Yamaha YZ250T1 Owner's Service Manual
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Yamaha YZ250T1 Owner's Service Manual

Yamaha YZ250T1 Owner's Service Manual

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OWNER'S SERVICE MANUAL
YZ250T1
LIT-11626-18-34
1P8-28199-10

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Summary of Contents for Yamaha YZ250T1

  • Page 1 OWNER’S SERVICE MANUAL YZ250T1 LIT-11626-18-34 1P8-28199-10...
  • Page 3 EC010000 YZ250T1 OWNER’S SERVICE MANUAL ©2004 by Yamaha Motor Corporation, U.S.A. 1st Edition, May 2004 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Corporation U.S.A. is expressly prohibited. Printed in Japan P/N. LIT-11626-18-34...
  • Page 4 EC020000 INTRODUCTION 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 This list is compiled from the purchase registrations sent to Yamaha Motor Cor- Will the warranty be void or canceled if I do not operate or maintain my new YZ or WR exactly as poration, U.S.A.

  • Page 6: Important Notice

    EC040001 IMPORTANT NOTICE THIS MACHINE IS DESIGNED STRICTLY FOR COMPETITION USE, ONLY ON A CLOSED COURSE. It is illegal for this machine to be operated on any public street, road, or highway. Off-road use on public lands may also be illegal. Please check local regulations before riding.
  • Page 7 5. GASOLINE IS HIGHLY FLAMMABLE. Always turn off the engine while refuel- ing. Take care to not spill any gasoline on the engine or exhaust system. Never refuel in the vicinity of an open flame, or while smoking. 6. GASOLINE CAN CAUSE INJURY. If you should swallow some gasoline, inhale excess gasoline vapors, or allow any gasoline to get into your eyes, con-...
  • Page 8 Some data in this manual may become out- dated due to improvements made to this model in the future. If there is any question you have regarding this manual or your machine, please consult your Yamaha dealer. EC070001 F.I.M. MACHINE WEIGHTS:...
  • Page 9 EC080000 HOW TO USE THIS MANUAL EC081000 PARTICULARLY IMPORTANT INFORMATION The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY INVOLVED! Failure to follow WARNING instructions could result in severe injury or death to the machine operator, a bystander, or a person inspecting or repairing the machine.
  • Page 10 EC083000 MANUAL FORMAT All of the procedures in this manual are organized in a sequential, step-by-step format. The informa- tion has been complied to provide the mechanic with an easy to read, handy reference that contains comprehensive explanations of all disassembly, repair, assembly, and inspection operations. In this revised format, the condition of a faulty component will precede an arrow symbol and the course of action required will follow the symbol, e.g., 9 Bearings...
  • Page 11 EC085002 ILLUSTRATED SYMBOLS (Refer to the illustration) SPEC INFO Illustrated symbols 1 to 7 are designed as thumb tabs to indicate the chapter’s number and content. General information INSP Specifications Regular inspection and adjustments Engine Chassis Electrical Tuning CHAS ELEC Illustrated symbols 8 to r are used to identify the specifications appearing in the text.
  • Page 12 EC090000 INDEX GENERAL INFORMATION INFO SPECIFICATIONS SPEC REGULAR INSPECTION AND INSP ADJUSTMENTS ENGINE CHASSIS CHAS ELECTRICAL ELEC TUNING...

  • Page 13: Table Of Contents

    EC0A0000 CONTENTS CHAPTER 1 GENERAL INFORMATION DESCRIPTION ..........1-1 MACHINE IDENTIFICATION ......1-2 IMPORTANT INFORMATION .....1-3 CHECKING OF CONNECTION ....1-6 SPECIAL TOOLS........1-7 CONTROL FUNCTIONS......1-9 FUEL AND ENGINE MIXING OIL.....1-12 STARTING AND BREAK-IN .....1-13 TORQUE-CHECK POINTS.......1-16 CLEANING AND STORAGE ....1-17 CHAPTER 2 SPECIFICATIONS GENERAL SPECIFICATIONS ....2-1 MAINTENANCE SPECIFICATIONS ...2-3 GENERAL TORQUE SPECIFICATIONS..2-13...
  • Page 14 CHAPTER 4 ENGINE SEAT, FUEL TANK AND SIDE COVERS .............4-1 EXHAUST PIPE AND SILENCER ....4-3 RADIATOR..........4-4 CARBURETOR AND REED VALVE...4-7 CYLINDER HEAD , CYLINDER AND PISTON .............4-18 CLUTCH AND PRIMARY DRIVEN GEAR ............4-33 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR......4-40 YPVS GOVERNOR ........4-49 WATER PUMP ..........4-52 CDI MAGNETO .........4-56...
  • Page 15 CHAPTER 6 ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ........6-1 IGNITION SYSTEM........6-2 SOLENOID VALVE SYSTEM .....6-7 TPS (THROTTLE POSITION SENSOR) SYSTEM............6-9 CHAPTER 7 TUNING ENGINE............7-1 CHASSIS...........7-13...

  • Page 16: General Information

    DESCRIPTION INFO EC100000 GENERAL INFORMATION EC110000 NOTE: DESCRIPTION 1 Clutch lever 9 The machine you have purchased may differ 2 “ENGINE STOP” button slightly from those shown in the following. 3 Front brake lever 9 Designs and specifications are subject to 4 Throttle grip change without notice.

  • Page 17: Machine Identification

    There are two significant reasons for knowing the serial number of your machine: 1. When ordering parts, you can give the num- ber to your Yamaha dealer for positive iden- tification of the model you own. 2. If your machine is stolen, the authorities will need the number to search for and identify your machine.

  • Page 18: Important Information

    IMPORTANT INFORMATION INFO EC130000 IMPORTANT INFORMATION EC131010 PREPARATION FOR REMOVAL AND DIS ASSEMBLY 1. Remove all dirt, mud, dust, and foreign material before removal and disassembly. When washing the machine with high pres- sured water, cover the parts as follows. 9 Silencer exhaust port 9 Side cover air intake port 9 Water pump housing hole at the bottom...
  • Page 19 IMPORTANT INFORMATION INFO EC132000 ALL REPLACEMENT PARTS 1. We recommend to use Yamaha genuine parts for all replacements. Use oil and/or grease recommended Yamaha assembly and adjustment. EC133000 GASKETS, OIL SEALS AND O-RINGS 1. All gaskets, oil seals, and O-rings should be replaced when an engine is overhauled.
  • Page 20 IMPORTANT INFORMATION INFO EC136000 CIRCLIPS 1. All circlips should be inspected carefully before reassembly. Always replace piston pin clips after one use. Replace distorted circlips. When installing a circlip 1, make sure that the sharp-edged corner 2 is posi- tioned opposite to the thrust 3 it receives. See the sectional view.

  • Page 21: Checking Of Connection

    CHECKING OF CONNECTION INFO EC1C0001 CHECKING OF CONNECTION Dealing with stains, rust, moisture, etc. on the connector. 1. Disconnect: 9 Connector 2. Dry each terminal with an air blower. 3. Connect and disconnect the connector two or three times. 4. Pull the lead to check that it will not come off.

  • Page 22: Special Tools

    SPECIAL TOOLS INFO EC140002 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 tech- niques. The shape and part number used for the special tool differ by country, so two types are provid- ed.
  • Page 23 Dynamic spark tester YM-34487 90890-06754 90890-06754 Ignition checker This instrument is necessary for checking the igni- tion system components. ACC-QUICK-GS-KT Quick gasket ® ACC-QUICK-GS-KT 90890-85505 90890-85505 YAMAHA Bond No. 1215 This sealant (Bond) is used for crankcase mating surface, etc.

  • Page 24: Control Functions

    CONTROL FUNCTIONS INFO EC150000 CONTROL FUNCTIONS EC151000 “ENGINE STOP” BUTTON The “ENGINE STOP” button 1 is located on the left handlebar. Continue pushing the “ENGINE STOP” button till the engine comes to a stop. EC152000 CLUTCH LEVER The clutch lever 1 is located on the left handle- bar;...
  • Page 25 CONTROL FUNCTIONS INFO EC156000 FRONT BRAKE LEVER The front brake lever 1 is located on the right handlebar. Pull it toward the handlebar to acti- vate the front brake. EC157000 REAR BRAKE PEDAL The rear brake pedal 1 is located on the right side of the machine.
  • Page 26 CONTROL FUNCTIONS INFO EC15R001 DETACHABLE SIDESTAND This sidestand 1 is used to support only the machine when standing or transporting it. 9 Never apply additional force to the side- stand. 9 Remove this sidestand before starting out. EC15F000 VALVE JOINT This valve joint 1 prevents fuel from flowing out and is installed to the fuel tank breather hose.

  • Page 27: Fuel And Engine Mixing Oil

    FUEL AND ENGINE MIXING OIL INFO EC160051 FUEL AND ENGINE MIXING OIL Mix oil with the gas at the ratio specified below. Always use fresh, name-brand gasoline, and mix the oil and gas the day of the race. Do not use premix that is more than a few hours old.

  • Page 28: Starting And Break-In

    STARTING AND BREAK-IN INFO EC190000 STARTING AND BREAK-IN Before starting the machine, perform the checks in the pre-operation check list. Never start or run the engine in a closed area. The exhaust fumes are poisonous; they can cause loss of consciousness and death in a very short time.
  • Page 29 STARTING AND BREAK-IN INFO EC194001 BREAK-IN PROCEDURES 1. Before starting the engine, fill the fuel tank with a break-in oil-fuel mixture as follows. Mixing oil: Mixing ratio: Yamalube “2-R” 15:1 2. Perform the pre-operation checks on the machine. 3. Start and warm up the engine. Check the idle speed, and check the operation of the controls and the “ENGINE STOP”...
  • Page 30 STARTING AND BREAK-IN INFO 9 After the break-in or before each race, you must check the entire machine for loose fit- tings and fasteners as per “TORQUE- CHECK POINTS”. Tighten all such fasteners as required. 9 When any of the following parts have been replaced, they must be broken in.

  • Page 31: Torque-Check Points

    TORQUE-CHECK POINTS INFO EC1A0013 TORQUE-CHECK POINTS Frame construction Frame to rear frame Combined seat and tank Fuel tank to frame Engine mounting Frame to engine Engine bracket to engine Engine bracket to frame Steering Steering shaft to Steering shaft to frame handlebar Steering shaft to handle crown Handle crown to handlebar...

  • Page 32: Cleaning And Storage

    CLEANING AND STORAGE INFO EC1B0000 CLEANING AND STORAGE EC1B1000 CLEANING Frequent cleaning of your machine will enhance its appearance, maintain good overall perfor- mance, and extend the life of many components. 1. Before washing the machine, block off the end of the exhaust pipe to prevent water from entering.
  • Page 33 CLEANING AND STORAGE INFO EC1B2001 STORAGE If your machine is to be stored for 60 days or more, some preventive measures must be taken avoid deterioration. After cleaning machine thoroughly, prepare it for storage as fol- lows: 1. Drain the fuel tank, fuel lines, and the carbu- retor float bowl.

  • Page 34: Specifications

    SPEC GENERAL SPECIFICATIONS EC200000 SPECIFICATIONS EC211000 GENERAL SPECIFICATIONS Model name: YZ250T1 (USA, CDN) YZ250 (EUROPE, ZA) YZ250T (AUS, NZ) Model code number: 1P81 (USA, CDN, ZA) 1P82 (EUROPE) 1P84 (AUS, NZ) Dimensions: USA, ZA AUS, NZ EUROPE ← Overall length...
  • Page 35 SPEC GENERAL SPECIFICATIONS Carburetor: Type/Manufacturer PWK38S/KEIHIN Spark plug: Type/Manufacturer BR8EG/NGK (resistance type) 0.5~0.6 mm (0.020~0.024 in) Clutch type: Wet, multiple-disc Transmission: USA, ZA, AUS, NZ EUROPE, CDN ← Primary reduction system Gear ← Primary reduction ratio 63/21 (3.000) ← Secondary reduction system Chain drive Secondary reduction ratio 50/14 (3.571)

  • Page 36: Maintenance Specifications

    SPEC MAINTENANCE SPECIFICATIONS EC212000 MAINTENANCE SPECIFICATIONS EC212100 ENGINE Item Standard Limit Cylinder head: USA, CDN, ZA, EUROPE AUS, NZ … Combustion chamber capacity 21.0 cm 21.5 cm (0.739 Imp oz, (0.757 Imp oz, 0.710 US oz) 0.727 US oz) … …...
  • Page 37 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Clutch housing thrust clearance 0.17~0.23 mm (0.007~0.009 in) … Clutch housing radial clearance 0.030~0.055 mm (0.001~0.002 in) … Clutch release method Inner push, cam push … Transmission: … Main axle deflection limit 0.01 mm (0.0004 in) …...
  • Page 38 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m•kg ft•lb M14S × 1.25 Spark plug M 8 × 1.25 Cylinder head (nut) M 8 × 1.25 (stud) M10 × 1.25 Cylinder (nut) M10 × 1.25 (stud) Power valve : M 5 ×...
  • Page 39 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m•kg ft•lb M10 × 1.25 Primary drive gear M20 × 1.0 Clutch boss M 6 × 1.0 Clutch spring M 6 × 0.75 Clutch cable adjust bolt and locknut M 5 ×...
  • Page 40 SPEC MAINTENANCE SPECIFICATIONS EC212201 CHASSIS Item Standard Limit Steering system: … Steering bearing type Taper roller bearing Front suspension: … Front fork travel 300 mm (11.8 in) Fork spring free length 465 mm (18.3 in) 460 mm (18.1 in) … Spring rate, STD K=4.3 N/mm (0.438 kg/mm,...
  • Page 41 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Wheel: … Front wheel type Spoke wheel … Rear wheel type Spoke wheel … 21 × 1.60/Aluminum Front rim size/Material … 19 × 2.15/Aluminum Rear rim size/Material Rim runout limit: … Radial 2.0 mm (0.08 in) …...
  • Page 42 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m•kg ft•lb M 8 × 1.25 Handle crown and outer tube M 8 × 1.25 Under bracket and outer tube M24 × 1.0 14.5 Handle crown and steering shaft M 8 ×...
  • Page 43 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m•kg ft•lb M 4 × 0.7 Rear brake master cylinder cap M10 × 1.25 Rear brake hose union bolt (caliper) M10 × 1.25 Rear brake hose union bolt (master cylinder) M20 ×...
  • Page 44 Ignition timing (B.T.D.C.) 0.18 mm (0.007 in) … Advancer type Electrical CDI: … Magneto-model (stator)/Manufacturer 5CU-10/YAMAHA … 720~1,080 Ω at 20°C (68°F) Source coil 1 resistance (color) (Black-Black/Red) … 44~66 Ω at 20°C (68°F) Source coil 2 resistance (color) (Green/Blue-Green/White) …...

  • Page 45: General Torque Specifications

    GENERAL TORQUE SPECIFICATIONS/ SPEC DEFINITION OF UNITS EC220001 GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard faste- ners with standard I.S.O. pitch threads. Torque specifications for special components or assem- blies are included in the applicable sections of this book. To avoid warpage, tighten multi-faste- ner assemblies in a crisscross fashion, in pro- gressive stages, until full torque is reached.

  • Page 46: Cable Routing Diagram

    SPEC CABLE ROUTING DIAGRAM EC240000 CABLE ROUTING DIAGRAM 1 Radiator hose A Pass the clutch cable on the out- H Pass the clutch cable in front of 2 Throttle cable side of the throttle cable and the center of the cylinder head 3 Clutch cable “ENGINE STOP”...
  • Page 47 SPEC CABLE ROUTING DIAGRAM 1 Clamp A Insert the tip of the fuel tank G Clamp to the frame the radiator 2 Radiator hose breather hose into the hole in breather hose and C.D.I. mag- 3 Solenoid valve lead the steering shaft cap. neto lead.
  • Page 48 SPEC CABLE ROUTING DIAGRAM 1 Clamp A Clamp the wireharness to the 2 High tension cord right engine bracket. 3 C.D.I.unit B Pass the high tension cord to 4 “ENGINE STOP” button lead the right of the radiator hose. 5 Ignition coil lead C Pass the C.D.I.
  • Page 49 SPEC CABLE ROUTING DIAGRAM A Install the brake hose so that its pipe portion 1 Master cylinder 2 Brake hose holder directs as shown and lightly touches the projec- 3 Brake hose tion on the caliper. B Pass the brake hose into the brake hose holders.
  • Page 50 SPEC CABLE ROUTING DIAGRAM A Install the brake hose so that its pipe portion 1 Brake hose 2 Master cylinder directs as shown and lightly touches the 3 “ENGINE STOP” button lead projection on the master cylinder. B Pass the “ENGINE STOP” button lead in 4 “ENGINE STOP”...

  • Page 51: Regular Inspection And Adjustments

    If you are a doubt as to what intervals to follow in maintaining and lubricating your machine, consult your Yamaha dealer. After...
  • Page 52 Replace bearing TIRE, WHEELS Inspect air pressure, wheel run-out, tire wear and spoke looseness Retighten sprocket bolt Inspect bearings Replace bearings Lubricate Lithium base grease THROTTLE, CONTROL CABLE Yamaha cable lube or Check routing and connection SAE 10W-30 motor oil Lubricate...

  • Page 53: Pre-Operation Inspection And Maintenance

    INSP PRE-OPERATION INSPECTION AND MAINTENANCE EC320000 PRE-OPERATION INSPECTION AND MAINTENANCE Before riding for break-in operation, practice or a race, make sure the machine is in good operating condition. Before using this machine, check the following points. EC321000 GENERAL INSPECTION AND MAINTENANCE Item Routine Page...

  • Page 54: Engine

    ENGINE/COOLANT LEVEL INSPECTION/ INSP COOLANT REPLACEMENT EC350000 ENGINE EC351011 COOLANT LEVEL INSPECTION Do not remove the radiator cap 1, drain bolt and hoses when the engine and radia- tor are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury.
  • Page 55 INSP COOLANT REPLACEMENT Take care so that coolant does not splash on painted surfaces. If it splashes, wash it away with water. 1. Place a container under the engine. 2. Remove: 9 Coolant drain bolt 1 3. Remove: 9 Radiator cap Drain the coolant completely.
  • Page 56 INSP RADIATOR CAP INSPECTION 9 Do not mix more than one type of ethyl- ene glycol antifreeze containing corro- sion inhibitors for aluminum engine. 9 Do not use water containing impurities or oil. Handling notes of coolant: The coolant is harmful so it should be handled with special care.
  • Page 57 RADIATOR CAP OPENING PRESSURE INSPECTION/ INSP COOLING SYSTEM INSPECTION EC356002 RADIATOR CAP OPENING PRESSURE INSPECTION 1. Attach: 9 Radiator cap tester 1 and adapter 2 Radiator cap tester: YU-24460-01/90890-01325 Adapter: YU-33984/90890-01352 NOTE: Apply water on the radiator cap seal. 3 Radiator cap 2.
  • Page 58 INSP CLUTCH ADJUSTMENT 4. Inspect: 9 Pressure Impossible to maintain the specified pres- sure for 10 seconds¡Repair. 9 Radiator 1 9 Radiator hose joint 2 Coolant leakage¡Repair or replace. 9 Radiator hose 3 Swelling¡Replace. EC359020 CLUTCH ADJUSTMENT 1. Check: 9 Clutch lever free play a Out of specification¡Adjust.
  • Page 59 THROTTLE CABLE ADJUSTMENT/ INSP THROTTLE LUBRICATION EC35A001 THROTTLE CABLE ADJUSTMENT 1. Check: 9 Throttle grip free play a Out of specification¡Adjust. Throttle grip free play ? a : 3~5 mm (0.12~0.20 in) 2. Adjust: 9 Throttle grip free play Throttle grip free play adjustment steps: 9 Loosen the locknut 1.
  • Page 60 INSP AIR FILTER CLEANING 3. Install: 9 Throttle cable cap 1 Nm (0.1 m•kg, 0.7 ft•lb) 9 Cap cover EC35G041 AIR FILTER CLEANING NOTE: Proper air filter maintenance is the biggest key to preventing premature engine wear and dam- age. Never run the engine without the air filter element in place;...
  • Page 61 INSP TRANSMISSION OIL LEVEL CHECK 3. Inspect: 9 Air filter element Damage¡Replace. 4. Apply: 9 Foam-air-filter oil or equivalent oil To the element. NOTE: Squeeze out the excess oil. Element should be wet but not dripping. 5. Install: 9 Filter guide 1 NOTE: Align the projection a on filter guide with the hole b in air filter element.
  • Page 62 INSP TRANSMISSION OIL REPLACEMENT 3. Check: 9 Transmission oil level Transmission oil level checking steps: 9 Remove the oil check bolt 1. 9 Inspect the oil level. NOTE: Be sure the machine is positioned straight up when inspecting the oil level. Never attempt to remove the oil check bolt just after high speed operation.
  • Page 63 INSP PILOT AIR SCREW ADJUSTMENT 4. Remove: 9 Oil drain bolt 1 9 Oil filler cap 2 Drain the transmission oil. 5. Install: 9 Aluminum washer 9 Oil drain bolt 1 20 Nm (2.0 m•kg, 14 ft•lb) 6. Fill: 9 Transmission oil Recommended oil: Yamalube 4 (10W-30) or SAE 10W-30 type SE motor oil...
  • Page 64 INSP IDLE SPEED ADJUSTMENT/MUFFLER INSPECTION/ SILENCER FIBER REPLACEMENT EC35M001 IDLE SPEED ADJUSTMENT 1. Start the engine and thoroughly warm it up. 2. Adjust: 9 Idle speed Adjustment steps: Turn the throttle stop screw 1 until the engine runs at the lowest possible speed. To increase idle speed ¡...

  • Page 65: Silencer Fiber Replacement

    Fully apply Quick gasket ® (Yamaha bond No. 1215) or equivalent as shown. Quick gasket ® ACC-QUICK-GS-KT Yamaha bond No. 1215: 90890-85505 5. Install: 9 Bolt (fiber) 1 10 Nm (1.0 m•kg, 7.2 ft•lb) 9 Silencer 2 9 Bolt (silencer) 3 12 Nm (1.2 m•kg, 8.7 ft•lb)

  • Page 66: Chassis

    INSP CHASSIS/BRAKE SYSTEM AIR BLEEDING EC360000 CHASSIS EC361030 BRAKE SYSTEM AIR BLEEDING Bleed the brake system if: 9 The system has been disassembled. 9 A brake hose has been loosened or removed. 9 The brake fluid is very low. 9 The brake operation is faulty. A dangerous loss of braking performance may occur if the brake system is not properly bled.
  • Page 67 INSP FRONT BRAKE ADJUSTMENT NOTE: If bleeding is difficult, it may be necessary to let the brake fluid system stabilize for a few hours. Repeat the bleeding procedure when the tiny bubbles in the system have disappeared. j. Add brake fluid to the level line on the reservoir.

  • Page 68: Rear Brake Adjustment

    REAR BRAKE ADJUSTMENT/ INSP FRONT BRAKE PAD INSPECTION AND REPLACEMENT EC364005 REAR BRAKE ADJUSTMENT 1. Check: 9 Brake pedal height a Out of specification¡Adjust. Brake pedal height a: Zero mm (Zero in) NOTE: The brake pedal height is the vertical distance from the inside top end of the footrest.
  • Page 69 INSP FRONT BRAKE PAD INSPECTION AND REPLACEMENT 9 Loosen the pad pin 2. 9 Remove the caliper 3 from the front fork. 9 Remove the pad pin and brake pads 4. 9 Connect the transparent hose 5 to the bleed screw 6 and place the suitable con- tainer under its end.
  • Page 70 INSP REAR BRAKE PAD INSPECTION AND REPLACEMENT 9 Install the pad pin plug 0. Pad pin plug: 3 Nm (0.3 m•kg, 2.2 ft•lb) 3. Inspect: 9 Brake fluid level Refer “BRAKE FLUID LEVEL INSPECTION” section. 4. Check: 9 Brake lever operation A softy or spongy feeling ¡...
  • Page 71 INSP REAR BRAKE PAD INSPECTION AND REPLACEMENT 9 Remove the pad pin 6 and brake pads 7. 9 Connect the transparent hose 8 to the bleed screw 9 and place the suitable con- tainer under its end. 9 Loosen the bleed screw and push the caliper piston in.
  • Page 72 REAR BRAKE PAD INSULATOR INSPECTION INSP BRAKE FLUID LEVEL INSPECTION EC36b000 REAR BRAKE PAD INSULATOR INSPECTION 1. Remove: 9 Brake pad Refer to “REAR BRAKE PAD INSPEC- TION AND REPLACEMENT” section. 2. Inspect: 9 Rear brake pad insulator 1 Damage ¡ Replace. EC367001 BRAKE FLUID LEVEL INSPECTION 1.
  • Page 73 INSP SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION EC368000 SPROCKETS INSPECTION 1. Inspect: 9 Sprocket teeth a Excessive wear ¡ Replace. NOTE: Replace the drive, driven sprockets and drive chain as a set. EC369002 DRIVE CHAIN INSPECTION 1. Measure: 9 Drive chain length (15 links) a Out of specification¡Replace.
  • Page 74 INSP DRIVE CHAIN SLACK ADJUSTMENT 4. Check: 9 Drive chain stiffness a Clean and oil the chain and hold as illustrated. Stiff¡Replace drive chain. 5. Install: 9 Drive chain 1 9 Joint 2 9 Master link clip 3 Be sure to install the master link clip to the direction as shown.
  • Page 75 INSP FRONT FORK INSPECTION 3. Adjust: 9 Drive chain slack Drive chain slack adjustment steps: 9 Loosen the axle nut 1 and locknuts 2. 9 Adjust chain slack turning adjusters 3. To tighten ¡ Turn adjuster 3 counter- clockwise. To loosen ¡ Turn adjuster 3 clockwise and push wheel forward.
  • Page 76 FRONT FORK OIL SEAL AND DUST SEAL CLEANING/ INSP FRONT FORK INTERNAL PRESSURE RELIEVING/ FRONT FORK REBOUND DAMPING FORCE ADJUSTMENT EC36D001 FRONT FORK OIL SEAL AND DUST SEAL CLEANING 1. Remove: 9 Protector 9 Dust seal 1 NOTE: Use a thin screw driver, and be careful not to damage the inner fork tube and dust seal.
  • Page 77 FRONT FORK COMPRESSION DAMPING FORCE INSP ADJUSTMENT Extent of adjustment: Maximum Minimum 20 clicks out Fully turned in (from maximum position position) 9 STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position.

  • Page 78: Rear Shock Absorber Inspection

    INSP REAR SHOCK ABSORBER INSPECTION Extent of adjustment: Maximum Minimum 20 clicks out Fully turned in (from maximum position position) 9 STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position.
  • Page 79 REAR SHOCK ABSORBER SPRING PRELOAD INSP ADJUSTMENT EC36M014 REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT 1. Elevate the rear wheel by placing the suit- able stand under the engine. 2. Remove: 9 Rear frame 3. Loosen: 9 Locknut 1 4. Adjust: 9 Spring preload By turning the adjuster 2.
  • Page 80 REAR SHOCK ABSORBER REBOUND DAMPING INSP FORCE ADJUSTMENT EC36N014 REAR SHOCK ABSORBER REBOUND DAMPING FORCE ADJUSTMENT 1. Adjust: 9 Rebound damping force By turning the adjuster 1. Stiffer a ¡ Increase the rebound damping force. (Turn the adjuster 1 in.) Softer b ¡...
  • Page 81 REAR SHOCK ABSORBER LOW COMPRESSION INSP DAMPING FORCE ADJUSTMENT EC36c000 REAR SHOCK ABSORBER LOW COMPRESSION DAMPING FORCE ADJUSTMENT 1. Adjust: 9 Low compression damping force By turning the adjuster 1. Stiffer a ¡ Increase the low compression damping force. (Turn the ad- juster 1 in.) Softer b ¡...
  • Page 82 REAR SHOCK ABSORBER HIGH COMPRESSION INSP DAMPING FORCE ADJUSTMENT EC36d000 REAR SHOCK ABSORBER HIGH COMPRESSION DAMPING FORCE ADJUSTMENT 1. Adjust: 9 High compression damping force By turning the adjuster 1. Stiffer a ¡ Increase the high compression damping force. (Turn the ad- juster 1 in.) Softer b ¡...
  • Page 83 TIRE PRESSURE CHECK/SPOKES INSPECTION AND INSP TIGHTENING/WHEEL INSPECTION EC36Q001 TIRE PRESSURE CHECK 1. Measure: 9 Tire pressure Out of specification ¡ Adjust. Standard tire pressure: 100 kPa (1.0 kgf/cm , 15 psi) NOTE: 9 Check the tire while it is cold. 9 Loose bead stoppers allow the tire to slip off its position on the rim when the tire pressure is low.
  • Page 84 INSP STEERING HEAD INSPECTION AND ADJUSTMENT 2. Inspect: 9 Bearing free play Exist play ¡ Replace. EC36U070 STEERING HEAD INSPECTION AND ADJUSTMENT 1. Elevate the front wheel by placing a suitable stand under the engine. 2. Check: 9 Steering shaft Grasp the bottom of the forks and gently rock the fork assembly back and forth.
  • Page 85 INSP STEERING HEAD INSPECTION AND ADJUSTMENT Ring nut wrench: YU-33975/90890-01403 Ring nut (initial tightening): 38 Nm (3.8 m•kg, 27ft•lb) 9 Loosen the ring nut one turn. 9 Retighten the ring nut using the ring nut wrench. Avoid over-tightening. Ring nut (final tightening): 7 Nm (0.7 m•kg, 5.1 ft•lb) 9 Check the steering shaft by turning it lock to lock.
  • Page 86 INSP LUBRICATION EC36a042 LUBRICATION Å Use Yamaha cable lube or equivalent on To ensure smooth operation of all components, these areas. lubricate your machine during setup, after break- ı Use SAE10W-30 motor oil or suitable chain in, and after every race.

  • Page 87: Electrical

    INSP ELECTRICAL/SPARK PLUG INSPECTION EC370000 ELECTRICAL EC371001 SPARK PLUG INSPECTION 1. Remove: 9 Spark plug 2. Inspect: 9 Electrode 1 Wear/Damage ¡ Replace. 9 Insulator color 2 Normal condition is a medium to light tan color. Distinctly different color ¡ Check the engine condition.
  • Page 88 INSP IGNITION TIMING CHECK EC372012 IGNITION TIMING CHECK 1. Remove: 9 Fuel tank Refer to “SEAT, FUEL TANK AND SIDE COVERS” section in the CHAPTER 4. 9 Spark plug 9 Crankcase cover (left) 2. Attach: 9 Dial gauge 1 9 Spark plug hole dial stand 2 Dial gauge: YU-3097/90890-01252 Spark plug hole dial stand:...
  • Page 89 INSP IGNITION TIMING CHECK 7. Adjust: 9 Ignition timing Adjustment steps: 9 Loosen the screws (stator) 1. 9 Align the punch mark on the rotor with punch mark on the stator 2 by moving the stator. 9 Tighten the screws (stator). Screw (stator): 8 Nm (0.8 m•kg, 5.8 ft•lb) 3-40...

  • Page 90: Seat, Fuel Tank And Side Covers

    SEAT, FUEL TANK AND SIDE COVERS EC400000 ENGINE EC4R0000 SEAT, FUEL TANK AND SIDE COVERS 19 Nm (1.9 m•kg, 13 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 19 Nm (1.9 m•kg, 13 ft•lb)
  • Page 91 SEAT, FUEL TANK AND SIDE COVERS EC4R3000 REMOVAL POINTS EC413110 Side cover 1. Remove: 9 Bolt (side cover) 9 Side cover (left and right) 1 NOTE: Draw the side cover downward to remove it because its claws a are inserted in the air cleaner case.

  • Page 92: Exhaust Pipe And Silencer

    EXHAUST PIPE AND SILENCER EC4S0000 EXHAUST PIPE AND SILENCER 12 Nm (1.2 m•kg, 8.7 ft•lb) 12 Nm (1.2 m•kg, 8.7 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 12 Nm (1.2 m•kg, 8.7 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) 14 Nm (1.4 m•kg, 10 ft•lb) 1 Silencer removal 2 Exhaust pipe removal Extent of removal:...

  • Page 93: Radiator

    RADIATOR EC450001 RADIATOR 1 Nm (0.1 m•kg, 0.7 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) 1 Nm (0.1 m•kg, 0.7 ft•lb) 1 Radiator removal Extent of removal: Extent of removal Order...
  • Page 94 RADIATOR EC456000 HANDLING NOTE Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury. When the engine has cooled, open the radiator cap by the following procedure: Place a thick rag, like a towel, over the radiator cap, slowly rotate the cap counter-...
  • Page 95 RADIATOR EC455000 ASSEMBLY AND INSTALLATION EC445354 Radiator 1. Install: 9 Radiator breather hose 1 9 Radiator hose 2 2 1 Nm (0.1 m•kg, 0.7 ft•lb) To radiator (right) 3. 2. Install: 9 Radiator (right) 1 9 Plain washer 2 9 Bolt [radiator (right)] 3 10 Nm (1.0 m•kg, 7.2 ft•lb) 9 Radiator hose 4 4 1 Nm (0.1 m•kg, 0.7 ft•lb)

  • Page 96: Carburetor And Reed Valve

    CARBURETOR AND REED VALVE EC460000 CARBURETOR AND REED VALVE 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Nm (0.1 m•kg, 0.7 ft•lb) 1 Carburetor removal 2 Reed valve removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CARBURETOR AND REED VALVE REMOVAL Preparation for Fuel tank...
  • Page 97 CARBURETOR AND REED VALVE EC468000 CARBURETOR DISASSEMBLY 4 Nm (0.4 m•kg, 2.9 ft•lb) 1 Carburetor disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks CARBURETOR DISASSEMBLY Mixing chamber top Throttle valve Refer to “REMOVAL POINTS”. Needle holder Jet needle Float chamber Float pin...
  • Page 98 CARBURETOR AND REED VALVE EC466020 HANDLING NOTE Do not loosen the screws {TPS (throttle position sensor)} except when changing the TPS (throttle position sensor) due to failure because it will cause a drop in engine performance. EC463000 REMOVAL POINTS EC463110 Throttle valve 1.
  • Page 99 CARBURETOR AND REED VALVE EC464000 INSPECTION EC464130 Carburetor 1. Inspect: 9 Carburetor body Contamination ¡ Clean. NOTE: 9 Use a petroleum based solvent for cleaning. Blow out all passages and jets with com- pressed air. 9 Never use a wire. 2.
  • Page 100 CARBURETOR AND REED VALVE EC464401 Jet needle 1. Inspect: 9 Jet needle 1 Bends/Wear ¡ Replace. 9 Clip groove Free play exists/Wear ¡ Replace. 9 Clip position Standard clip position: No.2 Groove *No.3 Groove *For EUROPE EC464511 Float height 1. Measure: 9 Float height a Out of specification ¡...
  • Page 101 CARBURETOR AND REED VALVE EC464600 Float 1. Inspect: 9 Float 1 Damage ¡ Replace. EC464701 Reed valve 1. Measure: 9 Reed valve bending a Out of specification ¡ Replace. Reed valve bending limit: 0.2 mm (0.008 in) 9 Valve stopper height b Out of specification ¡...
  • Page 102 CARBURETOR AND REED VALVE 2. Install: 9 Gasket (reed valve) 1 9 Plate (reed valve) 2 9 Reed valve assembly 3 9 Reed valve spacer 4 NOTE: Install the reed valve spacer with its chamfered side a to the right. 3.
  • Page 103 CARBURETOR AND REED VALVE 3. Install: 9 Pilot air screw 1 9 Throttle stop screw 2 Note the following installation points: 9 Turn in the pilot air screw until it is lightly seated. 9 Turn out the pilot air screw by the number of turns recorded before removing.
  • Page 104 CARBURETOR AND REED VALVE 7. Install: 9 Float chamber 1 9 Plate 2 9 Screw (float chamber) 3 8. Install: 9 Air vent hose [/=580 mm (22.8 in)] 1 9 Air vent hose [/=400mm (15.7 in)] 2 9 Overflow hose [/=280mm (11.0 in)] 3 9 Clamp 4 Refer to “CABLE ROUTING DIAGRAM”...
  • Page 105 CARBURETOR AND REED VALVE 10. Install: 9 Throttle cable 1 9 Locknut 2 4 Nm (0.4 m•kg, 2.9 ft•lb) 9 Mixing chamber top 3 9 Spring (throttle valve) 4 9 Ring 5 9 Throttle valve 6 NOTE: 9 While compressing the spring, connect the throttle cable.
  • Page 106 CARBURETOR AND REED VALVE 2. Tighten: 9 Screw (carburetor joint) 1 3. Tighten: 9 Screw (air cleaner joint) 1 NOTE: Place the screw head a with its top as shown and secure the clamp in alignment with the hori- zontal line b that passes the center of the car- buretor bore.

  • Page 107: Cylinder Head, Cylinder And Piston

    CYLINDER HEAD, CYLINDER AND PISTON EC470000 CYLINDER HEAD, CYLINDER AND PISTON EC478000 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) 10 Nm (1.0 m•kg, 7.2 ft•lb) 42 Nm (4.2 m•kg, 30 ft•lb)
  • Page 108 CYLINDER HEAD, CYLINDER AND PISTON EC478100 PISTON AND POWER VALVE 4 Nm (0.4 m•kg, 2.9 ft•lb) 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) 1 Piston and piston ring removal 2 Power valve removal Extent of removal:...
  • Page 109 CYLINDER HEAD, CYLINDER AND PISTON EC473000 REMOVAL POINTS EC473220 Push rod 1. Remove: 9 Bolt (push rod) 1 9 Push rod 2 NOTE: Insert the set pin 3 included in owner’s tool kit to remove the bolt (push rod). Be sure to use the set pin. If the set pin is not used, the power valve constituent parts will result in damage.
  • Page 110 CYLINDER HEAD, CYLINDER AND PISTON 3. Remove: 9 Piston ring 1 NOTE: Take care not to scratch the piston or damage the piston ring by expanding it more than neces- sary. EC474000 INSPECTION EC474102 Cylinder head 1. Eliminate: 9 Carbon deposits Use a rounded scraper 1.
  • Page 111 CYLINDER HEAD, CYLINDER AND PISTON EC474201 Cylinder 1. Eliminate: 9 Carbon deposits Use a rounded scraper 1. NOTE: Do not use a sharp instrument. Avoid scratching the aluminum. 2. Inspect: 9 Cylinder inner surface Score marks ¡ Repair or replace. Use #400~600 grit wet sandpaper.
  • Page 112 CYLINDER HEAD, CYLINDER AND PISTON 3. Measure: 9 Piston skirt diameter Use micrometer 1. Measure the specific distance b from the stepped surface a on inside of the piston. Out of specification ¡ Replace. Distance b b Piston dia. 17.5 mm 66.352~66.367 mm (0.69 in) (2.6120~2.6129 in)
  • Page 113 CYLINDER HEAD, CYLINDER AND PISTON 5. Check: 9 Free play There should be no noticeable free play. Free play exists ¡ Inspect the connecting rod for wear/Replace the pin and/or con- necting rod as required. EC474502 Piston ring 1. Install: 9 Piston ring Into the cylinder.
  • Page 114 CYLINDER HEAD, CYLINDER AND PISTON EC474602 Piston clearance 1. Calculate: 9 Piston clearance Out of limit ¡ Replace piston, and piston ring and/or cylinder. Refer to “Cylinder” and “Piston”. PISTON CYLINDER PISTON – CLEARANCE BORE DIAMETER Piston clearance: Standard <Limit> 0.045~0.050 mm 0.1 mm (0.0018~0.0020 in)
  • Page 115 CYLINDER HEAD, CYLINDER AND PISTON 3. Combination: Combine the piston and cylinder by the fol- lowing chart. Cylinder mark Piston mark (color) A (red) B (orange) C (green) D (purple) NOTE: When you purchase a cylinder, you cannot des- ignate its size. Choose the piston that matches the above chart.
  • Page 116 CYLINDER HEAD, CYLINDER AND PISTON EC475000 ASSEMBLY AND INSTALLATION EC475193 Power valve 1. Install: 9 Power valve 1 1 9 Valve holder 2 2 9 Bolt (valve holder 2) 3 6 Nm (0.6 m•kg, 4.3 ft•lb) NOTE: 9 Install the power valve 1 with its gouge a fac- ing upside.
  • Page 117 CYLINDER HEAD, CYLINDER AND PISTON 4. Install: 9 Spring 1 1 9 Link lever 2 9 Pulley 3 9 Spring 2 4 9 Plain washer 5 9 Valve shaft 6 NOTE: 9 Install the spring 1 to the link lever, and then to the cylinder.
  • Page 118 CYLINDER HEAD, CYLINDER AND PISTON 7. Install: 9 O-ring 1 9 Side holder 2 9 Screw (side holder) 3 4 Nm (0.4 m•kg, 2.9 ft•lb) 9 YPVS breather hose 4 NOTE: 9 Apply the lithium soap base grease on the O- rings.
  • Page 119 CYLINDER HEAD, CYLINDER AND PISTON 3. Install: 9 Piston 1 9 Piston pin 2 9 Piston pin clip 3 NOTE: 9 The arrow a on the piston dome must point to exhaust side. 9 Before installing the piston pin clip, cover the crankcase with a clean rag to prevent the pis- ton pin clip from falling into the crankcase cavi- Do not allow the clip open ends to meet the...
  • Page 120 CYLINDER HEAD, CYLINDER AND PISTON 4. Install: 9 Push rod 1 9 Bolt (push rod) 2 5 Nm (0.5 m•kg, 3.6 ft•lb) NOTE: 9 Insert the set pin 3 included in owner’s tool kit to install the bolt (push rod). 9 Do not forget to remove the set pin.
  • Page 121 CYLINDER HEAD, CYLINDER AND PISTON 8. Install: 9 Engine bracket 1 9 Bolt (engine bracket) 2 34 Nm (3.4 m•kg, 24 ft•lb) 9 Engine mounting bolt (upper) 3 64 Nm (6.4 m•kg, 46 ft•lb) 9. Install: 9 Spark plug 1 20 Nm (2.0 m•kg, 14 ft•lb) 9 Spark plug cap 2 4-32...

  • Page 122: Clutch And Primary Driven Gear

    CLUTCH AND PRIMARY DRIVEN GEAR EC490000 CLUTCH AND PRIMARY DRIVEN GEAR EC498000 CLUTCH PLATE AND FRICTION PLATE 10 Nm (1.0 m•kg, 7.2 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Clutch plate and friction plate removal Extent of removal: Extent of removal Order Part name Q’ty...
  • Page 123 CLUTCH AND PRIMARY DRIVEN GEAR EC498200 PRIMARY DRIVEN GEAR, PUSH ROD AND PUSH LEVER AXLE 75 Nm (7.5 m•kg, 54 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 1 Push rod and push lever axle removal 2 Push rod 1 disassembly Extent of removal: 3 Primary driven gear removal Extent of removal...
  • Page 124 CLUTCH AND PRIMARY DRIVEN GEAR EC493000 å å REMOVAL POINTS EC483211 Clutch boss 1. Remove: 9 Nut 1 9 Lock washer 2 9 Clutch boss 3 NOTE: Straighten the lock washer tab and use the clutch holding tool 4, 5 to hold the clutch boss. ∫...
  • Page 125 CLUTCH AND PRIMARY DRIVEN GEAR EC484500 Friction plate 1. Measure: 9 Friction plate thickness Out of specification ¡ Replace friction plate as a set. Measure at all four points. Friction plate thickness: Standard <Limit> 2.9~3.1 mm 2.8 mm (0.114~0.122 in) (0.110 in) EC484600 Clutch plate...
  • Page 126 CLUTCH AND PRIMARY DRIVEN GEAR EC495230 Clutch 1. Install: 9 Thrust plate [D=ø 42 mm (1.65 in)] 1 9 Spacer 2 9 Bearing 3 9 Primary driven gear 4 NOTE: Apply the transmission oil on the bearing, spacer and primary driven gear inner circumference. 2.
  • Page 127 CLUTCH AND PRIMARY DRIVEN GEAR 5. Install: 9 Friction plate 1 9 Clutch plate 2 NOTE: 9 Install the clutch plates and friction plates alter- nately on the clutch boss, starting with a friction plate and ending with a friction plate. 9 Apply the transmission oil on the friction plates and clutch plates.
  • Page 128 CLUTCH AND PRIMARY DRIVEN GEAR 10. Install: 9 O-ring 1 To clucth cover. 11. Install: 9 Clutch cover 1 9 Bolt (clutch cover) 2 10 Nm (1.0 m•kg, 7.2 ft•lb) NOTE: Tighten the bolts in stage, using a crisscross pattern. 12.

  • Page 129: Kick Axle, Shift Shaft And Primary Drive Gear

    KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C0000 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C8000 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) 1 Primary drive gear removal Extent of removal: Extent of removal Order...
  • Page 130 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C8100 KICK AXLE 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) 1 Kick axle and kick idle gear removal Extent of removal: 2 Shift shaft and stopper lever removal Extent of removal...
  • Page 131 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C3000 REMOVAL POINTS EC483111 Primary drive gear 1. Loosen: 9 Bolt (primary drive gear) 1 NOTE: Place an aluminum plate a between the teeth of the primary drive gear 2 and driven gear 3. EC4B3101 Kick axle assembly 1.
  • Page 132 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C4300 Kick gear, kick idle gear and ratchet wheel 1. Inspect: 9 Kick gear 1 9 Kick idle gear 2 9 Ratchet wheel 3 9 Gear teeth a 9 Ratchet teeth b Wear/Damage ¡...
  • Page 133 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C5000 ASSEMBLY AND INSTALLATION EC4C5130 Stopper lever 1. Install: 9 Tension spring 1 9 Holder 2 9 Bolt (holder) 3 10 Nm (1.0 m•kg, 7.2 ft•lb) 9 Plain washer 4 9 Stopper lever 5 9 Bolt (stopper lever) 6 10 Nm (1.0 m•kg, 7.2 ft•lb) NOTE:...
  • Page 134 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR 4. Install: 9 Bolt (shift guide) 1 10 Nm (1.0 m•kg, 7.2 ft•lb) EC4C5310 Shift shaft 1. Install: 9 Roller 1 9 Plain washer 2 9 Shift shaft 3 NOTE: Apply the transmission oil on the roller and shift shaft.
  • Page 135 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR 3. Install: 9 Spring guide 1 NOTE: Slide the spring guide into the kick axle, make sure the groove a in the spring guide fits on the stopper of the torsion spring. 4.
  • Page 136 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C5531 Primary drive gear 1. Install: 9 Thrust plate 1 9 Primary drive gear 2 9 Governor drive gear 3 9 Plain washer 4 9 Bolt (primary drive gear) 5 NOTE: 9 Install the plain washer with its chamfered side a toward you.
  • Page 137 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR 6. Install: 9 Bolt [crankcase cover (right)] 1 10 Nm (1.0 m•kg, 7.2 ft•lb) NOTE: Tighten the bolts in stage, using a crisscross pattern. 7. Install: 9 Kick starter 1 9 Plain washer 2 9 Bolt (kick starter) 3 30 Nm (3.0 m•kg, 22 ft•lb) NOTE:...

  • Page 138: Ypvs Governor

    YPVS GOVERNOR EC4K0000 YPVS GOVERNOR 5 Nm (0.5 m•kg, 3.6 ft•lb) 1 YPVS governor removal and disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks YPVS GOVERNOR REMOVAL Preparation for Crankcase cover (right) Refer to “KICK AXLE, SHIFT SHAFT AND removal PRIMARY DRIVE GEAR”...
  • Page 139 YPVS GOVERNOR EC4K3000 REMOVAL POINTS EC4K3100 Governor 1. Remove: 9 Dowel pin 1 NOTE: While compressing the spring, remove the dowel pin. EC4K4000 INSPECTION EC4K4100 Governor groove 1. Inspect: 9 Plain washer 1 9 Collar 2 Wear/Damage ¡ Replace. EC4K4200 Bearing 1.
  • Page 140 YPVS GOVERNOR 2. Install: 9 Ball 1 9 Retainer 2 To governor shaft 3. NOTE: Apply the transmission oil on the retainer and ball. 3. Install: 9 Dowel pin 1 NOTE: 9 While compressing the spring, install the dowel pin. 9 Make sure the dowel pin fits into the groove a in the retainer.

  • Page 141: Water Pump

    WATER PUMP EC4G0000 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) 1 Impeller shaft removal 2 Oil seal removal Extent of removal: Extent of removal Order Part name Q’ty Remarks WATER PUMP DISASSEMBLY...
  • Page 142 WATER PUMP EC4G3000 REMOVAL POINTS EC4G3110 Impeller shaft 1. Remove: 9 Impeller 1 9 Plain washer 2 9 Impeller shaft 3 NOTE: Hold the impeller shaft on its width across the flats a with spanners, etc. and remove the impeller. EC4G3210 Oil seal NOTE:...
  • Page 143 WATER PUMP EC444300 Impeller shaft gear 1. Inspect: 9 Gear teeth a Wear/Damage ¡ Replace. EC4H4600 Bearing 1. Inspect: 9 Bearing 1 Rotate inner race with a finger. Rough spot/Seizure ¡ Replace. EC444400 Oil seal 1. Inspect: 9 Oil seal 1 Wear/Damage ¡...
  • Page 144 WATER PUMP EC4G5220 Impeller shaft 1. Install: 9 Impeller shaft 1 NOTE: 9 Take care so that the oil seal lip is not dam- aged or the spring does not slip off its position. 9 When installing the impeller shaft, apply the lithium soap base grease on the oil seal lip and impeller shaft.

  • Page 145: Cdi Magneto

    CDI MAGNETO EC4L0000 CDI MAGNETO 8 Nm (0.8 m•kg, 5.8 ft•lb) 8 Nm (0.8 m•kg, 5.8 ft•lb) 56 Nm (5.6 m•kg, 40 ft•lb) 1 CDI magneto removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CDI MAGNETO REMOVAL Preparation for Seat and fuel tank Refer to “SEAT, FUEL TANK AND...
  • Page 146 CDI MAGNETO EC4L3000 REMOVAL POINTS EC4L3102 Rotor 1. Remove: 9 Nut (rotor) 1 9 Plain washer 2 Use the rotor holding tool 3. Rotor holding tool: YU-1235/90890-01235 2. Remove: 9 Rotor 1 Use the flywheel puller 2. Flywheel puller: YM-1189/90890-01189 NOTE: When installing the flywheel puller, turn it coun- terclockwise.
  • Page 147 CDI MAGNETO 2. Install: 9 Woodruff key 1 9 Rotor 2 NOTE: 9 Clean the tapered portions of the crankshaft and rotor. 9 When installing the woodruff key, make sure that its flat surface a is in parallel with the crankshaft center line b.
  • Page 148 CDI MAGNETO 7. Connect: 9 CDI magneto lead 1 Refer to “CABLE ROUTING DIAGRAM” section in the CHAPTER 2. 8. Install: 9 Gasket [crankcase cover (left)] 9 Crankcase cover (left) 1 9 Screw [crankcase cover (left)] 2 8 Nm (0.8 m•kg, 5.8 ft•lb) NOTE: Tighten the screws in stage, using a crisscross pattern.

  • Page 149: Engine Removal

    ENGINE REMOVAL EC4M0000 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) 75 Nm (7.5 m•kg, 54 ft•lb) 8 Nm (0.8 m•kg, 5.8 ft•lb) Extent of removal Order...
  • Page 150 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) 75 Nm (7.5 m•kg, 54 ft•lb) 8 Nm (0.8 m•kg, 5.8 ft•lb) 1 Engine removal Extent of removal: Extent of removal...

  • Page 151: Engine Removal

    ENGINE REMOVAL EC4M3000 REMOVAL POINTS EC4F3100 Drive sprocket 1. Remove: 9 Nut (drive sprocket) 1 9 Lock washer 2 NOTE: 9 Straighten the lock washer tab. 9 Loosen the nut while applying the rear brake. 2. Remove: 9 Drive sprocket 1 9 Drive chain 2 NOTE: Remove the drive sprocket together with the...

  • Page 152: Nm (3.4 M•Kg, 24 Ft•Lb)

    ENGINE REMOVAL EC4M5000 ASSEMBLY AND INSTALLATION EC4M5124 Engine installation 1. Install: 9 Engine 1 Install the engine from right side. 9 Pivot shaft 2 85 Nm (8.5 m•kg, 61 ft•lb) 9 Engine mounting bolt (lower) 3 64 Nm (6.4 m•kg, 46 ft•lb) 9 Engine mounting bolt (front) 4 64 Nm (6.4 m•kg, 46 ft•lb) 9 Engine bracket 5...

  • Page 153: Nm (7.5 M•Kg, 54 Ft•Lb)

    ENGINE REMOVAL EC4M5341 Drive sprocket 1. Install: 9 Drive sprocket 1 9 Drive chain 2 NOTE: Install the drive sprocket together with the drive chain. 2. Install: 9 Lock washer 1 9 Nut (drive sprocket) 2 75 Nm (7.5 m•kg, 54 ft•lb) NOTE: Tighten the nut while applying the rear brake.

  • Page 154: Crankcase And Crankshaft

    CRANKCASE AND CRANKSHAFT EC4N0000 CRANKCASE AND CRANKSHAFT 10 Nm (1.0 m•kg, 7.2 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 14 Nm (1.4 m•kg, 10 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Crankcase separation 2 Crankshaft removal Extent of removal: 3 Crankshaft bearing removal Extent of removal Order...
  • Page 155 CRANKCASE AND CRANKSHAFT EC4N3000 REMOVAL POINTS EC4N3212 Crankcase 1. Remove: 9 Crankcase (right) 1 Use the crankcase separating tool 2. Crankcase separating tool: YU-1135-A/90890-01135 NOTE: 9 Make appropriate bolts 3 as shown available by yourself and attach the tool with them. 9 Fully tighten the tool holding bolts, but make sure the tool body is parallel with the case.
  • Page 156 CRANKCASE AND CRANKSHAFT EC4N3401 Crankshaft bearing 1. Remove: 9 Bearing 1 NOTE: 9 Remove the bearing from the crankcase by pressing its inner race as shown in å. 9 If the bearing is removed together with the crankshaft, remove the bearing using a general bearing puller 2 as shown in ∫.
  • Page 157 CRANKCASE AND CRANKSHAFT EC4N4202 Crankshaft 1. Measure: 9 Runout limit a 9 Small end free play limit b 9 Connecting rod big end side clearance c 9 Crank width d Out of specification ¡ Replace. Use the dial gauge and a thickness gauge. Dial gauge: YU-3097/90890-01252 Standard...
  • Page 158 CRANKCASE AND CRANKSHAFT EC4N5284 Crankshaft 1. Install: 9 Crankshaft 1 Use the crankshaft installing tool 2, 3, 4. Crankshaft installing tool: Pot 2: YU-90050/90890-01274 Bolt 3: YU-90050/90890-01275 Adapter 4: YU-90063/90890-01278 å å å For USA and CDN ∫ Except for USA and CDN NOTE: 9 Hold the connecting rod at top dead center with one hand while turning the nut of the installing...
  • Page 159 To crankcase (right) 2. 4. Apply: 9 Sealant On the crankcase (right) 1. ® Quick gasket ACC-QUICK-GS-KT Yamaha bond No. 1215: 90890-85505 NOTE: Clean the contacting surface of crankcase (left and right) before applying the sealant. 5. Install: 9 Dowel pin 1 9 Crankcase (right) 2 To crankcase (left) 3.
  • Page 160 CRANKCASE AND CRANKSHAFT 6. Install: 9 Bolt (crankcase) 1 14 Nm (1.4 m•kg, 10 ft•lb) NOTE: Tighten the crankcase tightening bolts in stage, using a crisscross pattern. 7. Install: 9 Tension spring 1 9 Holder 2 9 Bolt (holder) 3 10 Nm (1.0 m•kg, 7.2 ft•lb) NOTE: Install the holder so that it contacts the projec-...

  • Page 161: Transmission, Shift Cam And Shift Fork

    TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H0000 TRANSMISSION, SHIFT CAM AND SHIFT FORK 1 Main axle, drive axle, shift cam and shift fork removal Extent of removal: Extent of removal Order Part name Q’ty Remarks TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVAL Preparation for Engine Refer to “ENGINE REMOVAL”...
  • Page 162 TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H3000 REMOVAL POINTS EC4H3230 Transmission 1. Remove: 9 Main axle 1 9 Drive axle 2 9 Shift cam 9 Shift fork 3 9 Shift fork 2 9 Shift fork 1 NOTE: 9 Remove assembly carefully. Note the position of each part.
  • Page 163 TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H4810 Shift fork, shift cam and segment 1. Inspect: 9 Shift fork 1 Wear/Damage/Scratches ¡ Replace. 2. Inspect: 9 Shift cam 1 9 Segment 2 Wear/Damage ¡ Replace. 3. Check: 9 Shift fork movement Unsmooth operation ¡...
  • Page 164 TRANSMISSION, SHIFT CAM AND SHIFT FORK 2. Install: 9 2nd wheel gear (23 T) 1 9 4th wheel gear (24 T) 2 9 3rd wheel gear (23 T) 3 9 5th wheel gear (20 T) 4 9 1st wheel gear (27 T) 5 9 O-ring 6 To drive axle 7.
  • Page 165 TRANSMISSION, SHIFT CAM AND SHIFT FORK 5. Install: 9 Shift fork 1 (L) 1 9 Shift fork 2 (C10) 2 9 Shift fork 3 (R) 3 9 Shift cam 4 To main axle and drive axle. NOTE: 9 Apply the molybdenum disulfide oil on the shift fork grooves.

  • Page 166: Chassis

    CHAS FRONT WHEEL AND REAR WHEEL EC500000 CHASSIS EC590000 FRONT WHEEL AND REAR WHEEL EC598000 FRONT WHEEL 23 Nm (2.3 m•kg, 17 ft•lb) 23 Nm (2.3 m•kg, 17 ft•lb) 105 Nm (10.5 m•kg, 75 ft•lb) 12 Nm (1.2 m•kg, 8.7 ft•lb) Extent of removal: 1 Front wheel removal 2 Wheel bearing removal...

  • Page 167: Rear Wheel

    CHAS FRONT WHEEL AND REAR WHEEL EC598100 REAR WHEEL 14 Nm (1.4 m•kg, 10 ft•lb) 125 Nm (12.5 m•kg, 90 ft•lb) 16 Nm (1.6 m•kg, 11 ft•lb) 42 Nm (4.2 m•kg, 30 ft•lb) 16 Nm (1.6 m•kg, 11 ft•lb) 1 Rear wheel removal 2 Wheel bearing removal 3 Brake disc removal Extent of removal:...
  • Page 168 CHAS FRONT WHEEL AND REAR WHEEL EC593000 REMOVAL POINTS EC523101 Rear wheel 1. Remove: 9 Wheel 1 NOTE: Push the wheel forward and remove the drive chain 2. EC513201 Wheel bearing (if necessary) 1. Remove: 9 Bearing 1 NOTE: Remove the bearing using a general bearing puller 2.
  • Page 169 CHAS FRONT WHEEL AND REAR WHEEL EC514200 Wheel axle 1. Measure: 9 Wheel axle bends Out of specification ¡ Replace. Use the dial gauge 1. Wheel axle bending limit: 0.5 mm (0.020 in) NOTE: The bending value is shown by one half of the dial gauge reading.
  • Page 170 CHAS FRONT WHEEL AND REAR WHEEL EC595000 ASSEMBLY AND INSTALLATION EC595101 Front wheel 1. Install: 9 Bearing (left) 1 9 Spacer 2 9 Bearing (right) 3 9 Oil seal 4 NOTE: 9 Apply the lithium soap base grease on the bearing and oil seal lip when installing.

  • Page 171: Front Wheel And Rear Wheel

    CHAS FRONT WHEEL AND REAR WHEEL 5. Install: 9 Wheel axle 1 NOTE: Apply the lithium soap base grease on the wheel axle. 6. Install: 9 Nut (wheel axle) 1 105 Nm (10.5 m•kg, 75 ft•lb) 7. Tighten: 9 Bolt (axle holder) 1 23 Nm (2.3 m•kg, 17 ft•lb) NOTE: Before tightening the bolt, fit the wheel axle to...
  • Page 172 CHAS FRONT WHEEL AND REAR WHEEL EC5251A1 Rear wheel 1. Install: 9 Bearing (right) 1 9 Circlip 2 9 Spacer 3 9 Bearing (left) 4 9 Oil seal 5 NOTE: 9 Apply the lithium soap base grease on the bearing and oil seal lip when installing. 9 Install the bearing with seal facing outward.
  • Page 173 CHAS FRONT WHEEL AND REAR WHEEL 3. Install: 9 Driven sprocket 1 9 Bolt (driven sprocket) 2 9 Plain washer (driven sprocket) 3 9 Nut (driven sprocket) 4 42 Nm (4.2 m•kg, 30 ft•lb) NOTE: Tighten the nuts in stage, using a crisscross pat- tern.
  • Page 174 CHAS FRONT WHEEL AND REAR WHEEL 8. Install: 9 Chain puller (right) 1 9 Plain washer 2 9 Nut (wheel axle) 3 NOTE: Temporarily tighten the nut (wheel axle) at this point. 9. Adjust: 9 Drive chain slack a Drive chain slack : 48~58 mm (1.9~2.3 in) Refer to “DRIVE CHAIN SLACK ADJUSTMENT”...

  • Page 175: Front Brake And Rear Brake

    CHAS FRONT BRAKE AND REAR BRAKE EC5A0000 FRONT BRAKE AND REAR BRAKE EC5A8000 FRONT BRAKE 10 Nm (1.0 m•kg, 7.2 ft•lb) 9 Nm (0.9 m•kg, 6.5 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb)

  • Page 176: Rear Brake

    CHAS FRONT BRAKE AND REAR BRAKE EC5A8100 REAR BRAKE 30 Nm (3.0 m•kg, 22 ft•lb) 1 Nm (0.1 m•kg, 0.7 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 26 Nm (2.6 m•kg, 19 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb)

  • Page 177: Caliper Disassembly

    CHAS FRONT BRAKE AND REAR BRAKE EC5A8200 CALIPER DISASSEMBLY 18 Nm (1.8 m•kg, 13 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) A Front B Rear 1 Front caliper disassembly...
  • Page 178 CHAS FRONT BRAKE AND REAR BRAKE EC5A8300 MASTER CYLINDER DISASSEMBLY 2 Nm (0.2 m•kg, 1.4 ft•lb) 2 Nm (0.2 m•kg, 1.4 ft•lb) A Front B Rear 1 Front master cylinder disassembly 2 Rear master cylinder disassembly Extent of removal: Extent of removal Order Part name Q’ty...
  • Page 179 CHAS FRONT BRAKE AND REAR BRAKE EC5A3000 REMOVAL POINTS EC5A3101 Brake fluid 1. Remove: [Front] 9 Master cylinder cap 1 [Rear] 9 Master cylinder cap 1 9 Protector NOTE: Do not remove the diaphragm. A Front B Rear 2. Connect the transparent hose 2 to the bleed screw 1 and place a suitable contain- er under its end.
  • Page 180 CHAS FRONT BRAKE AND REAR BRAKE EC533402 Piston seal kit 1. Remove: 9 Dust seal 1 9 Piston seal 2 NOTE: Remove the piston seals and dust seals by pushing them with a finger. Never attempt to pry out piston seals and dust seals.
  • Page 181 CHAS FRONT BRAKE AND REAR BRAKE 4. Inspect: 9 Master cylinder piston 1 9 Master cylinder cup 2 Wear/Damage/Score marks¡Replace master cylinder kit. A Front B Rear EC534214 Caliper 1. Inspect: 9 Caliper cylinder inner surface a Wear/Score marks¡Replace caliper as- sembly.
  • Page 182 CHAS FRONT BRAKE AND REAR BRAKE EC5A5801 Caliper piston 1. Clean: 9 Caliper 9 Piston seal 9 Dust seal 9 Caliper piston Clean them with brake fluid. 2. Install: 9 Piston seal 1 9 Dust seal 2 Always use new piston seals and dust seals.
  • Page 183 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: 9 Caliper 1 9 Bolt (caliper) 2 23 Nm (2.3 m•kg, 17 ft•lb) 3. Tighten: 9 Pad pin 3 18 Nm (1.8 m•kg, 13 ft•lb) 4. Install: 9 Pad pin plug 4 3 Nm (0.3 m•kg, 2.2 ft•lb) EC5A5121 Rear caliper...
  • Page 184 CHAS FRONT BRAKE AND REAR BRAKE EC5A5220 Master cylinder kit 1. Clean: 9 Master cylinder 9 Master cylinder kit Clean them with brake fluid. 2. Install: 9 Master cylinder cup (primary) 1 9 Master cylinder cup (secondary) 2 To master cylinder piston 3. NOTE: Apply the brake fluid on the master cylinder cup.
  • Page 185 CHAS FRONT BRAKE AND REAR BRAKE 4. Install: [Front] 9 Master cylinder kit 1 9 Plain washer 2 9 Circlip 3 9 Master cylinder boot 4 To master cylinder 5. [Rear] 9 Master cylinder kit 1 9 Push rod 2 9 Circlip 3 9 Master cylinder boot 4 To master cylinder 5.
  • Page 186 CHAS FRONT BRAKE AND REAR BRAKE EC5A5401 Rear master cylinder 1. Install: 9 Copper washer 1 9 Brake hose 2 9 Union bolt 3 30 Nm (3.0 m•kg, 22 ft•lb) Always use new copper washers. Install the brake hose so that its pipe por- tion a directs as shown and lightly touch- es the projection b on the master cylinder.
  • Page 187 CHAS FRONT BRAKE AND REAR BRAKE 4. Install: 9 Pin 1 9 Plain washer 2 9 Cotter pin 3 NOTE: After installing, check the brake pedal height. Refer to “REAR BRAKE ADJUSTMENT” section in the CHAPTER 3. EC5A5911 Front brake hose 1.
  • Page 188 CHAS FRONT BRAKE AND REAR BRAKE 4. Pass the brake hose through the cable guide 1. 5. Install: 9 Copper washer 1 9 Brake hose 2 9 Union bolt 3 30 Nm (3.0 m•kg, 22 ft•lb) Always use new copper washers. Install the brake hose so that its pipe por- tion a directs as shown and lightly touch- es the projection b on the master cylinder.
  • Page 189 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: 9 Brake hose holder 1 9 Screw (brake hose holder) 2 1 Nm (0.1 m•kg, 0.7 ft•lb) After installing the brake hose holders, make sure the brake hose does not contact the spring (rear shock absorber). If it does, correct its twist.
  • Page 190 CHAS FRONT BRAKE AND REAR BRAKE 2. Air bleed: 9 Brake system Refer to “BRAKE SYSTEM AIR BLEED- ING” section in the CHAPTER 3. 3. Inspect: 9 Brake fluid level Fluid at lower level¡Fill up. Refer to “BRAKE FLUID LEVEL INSPEC- TION”...

  • Page 191: Front Fork

    CHAS FRONT FORK EC550000 FRONT FORK 23 Nm (2.3 m•kg, 17 ft•lb) 20 Nm (2.0 m•kg, 14 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Front fork removal Extent of removal: Extent of removal Order...
  • Page 192 CHAS FRONT FORK EC558000 FRONT FORK DISASSEMBLY 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) 1 Oil seal removal 2 Damper rod removal Extent of removal: Extent of removal...
  • Page 193 CHAS FRONT FORK EC556000 HANDLING NOTE NOTE: The front fork requires careful attention. So it is recommended that the front fork be maintained at the dealers. To prevent an accidental explosion of air, the following instructions should be ob- served: 9 The front fork with a built-in piston rod has a very sophisticated internal con- struction and is particularly sensitive to...
  • Page 194 CHAS FRONT FORK Adjuster 1. Drain the outer tube of its front fork oil at its top. 2. Loosen: 9 Adjuster 1 3. Remove: 9 Adjuster 1 NOTE: 9While compressing the inner tube 2 , set the cap bolt ring wrench 4 between the inner tube and locknut 3 .
  • Page 195 CHAS FRONT FORK Base valve 1. Remove: 9 Base valve 1 From damper assembly 2. NOTE: Hold the damper assembly with the cap bolt ring wrench 3 and use the cap bolt wrench 4 to remove the base valve. Cap bolt wrench: YM-01500/90890-01500 Cap bolt ring wrench: YM-01501/90890-01501...
  • Page 196 CHAS FRONT FORK Base valve 1. Inspect: 9 Base valve 1 Wear/Damage¡Replace. Contamination¡Clean. 9 O-ring 2 Wear/Damage¡Replace. 9 Bush 3 Wear/Damage¡Replace base valve. 9 Spring 4 Damage/Fatigue¡Replace base valve. 9 Air bleed screw 5 Wear/Damage¡Replace base valve. EC554400 Fork spring 1.
  • Page 197 CHAS FRONT FORK EC554600 Outer tube 1. Inspect: 9 Outer tube 1 Score marks/Wear/Damage¡Replace. Adjuster 1. Inspect: 9 Adjuster 1 9 O-ring 2 Wear/Damage¡Replace. EC555000 ASSEMBLY AND INSTALLATION EC5551D0 Front fork assembly 1. Wash the all parts in a clean solvent. 2.
  • Page 198 CHAS FRONT FORK 4. After filling, pump the damper assembly 1 slowly up and down (about 200 mm (7.9 in) stroke) several times to bleed the damper assembly of air. NOTE: Be careful not to excessive full stroke. A stroke of 200 mm (7.9 in) or more will cause air to enter.
  • Page 199 CHAS FRONT FORK 9. Tighten: 9 Base valve 1 29 Nm (2.9 m•kg, 21 ft•lb) NOTE: Hold the damper assembly with the cap bolt ring wrench 2 and use the cap bolt wrench 3 to tighten the base valve with specified torque. Cap bolt wrench: YM-01500/90890-01500 Cap bolt ring wrench:...
  • Page 200 CHAS FRONT FORK 14. Install: 9 Dust seal 1 9 Stopper ring 2 9 Oil seal 3 9 Oil seal washer 4 9 Slide metal 5 To inner tube 6. NOTE: 9 Apply the fork oil on the inner tube. 9 When installing the oil seal, use vinyl seat a with fork oil applied to protect the oil seal lip.
  • Page 201 CHAS FRONT FORK 17. Install: 9 Slide metal 1 9 Oil seal washer 2 To outer tube slot. NOTE: Press the slide metal into the outer tube with fork seal driver 3. Fork seal driver: YM-01442/90890-01442 18. Install: 9 Oil seal 1 NOTE: Press the oil seal into the outer tube with fork seal driver 2.
  • Page 202 CHAS FRONT FORK 21. Check: 9 Inner tube smooth movement Tightness/Binding/Rough spots ¡ Repeat the steps 14 to 20. 22. Measure: 9 Distance a Out of specification¡Turn into the locknut. Distance a a : 19 mm (0.75 in) or more Between damper assembly 1 bottom and locknut 2 bottom.
  • Page 203 CHAS FRONT FORK 26. Install: 9 Push rod 1 9 Copper washer 2 9 Adjuster 3 To damper assembly 4. NOTE: 9While compressing the inner tube 5, set the cap bolt ring wrench 7 between the inner tube and locknut 6. 9Fully finger tighten the adjuster onto the damper assembly.
  • Page 204 CHAS FRONT FORK Never fail to make the oil amount adjustment between maximum minimum amount and always adjust each front fork to the same setting. Uneven adjustment can cause poor handling and loss of stability. 9 Be sure to use recommended fork oil. If other oils are used, they may have an ex- cessively adverse effect on the front fork performance.
  • Page 205 CHAS FRONT FORK 3. Adjust: 9 Front fork top end a Front fork top end (standard) a: Zero mm (Zero in) 4. Tighten: 9 Pinch bolt (handle crown) 1 23 Nm (2.3 m•kg, 17 ft•lb) 9 Pinch bolt (under bracket) 2 20 Nm (2.0 m•kg, 14 ft•lb) Tighten the under bracket to specified torque.

  • Page 206: Handlebar

    CHAS HANDLEBAR EC5B0000 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) 4 Nm (0.4 m•kg, 2.9 ft•lb) 1 Handlebar removal Extent of removal: Extent of removal...
  • Page 207 CHAS HANDLEBAR EC5B8000 THROTTLE DISASSEMBLY 4 Nm (0.4 m•kg, 2.9 ft•lb) 1 Throttle disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks THROTTLE DISASSEMBLY Grip cap (lower) Grip cap (upper) Grip assembly Grip (right) Refer to “REMOVAL POINTS”. Tube guide 5-42...
  • Page 208 CHAS HANDLEBAR EC5B3000 REMOVAL POINTS EC5B3100 Master cylinder 1. Remove: 9 Master cylinder bracket 1 9 Master cylinder 2 9 Do not let the master cylinder hang on the brake hose. 9 Keep the master cylinder cap side horizontal to prevent air from coming in. EC5B3200 Grip 1.
  • Page 209 CHAS HANDLEBAR 2. Install: 9 Grip cap (upper) 1 9 Grip cap (lower) 2 9 Bolt (grip cap) 3 NOTE: Temporarily tighten the bolts (grip cap). EC5B5210 Handlebar 1. Install: 9 Handlebar 1 9 Handlebar holder 2 9 Bolt (handlebar holder) 3 28 Nm (2.8 m•kg, 20 ft•lb) NOTE: 9 The upper handlebar holder should be installed...
  • Page 210 CHAS HANDLEBAR 3. Install: 9 Collar 1 9 Cap cover 2 9 Throttle 3 NOTE: 9 Apply the lithium soap base grease on the throttle grip sliding surface. 9 Tighten the grip cap bolts temporarily without the throttle being fixed to the handlebar. 4.
  • Page 211 CHAS HANDLEBAR 9. Install: 9 Master cylinder 1 9 Master cylinder bracket 2 9 Bolt (master cylinder bracket) 3 9 Nm (0.9 m•kg, 6.5 ft•lb) NOTE: 9 Install the bracket so that the arrow mark a faces upward. 9 First tighten the bolt on the upper side of the master cylinder bracket, and then tighten the bolt on the lower side.
  • Page 212 CHAS HANDLEBAR 12. Install: 9 Clutch cable 1 NOTE: Apply the lithium soap base grease on the clutch cable end. 13. Adjust: 9 Clutch lever free play Refer to “CLUTCH ADJUSTMENT” section in the CHAPTER 3. 14. Clamp the clamp portion a of the number plate to the handlebar.

  • Page 213: Steering

    CHAS STEERING EC560000 STEERING 23 Nm (2.3 m•kg, 17 ft•lb) 145 Nm (14.5 m•kg, 105 ft•lb) TIGHTENING STEPS: 9 Tighten ring nut. 38 Nm (3.8 m•kg, 27 ft•lb) 9 Loosen it one turn. 9 Retighten it. 7 Nm (0.7 m•kg, 5.1 ft•lb) 4Nm (0.4 m•kg, 2.9 ft•lb) 20 Nm (2.0 m•kg, 14 ft•lb) 1 Under bracket removal 2 Bearing removal...
  • Page 214 CHAS STEERING EC563000 REMOVAL POINTS EC563202 Ring nut 1. Remove: 9 Ring nut 1 Use the ring nut wrench 2. Ring nut wrench: YU-33975/90890-01403 Support the steering shaft so that it may not fall down. EC563300 Bearing (lower) 1. Remove: 9 Bearing (lower) 1 Use the floor chisel 2.
  • Page 215 CHAS STEERING EC564101 Bearing and bearing race 1. Wash the bearings and bearing races with a solvent. 2. Inspect: 9 Bearing 1 9 Bearing race Pitting/Damage ¡ Replace bearings and bearing races as a set. Install the bearing in the bearing races. Spin the bearings by hand.
  • Page 216 CHAS STEERING 4. Install: 9 Ring nut 1 7 Nm (0.7 m•kg, 5.1 ft•lb) Tighten the ring nut using the ring nut wrench 2. Refer to “STEERING HEAD INSPECTION AND ADJUSTMENT” section in the CHAP- TER 3. 5. Check the steering shaft by turning it lock to lock.
  • Page 217 CHAS STEERING 9. Install: 9 Steering shaft cap 1 10. After tightening the nut, check the steering for smooth movement. If not, adjust the steering by loosening the ring nut little by little. 11. Adjust: 9 Front fork top end a Front fork top end (standard) a: Zero mm (Zero in) 12.

  • Page 218: Swingarm

    CHAS SWINGARM EC570000 SWINGARM 53 Nm (5.3 m•kg, 38 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 19 Nm (1.9 m•kg, 13 ft•lb) 85 Nm (8.5 m•kg, 61 ft•lb) 80 Nm (8.0 m•kg, 58 ft•lb) Extent of removal: 1 Swingarm removal Extent of removal Order Part name...
  • Page 219 CHAS SWINGARM EC578000 SWINGARM DISASSEMBLY 80 Nm (8.0 m•kg, 58 ft•lb) 2 Nm (0.2 m•kg, 1.4 ft•lb) 5 Nm (0.5 m•kg, 3.6 ft•lb) 80 Nm (8.0 m•kg, 58 ft•lb) 1 Swingarm disassembly 2 Connecting rod removal and disassembly Extent of removal: 3 Relay arm removal and disassembly Extent of removal Order...
  • Page 220 CHAS SWINGARM EC573000 REMOVAL POINTS 1. Remove: 9 Cap (left) 1 NOTE: Remove with a slotted-head screwdriver insert- ed under the mark a on the cap (left). EC573201 Bearing 1. Remove: 9 Bearing 1 NOTE: Remove the bearing by pressing its outer race. EC574010 INSPECTION Wash the bearings, bushes, collars, and covers in...
  • Page 221 CHAS SWINGARM EC574311 Connecting rod 1. Inspect: 9 Bearing 1 9 Collar 2 Free play exists/Unsmooth revolution/Rust ¡ Replace bearing and collar as a set. 2. Inspect: 9 Oil seal 3 Damage ¡ Replace. EC575000 ASSEMBLY AND INSTALLATION EC575202 Bearing and oil seal 1.
  • Page 222 CHAS SWINGARM 3. Install: 9 Bearing 1 9 Oil seal 2 To connecting rod. NOTE: 9 Apply the molybdenum disulfide grease on the bearing when installing. 9 Install the bearing by pressing it on the side hav- ing the manufacture's marks or numbers. Installed depth of bearings a: 5 mm (0.20 in) EC5751B3...
  • Page 223 CHAS SWINGARM 4. Install: 9 Connecting rod 1 9 Bolt (connecting rod) 2 9 Plain washer 3 9 Nut (connecting rod) 4 80 Nm (8.0 m•kg, 58 ft•lb) To relay arm 5. NOTE: Apply the molybdenum disulfide grease on the bolt.
  • Page 224 CHAS SWINGARM 8. Install: 9 Bolt (connecting rod) 1 9 Plain washer 2 9 Nut (connecting rod) 3 NOTE: 9 Apply the molybdenum disulfide grease on the bolt. 9 Do not tighten the nut yet. 9. Install: 9 Bolt (rear shock absorber-relay arm) 1 9 Nut (rear shock absorber-relay arm) 2 53 Nm (5.3 m•kg, 38 ft•lb) NOTE:...
  • Page 225 CHAS SWINGARM 13. Install: 9 Bolt [chain tensioner (lower)] 1 9 Plain washer 2 9 Collar 3 9 Chain tensioner 4 9 Nut [chain tensioner (lower)] 5 19 Nm (1.9 m•kg, 13 ft•lb) 14. Install: 9 Chain support 1 9 Support cover 2 9 Bolt {chain support [/=50mm (1.97in)]} 3 9 Nut (chain support) 4 7 Nm (0.7 m•kg, 5.1 ft•lb)

  • Page 226: Rear Shock Absorber

    CHAS REAR SHOCK ABSORBER EC580000 REAR SHOCK ABSORBER 56 Nm (5.6 m•kg, 40 ft•lb) 53 Nm (5.3 m•kg, 38 ft•lb) 32 Nm (3.2 m•kg, 23 ft•lb) 29 Nm (2.9 m•kg, 21 ft•lb) 1 Rear shock absorber removal 2 Rear shock absorber disassembly Extent of removal: Extent of removal Order...
  • Page 227 1. Wear eye protection to prevent eye damage from escaping gas and/or metal chips. To dispose of a damaged or worn-out shock absorber, take the unit to your Yamaha dealer for this disposal procedure. 5-62...
  • Page 228 CHAS REAR SHOCK ABSORBER EC583000 REMOVAL POINTS EC583320 Bearing 1. Remove: 9 Stopper ring (upper bearing) 1 NOTE: Press in the bearing while pressing its outer race and remove the stopper ring. 2. Remove: 9 Upper bearing 1 NOTE: Remove the bearing by pressing its outer race. 3.
  • Page 229 CHAS REAR SHOCK ABSORBER EC585000 ASSEMBLY AND INSTALLATION EC585320 Bearing 1. Install: 9 Upper Bearing 1 NOTE: Install the bearing parallel until the stopper ring groove appears by pressing its outer race. Do not apply the grease on the bearing outer race because it will wear the rear shock absorber surface on which the bear- ing is press fitted.
  • Page 230 CHAS REAR SHOCK ABSORBER 3. Adjust: 9 Spring length (installed) a Spring length (installed) a: Standard Extent of length adjustment 251 mm (9.88 in) 240.5~258.5 mm *253 mm (9.96 in) (9.47~10.18 in) *For EUROPE NOTE: The length of the spring (installed) changes 1.5 mm (0.06 in) per turn of the adjuster.
  • Page 231 CHAS REAR SHOCK ABSORBER 3. Install: 9 Rear shock absorber 4. Install: 9 Bolt (rear shock absorber-frame) 1 9 Plain washer 2 9 Nut (rear shock absorber-frame) 3 56 Nm (5.6 m•kg, 40 ft•lb) NOTE: Apply the molybdenum disulfide grease on the bolt.

  • Page 232: Electrical Components And Wiring Diagram

    ELEC ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC600000 ELECTRICAL EC610000 ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC611000 ELECTRICAL COMPONENTS COLOR CODE B....Black 1 CDI unit L ....Blue 2 “ENGINE STOP” button O ....Orange 3 Ignition coil R ....Red 4 TPS (throttle position sensor) Y....Yellow 5 Solenoid valve B/L....Black/Blue...

  • Page 233: Ignition System

    ELEC IGNITION SYSTEM EC620000 IGNITION SYSTEM EC621003 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 *Clean or replace Spark gap test spark plug.
  • Page 234 ELEC IGNITION SYSTEM EC622001 å å SPARK GAP TEST 1. Disconnect the spark plug cap from spark plug. 2. Connect the dynamic spark tester 1 (igni- tion checker 2 ) as shown. 9 Spark plug cap 3 9 Spark plug 4 A For USA and CDN B Except for USA and CDN 3.
  • Page 235 ELEC IGNITION SYSTEM EC626003 IGNITION COIL INSPECTION 1. Inspect: 9 Primary coil resistance Out of specification ¡ Replace. Tester (+) lead ¡ Yellow lead 1 Tester (–) lead ¡ Black lead 2 Primary coil Tester selector resistance position 0.20~0.30Ω at Ω...
  • Page 236 ELEC IGNITION SYSTEM EC62B000 SPARK PLUG CAP INSPECTION 1.Inspect: 9 Spark plug cap Loose connection ¡ Tighten. Deteriorated/Damaged ¡ Replace. 9 Spark plug cap resistance Out of specification ¡ Replace. Tester (+) lead ¡Spark plug lead terminal 1 Tester (–) lead ¡Spark plug terminal 2 Spark plug cap Tester selector resistance...
  • Page 237 ELEC IGNITION SYSTEM 3. Inspect: 9 Source coil 2 resistance Out of specification ¡ Replace. Tester (+) lead ¡Green/ Blue lead 1 Tester (–) lead ¡Green/ White lead 2 Source coil 2 Tester selector resistance position 44~66Ω at Ω × 10 20°C (68°F) EC628000 CDI UNIT INSPECTION...

  • Page 238: Solenoid Valve System

    ELEC SOLENOID VALVE SYSTEM EC650001 SOLENOID VALVE SYSTEM EC651032 INSPECTION STEPS If the solenoid valve will not operate, use the following inspection steps. No good Check each couplers and Repair or replace. wire connection. No good Check solenoid Check solenoid valve. Replace.
  • Page 239 ELEC SOLENOID VALVE SYSTEM EC624000 COUPLERS AND LEADS CONNECTION INSPECTION 1. Check: 9 Couplers and leads connection Rust/ Dust/ Looseness/Short-circuit ¡ Repair or replace. EC652040 SOLENOID VALVE OPERATION 1. Disconnect the solenoid valve coupler. 2. Connect 12V battery to the solenoid valve coupler.

  • Page 240: Tps (Throttle Position Sensor) System

    ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM EC690000 TPS (THROTTLE POSITION SENSOR) SYSTEM EC691001 INSPECTION STEPS If the TPS will not operate, use the following inspection steps. No good Check entire ignition Repair or replace. system for connection. No good Check TPS. TPS coil Replace.
  • Page 241 ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM EC69A000 HANDLING NOTE Do not loosen the screws {TPS (throttle position sensor)} except when changing the TPS (throttle position sensor) due to failure because it will cause a drop in engine performance. EC624000 COUPLERS AND LEADS CONNECTION INSPECTION 1.
  • Page 242 ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM 3. Inspect: 9 TPS coil variable resistance Check that the resistance in increased as the lever 1 is moved from the full close position to the full open position. Out of specification ¡ Replace. Tester (+) lead ¡Yellow lead 2 Tester (–) lead ¡Black lead 3 TPS coil variable...
  • Page 243 ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM 4. Install: 9 TPS 1 9 Screw (TPS) 2 NOTE: 9 Align the slot a in the TPS with the projection b on the carburetor while the lever 3 is held down. 9 Temporarily tighten the screws (TPS). 5.
  • Page 244 ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM 8. Start the engine. 9. Adjust: 9 TPS output voltage Adjustment steps: Adjust the installation angle of the TPS 1 to obtain the specified output volt- age. TPS output Tester selector voltage position 0.5~0.7V DCV-20 10.
  • Page 245 ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM EC694000 TPS INPUT VOLTAGE INSPECTION 1. Disconnect the TPS coupler. 2. Start the engine. 3. Inspect: 9 TPS input voltage Out of specification ¡ Replace the CDI unit. Tester (+) lead ¡Blue lead 1 Tester (–) lead ¡Black/Blue lead 2 TPS input Tester selector...

  • Page 246: Tuning

    SETTING EC700000 TUNING EC710000 ENGINE EC711001 Carburetor setting 9 The role of fuel is to cool the engine, and in the case of a 2-stroke engine, to lubricate the engine in addition to power generation. Accord- ingly, if a mixture of air and fuel is too lean, abnormal combustion will occur, and engine seizure may result.
  • Page 247 SETTING That is: 9 Higher temperature expands the air with its resultant reduced density. 9 Higher humidity reduces the amount of oxygen in the air by so much of the water vapor in the same air. 9 Lower atmospheric pressure (at a high altitude) reduces the density of the air.
  • Page 248 SETTING EC714032 Effects of setting parts in relation to throt- tle valve opening Throttle valve opening Setting part Full-closed 1/4 3/4 Full-open Pilot jet Pilot air screw Diameter of straight portion Clip position Throttle valve Power jet Main jet NOTE: The power jet closes at 8,500 rpm of the engine, after which only the main jet dominates.
  • Page 249 SETTING EC716001 Pilot air screw adjustment The richness of air-fuel mixture with full closed to 1/8 throttle can be set by turning the pilot air screw 1. Turning in the pilot air screw will enrich the mix- ture at low speeds, and turning out it will lean out the mixture.
  • Page 250 SETTING 1. Too rich at intermediate speeds Rough engine operation is felt and the engine will not pick up speed smoothly. In this case, step up the jet needle clip by one groove and move down the needle to lean out the mixture.
  • Page 251 SETTING EC719081 Jet needle adjustment (For USA, CDN, ZA, AUS and NZ) On the carburetors used in the YZ250, the main nozzle is press-fitted, so it can not be replaced. Therefore, carburetor setting requires the change of the jet needle. 1.
  • Page 252 SETTING EC719081 Jet needle adjustment (For EUROPE) On the carburetors used in the YZ250, the main nozzle is press-fitted, so it can not be replaced. Therefore, carburetor setting requires the change of the jet needle. 1. The jet needle setting parts, having the same taper angle, are available in different straight portion diameters and in different taper start- ing positions.
  • Page 253 SETTING EC71B011 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 relationship between the fuel flow and the throttle opening, the fuel flow relates to the jet needle straight por- tion diameter around 1/8 to 1/4 throttle opening,...
  • Page 254 SETTING EC71Q000 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 Rich...
  • Page 255 SETTING EC71C030 Road condition and examples of carburetor setting Conditions General condition Sandy condition Under 10°C 10~25°C Over 25°C Under 10°C 10~25°C Over 25°C (50°F) (50~77°F) (77°F) (50°F) (50~77°F) (77°F) Parts (Winter) (Spring, Autumn) (Summer) (Winter) (Spring, Autumn) (Summer) #178 #180 #178 Main jet...
  • Page 256 SETTING Symptom Setting Checking Number of turns-back ¡ 0~1/4 throttle Use jet needle having a smaller Hard breathing diameter. Correct properly Speed down Overflow from carburetor 0~1/4 throttle Use jet needle having a larger Poor acceleration diameter. White smoke Unstable at low speeds Lower jet needle clip position.
  • Page 257 SETTING EC71M010 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 258: Chassis

    SETTING EC720000 CHASSIS EC71P002 Selection of the secondary reduction ratio (Sprocket) Secondary Number of driven sprocket teeth reduction Number of drive sprocket teeth ratio Standard secondary 50/14 (3.571) reduction ratio *49/14 (3.500) *For EUROPE and CDN <Requirement for selection of secondary gear reduction ratio>...
  • Page 259 SETTING EC72N000 Drive and driven sprockets setting parts Part name Size Part number Drive sprocket 1 9383E-13144 (STD) 9383E-14215 Driven sprocket 2 1C3-25447-00 1C3-25448-00 *(STD) 1C3-25449-00 (STD) 1C3-25450-00 1C3-25451-00 1C3-25452-00 *For EUROPE and CDN EC721003 Tire pressure Tire pressure should be adjust to suit the road surface condition of the circuit.
  • Page 260 SETTING EC722011 Front fork setting The front fork setting should be made depending on the rider’s feeling of an actual run and the cir- cuit conditions. The front fork setting includes the following three factors: 1. Setting of air spring characteristics 9 Change the fork oil amount.
  • Page 261 SETTING EC727030 Spring preload adjustment The spring preload is adjusted by installing the adjustment washer 1 between the spacer 2 and fork spring 3. Do not install three or more adjustment washers for each front fork. Always adjust each front fork to the same setting.
  • Page 262 SETTING 2. Use of stiff spring Generally a stiff spring gives a stiff riding feeling. Rebound damping tends to become weaker, resulting in lack of a sense of con- tact with the road surface or in a vibrating handlebar. To set a stiff spring: 9 Change the rebound damping.
  • Page 263 SETTING EC72P010 Front fork setting parts 9 Adjustment washer 1 TYPE (thickness) PART NUMBER T=2.3 mm (0.09 in) 1C3-23364-00 9 Front fork spring 2 I.D. SPRING SPRING TYPE MARK RATE PART NUMBER (slits) 0.398 1C3-23141-00 0.408 1C3-23141-10 SOFT 0.418 1C3-23141-20 0.428 1C3-23141-30 IIII...
  • Page 264 SETTING EC72B000 Rear suspension setting The rear suspension setting should be made depending on the rider’s feeling of an actual run and the circuit conditions. The rear suspension setting includes the follow- ing two factors: 1. Setting of spring preload 9 Change the set length of the spring.
  • Page 265 SETTING NOTE: 9 If the machine is new and after it is broken in, the same set length of the spring may change because of the initial fatigue, etc. of the spring. Therefore, be sure to make re-evaluation. 9 If the standard figure cannot be achieved by adjusting the spring adjuster and changing the spring set length, replace the spring with an optional one and make re-adjustment.
  • Page 266 SETTING When using a rear cushion other than cur- rently installed, use the one whose overall length a does not exceed the standard as it may result in faulty performance. Never use one whose overall length is greater than standard. Length a of standard shock: 490.5 mm (19.31 in) å...
  • Page 267 SETTING EC72Q011 Rear shock absorber setting parts 9 Rear shock spring 1 [Equal pitch spring ] I.D. SPRING SPRING SPRING TYPE COLOR FREE RATE PART NUMBER /POINT LENGTH 5UN-22212-00 Brown/1 SOFT 5UN-22212-10 Green/1 5UN-22212-20 Red/1 5UN-22212-30 Black/1 5UN-22212-40 Blue/1 5UN-22212-50 Yellow/1 STIFF 5UN-22212-60...

  • Page 268: Suspension Setting

    SETTING EC72H010 Suspension setting 9 Front fork NOTE: 9 If any of the following symptoms is experienced with the standard position as the base, make reset- ting by reference to the adjustment procedure given in the same chart. 9 Before any change, set the rear shock absorber sunken length to the standard figure 90~100 mm (3.5~3.9 in).
  • Page 269 SETTING 9 Rear shock absorber NOTE: 9 If any of the following symptoms is experienced with the standard position as the base, make reset- ting by reference to the adjustment procedure given in the same chart. 9 Adjust the rebound damping in 2-click increments or decrements. 9 Adjust the low compression damping in 1-click increments or decrements.
  • Page 270 YAMAHA MOTOR CO., LTD. PRINTED ON RECYCLED PAPER PRINTED IN JAPAN 2004.5—2.8 × 1 ! 2500 SHINGAI IWATA SHIZUOKA JAPAN...

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