1-8 INCLUDED PARTS...................1-9 SIDESTAND (for YZ250)................1-9 NIPPLE WRENCH..................1-9 VALVE JOINT.....................1-9 SET PIN......................1-9 IMPORTANT INFORMATION .................1-10 PREPARATION FOR REMOVAL AND DISASSEMBLY......1-10 REPLACEMENT PARTS................1-10 GASKETS, OIL SEALS AND O-RINGS ...........1-10...
Page 10 BREAK-IN PROCEDURES ..............1-20 MAINTENANCE AFTER BREAK-IN ..............1-22 MAJOR MAINTENANCE................1-22 AIR FILTER MAINTENANCE ..............1-22 TORQUE-CHECK POINTS................1-23 MOTORCYCLE CARE AND STORAGE ............1-25 CARE......................1-25 STORAGE ....................1-26...
Page 11: Safety Information
Yamaha ma- accidents. Many accidents have been chine, and take care to maintain it properly and caused by an automobile driver who did not operate it safely.
Page 12 1. Always wear an approved helmet. Yamaha can neither endorse nor recommend 2. Wear a face shield or goggles. Wind in your the use of accessories not sold by Yamaha or unprotected eyes could contribute to an im- modifications not specifically recommended by...
Page 13 SAFETY INFORMATION Aftermarket Tires and Rims The tires and rims that came with your motorcy- cle were designed to match the performance ca- pabilities and to provide the best combination of handling, braking, and comfort. Other tires, rims, sizes, and combinations may not be appropriate. Refer to “CHECKING THE TIRES”...
Page 14: Location Of Important Labels
LOCATION OF IMPORTANT LABELS EAM20085 LOCATION OF IMPORTANT LABELS Please read the following important labels carefully before operating this vehicle.
Page 15 LOCATION OF IMPORTANT LABELS...
Page 16 LOCATION OF IMPORTANT LABELS AUS, NZL, ZAF...
Page 17: Description
DESCRIPTION EAM20086 DESCRIPTION 11.Check bolt (Transmission oil level) 1. Clutch lever 12.Rear brake pedal 2. Engine stop switch 13.Valve joint 3. Front brake lever 14.Fuel cock 4. Throttle grip 15.Starter knob 5. Radiator cap 16.Drive chain 6. Fuel tank cap 17.Air filter 7.
Page 18: Identification
There are two significant reasons for knowing the serial number of your vehicle: 1. When ordering parts, you can give the num- ber to your Yamaha dealer for positive identi- fication of the model you own. 2. If your vehicle is stolen, the authorities will need the number to search for and identify your vehicle.
Page 19: Included Parts
INCLUDED PARTS EAM20088 INCLUDED PARTS EAM30372 SIDESTAND (for YZ250) This sidestand “1” is used to support only the machine when standing or transporting it. EWA20260 WARNING • Never apply additional force to the sides- tand. • Remove this sidestand before starting out. EAM30535 SET PIN This set pin “1”...
Page 20: Important Information
2. Use proper special tools and equipment. Re- used for repair of the vehicle, including periodic fer to “SPECIAL TOOLS” on page 1-14. replacement parts, are new YAMAHA genuine parts and recommended parts. Do not use any used parts, because these may...
Page 21: Lock Washers/Plates And Cotter Pins
IMPORTANT INFORMATION 1. Oil 2. Lip 3. Spring 4. Grease EAM30012 LOCK WASHERS/PLATES AND COTTER PINS After removal, replace lock washers/plates “1” and cotter pins with new ones. After the bolt or nut has been tightened to specification, firmly bend the lock tabs along a flat of the bolt or nut. EAM30014 CIRCLIPS When assembling parts, always use new cir-...
Page 22: Basic Service Information
BASIC SERVICE INFORMATION • There are many types of coupler locks; EAM20120 BASIC SERVICE INFORMATION therefore, be sure to check the type of cou- pler lock before disconnecting the coupler. EAM30181 ELECTRICAL SYSTEM Checking the electrical system ECA14371 NOTICE Never insert the tester probes into the cou- pler terminal slots.
Page 23 BASIC SERVICE INFORMATION • If the pin “1” on the terminal is flattened, bend it up. • After disassembling or assembling a coupler, pull on the leads to make sure that they are in- stalled securely. 5. Check: • No continuity Digital circuit tester (CD732) 90890-03243 Model 88 Multimeter with tachom-...
Page 24: Special Tools
SPECIAL TOOLS EAM20121 SPECIAL TOOLS The following special tools are required for accurate and complete adjustment and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or improvised tech- niques. The shape and tool number used for the special tool differ by country, so two types are provid- ed.
Page 25 SPECIAL TOOLS Reference Tool name/Tool No. Illustration pages Piston pin puller set 90890-01304 Piston pin puller YU-01304 YU-01304 Rotor holding tool 5-16, 5-17 90890-01235 Universal magneto and rotor holder YU-01235 Flywheel puller 5-16 90890-01189 Flywheel puller YM-01189 Universal clutch holder 5-27, 5-29 90890-04086 Universal clutch holder...
Page 26 SPECIAL TOOLS Reference Tool name/Tool No. Illustration pages Crankcase separating tool 5-36, 5-39 90890-01135 Crankcase separator YU-01135-B Yamaha bond No. 1215 5-37 90890-85505 (Three bond No.1215®) Crankshaft installer pot 5-39 90890-01274 Installing pot YU-90058 YU-90058/YU-90059 Crankshaft installer bolt 5-39 90890-01275...
Page 27 SPECIAL TOOLS Reference Tool name/Tool No. Illustration pages Radiator cap tester 6-3, 6-3 90890-01325 Mityvac cooling system tester kit YU-24460-A YU-24460-A Radiator cap tester adapter 6-3, 6-3 90890-01352 Pressure tester adapter YU-33984 YU-33984 Ignition checker 90890-06754 Oppama pet–4000 spark checker YM-34487 1-17...
Page 28: Instrument And Control Functions
INSTRUMENT AND CONTROL FUNCTIONS EAM20181 INSTRUMENT AND CONTROL FUNCTIONS EAM30182 ENGINE STOP SWITCH The engine stop switch “1” is located on the left handlebar. Continue pushing the engine stop switch till the engine comes to a stop. EAM30188 FRONT BRAKE LEVER The front brake lever “1”...
Page 29: Fuel Cock (For Yz250X)
INSTRUMENT AND CONTROL FUNCTIONS in this position. EAM30190 SIDESTAND (for YZ250X) EAM30537 FUEL COCK (for YZ250X) This sidestand “1” is used to support only the The fuel cock supplies fuel from the tank to car- machine when standing or transporting it. buretor and also filters the fuel.
Page 30: Starting And Break-In
STARTING AND BREAK-IN engine by kicking the kickstarter forcefully EAM20123 STARTING AND BREAK-IN with firm stroke. 4. Run the engine at idle or slightly higher until it EAM30538 warms up: this usually takes about one or two FUEL AND ENGINE MIXING OIL minutes.
Page 31 STARTING AND BREAK-IN of cables, free play of the brake, stretch of the drive chain, looseness of the spoke, and so ECA25821 NOTICE After a break-in or after each race, always check the points shown in “TORQUE- CHECK POINTS” for tightening torques and retighten them.
Page 32: Maintenance After Break-In
Disassemble the carburetor and clean the AIR FILTER MAINTENANCE small holes, blowing them with compressed Apply the Yamaha foam air filter oil or other qual- air. ity foam air filter oil to the element. (Excess oil in • CDI magneto...
Page 33: Torque-Check Points
TORQUE-CHECK POINTS EAM20125 TORQUE-CHECK POINTS Frame construction Frame to rear frame Combined seat and fuel tank Fuel tank to frame Engine mounting Frame to engine Engine bracket to engine Engine bracket to frame Seat Seat to frame Steering Steering stem to handlebar Steering stem to frame Steering stem to upper bracket Upper bracket to handlebar...
Page 34 TORQUE-CHECK POINTS Plastic cover Tightening of front fender Tightening of fork leg protector Tightening of air scoop Left cover to rear frame Tightening of side cover Tightening of rear fender Tightening of mud flap Tightening of rear brake disc cover Tightening of rear brake caliper cover Concerning the tightening torque, refer to “TIGHTENING TORQUES”...
Page 35: Motorcycle Care And Storage
MOTORCYCLE CARE AND STORAGE ucts are used on hard-to-remove dirt, do EAM20126 MOTORCYCLE CARE AND STOR- not leave the cleaner on the affected area any longer than instructed. Also, thorough- ly rinse the area off with water, immediately dry it, and then apply a corrosion protec- EAM30200 CARE tion spray.
Page 36: Storage
Salt sprayed on roads in the winter may remain well into spring. • Consult a Yamaha dealer for advice on what 1. Clean the motorcycle with cold water and a products to use.
Page 37 MOTORCYCLE CARE AND STORAGE stored. Long-term Before storing your motorcycle for several months: 1. Follow all the instructions in “CARE” on page 1-25. 2. Drain the fuel tank, fuel lines, and the carbu- retor float bowl. 3. Perform the following steps to protect the cyl- inder, piston rings, etc.
Page 38 MOTORCYCLE CARE AND STORAGE 1-28...
Page 39 SPECIFICATIONS GENERAL SPECIFICATIONS................2-1 ENGINE SPECIFICATIONS ................2-2 CHASSIS SPECIFICATIONS ................2-5 ELECTRICAL SPECIFICATIONS ..............2-8 TIGHTENING TORQUES .................2-9 GENERAL TIGHTENING TORQUE SPECIFICATIONS......2-9 ENGINE TIGHTENING TORQUES............2-10 CHASSIS TIGHTENING TORQUES............2-12 CABLE ROUTING DIAGRAM ................2-15...
Page 40: Specifications
GENERAL SPECIFICATIONS EAM20127 GENERAL SPECIFICATIONS Model Model B9U9 (YZ250_CAN) B9UA (YZ250_AUT/BEL/CHE/CYP/CZE/DEU/DNK/ ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL/ITA/ NLD/NOR/POL/PRT/SVK/SVN/SWE/TUR) B9UC (YZ250_AUS/NZL/ZAF) BF1M (YZ250X_CAN) BF1R (YZ250X_AUS) Dimensions Overall length 2180 mm (85.8 in) (YZ250X_AUS) 2185 mm (86.0 in) (YZ250, YZ250X_CAN) Overall width 825 mm (32.5 in) Overall height 1285 mm (50.6 in) (YZ250X_AUS) 1290 mm (50.8 in) (YZ250, YZ250X_CAN) Seat height...
Page 41: Engine Specifications
ENGINE SPECIFICATIONS EAM20128 ENGINE SPECIFICATIONS Engine Combustion cycle 2-stroke Cooling system Liquid cooled Induction system Reed valve Displacement 249 cm³ (YZ250) 250 cm³ (YZ250X) Number of cylinders Single cylinder Bore  stroke 66.4  72.0 mm (2.61  2.83 in) Compression ratio 7.9–9.4 : 1 (YZ250X) 8.9–10.6 : 1 (YZ250)
Page 42 0.01 mm (0.0004 in) Drive axle runout limit 0.01 mm (0.0004 in) Secondary reduction ratio 3.571 (50/14) Final drive Chain Air filter Air filter element Wet element Air filter oil grade Yamaha foam air filter oil or other quality foam air filter oil...
Page 43 ENGINE SPECIFICATIONS Carburetor Type  quantity PWK38  1 ID mark 1P86 40 (YZ250_AUS/AUT/BEL/CHE/CYP/CZE/DEU/ DNK/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL/ ITA/NLD/NOR/NZL/POL/PRT/SVK/SVN/SWE/ TUR/ZAF, YZ250X_AUS) 1P87 50 (YZ250_CAN, YZ250X_CAN) Main jet #178 (YZ250_CAN, YZ250X_CAN) #180 (YZ250_AUS/AUT/BEL/CHE/CYP/CZE/DEU/ DNK/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL/ ITA/NLD/NOR/NZL/POL/PRT/SVK/SVN/SWE/ TUR/ZAF, YZ250X_AUS) Main air jet #200 Jet needle N3-EW-2 (YZ250_CAN, YZ250X_CAN) N3-EW-3 (YZ250_AUS/AUT/BEL/CHE/CYP/CZE/DEU/ DNK/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL/...
Page 44: Chassis Specifications
CHASSIS SPECIFICATIONS EAM20129 CHASSIS SPECIFICATIONS Chassis Frame type Semi double cradle 27.7  Caster angle Trail 122 mm (4.8 in) Front wheel Wheel type Spoke wheel Rim size 21 x 1.60 Radial wheel runout limit 2.0 mm (0.08 in) Lateral wheel runout limit 2.0 mm (0.08 in) Wheel axle bending limit 0.50 mm (0.02 in)
Page 45 Fork spring free length limit 449.0 mm (17.68 in) Inner tube bending limit 0.2 mm (0.01 in) Recommended oil Yamaha Suspension Oil S1 Quantity (left) 515.0 cm³ (17.41 US oz, 18.16 Imp.oz) Quantity (right) 515.0 cm³ (17.41 US oz, 18.16 Imp.oz)
Page 46 CHASSIS SPECIFICATIONS Compression damping Adjusting system Mechanical adjustable type Fast compression damping Unit for adjustment Turn Adjustment value from the start position (Soft) Adjustment value from the start position 1-3/8 (YZ250) (STD) 1-5/8 (YZ250X) Adjustment value from the start position (Hard) Slow compression damping Unit for adjustment...
Page 47: Electrical Specifications
ELECTRICAL SPECIFICATIONS EAM20130 ELECTRICAL SPECIFICATIONS Ignition system Ignition system Ignition timing (B.T.D.C.) 0.18 mm (0.01 in) 248.0–372.0  Pickup coil resistance 720.0–1080.0  Charging coil 1 resistance 44.0–66.0  Charging coil 2 resistance Ignition coil 0.20–0.30  Primary coil resistance Secondary coil resistance 9.52–14.28 k...
Page 48: Tightening Torques
TIGHTENING TORQUES EAM20131 TIGHTENING TORQUES EAM30205 GENERAL TIGHTENING TORQUE SPECIFICATIONS This chart specifies tightening torques for stan- dard fasteners with a standard ISO thread pitch. Tightening torque specifications for special com- ponents or assemblies are provided for each chapter of this manual. To avoid warpage, tight- en multi-fastener assemblies in a crisscross pat- tern and progressive stages until the specified tightening torque is reached.
Page 49: Engine Tightening Torques
TIGHTENING TORQUES EAM30203 ENGINE TIGHTENING TORQUES - marked portion shall be checked for torque tightening after break-in or before each race. Thread Item Q’ty Tightening torques Remarks size Spark plug M14S 20 N·m (2.0 kgf·m, 15 lb·ft) Cylinder head nut 25 N·m (2.5 kgf·m, 18 lb·ft) Cylinder head stud bolt 13 N·m (1.3 kgf·m, 9.6 lb·ft)
Page 50 TIGHTENING TORQUES Thread Item Q’ty Tightening torques Remarks size Silencer bolt 12 N·m (1.2 kgf·m, 8.9 lb·ft) / Fiber bolt 10 N·m (1.0 kgf·m, 7.4 lb·ft) Crankcase bolt 14 N·m (1.4 kgf·m, 10 lb·ft) Crankcase cover screw (left) 5 N·m (0.5 kgf·m, 3.7 lb·ft) Drive sprocket cover screw 5 N·m (0.5 kgf·m, 3.7 lb·ft) Crankcase cover screw (right)
Page 51: Chassis Tightening Torques
TIGHTENING TORQUES EAM30204 CHASSIS TIGHTENING TORQUES - marked portion shall be checked for torque tightening after break-in or before each race. Thread Item Q’ty Tightening torques Remarks size Upper bracket pinch bolt 21 N·m (2.1 kgf·m, 15 lb·ft)  Lower bracket pinch bolt 21 N·m (2.1 kgf·m, 15 lb·ft) ...
Page 52 TIGHTENING TORQUES Thread Item Q’ty Tightening torques Remarks size Front brake disc bolt 12 N·m (1.2 kgf·m, 8.9 lb·ft) / Rear brake disc bolt 12 N·m (1.2 kgf·m, 8.9 lb·ft) / Footrest bracket bolt 55 N·m (5.5 kgf·m, 41 lb·ft) Rear brake pedal bolt 26 N·m (2.6 kgf·m, 19 lb·ft) ...
Page 53 TIGHTENING TORQUES Thread Item Q’ty Tightening torques Remarks size Fuel tank bolt 10 N·m (1.0 kgf·m, 7.4 lb·ft)  Fuel cock screw 4.0 N·m (0.40 kgf·m, 3.0 lb·ft)  Fuel tank screw (seat set side) 7 N·m (0.7 kgf·m, 5.2 lb·ft) Fuel tank screw (fitting band side) 7 N·m (0.7 kgf·m, 5.2 lb·ft) Fuel tank bracket bolt...
Page 54: Cable Routing Diagram
CABLE ROUTING DIAGRAM EAM20152 CABLE ROUTING DIAGRAM Frame and engine (left side view) 2-15...
Page 55 CABLE ROUTING DIAGRAM 1. Engine stop switch lead 2. Throttle cable 3. Clutch cable 4. Clamp 5. Throttle position sensor lead 6. Radiator breather hose 7. Air vent hose 8. Crankcase breather hose 9. Overflow hose A. Pass the clutch cable on the outside of the throttle cable and engine stop switch lead.
Page 56 CABLE ROUTING DIAGRAM Frame and engine (left side view) 2-17...
Page 57 CABLE ROUTING DIAGRAM 1. Ignition coil lead 2. Clamp 3. CDI magneto lead 4. Neutral switch lead 5. Radiator breather hose 6. YPVS breather hose 7. Connector cover A. Clamp the ignition coil lead to the frame at its locating tape. Clamp it in front of the radiator fitting boss.
Page 58 CABLE ROUTING DIAGRAM Frame and engine (right side view) 2-19...
Page 59 CABLE ROUTING DIAGRAM 1. Clamp 2. Throttle position sensor lead 3. High tension cord 4. CDI unit band 5. CDI unit 6. CDI unit lead 7. Joint connector 8. Connector cover 9. Radiator hose 10.Radiator breather hose 11.CDI unit stay A.
Page 60 CABLE ROUTING DIAGRAM Handlebar (front view) 2-21...
Page 61 CABLE ROUTING DIAGRAM 1. Brake hose 2. Master cylinder 3. Engine stop switch lead 4. Engine stop switch 5. Throttle cable 6. Clutch cable 7. Clamp 8. Cable guide A. Install the brake hose so that its pipe portion directs as shown and lightly touches the pro- jection on the master cylinder.
Page 62 CABLE ROUTING DIAGRAM Rear brake (right side view) 2-23...
Page 63 CABLE ROUTING DIAGRAM 1. Master cylinder 2. Brake hose holder 3. Brake hose A. Pass the brake hose into the brake hose holders. B. If the brake hose contacts the rear shock absorber spring, correct its twist. C. Install the brake hose so that its pipe portion directs as shown and lightly touches the pro- jection on the master cylinder.
Page 64 CABLE ROUTING DIAGRAM 2-25...
Page 65 PERIODIC CHECKS AND ADJUSTMENTS MAINTENANCE INTERVALS................3-1 MAINTENANCE INTERVALS ..............3-1 PRE-OPERATION INSPECTION AND MAINTENANCE .........3-4 GENERAL INSPECTION AND MAINTENANCE........3-4 ENGINE ......................3-5 ADJUSTING THE PILOT AIR SCREW ............3-5 CHECKING THE ENGINE IDLING SPEED ..........3-5 CHECKING THE THROTTLE GRIP............3-5 CHECKING THE SPARK PLUG ..............3-6 CHECKING THE TRANSMISSION OIL LEVEL .........3-6 CHANGING THE TRANSMISSION OIL.............3-7 ADJUSTING THE CLUTCH LEVER FREE PLAY........3-7...
Page 66 CHECKING THE CHASSIS FASTENERS ..........3-24 CHECKING AND LUBRICATING THE CABLES ........3-24 LUBRICATING THE BRAKE LEVER ............3-24 LUBRICATING THE CLUTCH LEVER.............3-25 LUBRICATING THE PEDAL ..............3-25 CHECKING THE SIDESTAND (for YZ250X) ...........3-25 LUBRICATING THE SIDESTAND (for YZ250X) ........3-25 ELECTRICAL SYSTEM..................3-26 CHECKING THE IGNITION TIMING............3-26...
Page 67: Maintenance Intervals
(e.g., rain, dirt, etc.). Therefore, earlier inspection is required by reference to the list below. Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools, data and technical skills.
Page 68 • Replace. • Check chain slack, alignment and condition.   • Adjust and thoroughly lubricate 16 * Drive chain chain with Yamaha chain and cable lube or equivalent. • Replace.  • Check coolant level and for leak-  ...
Page 69 MAINTENANCE INTERVALS Every Every Every After race third race fifth race Item Routine break-in (about 2.5 (about 7.5 (about 12.5 required hours) hours) hours) • Check operation and for oil leak- age.   • Adjust if necessary. • Clean dust seal and lubricate with lithium-soap-based grease.
Page 70: Pre-Operation Inspection And Maintenance
PRE-OPERATION INSPECTION AND MAINTENANCE EAM20134 PRE-OPERATION INSPECTION AND MAINTENANCE Before riding for break-in operation, practice or a race, make sure the machine is in good operating con- dition. Before using this machine, check the following points. EAM30209 GENERAL INSPECTION AND MAINTENANCE Item Inspect Page...
Page 71: Engine
ENGINE EAM20135 ENGINE EAM30607 ADJUSTING THE PILOT AIR SCREW 1. Adjust: • Pilot air screw “1” EAM30475 CHECKING THE THROTTLE GRIP Prior to adjusting throttle grip free play, the en- gine idling speed should be adjusted. 1. Check: • Throttle grip free play “a” To optimize the fuel flow at a smaller throttle Out of specification ...
Page 72: Checking The Spark Plug
ENGINE G088879 7. Install: EAM30254 • Spark plug CHECKING THE SPARK PLUG 1. Disconnect: Spark plug • Spark plug cap 20 N·m (2.0 kgf·m, 15 lb·ft) 2. Remove: • Spark plug ECA13330 Before installing the spark plug, clean the spark NOTICE plug and gasket surface.
Page 73: Changing The Transmission Oil
ENGINE c. Inspect the gasket (oil check bolt), replace Oil drain bolt if damaged. 23 N·m (2.3 kgf·m, 17 lb·ft) d. Tighten the oil check bolt. 7. Fill: Oil check bolt • Transmission oil 10 N·m (1.0 kgf·m, 7.4 lb·ft) Type Motor oil SAE 10W-40 type SG or higher...
Page 74: Adjusting The Clutch Lever Position
ENGINE 2. Tighten: • Locknut If the clutch lever free play cannot be obtained on the handlebar side, use the adjuster on the Locknut (clutch lever position) clutch cable side. 4.8 N·m (0.48 kgf·m, 3.5 lb·ft) Clutch cable side EAM30219 CLEANING THE AIR FILTER ELEMENT a.
Page 75: Checking The Carburetor Joint
4. Check: • Air filter element Damage  Replace. 5. Apply: Yamaha foam air filter oil or other quality foam air filter oil. a. Put the air filter element into a plastic bag and drip the filter oil into the bag.
Page 76: Checking The Carburetor Hoses
ENGINE b. Remove the inner pipe “1”. EAM30542 CHECKING THE CARBURETOR HOSES c. Replace the fiber “2”. The following procedure applies to all of the fuel d. Install the inner pipe. and vacuum hoses. 1. Check: Apply heat-resistant sealant to the areas shown, •...
Page 77: Checking The Coolant Level
ENGINE up to the maximum level. Fiber bolt “1” 10 N·m (1.0 kgf·m, 7.4 lb·ft) LOCTITE® Silencer bolt “2” 12 N·m (1.2 kgf·m, 8.9 lb·ft) LOCTITE® Side cover bolt 7 N·m (0.7 kgf·m, 5.2 lb·ft) 1. Radiator ECA24260 NOTICE • Adding water instead of coolant lowers the antifreeze content.
Page 78 ENGINE gine is hot. Scalding hot fluid and steam may EWA13040 WARNING be blown out, which could cause serious in- • If coolant splashes in your eyes, thorough- jury. When the engine has cooled, open the ly wash them with water and consult a doc- radiator cap as follows: tor.
Page 79: Chassis
CHASSIS air must be removed by bleeding the brake EAM20136 CHASSIS system. Air in the brake system will consid- erably reduce braking performance. EAM30479 ADJUSTING THE FRONT DISC BRAKE ECA13490 NOTICE There should be no free play at the brake lever After adjusting the brake lever position, end.
Page 80: Checking The Brake Fluid Level
CHASSIS c. Tighten the locknut to specification. A. Front brake B. Rear brake Rear brake pedal adjusting lock- EWA13090 6 N·m (0.6 kgf·m, 4.4 lb·ft) WARNING • Use only the designated brake fluid. Other EWA19150 brake fluids may cause the rubber seals to WARNING deteriorate, causing leakage and poor A soft or spongy feeling in the brake pedal...
Page 81: Checking The Rear Brake Pads
CHASSIS Loose connection  Tighten the holder bolt. 3. Hold the vehicle upright and apply the rear brake several times. 4. Check: • Brake hose Brake fluid leakage  Replace the damaged hose. Refer to “REAR BRAKE” on page 4-22. EAM30499 CHECKING THE BRAKE OPERATION 1.
Page 82: Drive Chain Slack
CHASSIS immediately. b. Install the reservoir diaphragm. c. Connect the plastic hose “1” to the bleed i. Tighten the bleed screw. screw “2” securely, and place a container under the end of the plastic hose. Brake caliper bleed screw 6 N·m (0.6 kgf·m, 4.4 lb·ft) j.
Page 83: Lubricating The Drive Chain
CHASSIS EAM30251 LUBRICATING THE DRIVE CHAIN The drive chain consists of many interacting parts. If the drive chain is not maintained proper- ly, it will wear out quickly. Therefore, the drive chain should be serviced, especially when the vehicle is used in dusty areas. This vehicle has a drive chain with small rubber O-rings between each side plate.
Page 84: Lubricating The Steering Head
CHASSIS Steering ring nut (final tightening torque) 7 N·m (0.7 kgf·m, 5.2 lb·ft) e. Check the steering head for looseness or binding by turning the front fork all the way in both directions. If any binding is felt, re- move the lower bracket and check the up- per and lower bearings.
Page 85: Adjusting The Front Fork Legs
CHASSIS 4. Check: • Front fork operation Push down hard on the handlebar several times and check if the front fork rebounds smoothly. Unsmooth operation  Correct or replace. Refer to “FRONT FORK” on page 4-38. 5. Check: • Protector guide “1” Out of specification ...
Page 86: Checking The Rear Shock Absorber Assembly
CHASSIS clicks always represents the entire adjusting each damping force adjusting mechanism and range. To obtain a precise adjustment, it would to modify the specifications as necessary. be advisable to check the number of clicks of each damping force adjusting mechanism and to modify the specifications as necessary.
Page 87: Adjusting The Rear Shock Absorber Assembly
CHASSIS absorber assembly. Direction “b” Refer to “REAR SHOCK ABSORBER AS- Spring preload is increased (suspen- SEMBLY” on page 4-54. sion is harder). 3. Check: Direction “c” • Rear shock absorber assembly smooth ac- Spring preload is decreased (suspen- tion sion is softer).
Page 88 CHASSIS Direction “a” Direction “a” Rebound damping is increased (sus- Compression damping is increased pension is harder). (suspension is harder). Direction “b” Direction “b” Rebound damping is decreased (sus- Compression damping is decreased pension is softer). (suspension is softer). Rebound damping Fast compression damping Minimum (soft) Minimum (soft)
Page 89: Checking The Swingarm Operation
CHASSIS page 4-60. Direction “a” Compression damping is increased EAM30501 (suspension is harder). CHECKING THE CONNECTING ARM AND Direction “b” RELAY ARM Compression damping is decreased Refer to “CHECKING THE CONNECTING ARM (suspension is softer). AND RELAY ARM” on page 4-56. EAM30243 Slow compression damping CHECKING THE TIRES...
Page 90: Checking The Wheels
CHASSIS After replacing a tire or a wheel, always balance the wheel. EAM30246 CHECKING THE WHEEL BEARINGS 1. Check: • Wheel bearing Refer to “CHECKING THE FRONT WHEEL” on page 4-4 and “CHECKING THE REAR G089059 WHEEL” on page 4-8. A tight spoke will emit a clear, ringing tone;...
Page 91: Lubricating The Clutch Lever
CHASSIS EAM30503 LUBRICATING THE CLUTCH LEVER 1. Lubricate the pivoting points and metal-to- metal moving parts of the following parts. • Clutch lever Recommended lubricant Lithium-soap-based grease EAM30250 LUBRICATING THE PEDAL 1. Lubricate the pivoting point and metal-to-met- al moving parts of the pedal. Recommended lubricant Lithium-soap-based grease EAM30504...
Page 92: Electrical System
ELECTRICAL SYSTEM 6. Check: EAM20137 ELECTRICAL SYSTEM • Ignition timing Punch mark “a” on rotor should be aligned EAM30255 with punch mark “b” on stator. CHECKING THE IGNITION TIMING Not aligned  Adjust. 1. Remove: • Fuel tank Refer to “FUEL TANK” on page 7-1. •...
Page 93 CHASSIS GENERAL CHASSIS..................4-1 REMOVING THE NUMBER PLATE............4-2 REMOVING THE SIDE COVER..............4-2 FRONT WHEEL....................4-3 REMOVING THE FRONT WHEEL.............4-4 DISASSEMBLING THE FRONT WHEEL...........4-4 CHECKING THE FRONT WHEEL .............4-4 ASSEMBLING THE FRONT WHEEL............4-5 INSTALLING THE FRONT WHEEL ............4-5 REAR WHEEL ....................4-7 REMOVING THE REAR WHEEL ...............4-8 DISASSEMBLING THE REAR WHEEL .............4-8 CHECKING THE REAR WHEEL..............4-8 CHECKING AND REPLACING THE REAR WHEEL SPROCKET ....4-8...
Page 94 HANDLEBAR ....................4-32 REMOVING THE HANDLEBAR...............4-33 CHECKING THE HANDLEBAR ...............4-33 INSTALLING THE HANDLEBAR .............4-33 FRONT FORK....................4-38 REMOVING THE FRONT FORK LEGS...........4-40 DISASSEMBLING THE FRONT FORK LEGS .........4-40 CHECKING THE FRONT FORK LEGS ...........4-41 ASSEMBLING THE FRONT FORK LEGS ..........4-42 INSTALLING THE FRONT FORK LEGS ..........4-48 STEERING HEAD...................4-50 REMOVING THE LOWER BRACKET............4-51 CHECKING THE STEERING HEAD ............4-51...
Page 95: General Chassis
GENERAL CHASSIS EAM20094 GENERAL CHASSIS Removing the seat and side cover Order Job/Parts to remove Q’ty Remarks Seat Air scoop (right) Air scoop (left) Side cover (left) Side cover (right) Number plate...
Page 96: Removing The Number Plate
GENERAL CHASSIS EAM30371 REMOVING THE NUMBER PLATE 1. Remove: • Number plate bolt • Number plate “1” • The projection “a” is inserted into the band of the number plate. Pull the band off the projec- tion before removal. • Remove the clutch cable “2” from the cable guide “b”...
Page 97: Front Wheel
FRONT WHEEL EAM20095 FRONT WHEEL Removing the front wheel 21 N ・ m (2.1 kgf ・ m, 15 lb ・ ft) 21 N ・ m (2.1 kgf ・ m, 15 lb ・ ft) 105 N ・ m (10.5 kgf ・ m, 77 lb ・ ft) 12 N ・...
Page 98: Removing The Front Wheel
FRONT WHEEL 3. Check: EAM30017 REMOVING THE FRONT WHEEL • Spoke 1. Use a maintenance stand to raise the front Bend/damage  Replace. wheel off the ground. Loose  Tighten. EWA13120 Tap the spokes with a screwdriver. WARNING Securely support the vehicle so that there is no danger of it falling over.
Page 99: Assembling The Front Wheel
FRONT WHEEL 7. Check: • Bearing Front wheel turns roughly or is loose  Re- place the wheel bearings. • Oil seal Damage/wear  Replace. EAM30020 ASSEMBLING THE FRONT WHEEL 1. Install: G088898 • Bearing (left side) “1” 2. Install: •...
Page 100 FRONT WHEEL 2. Install: • Front wheel axle “1” Apply the lithium-soap-based grease to the front wheel axle. 3. Tighten: • Front wheel axle nut “1” Front wheel axle nut 105 N·m (10.5 kgf·m, 77 lb·ft) ECA24430 NOTICE Before tightening the front wheel axle nut, push down hard on the handlebar(s) several times and check if the front fork rebounds smoothly.
Page 101: Rear Wheel
REAR WHEEL EAM20096 REAR WHEEL Removing the rear wheel 12 N ・ m (1.2 kgf ・ m, 8.9 lb ・ ft) 125 N ・ m (12.5 kgf ・ m, 92 lb ・ ft) 19 N ・ m (1.9 kgf ・ m, 14 lb ・ ft) 42 N ・...
Page 102: Removing The Rear Wheel
REAR WHEEL Refer to “CHECKING THE TIRES” on page EAM30022 REMOVING THE REAR WHEEL 3-23 and “CHECKING THE WHEELS” on 1. Use a maintenance stand to raise the rear page 3-24. wheel off the ground. 3. Check: EWA13120 • Spoke WARNING Refer to “CHECKING THE FRONT WHEEL”...
Page 103: Assembling The Rear Wheel
REAR WHEEL Tighten the self-locking nuts in stages and in a crisscross pattern. EAM30026 ASSEMBLING THE REAR WHEEL 1. Install: • Bearing (right side) “1” • Circlip “2” • Spacer “3” G088898 • Bearing (left side) “4” 2. Install: • Oil seal “5” •...
Page 104 REAR WHEEL 2. Install: 5. Adjust: • Drive chain “1” • Drive chain slack “a” Drive chain slack (Maintenance Push the rear wheel “2” forward and install the stand) drive chain. 48.0–58.0 mm (1.89–2.28 in) Refer to “DRIVE CHAIN SLACK” on page 3-16.
Page 105: Front Brake
FRONT BRAKE EAM20097 FRONT BRAKE Removing the front brake caliper 30 N ・ m (3.0 kgf ・ m, 22 lb ・ ft) 28 N ・ m (2.8 kgf ・ m, 21 lb ・ ft) 6 N ・ m (0.6 kgf ・ m, 4.4 lb ・ ft) 17 N ・...
Page 106 FRONT BRAKE Disassembling the front brake caliper 6 N ・ m (0.6 kgf ・ m, 4.4 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Brake caliper piston Brake caliper piston dust seal Brake caliper piston seal Bleed screw 4-12...
Page 107 FRONT BRAKE Removing the front brake master cylinder 1.5 N ・ m (0.15 kgf ・ m, 1.1 lb ・ ft) 6 N ・ m (0.6 kgf ・ m, 4.4 lb ・ ft) 6 N ・ m (0.6 kgf ・ m, 4.4 lb ・ ft) 9 N ・...
Page 108 FRONT BRAKE Disassembling the front brake master cylinder Order Job/Parts to remove Q’ty Remarks Push rod Dust boot Circlip Washer Brake master cylinder kit 4-14...
Page 109: Introduction
FRONT BRAKE b. Remove the brake caliper. EAM30028 INTRODUCTION c. Hold the dial gauge at a right angle against EWA19210 the brake disc surface. WARNING d. Measure the runout 1.5 mm (0.06 in) If you need to disassemble the disc brake above the brake disc edge.
Page 110 FRONT BRAKE 3. Install: • Brake pad a. Connect the plastic hose “1” to the bleed screw “2” and place a container under the end of the plastic hose. b. Loosen the pad pin “2”. c. Remove the brake caliper “3” from the front fork.
Page 111: Removing The Front Brake Caliper
FRONT BRAKE EAM30031 DISASSEMBLING THE FRONT BRAKE CALIPER 1. Remove: • Brake caliper piston “1” • Brake caliper piston dust seal “2” • Brake caliper piston seal “3” f. Install the pad pin plug “6”. Brake pad pin plug 2.5 N·m (0.25 kgf·m, 1.8 lb·ft) a.
Page 112: Assembling The Front Brake Caliper
FRONT BRAKE • Brake fluid delivery passages EWA13531 WARNING (brake caliper body) Proper brake hose routing is essential to in- Obstruction  Blow out with compressed air. sure safe vehicle operation. ECA24460 NOTICE Make sure that the pipe portion “a” of the brake hose touches the projection “b”...
Page 113: Removing The Front Brake Master Cylinder
FRONT BRAKE reservoir up to the specified level. tainer under the master cylinder and the end of the brake hose. Specified brake fluid DOT 4 EAM30037 CHECKING THE FRONT BRAKE MASTER EWA13090 CYLINDER WARNING 1. Check: • Use only the designated brake fluid. Other •...
Page 114: Installing The Front Brake Master Cylinder
FRONT BRAKE stall them as shown. Wrong orientation in in- stallation causes poor braking performance. EAM30039 INSTALLING THE FRONT BRAKE MASTER CYLINDER 1. Install: • Brake master cylinder “1” Front brake master cylinder hold- er bolt 9 N·m (0.9 kgf·m, 6.6 lb·ft) •...
Page 115: Brake System
FRONT BRAKE system. Refer to “BLEEDING THE HYDRAULIC Turn the handlebar toward right and left to make sure that the brake hose does not touch other BRAKE SYSTEM” on page 3-15. parts (e.g., wire harness, cables, leads). Adjust if necessary. 3.
Page 116: Rear Brake
REAR BRAKE EAM20098 REAR BRAKE Removing the rear brake caliper Order Job/Parts to remove Q’ty Remarks Drain. Brake fluid Refer to “BLEEDING THE HYDRAULIC BRAKE SYSTEM” on page 3-15. Protector Union bolt Copper washer Rear brake hose Brake pad pin plug Brake pad pin Rear brake pad assembly Rear brake caliper bracket...
Page 117 REAR BRAKE Disassembling the rear brake caliper 6 N ・ m (0.6 kgf ・ m, 4.4 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Brake caliper piston Brake caliper piston dust seal Brake caliper piston seal Bleed screw 4-23...
Page 118 REAR BRAKE Removing the rear brake master cylinder 1.5 N ・ m (0.15 kgf ・ m, 1.1 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) 30 N ・ m (3.0 kgf ・ m, 22 lb ・ ft) Order Job/Parts to remove Q’ty...
Page 119 REAR BRAKE Disassembling the rear brake master cylinder Order Job/Parts to remove Q’ty Remarks Dust boot Circlip Push rod Brake master cylinder kit 4-25...
Page 120: Introduction
REAR BRAKE EAM30040 INTRODUCTION Brake disc runout limit (as mea- sured on wheel) EWA19260 0.15 mm (0.0059 in) WARNING If you need to disassemble the disc brake components, observe the following precau- 4. Adjust: • Brake disc runout tions. • Never disassemble the brake components Refer to “CHECKING THE FRONT BRAKE DISC”...
Page 121 REAR BRAKE d. Install the brake pad “3” and the pad pin “4”. • Install the brake pads with their projections “a” into the brake caliper recesses “b”. • Temporarily tighten the pad pin at this point. 2. Measure: • Brake pad wear limit “a” Out of specification ...
Page 122: Removing The Rear Brake Caliper
REAR BRAKE 4. Check: • Brake fluid level Refer to “CHECKING THE BRAKE FLUID LEVEL” on page 3-14. 5. Check: • Brake pedal operation A softy or spongy feeling  Bleed the brake system. Refer to “BLEEDING THE HYDRAULIC BRAKE SYSTEM” on page 3-15. b.
Page 123: Installing The Rear Brake Caliper
REAR BRAKE cleaning and lubricating. Brake pad pin • Never use solvents on internal brake com- 17 N·m (1.7 kgf·m, 13 lb·ft) ponents as they will cause the piston seals Brake pad pin plug to swell and distort. 2.5 N·m (0.25 kgf·m, 1.8 lb·ft) •...
Page 124: Checking The Rear Brake Master Cylinder
REAR BRAKE tem. Specified brake fluid 1. Remove: DOT 4 • Union bolt 1. Wash the brake master cylinder and the • Copper washer brake master cylinder kit with brake fluid. • Brake hose 2. Install: • Primary cylinder cup “1” To drain any remaining brake fluid, place a con- •...
Page 125: Installing The Rear Brake Master Cylinder
REAR BRAKE 4. Install: to the specified level. • Brake master cylinder kit “1” Specified brake fluid • Push rod “2” DOT 4 • Circlip “3” • Dust boot “4” EWA13090 WARNING • Before installation, apply brake fluid to the •...
Page 126 HANDLEBAR EAM20099 HANDLEBAR Removing the handlebar Order Job/Parts to remove Q’ty Remarks Refer to “GENERAL CHASSIS” on page Number plate 4-1. Clutch cable Clutch lever holder Engine stop switch Brake master cylinder Throttle cable cap Throttle cable Right grip Cap cover Collar Left grip Upper handlebar holder...
Page 127: Handlebar
HANDLEBAR EAM30052 EAM30054 REMOVING THE HANDLEBAR INSTALLING THE HANDLEBAR 1. Stand the vehicle upright on a level surface. 1. Stand the vehicle upright on a level surface. EWA13120 EWA13120 WARNING WARNING Securely support the vehicle so that there is Securely support the vehicle so that there is no danger of it falling over.
Page 128 HANDLEBAR stalled with the punch marks “a” facing for- Lower handlebar holder nut ward. 40 N·m (4.0 kgf·m, 30 lb·ft) • Install the handlebar so that the marks “b” are in place on both sides. • Install the handlebar so that the projection “c” of the upper handlebar holders is positioned at the mark on the handlebar as shown.
Page 129 HANDLEBAR • Pass the engine stop switch lead in the middle of the clutch lever holder. 0 mm (0 in) 0 mm (0 in) 10.Install: • Grip cap (upper) “1” • Grip cap (lower) “2” • Grip cap bolt “3” 7.
Page 130 HANDLEBAR Throttle cable cap screw 0.5 N·m (0.05 kgf·m, 0.37 lb·ft) 12.Install: • Throttle cable “1” (to tube guide “2”) 15.Adjust: Apply the lithium soap base grease on the throt- • Throttle grip free play tle cable end and tube guide cable winding por- Refer to “CHECKING THE THROTTLE tion.
Page 131 HANDLEBAR 18.Install: • Grip cap bolt “1” Grip cap bolt 3.8 N·m (0.38 kgf·m, 2.8 lb·ft) EWA21080 WARNING After tightening the bolts, check that the throttle grip “2” moves smoothly. If it does not, retighten the bolts for adjustment. 4-37...
Page 132: Front Fork
FRONT FORK EAM20100 FRONT FORK Removing the front fork legs Order Job/Parts to remove Q’ty Remarks Use a maintenance stand to raise the front wheel off the ground. Front wheel Refer to “FRONT WHEEL” on page 4-3. Front brake caliper Refer to “FRONT BRAKE”...
Page 133 FRONT FORK Disassembling the front fork leg Order Job/Parts to remove Q’ty Remarks Adjuster Fork spring Damper adjusting rod Dust seal Stopper ring Inner tube Outer tube Piston metal Protector guide Slide metal Washer Oil seal Base valve Damper assembly Upper spring seat 4-39...
Page 134: Removing The Front Fork Legs
FRONT FORK • Hold the locknut and remove the adjuster. EAM30055 REMOVING THE FRONT FORK LEGS 1. Use a maintenance stand to raise the front ECA24520 NOTICE wheel off the ground. Do not remove the locknut as the damper rod EWA13120 may go into the damper assembly and not be WARNING...
Page 135: Checking The Front Fork Legs
FRONT FORK dial gauge reading. EWA13650 WARNING Do not attempt to straighten a bent inner tube as this may dangerously weaken it. 2. Check: • Outer tube Scratches/wear/damage  Replace. 3. Measure: • Fork spring free length “a” 5. Remove: Out of specification ...
Page 136: Assembling The Front Fork Legs
1. Stretch the damper assembly fully. 2. Fill: • Damper assembly Recommended oil Yamaha Suspension Oil S1 Standard oil amount 205 cm³ (6.93 US oz, 7.21 Imp.oz) 6. Check: • Upper spring seat “1”...
Page 137 FRONT FORK Standard oil level 145–148 mm (5.71–5.83 in) From top of fully stretched damper assembly. 7. Install: • Base valve “1” (to the damper assembly “2”) First bring the damper rod pressure to a maxi- mum. Then install the base valve while releasing the damper rod pressure.
Page 138 FRONT FORK 10.After filling, pump the damper assembly “1” 13.Check: • Damper assembly smooth movement slowly up and down more than 10 times to Tightness/binding/rough spots  Repeat the distribute the fork oil. steps (1) to (12). 11.While protecting the damper assembly “1” with a cloth and compressing fully, allow ex- 14.Install: cessive oil to overflow on the base valve side.
Page 139 FRONT FORK G088922 G088923 18.Install: 15.Install: • Oil seal “1” • Piston metal “1” Using a fork seal driver “2”, press the oil seal in Install the piston metal onto the slot on inner tube. until the stopper ring groove fully appears. Fork seal driver 90890-01502 Fork seal driver (48)
Page 140 FRONT FORK 21.Check: 24.Install: • Inner tube smooth movement • Damper assembly “1” Tightness/binding/rough spots  Repeat the (to the inner tube “2”) steps (14) to (20). ECA24560 NOTICE Allow the damper assembly to slide slowly down the inner tube until it contacts the bot- tom of the inner tube.
Page 141 30.Fill: • Front fork leg Recommended oil If it is installed with a gap out of specification, Yamaha Suspension Oil S1 correct damping force cannot be obtained. Standard oil amount 320 cm³ (10.8 US oz, 11.3 Imp.oz) Extent of adjustment 300–365 cm³...
Page 142: Installing The Front Fork Legs
FRONT FORK 31.Install: 2. Tighten: • Damper assembly “1” • Damper assembly “1” (to the outer tube) Damper assembly (front fork) 30 N·m (3.0 kgf·m, 22 lb·ft) Temporarily tighten the damper assembly. Use the cap bolt ring wrench “2” to tighten the damper assembly.
Page 143 FRONT FORK 4. Tighten: • Upper bracket pinch bolt “1” Upper bracket pinch bolt 21 N·m (2.1 kgf·m, 15 lb·ft) • Lower bracket pinch bolt “2” Lower bracket pinch bolt 21 N·m (2.1 kgf·m, 15 lb·ft) EWA19320 7. Adjust: WARNING •...
Page 144: Steering Head
STEERING HEAD EAM20101 STEERING HEAD Removing the lower bracket 21 N ・ m (2.1 kgf ・ m, 15 lb ・ ft) 145 N ・ m (14.5 kgf ・ m, 107 lb ・ ft) 38 N ・ m (3.8 kgf ・ m, 28 lb ・ ft) 7 N ・...
Page 145: Removing The Lower Bracket
STEERING HEAD EAM30060 ECA14270 REMOVING THE LOWER BRACKET NOTICE 1. Use a maintenance stand to raise the front If the bearing race is not installed properly, wheel off the ground. the steering head pipe could be damaged. EWA13120 WARNING Always replace the bearing and the bearing race Securely support the vehicle so that there is as a set.
Page 146 STEERING HEAD • Upper bearing “1” • Bearing race cover “2” Apply the lithium-soap-based grease on the bearing and bearing race cover lip. 5. Check the steering stem by turning this lock to lock. If there is any binding, remove the steering stem and check the steering bear- ing.
Page 147 STEERING HEAD 11.Tighten: • Upper bracket pinch bolt “1” Upper bracket pinch bolt 21 N·m (2.1 kgf·m, 15 lb·ft) • Lower bracket pinch bolt “2” Lower bracket pinch bolt 21 N·m (2.1 kgf·m, 15 lb·ft) EWA19330 8. Install: WARNING • Steering stem nut “1” Tighten the lower bracket to specified torque.
Page 148: Rear Shock Absorber Assembly
REAR SHOCK ABSORBER ASSEMBLY EAM20102 REAR SHOCK ABSORBER ASSEMBLY Removing the rear shock absorber assembly Order Job/Parts to remove Q’ty Remarks Refer to “GENERAL CHASSIS” on page Seat 4-1. Silencer Refer to “ENGINE REMOVAL” on page 5-1. Air filter case joint clamp Rear frame Rear shock absorber assembly lower bolt Rear shock absorber assembly upper bolt...
Page 149 REAR SHOCK ABSORBER ASSEMBLY Disassembling the relay arm 80 N ・ m (8.0 kgf ・ m, 59 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Relay arm Connecting arm Collar Oil seal Washer Bearing 4-55...
Page 150: Handling The Rear Shock Absorber
• To dispose of a damaged or a worn-out rear • Spring shock absorber, take the unit to your Damage/wear  Replace. Yamaha dealer for this disposal procedure. • Spring guide Damage/wear  Replace. • Bearing Damage/wear  Replace.
Page 151: Installing The Relay Arm
REAR SHOCK ABSORBER ASSEMBLY • Collar EAM30070 INSTALLING THE REAR SHOCK Damage/pitting/scratches  Replace the ABSORBER ASSEMBLY bearings and collars as a set. 1. Lubricate: 3. Check: • Bearing (lower side) • Oil seal • Dust seal Damage/pitting  Replace. •...
Page 152 REAR SHOCK ABSORBER ASSEMBLY • Rear shock absorber assembly lower nut Rear shock absorber assembly lower nut 53 N·m (5.3 kgf·m, 39 lb·ft) 8. Install: • Rear frame “1” • Rear frame bolt (upper) “2” Rear frame bolt (upper) 32 N·m (3.2 kgf·m, 24 lb·ft) 5.
Page 153: Swingarm
SWINGARM EAM20103 SWINGARM Removing the swingarm 7 N ・ m (0.7 kgf ・ m, 5.2 lb ・ ft) 70 N ・ m (7.0 kgf ・ m, 52 lb ・ ft) 6 N ・ m (0.6 kgf ・ m, 4.4 lb ・ ft) 85 N ・...
Page 154: Removing The Swingarm
SWINGARM • Bearing EAM30071 REMOVING THE SWINGARM 4. Check: 1. Use a maintenance stand to raise the rear • Oil seal wheel off the ground. Damage  Replace. EWA13120 • Bearing WARNING • Thrust bearing Securely support the vehicle so that there is •...
Page 155 SWINGARM 4. Install: • Rear wheel Refer to “REAR WHEEL” on page 4-7. 5. Adjust: • Drive chain slack Refer to “DRIVE CHAIN SLACK” on page 3-16. Drive chain slack (Maintenance stand) 48.0–58.0 mm (1.89–2.28 in) 4-61...
Page 156: Chain Drive
CHAIN DRIVE EAM20104 CHAIN DRIVE Removing the drive chain 75 N ・ m (7.5 kgf ・ m, 55 lb ・ ft) 5 N ・ m (0.5 kgf ・ m, 3.7 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Drive sprocket Refer to “ENGINE REMOVAL”...
Page 157: Removing The Drive Chain (For Yz250)
CHAIN DRIVE the illustration. EAM30556 REMOVING THE DRIVE CHAIN (for YZ250) 1. Use a maintenance stand to raise the rear wheel off the ground. EWA13120 WARNING Securely support the vehicle so that there is no danger of it falling over. 2.
Page 158: Checking The Drive Chain (For Yz250X)
CHAIN DRIVE tion of the drive chain using the following formula. Drive chain 15-link section length “c” = (length “a” between pin inner sides + length “b” between pin outer sides)/2 G088940 4. Check: • Drive chain roller “1” Damage/wear  Replace the drive chain. •...
Page 159: Checking The Drive Sprocket
CHAIN DRIVE • Do not soak the drive chain in kerosene for a set. Bent tooth  Replace the drive sprocket and more than ten minutes, otherwise the O- rings can be damaged. the rear wheel sprocket as a set. G088904 G088940 b.
Page 160: Installing The Drive Chain (For Yz250X)
CHAIN DRIVE rivet tool. (Use goods on the market.) a. When press fitting the master link plate “1”, make sure the space “a” between the end of the connecting pin “2” and the mas- ter link plate is 1.2–1.4 mm (0.05–0.06 in). G089070 2.
Page 161 CHAIN DRIVE • Drive sprocket nut Refer to “ENGINE REMOVAL” on page 5-1. Drive sprocket nut 75 N·m (7.5 kgf·m, 55 lb·ft) ECA14300 NOTICE Never install a new drive chain onto worn drive chain sprockets; this will dramatically shorten the drive chain’s life. 4.
Page 162 CHAIN DRIVE 4-68...
Page 163 ENGINE ENGINE REMOVAL..................5-1 REMOVING THE ENGINE .................5-3 INSTALLING THE ENGINE................5-3 CYLINDER HEAD, CYLINDER AND PISTON ..........5-4 REMOVING THE CYLINDER HEAD............5-6 REMOVING THE PUSH ROD..............5-6 REMOVING THE PISTON .................5-6 CHECKING THE CYLINDER HEAD ............5-7 CHECKING THE CYLINDER AND PISTON ..........5-7 COMBINATION OF PISTON AND CYLINDER ..........5-8 CHECKING THE PISTON RING ..............5-9 CHECKING THE PISTON PIN ..............5-9 CHECKING THE SMALL END BEARING..........5-10...
Page 164 CHECKING THE CLUTCH SPRINGS............5-27 CHECKING THE CLUTCH HOUSING .............5-27 CHECKING THE CLUTCH BOSS............5-28 CHECKING THE PRESSURE PLATE .............5-28 CHECKING THE PUSH LEVER SHAFT..........5-28 CHECKING THE PUSH RODS ..............5-28 CHECKING THE PRIMARY DRIVE GEAR..........5-28 CHECKING THE PRIMARY DRIVEN GEAR ...........5-28 INSTALLING THE CLUTCH..............5-28 SHIFT SHAFT....................5-31 REMOVING THE SEGMENT ..............5-32 CHECKING THE SHIFT SHAFT ..............5-32...
Page 165: Engine Removal
ENGINE REMOVAL EAM20105 ENGINE REMOVAL Removing the exhaust pipe 15 mm (0.59 in) 17 mm (0.67 in) Order Job/Parts to remove Q’ty Remarks Refer to “GENERAL CHASSIS” on page Right side cover 4-1. Washer [ø = 26 mm (1.02 in)] Washer [ø...
Page 166 ENGINE REMOVAL Removing the engine Order Job/Parts to remove Q’ty Remarks Drain. Transmission oil Refer to “CHANGING THE TRANSMISSION OIL” on page 3-7. Refer to “GENERAL CHASSIS” on page Seat 4-1. Fuel tank Refer to “FUEL TANK” on page 7-1. Neutral switch Disconnect the neutral switch lead.
Page 167: Removing The Engine
ENGINE REMOVAL EAM30161 REMOVING THE ENGINE Engine mounting nut (front side) 64 N·m (6.4 kgf·m, 47 lb·ft) Make sure that the couplers, hoses and cables • Engine bracket “8” are disconnected. • Engine bracket bolt (upper side) “9” 1. Lift the engine “1” up to the point where the •...
Page 168: Cylinder Head, Cylinder And Piston
CYLINDER HEAD, CYLINDER AND PISTON EAM20190 CYLINDER HEAD, CYLINDER AND PISTON Removing the cylinder head and cylinder 34 N ・ m (3.4 kgf ・ m, 25 lb ・ ft) 64 N ・ m (6.4 kgf ・ m, 47 lb ・ ft) 20 N ・...
Page 169 CYLINDER HEAD, CYLINDER AND PISTON Disassembling the YPVS system 15 16 Order Job/Parts to remove Q’ty Remarks Piston pin clip Piston pin Piston Small end bearing Piston ring set Power valve cover Side holder Thrust plate Power valve holder 1 Power valve shaft Power valve link lever Pulley...
Page 170: Removing The Cylinder Head
CYLINDER HEAD, CYLINDER AND PISTON EAM30086 REMOVING THE CYLINDER HEAD 1. Remove: • Cylinder head nut Loosen each nut 1/2 of a turn at a time. After all of the nuts are fully loosened, remove them. EAM30543 REMOVING THE PUSH ROD 1.
Page 171: Checking The Cylinder Head
CYLINDER HEAD, CYLINDER AND PISTON b. Measure the warpage. c. If the limit is exceeded, resurface the cylin- der head as follows. d. Place a 400–600 grit wet sandpaper on the surface plate and resurface the cylin- der head using a figure-eight sanding pat- tern.
Page 172: Combination Of Piston And Cylinder
CYLINDER HEAD, CYLINDER AND PISTON Diameter 66.352–66.367 mm (2.6123– 2.6129 in) 2. Check: • Piston mark “a” Piston mark “a” Piston size (color) a. 17.5 mm (0.69 in) from the bottom edge of 66.352–66.355 mm A (red) the piston (2.61228–2.61240 in) e.
Page 173: Checking The Piston Ring
CYLINDER HEAD, CYLINDER AND PISTON EAM30548 CHECKING THE PISTON RING 1. Measure: • Piston ring side clearance Out of specification  Replace the piston and piston ring as a set. Before measuring the piston ring side clearance, eliminate any carbon deposits from the piston ring grooves and piston ring.
Page 174: Checking The Small End Bearing
CYLINDER HEAD, CYLINDER AND PISTON 4. Calculate: • Piston-pin-to-piston-pin-bore clearance Out of specification  Replace the piston pin and piston as a set. Piston-pin-to-piston-pin-bore clearance = Piston pin bore inside diameter “b” - Piston pin outside diameter “a” Piston-pin-to-piston-pin-bore clearance 0.004–0.020 mm (0.0002–0.0008 EAM30552 CHECKING THE POWER VALVE HOLE ON...
Page 175 CYLINDER HEAD, CYLINDER AND PISTON 4. Check: • Spring 1 “1” • Power valve link lever “2” • Pulley “3” • Spring 2 “4” • Washer “5” • Power valve shaft “6” • Install the spring 1 to the power valve link lever, and then to the cylinder.
Page 176: Installing The Piston And Cylinder
CYLINDER HEAD, CYLINDER AND PISTON 8. Install: • Gasket (power valve cover) “1” First tighten the power valve link lever bolt, and • Power valve cover “2” then tighten the pulley bolts. • Power valve cover screw “3” Power valve cover screw 4.0 N·m (0.40 kgf·m, 3.0 lb·ft) •...
Page 177 CYLINDER HEAD, CYLINDER AND PISTON 4. Lubricate: 2. Install: • Piston • Cylinder gasket “1” • Piston ring • Small end bearing “2” • Cylinder (with the recommended lubricant) (with the recommended lubricant) • Dowel pin “3” Recommended lubricant Recommended lubricant Engine oil Engine oil 5.
Page 178: Installing The Cylinder Head
CYLINDER HEAD, CYLINDER AND PISTON • Push rod bolt “2” 2. Install: • O-ring “1” Push rod bolt • Dowel pin “2” 4.5 N·m (0.45 kgf·m, 3.3 lb·ft) Apply the lithium soap base grease on the O- ECA27140 rings. NOTICE Be sure to use the set pin.
Page 179: Cdi Magneto
CDI MAGNETO EAM20191 CDI MAGNETO Removing the CDI magneto Order Job/Parts to remove Q’ty Remarks Refer to “GENERAL CHASSIS” on page Seat 4-1. Fuel tank Refer to “FUEL TANK” on page 7-1. Radiator bolt Refer to “RADIATOR” on page 6-2. CDI magneto lead Disconnect.
Page 180: Removing The Rotor
CDI MAGNETO • Stator outer surface “b” EAM30562 REMOVING THE ROTOR Damage  Inspect the crankshaft runout and 1. Remove: crankshaft bearing. • Rotor nut “1” If necessary, replace CDI magneto and/or • Washer “2” stator. While holding the rotor with the rotor holding tool “3”, loosen the rotor nut.
Page 181 CDI MAGNETO • Clean the tapered portions of the crankshaft and rotor. • When installing the woodruff key, make sure that its flat surface “a” is in parallel with the crankshaft center line “b”. • When installing the rotor, align the keyway “c” of the rotor with the woodruff key.
Page 182 KICKSTARTER EAM20112 KICKSTARTER Removing the primary drive gear and kickstarter shaft Order Job/Parts to remove Q’ty Remarks Drain. Transmission oil Refer to “CHANGING THE TRANSMISSION OIL” on page 3-7. Radiator hose 4 Disconnect at water pump side. Kickstarter lever Ball Spring Kick crank boss Crankcase cover (right)
Page 183: Kickstarter
KICKSTARTER EAM30570 REMOVING THE PRIMARY DRIVE GEAR 1. Loosen: • Primary drive gear bolt “1” Place an aluminum plate “a” between the teeth of the primary drive gear “2” and driven gear “3”. EAM30103 CHECKING THE KICK GEAR, KICK IDLE GEAR AND RATCHET WHEEL 1.
Page 184: Installing The Kick Idle Gear
KICKSTARTER case and make sure the kick shaft stopper “a” fits into the kick shaft ratchet wheel guide. 2. Install: • Torsion spring “1” (to the kick shaft “2”) 5. Install: • Torsion spring “1” Make sure the stopper “a” of the torsion spring fits into the hole “b”...
Page 185: Installing The Primary Drive Gear
KICKSTARTER EAM30571 INSTALLING THE PRIMARY DRIVE GEAR Kickstarter lever 30 N·m (3.0 kgf·m, 22 lb·ft) 1. Install: • Thrust plate “1” • Primary drive gear “2” Install the kickstarter closest to but not contact- • Governor drive gear “3” ing the clutch cover mounting boss “a”. •...
Page 186: Ypvs Governor
YPVS GOVERNOR EAM20192 YPVS GOVERNOR Removing the YPVS governor 5 N ・ m (0.5 kgf ・ m, 3.7 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Crankcase cover (right) Refer to “KICKSTARTER” on page 5-18. Governor assembly Dowel pin Retainer Ball Retainer weight...
Page 187: Removing The Governor
YPVS GOVERNOR EAM30566 EAM30569 REMOVING THE GOVERNOR INSTALLING THE GOVERNOR 1. Remove: 1. Install: • Dowel pin “1” • Governor gear “1” • Compression spring “2” • Plate “3” While compressing the spring, remove the dow- • Washer “4” el pin. •...
Page 188 YPVS GOVERNOR 3. Install: • Dowel pin “1” • While compressing the spring, install the dowel pin. • Make sure the dowel pin fits into the groove “a” in the retainer. 4. Install: • Governor assembly “1” Align the groove “a” in the governor with the fork “b”...
Page 189 CLUTCH EAM20111 CLUTCH Removing the clutch Order Job/Parts to remove Q’ty Remarks Drain. Transmission oil Refer to “CHANGING THE TRANSMISSION OIL” on page 3-7. Bolt (brake pedal) Shift the brake pedal downward. Rotor and stator Refer to “CDI MAGNETO” on page 5-15. Clutch cable Disconnect at engine side.
Page 190 CLUTCH Removing the clutch boss Order Job/Parts to remove Q’ty Remarks Push rod 1 Circlip Washer Bearing Push rod 2 Lock washer Clutch boss Thrust washer [D = ø44 mm (1.73 in)] Primary driven gear Bearing Spacer 1 Thrust washer [D = ø42 mm (1.65 in)] Push lever shaft 5-26...
Page 191: Clutch
CLUTCH 2. Measure: EAM30108 REMOVING THE CLUTCH • Clutch plate warpage 1. Remove: (with a surface plate and thickness gauge) • Clutch boss nut “1” Out of specification  Replace the clutch • Lock washer plates as a set. • Clutch boss “2” Thickness gauge 90890-03268 •...
Page 192: Checking The Clutch Boss
CLUTCH EAM30113 CHECKING THE CLUTCH BOSS 1. Check: • Clutch boss splines Damage/pitting/wear  Replace the clutch boss. Pitting on the clutch boss splines will cause er- ratic clutch operation. 2. Measure: • Push rod 2 bending limit Out of specification  Replace. Push rod bending limit 0.30 mm (0.012 in) EAM30117...
Page 193 CLUTCH Universal clutch holder 90890-04086 Universal clutch holder YM-91042 2. Install: • Thrust washer [D = ø42 mm (1.65 in)] “1” • Spacer “2” • Bearing “3” • Primary driven gear “4” 5. Bend the lock washer “1” tab. Apply the transmission oil on the bearing, spacer and primary driven gear inner circumference.
Page 194 CLUTCH Apply the lithium soap base grease on the bear- Tighten the bolts in stage, using a crisscross pat- ing, washer and push rod 1. tern. 11.Install: • O-ring “1” (to clutch cover) 8. Install: • Push rod 2 “1” •...
Page 195: Shift Shaft
SHIFT SHAFT EAM20113 SHIFT SHAFT Removing the shift shaft and stopper lever Order Job/Parts to remove Q’ty Remarks Shift pedal Shift shaft Segment bolt Segment Shift guide Roller Shift lever assembly Stopper lever Holder Tension spring 5-31...
Page 196: Removing The Segment
SHIFT SHAFT EAM30124 REMOVING THE SEGMENT 1. Remove: • Segment bolt “1” • Segment “2” Turn the segment counterclockwise until it stops and loosen the bolt. ECA24670 NOTICE If the segment gets an impact, the stopper le- ver may be damaged. Take care not to give EAM30127 CHECKING THE STOPPER LEVER an impact to it when removing the bolt.
Page 197 SHIFT SHAFT 2. Install: 4. Install: • Segment “1” • Shift lever assembly • Segment bolt (to the shift guide) Segment 5. Install: 30 N·m (3.0 kgf·m, 22 lb·ft) • Shift lever assembly “1” • Shift guide “2” • Align the notch “a” on the segment with the pin The shift lever assembly is installed at the same “b”...
Page 198 SHIFT SHAFT Apply the transmission oil on the roller and shift shaft. 8. Install: • Shift pedal “1” • Shift pedal bolt “2” Shift pedal bolt 12 N·m (1.2 kgf·m, 8.9 lb·ft) Install the shift pedal so that the top of the shift pedal outer diameter “a”...
Page 199 CRANKCASE EAM20116 CRANKCASE Separating the crankcase 14 N ・ m (1.4 kgf ・ m, 10 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) 10 N ・...
Page 200: Crankcase
CRANKCASE EAM30147 DISASSEMBLING THE CRANKCASE 1. Remove: • Crankcase (right) “1” (with the crankcase separating tool “2”) Crankcase separating tool 90890-01135 Crankcase separator YU-01135-B • Make appropriate bolts “3” as shown available EAM30150 CHECKING THE CRANKCASE by yourself and attach the tool with them. 1.
Page 201 14 N·m (1.4 kgf·m, 10 lb·ft) 4. Apply: • Sealant (on the crankcase (right) “1”) Tighten the crankcase bolts in stage, using a Yamaha bond No. 1215 crisscross pattern. 90890-85505 (Three bond No.1215®) Clean the contacting surface of crankcase (left/right) before applying the sealant.
Page 202: Crankshaft
CRANKSHAFT EAM20193 CRANKSHAFT Removing the crankshaft assembly Order Job/Parts to remove Q’ty Remarks Separate. Crankcase Refer to “CRANKCASE” on page 5-35. Transmission Refer to “TRANSMISSION” on page 5-40. Crankshaft assembly 5-38...
Page 203: Removing The Crankshaft
CRANKSHAFT shaft. EAM30491 REMOVING THE CRANKSHAFT 1. Remove: Crank assembly width 59.95–60.00 mm (2.360–2.362 in) • Crankshaft “1” (with the crankcase separating tool “2”) Crankcase separating tool 90890-01135 Crankcase separator YU-01135-B Make appropriate bolts “3” as shown available by yourself and attach the tool with them. ECA22290 NOTICE Do not use a hammer to drive out the crank-...
Page 204 TRANSMISSION EAM20118 TRANSMISSION Removing the transmission, shift drum assembly, and shift forks Order Job/Parts to remove Q’ty Remarks Engine Refer to “ENGINE REMOVAL” on page 5-1. Crankcase Refer to “CRANKCASE” on page 5-35. Main axle Drive axle Shift cam Shift fork 3 (R) Shift fork 2 (C10) Shift fork 1 (L) Collar...
Page 205: Transmission
TRANSMISSION EAM30153 REMOVING THE TRANSMISSION 1. Remove: • Main axle “1” • Drive axle “2” • Shift cam • Shift fork 3 • Shift fork 2 • Shift fork 1 • Remove assembly carefully. Note the position of each part. Pay particular attention to the lo- EAM30155 CHECKING THE SHIFT DRUM ASSEMBLY cation and direction of shift forks.
Page 206: Installing The Transmission
TRANSMISSION • 3rd wheel gear (23T/YZ250) (21T/YZ250X) “3” • 5th wheel gear (20T/YZ250) (21T/YZ250X) “4” • 1st wheel gear (27T) “5” • O-ring “6” (to drive axle “7”) • Apply the molybdenum disulfide oil on the in- ner and end surface of the idler gear and on the inner surface of the sliding gear, then install.
Page 207 TRANSMISSION 4. Install: • Collar “1” • Apply the lithium soap base grease on the oil seal lip. • When installing the collar into the crankcase, pay careful attention to the crankcase oil seal lip. • Install the spacer with its chamfered side “a” facing the crankcase.
Page 208 TRANSMISSION 5-44...
Page 209 COOLING SYSTEM COOLING SYSTEM DIAGRAMS ..............6-1 RADIATOR......................6-2 CHECKING THE RADIATOR..............6-3 INSTALLING THE RADIATOR..............6-3 WATER PUMP ....................6-5 DISASSEMBLING THE WATER PUMP.............6-6 CHECKING THE WATER PUMP ...............6-6 ASSEMBLING THE WATER PUMP............6-6...
Page 210: Cooling System
COOLING SYSTEM DIAGRAMS EAM20186 COOLING SYSTEM DIAGRAMS 1. Radiator hose 1 2. Radiator (right) 3. Radiator hose 4 4. Water pump 5. Radiator (left)
Page 211 RADIATOR EAM20138 RADIATOR Removing the radiator 1.5 N ・ m (0.15 kgf ・ m, 1.1 lb ・ ft) 1.5 N ・ m (0.15 kgf ・ m, 1.1 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) 10 N ・...
Page 212: Radiator
RADIATOR EAM30341 CHECKING THE RADIATOR Radiator cap valve opening pres- sure EWA13030 93.3–122.7 kPa (0.93–1.23 WARNING kgf/cm², 13.5–17.8 psi) A hot radiator is under pressure. Therefore, do not remove the radiator cap when the en- No stay  Replace. gine is hot. Scalding hot fluid and steam may be blown out, which could cause serious in- Radiator cap tester jury.
Page 213 RADIATOR G089031 4. Activate the tester to apply the test pressure. Test pressure value 122.7 kPa (1.23 kgf/cm², 17.8 psi) ECA24270 NOTICE • Do not apply such a high pressure as ex- ceeds the test pressure. • Make sure that a checkup after the cylinder head gasket is replaced is made after 3 min- utes of warm-up.
Page 214: Water Pump
WATER PUMP EAM20139 WATER PUMP Removing the water pump 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) 14 N ・ m (1.4 kgf ・ m, 10 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) Order Job/Parts to remove Q’ty...
Page 215: Disassembling The Water Pump
WATER PUMP EAM30494 DISASSEMBLING THE WATER PUMP • Remove the oil seal when the coolant level changes frequently more than usual, coolant has discolored, or engine oil has become milky. • Do not use the removed oil seal. 1. Remove: •...
Page 216 WATER PUMP 4. Install: • Dowel pin “1” • Gasket “2” 5. Install: • Water pump housing “1” • Water pump housing cover bolt “2” Water pump housing cover bolt 10 N·m (1.0 kgf·m, 7.4 lb·ft) • Washer “3” • Coolant drain bolt “4” Coolant drain bolt 10 N·m (1.0 kgf·m, 7.4 lb·ft)
Page 217 FUEL SYSTEM FUEL TANK ......................7-1 AIR FILTER.......................7-2 CARBURETOR....................7-3 HANDLING NOTE ..................7-6 CHECKING THE CARBURETOR ..............7-6 CHECKING THE REED VALVE..............7-7 INSTALLING THE REED VALVE...............7-7 ASSEMBLING THE CARBURETOR............7-8 INSTALLING THE CARBURETOR ............7-10 MEASURING AND ADJUSTING THE FUEL LEVEL .......7-11...
Page 218: Fuel Tank
FUEL TANK EAM20140 FUEL TANK Removing the fuel tank 7 N ・ m (0.7 kgf ・ m, 5.2 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.2 lb ・ ft) 4.0 N ・...
Page 219: Air Filter
AIR FILTER EAM20201 AIR FILTER Removing the air filter element 3.5 N ・ m (0.35 kgf ・ m, 2.6 lb ・ ft) 2.0 N ・ m (0.20 kgf ・ m, 1.5 lb ・ ft) 8 N ・ m (0.8 kgf ・ m, 5.9 lb ・ ft) 8 N ・...
Page 220 CARBURETOR EAM20194 CARBURETOR Removing the carburetor and reed valve 10 N ・ m (1.0 kgf ・ m, 7.4 lb ・ ft) 1.0 N ・ m (0.10 kgf ・ m, 0.73 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Fuel tank Refer to “FUEL TANK”...
Page 221 CARBURETOR Disassembling the carburetor Order Job/Parts to remove Q’ty Remarks Mixing chamber top Gasket Throttle valve Ring Throttle valve spring Jet needle holder Spring Collar Jet needle Carburetor breather hose Overflow hose Starter plunger Fuel cut solenoid valve Throttle position sensor Lever comp...
Page 222 CARBURETOR Disassembling the carburetor Order Job/Parts to remove Q’ty Remarks Throttle stop screw Pilot air screw Plug Float chamber Float pin Float Needle valve Main jet Pilot jet Power jet...
Page 223: Carburetor
CARBURETOR EAM30580 HANDLING NOTE ECA27120 NOTICE Do not loosen the screw (throttle position sensor) “1” except when changing the throt- tle position sensor due to failure because it will cause a drop in engine performance. 6. Check: • Needle valve “1” •...
Page 224: Checking The Reed Valve
CARBURETOR 8. Check: • Valve stopper height “b” • Free movement Out of specification  Replace. Stick  Repair or replace. Valve stopper height 10.3–10.7 mm (0.41–0.42 in) Insert the throttle valve “2” into the carburetor body while pulling up the lever “1”, and check for free movement.
Page 225: Assembling The Carburetor
CARBURETOR • Solenoid valve “2” 2. Install: • Gasket (reed valve) “1” (to carburetor) • Reed valve plate “2” ECA27130 NOTICE • Reed valve assembly “3” Before installing the solenoid valve, blow air • Reed valve spacer “4” on the solenoid valve and its installing loca- tion on the carburetor in order to remove any Install the reed valve spacer with its chamfered foreign particles such as chips etc.
Page 226 CARBURETOR 8. Install: 5. Install: • Air vent hose [L = 580 mm (22.8 in)] “1” • Pilot jet “1” • Air vent hose [L = 400 mm (15.7 in)] “2” • Main jet “2” • Overflow hose [L = 280 mm (11.0 in)] “3” •...
Page 227: Installing The Carburetor
CARBURETOR 10.Install: • Throttle cable “1” • Locknut “2” Locknut (throttle cable carburetor side) 4.0 N·m (0.40 kgf·m, 3.0 lb·ft) • Mixing chamber top “3” • Spring (throttle valve) “4” • Ring “5” • Throttle valve “6” • While compressing the spring, connect the throttle cable.
Page 228: Measuring And Adjusting The Fuel Level
CARBURETOR 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 hor- izontal line “b” that passes the center of the car- buretor. a. Hold the carburetor in an upside down po- sition.
Page 229 ELECTRICAL SYSTEM WIRING DIAGRAM...................8-1 COLOR CODE ...................8-1 IGNITION SYSTEM ..................8-2 TROUBLESHOOTING ................8-2 SOLENOID VALVE SYSTEM ................8-3 TROUBLESHOOTING ................8-3 THROTTLE POSITION SENSOR SYSTEM .............8-4 TROUBLESHOOTING ................8-4 ELECTRICAL COMPONENTS.................8-5 CHECKING THE SWITCHES ..............8-6 CHECKING THE IGNITION SPARK GAP..........8-8 CHECKING THE SPARK PLUG CAP ............8-8 CHECKING THE IGNITION COIL ..............8-8 CHECKING THE PICKUP COIL..............8-9 CHECKING THE SOURCE COIL...............8-9...
Page 230: Wiring Diagram
WIRING DIAGRAM EAM20195 WIRING DIAGRAM 1. CDI unit 2. Engine stop switch 3. Ignition coil 4. Throttle position sensor 5. Solenoid valve 6. Neutral switch 7. CDI magneto 8. Spark plug EAM30608 COLOR CODE Black Blue Orange Sky blue Yellow Black/Blue Black/Red Black/White...
Page 231: Ignition System
IGNITION SYSTEM EAM20142 IGNITION SYSTEM EAM30278 TROUBLESHOOTING The ignition system fails to operate (no spark or intermittent spark). Before troubleshooting, remove the following part(s): 1. Seat 2. Fuel tank 1. Check the spark plug. Refer to “CHECKING THE SPARK Re-gap or replace the spark plug. NG...
Page 232: Solenoid Valve System
SOLENOID VALVE SYSTEM EAM20196 SOLENOID VALVE SYSTEM EAM30581 TROUBLESHOOTING If the solenoid valve will not operate, use the following inspection steps. Before troubleshooting, remove the following part(s): 1. Seat 2. Fuel tank Use 12 V battery in this inspection. 1. Check each couplers and wire con- Reconnect.
Page 233: Troubleshooting
THROTTLE POSITION SENSOR SYSTEM EAM20197 THROTTLE POSITION SENSOR SYSTEM EAM30582 TROUBLESHOOTING If the throttle position sensor will not operate, use the following inspection steps. Before troubleshooting, remove the following part(s): 1. Seat 2. Fuel tank 1. Check entire ignition system for Reconnect.
Page 234: Electrical Components
ELECTRICAL COMPONENTS EAM20147 ELECTRICAL COMPONENTS 1. CDI unit 2. Engine stop switch 3. Ignition coil 4. Throttle position sensor 5. Solenoid valve 6. Neutral switch...
Page 235: Checking The Switches
ELECTRICAL COMPONENTS EAM30289 CHECKING THE SWITCHES 1. Engine stop switch...
Page 236 ELECTRICAL COMPONENTS Check each switch for continuity with the digital circuit tester. If the continuity reading is incorrect, check the wiring connections and if necessary, replace the switch. ECA14371 NOTICE Never insert the tester probes into the coupler terminal slots. Always insert the probes from the opposite end “a”...
Page 237: Checking The Ignition Spark Gap
ELECTRICAL COMPONENTS EAM30294 CHECKING THE IGNITION SPARK GAP Digital circuit tester (CD732) 90890-03243 1. Check: Model 88 Multimeter with tachom- • Ignition spark gap eter Out of specification  Perform the ignition YU-A1927 system troubleshooting, starting with step (3). Refer to “TROUBLESHOOTING” on page 8-2.
Page 238: Checking The Pickup Coil
ELECTRICAL COMPONENTS a. Connect the digital circuit tester () to the pickup coil coupler as shown. Digital circuit tester (CD732) 90890-03243 Model 88 Multimeter with tachom- eter YU-A1927 • Positive tester probe  White/Red “1” • Negative tester probe  c.
Page 239: Checking The Solenoid Valve Operation
ELECTRICAL COMPONENTS • Positive battery lead  Red “1” • Negative battery lead  Red “2” b. Measure the source coil resistance (B/R– 3. Check: • Charging coil 2 resistance (G/L–G/W) 3. Check: Out of specification  Replace the CDI mag- •...
Page 240: Handling Note
ELECTRICAL COMPONENTS to the full open position. EAM30587 HANDLING NOTE Out of specification  Replace. ECA27120 • Positive tester probe  NOTICE Yellow “2” Do not loosen the screw (throttle position • Negative tester probe  sensor) “1” except when changing the throt- Black “3”...
Page 241: Idling Speed
ELECTRICAL COMPONENTS • Align the slot “a” in the throttle position sensor with the projection “b” on the carburetor while the lever “3” is held down. • Temporarily tighten the screw (throttle position sensor). 8. Start the engine. 9. Adjust: •...
Page 242: Checking The Throttle Position Sensor Input Voltage
ELECTRICAL COMPONENTS by aligning the marks “a” that were put before re- moval. 14.Install: • Carburetor Refer to “CARBURETOR” on page 7-3. EAM30305 CHECKING THE THROTTLE POSITION SENSOR INPUT VOLTAGE 1. Disconnect the throttle position sensor cou- pler. 2. Start the engine. 3.
Page 243 TROUBLESHOOTING TROUBLESHOOTING..................9-1 GENERAL INFORMATION ................9-1 TROUBLESHOOTING OF ENGINE............9-1 TROUBLESHOOTING OF CLUTCH............9-6 TROUBLESHOOTING OF TRANSMISSION ..........9-7 TROUBLESHOOTING OF COOLING SYSTEM ........9-8 TROUBLESHOOTING OF BRAKE ............9-9 TROUBLESHOOTING OF SUSPENSION..........9-9 TROUBLESHOOTING OF STEERING/HANDLING ........9-11...
Page 244: Troubleshooting
TROUBLESHOOTING EAM20148 TROUBLESHOOTING EAM30309 GENERAL INFORMATION Troubleshooting information provided here does not cover all the trouble symptoms, possible causes, and remedial actions. Some items may not apply depending on the model. Use this information as a guide and quick reference matrix when performing basic troubleshooting. Refer to the each chapter for detailed information on checking, adjustment, and replacement.
Page 245 TROUBLESHOOTING Symptom Possible cause Actions Measure the compression pres- — sure. Tighten the spark plugs to the Loose spark plug specified torque. Tighten bolts or nuts on cylinder Loose cylinder head or cylinder head and cylinder to the specified torque. Compression pressure is low Damaged cylinder head gasket Replace the cylinder head gasket.
Page 246 TROUBLESHOOTING Symptom Possible cause Actions Damaged or worn needle valve Replace the needle valve. Adjust the fuel level to the proper Incorrect fuel level level. Bent, worn, or damaged starter Replace the starter plunger. plunger Incorrectly adjusted starter cable Adjust the starter cable. Clogged or damaged carburetor Clean, repair, or replace the car- breather hose...
Page 247 TROUBLESHOOTING Symptom Possible cause Actions Water or foreign material in fuel, Change fuel. degraded fuel Clogged carburetor air passage Clean the carburetor. Incorrectly adjusted throttle cable Adjust the throttle grip free play. Improperly synchronized carbure- Adjust synchronization of carbure- tors tors.
Page 248 TROUBLESHOOTING Symptom Possible cause Actions Check the air induction system. Failed air induction system Repair or replace faulty parts. Clogged vacuum hose Clean the vacuum hose. Cracks and damage in vacuum Replace the vacuum hose. hose — Damaged carburetor joint Replace the carburetor joint.
Page 249 TROUBLESHOOTING EAM30510 TROUBLESHOOTING OF CLUTCH Manual clutch Symptom Possible cause Actions Improperly assembled clutch Reassemble the clutch. Improperly adjusted clutch cable Adjust the clutch lever free play. Tighten the clutch spring bolts to Loose clutch spring the specified torque. Replace the clutch springs as a Fatigued clutch spring set.
Page 250 TROUBLESHOOTING Symptom Possible cause Actions Replace the primary drive gear or Damaged or worn primary driven crankshaft, and the clutch housing gear as a set. Tighten the clutch boss nut to the Loose clutch boss nut specified torque. Clutch noise Fatigued clutch damper Replace the clutch housing.
Page 251 TROUBLESHOOTING EAM30512 TROUBLESHOOTING OF COOLING SYSTEM Symptom Possible cause Actions Carbon buildup in piston head and Clean the piston head and com- combustion chamber bustion chamber. Clogged engine cooling water Check and clean the engine cool- passages ing water passages. Damaged or leaking radiator Replace the radiator.
Page 252 TROUBLESHOOTING EAM30513 TROUBLESHOOTING OF BRAKE Symptom Possible cause Actions Worn brake pad Replace the brake pads as a set. Worn or deflected brake disc Replace the brake disc. Air in hydraulic brake system Bleed the hydraulic brake system. Check the hydraulic brake system Brake fluid leakage and repair or replace faulty parts as necessary.
Page 253 TROUBLESHOOTING Symptom Possible cause Actions Fatigued or broken fork spring Replace the fork spring. Incorrect oil viscosity (low) Change to recommended fork oil. Incorrect oil level (low) Adjust to the specified oil level. Improperly adjusted spring pre- Adjust the spring preload. Front fork is soft load (soft) Improperly adjusted rebound...
Page 254 TROUBLESHOOTING Symptom Possible cause Actions Oil leaking from rear shock Replace the rear shock absorber. absorber Gas leaking from rear shock Replace the rear shock absorber. absorber Fatigued or damaged rear shock Replace the rear shock absorber. absorber spring Rear suspension is soft Improperly adjusted rear shock Adjust the spring preload.
Page 255 TROUBLESHOOTING Symptom Possible cause Actions Incorrect wheel balance Adjust the wheel balance. Tighten the spoke and adjust the Loose spoke runout. Damaged or worn wheel bearing Replace the wheel bearing. Worn, deformed, or incorrect tire Replace the tire. Front wheel vibration Loose wheel axle or wheel axle Tighten the wheel axle or wheel axle nut to the specified torque.
Page 256 TROUBLESHOOTING 9-13...
Page 257 TUNING ENGINE ......................10-1 CARBURETOR SETTING................10-1 ATMOSPHERIC CONDITIONS AND CARBURETOR SETTINGS ..10-1 TEST RUN....................10-1 EFFECTS OF THE SETTING PARTS ON THE THROTTLE VALVE OPENING ....................10-2 MAIN JET ADJUSTMENT ................10-2 ADJUSTING THE POWER JET ...............10-2 PILOT AIR SCREW ADJUSTMENT............10-2 PILOT JET ADJUSTMENT...............10-3 JET NEEDLE ADJUSTMENT..............10-3 JET NEEDLE GROOVE POSITION ADJUSTMENT........10-4 RELATIONSHIP WITH THROTTLE OPENING ........10-4...
Page 258: Engine
ENGINE in the air by so much of the water vapor in the EAM20198 ENGINE same air. • Lower atmospheric pressure (at a high alti- EAM30590 tude) reduces the density of the air. CARBURETOR SETTING • The role of fuel is to cool the engine, and in the EAM30592 case of a 2-stroke engine, to lubricate the en- TEST RUN...
Page 259: Effects Of The Setting Parts On The Throttle Valve Opening
ENGINE EAM30593 EFFECTS OF THE SETTING PARTS ON THE THROTTLE VALVE OPENING EAM30604 ADJUSTING THE POWER JET The richness of air-fuel mixture under 8500 r/min to the extent of 1/2 to full opened throttle can be set by changing the power jet “1”. A larger size jet results in a richer mixture, and a smaller size in a leaner mixture.
Page 260: Pilot Jet Adjustment
ENGINE EAM30596 PILOT JET ADJUSTMENT The richness of air-fuel mixture with the throttle fully closed to 1/2 open can be set by turning the pilot jet “1”. It is changed when adjustment can- N3EG not be made by the pilot air screw alone. N3EH A larger size jet results in a richer mixture at low N3EW...
Page 261: Jet Needle Groove Position Adjustment
ENGINE EAM30605 RELATIONSHIP WITH THROTTLE OPENING The flow of the fuel through the carburetor main system is controlled by the main jet and then, it is further regulated by the area between the main nozzle and the jet needle. On the relation- ship between the fuel flow and the throttle open- ing, the fuel flow relates to the jet needle straight portion diameter around 1/8 to 1/4 throttle open-...
Page 262: Carburetor Setting Parts
ENGINE EAM30599 CARBURETOR SETTING PARTS Part name Size Part number Main jet “1” Rich #190 4MX-14943-45 #188 4MX-14943-95 #185 4MX-14943-44 #182 4MX-14943-94 *(STD) #180 4MX-14943-43 (STD) #178 4MX-14943-93 #175 4MX-14943-42 #172 4MX-14943-92 #170 4MX-14943-41 #168 4MX-14943-91 #165 4MX-14943-40 Lean #162 4MX-14943-90 Pilot jet “2”...
Page 263: Road Condition And Examples Of Carburetor Setting
ENGINE EAM30601 ROAD CONDITION AND EXAMPLES OF CARBURETOR SETTING General condition Sandy condition 15–25 C 15–25 C Under 10 C Over 25 C Under 10 C Over 25 C (59–77 F) (59–77 F) (50 F) (77 F) (50 F) (77 F) (Spring, (Spring, (Winter)
Page 264 ENGINE Symptom Setting Checking Lean mixture Lower jet needle clip position. (1 groove down) Rich mixture Raise jet needle clip position. (1 groove up) • 1/4–3/4 throttle Lower jet needle clip position. (1 Leaner *Hard breathing groove down) Lack of speed (Standard) 1.
Page 265: Change Of The Heat Range Of Spark Plugs
ENGINE EAM30603 CHANGE OF THE HEAT RANGE OF SPARK PLUGS Judging from the discoloration of spark plugs, if they are found improper, it can be corrected by the following two methods; changing carburetor settings and changing the heat range of spark plug.
Page 266: Chassis
CHASSIS EAM20119 EAM30169 CHASSIS DRIVE AND REAR WHEEL SPROCKETS SETTING PARTS EAM30168 SELECTION OF THE SECONDARY Part name Type Part number REDUCTION RATIO (SPROCKET) Drive 9383E-13216 sprocket “1” Secondary reduction ratio = Number of (STD) 9383E-14215 rear wheel sprocket teeth/Number of Rear wheel 17D-25447-50 drive sprocket teeth...
Page 267: Front Fork Setting
• Change the compression damping force. Turn in one or two clicks. Recommended oil Yamaha Suspension Oil S1 Generally a soft spring gives a soft riding feeling. Standard oil amount 320 cm³ (10.8 US oz, 11.3 Imp.oz) Rebound damping tends to become stronger...
Page 268: Front Fork Setting Parts
CHASSIS EAM30175 REAR SUSPENSION SETTING Generally a stiff spring gives a stiff riding feeling. The rear shock absorber setting should be made Rebound damping tends to become weaker, re- depending on the rider’s feeling of an actual run sulting in lack of a sense of contact with the road and the circuit conditions.
Page 269: Setting Of Spring After Replacement
CHASSIS the same set length of the spring may change because of the initial fatigue, etc. of the spring. Therefore, be sure to make reevaluation. • If the standard figure cannot be achieved by adjusting the adjuster and changing the set length, replace the spring with an optional one and make readjustment.
Page 270 CHASSIS color and quantity of I.D. marks. • Spring preload adjusting positions Spring preload adjusting positions Minimum Position in which the spring is turned in 1.5 mm (0.06 in) from its free length. Standard Position in which the spring is turned in 12.0 mm (0.47 in) from its free length.
Page 271: Suspension Setting (Front Fork)
CHASSIS EAM30179 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).
Page 272: Suspension Setting (Rear Shock Absorber)
CHASSIS Section Symptom Check Adjust Large Medium Small Jump Compression Turn adjuster clockwise (about 2 damping force clicks) to increase damping. Turn adjuster counterclockwise Rebound damp- (about 2 clicks) to decrease ing force damping. Low front, tend-   ing to lower front Set sunken length for 95–100 posture Balance with rear...
Page 273 CHASSIS Section Symptom Check Adjust Large Medium Small Jump Turn adjuster counterclockwise Rebound damp- (about 2 clicks) to decrease Heavy and drag- ing force   damping. ging Spring Replace with soft spring. Turn adjuster counterclockwise Rebound damp- (about 2 clicks) to decrease ing force damping.

This manual is also suitable for:

Yz250 2021 Yz250x 2021 Yz250m 2021 Yz250xm 2021

Yamaha YZ 2021 Series Owner's Service Manual

Quick Links

Troubleshooting

Need help?

Questions and answers

Subscribe to Our Youtube Channel

Related Manuals for Yamaha YZ 2021 Series

Summary of Contents for Yamaha YZ 2021 Series