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OWNER'S SERVICE MANUAL
YZ450FT
LIT-11626-18-44
5XD-28199-11

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   Summary of Contents for Yamaha YZ450FT

  • Page 1

    OWNER’S SERVICE MANUAL YZ450FT LIT-11626-18-44 5XD-28199-11...

  • Page 3

    EC010000 YZ450FT OWNER’S SERVICE MANUAL ©2004 by Yamaha Motor Corporation, U.S.A. 1st Edition, June 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-11626-18-44...

  • Page 4

    EC020000 INTRODUCTION Congratulations on your purchase of a Yamaha YZ series. This model is the culmina- tion of Yamaha’s vast experience in the pro- duction of pacesetting racing machines. It represents the highest grade of craftsmanship and reliability that have made Yamaha a leader.

  • Page 6: Important Notice

    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 regula- tions before riding.

  • Page 7

    6. GASOLINE CAN CAUSE INJURY. If you should swallow some gasoline, inhale excess gasoline vapors, or allow any gasoline to get into your eyes, contact a doctor immediately. If any gasoline spills onto your skin or clothing, immediately wash skin areas with soap and water, and change your clothes.

  • Page 8

    If you have any questions regarding the operation or maintenance of your machine, please consult your Yamaha dealer. NOTE: This manual should be considered a perma- nent part of this machine and should remain with it even if the machine is subsequently sold.

  • Page 9: General

    EC080000 HOW TO USE THIS MANUAL EC081000 PARTICULARLY IMPORTANT INFORMATION The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY INVOLVED! WARNING 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., •...

  • Page 11: Regular

    ILLUSTRATED SYMBOLS (Refer to the illustration) SPEC Illustrated symbols 1 to 7 are designed as INFO thumb tabs to indicate the chapter’s number and content. INSP 1 General information 2 Specifications 3 Regular inspection and adjustments 4 Engine 5 Chassis 6 Electrical –...

  • Page 12

    EC090000 INDEX GENERAL INFORMATION INFO SPECIFICATIONS SPEC REGULAR INSPECTION AND INSP ADJUSTMENTS ENGINE CHASSIS CHAS – ELECTRICAL ELEC TUNING...

  • Page 13: Chassis

    EC0A0000 CONTENTS CHAPTER 1 GENERAL INFORMATION DESCRIPTION ...........1-1 MACHINE IDENTIFICATION .....1-2 IMPORTANT INFORMATION ....1-3 CHECKING OF CONNECTION ....1-6 SPECIAL TOOLS ........1-7 CONTROL FUNCTIONS ......1-10 FUEL ............1-13 STARTING AND BREAK-IN ....1-14 TORQUE-CHECK POINTS ......1-18 CLEANING AND STORAGE ....1-19 CHAPTER 2 SPECIFICATIONS GENERAL SPECIFICATIONS ....2-1 MAINTENANCE SPECIFICATIONS ..2-4 GENERAL TORQUE...

  • Page 14: Table Of Contents

    CHAPTER 4 ENGINE SEAT, FUEL TANK AND SIDE COVERS ........4-1 EXHAUST PIPE AND SILENCER .....4-3 RADIATOR ..........4-5 CARBURETOR ..........4-8 CAMSHAFTS ...........4-21 CYLINDER HEAD ........4-29 VALVES AND VALVE SPRINGS ....4-33 CYLINDER AND PISTON ......4-42 CLUTCH ...........4-48 OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) ..4-55 BALANCER ..........4-62 OIL PUMP ..........4-65 KICK AXLE AND SHIFT SHAFT .....4-69...

  • Page 15: Electrical

    CHAPTER 6 ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ......6-1 MAP-CONTROLLED CDI UNIT ....6-2 IGNITION SYSTEM ........6-3 TPS (THROTTLE POSITION SENSOR) SYSTEM .............6-7 CHAPTER 7 TUNING ENGINE ............7-1 CHASSIS ..........7-11...

  • Page 16: Description, General Information

    DESCRIPTION INFO EC100000 GENERAL INFORMATION EC110000 DESCRIPTION NOTE: 1 Clutch lever • The machine you have purchased may differ 2 Hot starter lever 3 Front brake lever slightly from those shown in the following. 4 Throttle grip • Designs and specifications are subject to 5 Radiator cap 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 number to your Yamaha dealer for positive identification 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 DISASSEMBLY 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. • Silencer exhaust port •...

  • 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 by Yamaha for assembly and adjustment. EC133000 GASKETS, OIL SEALS AND O-RINGS 1. All gaskets, oil seals, and O-rings should be replaced when an engine is overhauled.

  • 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: • 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 EC140001 SPECIAL TOOLS The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or improvised techniques. The shape and part number used for the special tool differ by country, so two types are provided.

  • Page 23

    SPECIAL TOOLS INFO Part number Tool name/How to use Illustration YU-33975, 90890-01403 Ring nut wrench YU-33975 90890-01403 This tool is used when tighten the steering ring nut to specification. YM-01442, 90890-01442 Fork seal driver YM-01442 90890-01442 This tool is used when install the fork oil seal. YM-01500, 90890-01500 Cap bolt wrench YM-01500...

  • Page 24

    YM-34487 90890-06754 90890-06754 Ignition checker This instrument is necessary for checking the ignition 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 sur- face, etc. 1 - 9...

  • Page 25: 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 han- dlebar;...

  • Page 26

    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 27

    CONTROL FUNCTIONS INFO EC15R001 DETACHABLE SIDESTAND This sidestand 1 is used to support only the machine when standing or transporting it. WARNING • Never apply additional force to the side- stand. • 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 28: Fuel

    FUEL INFO FUEL Always use the recommended fuel as stated below. Also, be sure to use new gasoline the day of a race. Recommended fuel: Premium unleaded gasoline only with a research octane number of 95 or higher. CAUTION: Use only unleaded gasoline. The use of leaded gasoline will cause severe damage to the engine internal parts such as valves, piston rings, and exhaust system, etc.

  • Page 29: Starting And Break-in

    STARTING AND BREAK-IN INFO STARTING AND BREAK-IN WARNING 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. Always operate the machine in a well-ventilated area. CAUTION: •...

  • Page 30

    STARTING AND BREAK-IN INFO 6. Return the cold starter knob to its original position and run the engine at 3,000 ~ 5,000 r/min for 1 or 2 minutes. NOTE: Since this model is equipped with an accelera- tor pump, if the engine is raced (the throttle opened and closed), the air/fuel mixture will be too rich and the engine may stall.

  • Page 31

    STARTING AND BREAK-IN INFO STARTING A WARM ENGINE Do not operate the cold starter knob and throt- tle. Pull the hot starter lever 1 and start the engine by kicking the kick starter forcefully with a firm stroke. As soon as the engine starts, release the hot starter lever to close the air passage.

  • Page 32

    STARTING AND BREAK-IN INFO BREAK-IN PROCEDURES 1. Before starting the engine, fill the fuel tank with the fuel. 2. Perform the pre-operation checks on the machine. 3. Start and warm up the engine. Check the idle speed, and check the operation of the controls and the “ENGINE STOP”...

  • Page 33: Torque-check Points

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

  • Page 34: 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 performance, and extend the life of many com- ponents. 1. Before washing the machine, block off the end of the exhaust pipe to prevent water from entering.

  • Page 35

    CLEANING AND STORAGE INFO 8. Automotive wax may be applied to all painted or chromed surfaces. Avoid combi- nation cleaner-waxes, as they may contain abrasives. 9. After completing the above, start the engine and allow it to idle for several min- utes.

  • Page 36: General Specifications

    SPEC GENERAL SPECIFICATIONS EC200000 SPECIFICATIONS EC211000 GENERAL SPECIFICATIONS Model name: YZ450FT (USA, CDN, AUS, NZ) YZ450F (EUROPE, ZA) Model code number: 5XD5 (USA) 5XD6 (EUROPE) 5XD8 (CDN, AUS, NZ, ZA) Dimensions: USA, ZA, F, CDN AUS, NZ (Except for F) ←...

  • Page 37

    SPEC GENERAL SPECIFICATIONS Oil type or grade: Engine oil (For USA and CDN) At 5 °C (40 °F) or higher È Yamalube 4 (20W-40) or SAE 20W-40 type SG motor oil (Non-Friction modified) At 15 °C (60 °F) or lower É Yamalube 4 (10W-30) or SAE 10W-30 type SG motor oil (Non-Friction modified) and/or Yamalube 4-R (15W-50) (Non-Friction modi-...

  • Page 38

    SPEC GENERAL SPECIFICATIONS Transmission: Primary reduction system Gear Primary reduction ratio 61/23 (2.652) Secondary reduction system Chain drive Secondary reduction ratio 51/14 (3.643) Transmission type Constant mesh, 4-speed Operation Left foot operation Gear ratio: 1st 27/14 (1.929) 25/16 (1.563) 23/18 (1.278) 21/20 (1.050) Chassis: Frame type...

  • Page 39: Maintenance Specifications

    SPEC MAINTENANCE SPECIFICATIONS MAINTENANCE SPECIFICATIONS ENGINE Item Standard Limit Cylinder head: Warp limit ---- 0.05 mm (0.002 in) Cylinder: Bore size 95.00 ~ 95.01 mm ---- (3.7402 ~ 3.7406 in) Out of round limit ---- 0.05 mm (0.002 in) Camshaft: Drive method Chain drive (Left) ----...

  • Page 40

    SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Cam chain: Cam chain type/No. of links 98XRH2010-118M/118 ---- Cam chain adjustment method Automatic ---- Valve, valve seat, valve guide: Valve clearance (cold) 0.10 ~ 0.15 mm ---- (0.0039 ~ 0.0059 in) 0.20 ~ 0.25 mm ---- (0.0079 ~ 0.0098 in) Valve dimensions:...

  • Page 41

    SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Valve spring: Free length 37.03 mm (1.46 in) 36.03 mm (1.42 in) 37.68 mm (1.48 in) 36.68 mm (1.44 in) Set length (valve closed) 27.87 mm (1.10 in) ---- 27.38 mm (1.08 in) ---- Compressed force (installed) 111.3 ~ 127.9 N at 27.87 mm ----...

  • Page 42

    SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Piston rings: Top ring: Type Barrel ---- Dimensions (B × T) 1.2 × 3.5 mm (0.05 × 0.14 in) ---- End gap (installed) 0.20 ~ 0.30 mm 0.55 mm (0.008 ~ 0.012 in) (0.022 in) Side clearance (installed) 0.030 ~ 0.065 mm 0.12 mm...

  • Page 43

    SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Clutch: Friction plate thickness 2.92 ~ 3.08 mm 2.8 mm (0.115 ~ 0.121 in) (0.110 in) Quantity ---- Clutch plate thickness 1.1 ~ 1.3 mm (0.043 ~ 0.051 in) ---- Quantity ---- Warp limit ---- 0.1 mm (0.004 in)

  • Page 44

    SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Lubrication system: Oil filter type Paper type ---- Oil pump type Trochoid type ---- Tip clearance “A” 0.12 mm or less 0.20 mm (0.0047 in or less) (0.008 in) Tip clearance “B” 0.09 ~ 0.17 mm 0.24 mm (0.0035 ~ 0.0067 in) (0.009 in)

  • Page 45

    SPEC MAINTENANCE SPECIFICATIONS Item Standard Lubrication chart: Pressure feed Oil tank Splashed scavenge Camshaft Cylinder head Valve lifter Piston Transmission gears Piston pin Main axle Crank pin Oil filter Drive axle Check ball Oil pump rotor 1 Oil pump rotor 2 Oil strainer Oil pan 2 - 10...

  • Page 46

    SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m·kg ft·lb M10S × 1.0 Spark plug M6 × 1.0 Camshaft cap M12 × 1.0 Cylinder head blind plug screw M6 × 1.0 Cylinder head (stud bolt) M8 × 1.25 M10 ×...

  • Page 47

    SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m·kg ft·lb Oil hose clamp — M6 × 1.0 Clutch cover M6 × 1.0 Crankcase cover (right) M6 × 1.0 Crankcase cover (left) M6 × 1.0 Crankcase M6 × 1.0 Clutch cable holder M10 ×...

  • Page 48

    SPEC MAINTENANCE SPECIFICATIONS EC212201 CHASSIS Item Standard Limit Steering system: Steering bearing type Taper roller bearing ---- Front suspension: USA, CDN, EUROPE AUS, NZ, ZA 300 mm (11.8 in) ← Front fork travel ---- 465 mm (18.3 in) ← Fork spring free length 460 mm (18.1 in) Spring rate, STD K = 4.5 N/mm...

  • Page 49

    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) Lateral ---- 2.0 mm (0.08 in)

  • Page 50

    SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m·kg ft·lb M8 × 1.25 Handle crown and outer tube M8 × 1.25 Under bracket and outer tube M24 × 1.0 Handle crown and steering shaft 14.5 M8 × 1.25 Handlebar holder (upper) M28 ×...

  • Page 51

    SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q’ty m·kg ft·lb M20 × 1.5 Rear wheel axle and nut 12.5 M8 × 1.25 Driven sprocket and wheel hub Nipple (spoke) — M6 × 1.0 Disc cover and rear brake caliper M6 ×...

  • Page 52

    Source coil 2 resistance (color) ---- (Black – Pink) 248 ~ 372 Ω at 20 °C (68 °F) Pickup coil resistance (color) ---- (White – Red) CDI unit-model/manufacturer 5XD-50/YAMAHA (For USA) ---- 5XD-60/YAMAHA (Except for ---- USA) Ignition coil: Model/manufacturer 5TA-10/DENSO...

  • Page 53: General Torque Specifications, Definition Of Units

    GENERAL TORQUE SPECIFICATIONS/ SPEC DEFINITION OF UNITS EC220001 GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasten- ers with standard I.S.O. pitch threads. Torque specifications for special components or assemblies are included in the applicable sec- tions of this book. To avoid warpage, tighten multi-fastener assemblies in a crisscross fash- ion, in progressive stages, until full torque is reached.

  • Page 54: Lubrication Diagrams

    SPEC LUBRICATION DIAGRAMS LUBRICATION DIAGRAMS 1 Oil delivery pipe 2 Intake camshaft 3 Exhaust camshaft 4 Oil cleaner element 5 Oil pump 6 Main axle 7 Drive axle D - D A - A 2 - 19...

  • Page 55

    SPEC LUBRICATION DIAGRAMS 1 Camshaft 2 Connecting rod 3 Oil cleaner element 4 Crankshaft 5 Main axle 6 Drive axle 7 Oil delivery pipe 2 - 20...

  • Page 56: Cable Routing Diagram

    SPEC CABLE ROUTING DIAGRAM EC240000 CABLE ROUTING DIAGRAM 1 Fuel tank breather hose F Radiator breather hose Ë Pass the cylinder head breather 2 Oil tank breather hose G CDI magneto lead hose on the outside of the radia- 3 Hot starter cable H Carburetor breather hose tor hose 1 and on the inside of 4 Radiator hose 4...

  • Page 57

    SPEC CABLE ROUTING DIAGRAM Î Fasten the “ENGINE STOP” but- Ò Make sure that the TPS coupler × Fasten the neutral switch lead, ton lead and sub wire harness to does not go outside the chassis. CDI magneto lead and radiator Ó...

  • Page 58

    SPEC CABLE ROUTING DIAGRAM Û Position the neutral switch lead, CDI magneto lead and radiator breather hose at the left of the frame. Û Í Ù Î Ï Ð Ñ Ð Ò È Ó Ø Ê × É Ö Õ Ê...

  • Page 59

    SPEC CABLE ROUTING DIAGRAM 1 CDI unit È Pass the hot starter cable and Î Insert the CDI unit band over the 2 Hot starter cable throttle cables through the cable CDI unit bracket as far as possi- 3 Throttle cable (return) guides.

  • Page 60

    SPEC CABLE ROUTING DIAGRAM 1 Master cylinder È Install the brake hose so that its 2 Brake hose holder pipe portion directs as shown 3 Brake hose and lightly touches the projec- tion on the caliper. É Pass the brake hose into the brake hose holders.

  • Page 61

    SPEC CABLE ROUTING DIAGRAM 1 Throttle cable È Fasten the “ENGINE STOP” but- 2 Fuel tank breather hose ton lead to the handlebar with 3 Clamp the plastic band. 4 Clutch cable É Pass the brake hose in front of 5 Hot starter cable the number plate.

  • Page 62: Maintenance Intervals

    If you are a doubt as to what intervals to follow in maintaining and lubricating your machine, consult your Yamaha dealer. Every...

  • Page 63

    INSP MAINTENANCE INTERVALS Every Every After Every As re- third fifth Item Remarks break-in race quired 500 km) 1,000 km) SHIFT FORK, SHIFT CAM, GUIDE BAR Inspect Inspect wear ROTOR NUT Retighten MUFFLER Inspect and retighten Clean Replace * Whichever comes first CRANK Inspect and clean CARBURETOR...

  • Page 64

    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 HOT STARTER, CLUTCH LEVER Inspect free play 3 - 3...

  • Page 65: 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. GENERAL INSPECTION AND MAINTENANCE Item Routine Page...

  • Page 66: Engine

    INSP ENGINE/COOLANT LEVEL INSPECTION EC350000 ENGINE EC351011 COOLANT LEVEL INSPECTION WARNING 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 67

    INSP COOLANT REPLACEMENT EC353011 COOLANT REPLACEMENT WARNING Do not remove the radiator cap when the engine is hot. CAUTION: Take care so that coolant does not splash on painted surfaces. If it splashes, wash it away with water. 1. Place a container under the engine. 2.

  • Page 68

    INSP RADIATOR CAP INSPECTION CAUTION: • Do not mix more than one type of ethyl- ene glycol antifreeze containing corro- sion inhibitors for aluminum engine. • Do not use water containing impurities or oil. Handling notes of coolant: The coolant is harmful so it should be han- dled with special care.

  • Page 69

    RADIATOR CAP OPENING PRESSURE INSPECTION/ INSP COOLING SYSTEM INSPECTION EC356001 RADIATOR CAP OPENING PRESSURE INSPECTION 1. Attach: • 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 70

    INSP CLUTCH ADJUSTMENT NOTE: • Do not apply pressure more than specified pressure. • Radiator should be filled fully. 4. Inspect: • Pressure Impossible to maintain the specified pres- sure for 10 seconds → Repair. • Radiator • Radiator hose joint Coolant leakage →...

  • Page 71

    THROTTLE CABLE ADJUSTMENT/ INSP THROTTLE LUBRICATION EC35A001 THROTTLE CABLE ADJUSTMENT 1. Check: • Throttle grip free play a Out of specification → Adjust. Throttle grip free play a: 3 ~ 5 mm (0.12 ~ 0.20 in) 2. Adjust: • Throttle grip free play Throttle grip free play adjustment steps: •...

  • Page 72

    HOT STARTER LEVER ADJUSTMENT/ INSP AIR FILTER CLEANING HOT STARTER LEVER ADJUSTMENT 1. Check: • Hot starter lever free play a Out of specification → Adjust. Hot starter lever free play a: 3 ~ 6 mm (0.12 ~ 0.24 in) 2.

  • Page 73

    INSP AIR FILTER CLEANING 2. Clean: • Air filter element Clean them with solvent. NOTE: After cleaning, remove the remaining solvent by squeezing the element. CAUTION: • Do not twist the element when squeezing the element. • Leaving too much of solvent in the ele- ment may result in poor starting.

  • Page 74

    INSP ENGINE OIL LEVEL INSPECTION 7. Install: • Air filter element 1 • Washer • Fitting bolt 2 Nm (0.2 m · kg, 1.4 ft · lb) NOTE: Align the projection a on filter guide with the hole b in air filter case. ENGINE OIL LEVEL INSPECTION 1.

  • Page 75

    INSP ENGINE OIL LEVEL INSPECTION 4. Inspect: • Oil level Oil level should be between maximum a and minimum b marks. Oil level low → Add oil to proper level. NOTE: When inspecting the oil level, do not screw the oil level gauge into the oil tank.

  • Page 76

    INSP ENGINE OIL REPLACEMENT 5. Start the engine and let it warm up for sev- eral minutes. CAUTION: When the oil tank is empty, never start the engine. 6. Idle the engine more than 10 seconds while keeping the machine upright. Then stop the engine and add the oil to the maxi- mum level.

  • Page 77: Engine Oil Replacement

    INSP ENGINE OIL REPLACEMENT 6. If the oil filter is to be replaced during this oil change, remove the following parts and reinstall them. Replacement steps: • Remove the oil filter cover 1 and oil filter element 2. • Check the O-rings 3, if cracked or dam- aged, replace them with a new one.

  • Page 78

    INSP PILOT SCREW ADJUSTMENT 10. Install: • Oil filler plug 11. Inspect: • Engine (for oil leaks) • Oil level Refer to “ENGINE OIL LEVEL INSPEC- TION”. 12. Check: • Oil pressure Checking steps: • Slightly loosen the oil gallery bolt 1. •...

  • Page 79

    IDLE SPEED ADJUSTMENT/ INSP VALVE CLEARANCE ADJUSTMENT EC35M021 IDLE SPEED ADJUSTMENT 1. Start the engine and thoroughly warm it up. 2. Adjust: • Idle speed Adjustment steps: • Adjust the pilot screw. Refer to “PILOT SCREW ADJUSTMENT” section. • Turn the throttle stop screw 1 until the specified engine idling speed.

  • Page 80

    INSP VALVE CLEARANCE ADJUSTMENT 3. Remove: • Timing plug 1 • Straight plug 2 • O-ring 4. Check: • Valve clearance Out of specification → Adjust. Valve clearance (cold): Intake valve: 0.10 ~ 0.15 mm (0.0039 ~ 0.0059 in) Exhaust valve: 0.20 ~ 0.25 mm (0.0079 ~ 0.0098 in) Checking steps:...

  • Page 81

    INSP VALVE CLEARANCE ADJUSTMENT 5. Adjust: • Valve clearance Adjustment steps: • Loosen the timing chain tensioner cap bolt. • Remove the timing chain tensioner and camshaft caps. NOTE: Remove the camshaft cap bolts in a criss- cross pattern from the outside working inwards.

  • Page 82

    INSP VALVE CLEARANCE ADJUSTMENT • Round off the last digit of the installed pad number to the nearest increment. Last digit of pad Rounded value number 0, 1 or 2 4, 5 or 6 8 or 9 EXAMPLE: Installed pad number = 148 Rounded off value = 150 NOTE: Pads can only be selected in 0.05 mm incre-...

  • Page 83

    INSP VALVE CLEARANCE ADJUSTMENT • Install the timing chain tensioner. Refer to “CAMSHAFTS” section in the CHAPTER 4. NOTE: Turn the crankshaft counterclockwise sev- eral turns so that the installed parts settle into the right position. • Recheck the valve clearance. •...

  • Page 84: Valve Clearance Adjustment

    INSP VALVE CLEARANCE ADJUSTMENT INTAKE INSTALLED PAD NUMBER MEASURED CLEARANCE 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240 0.00 ~ 0.04 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 0.05 ~ 0.09 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 0.10 ~ 0.15...

  • Page 85

    INSP CHASSIS/BRAKE SYSTEM AIR BLEEDING EC360000 CHASSIS EC361012 BRAKE SYSTEM AIR BLEEDING WARNING Bleed the brake system if: • The system has been disassembled. • A brake hose has been loosened or removed. • The brake fluid is very low. •...

  • Page 86

    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 disap- peared. Add brake fluid to the level line on the reservoir.

  • Page 87: Rear Brake Adjustment

    REAR BRAKE ADJUSTMENT/ INSP FRONT BRAKE PAD INSPECTION AND REPLACEMENT EC364002 REAR BRAKE ADJUSTMENT 1. Check: • Brake pedal height a Out of specification → Adjust. Brake pedal height a: 5 mm (0.20 in) 2. Adjust: • Brake pedal height Pedal height adjustment steps: •...

  • Page 88

    INSP FRONT BRAKE PAD INSPECTION AND REPLACEMENT • Loosen the pad pin 2. • Remove the caliper 3 from the front fork. • Remove the pad pin and brake pads 4. • Connect the transparent hose 5 to the bleed screw 6 and place the suitable con- tainer under its end.

  • Page 89

    INSP REAR BRAKE PAD INSPECTION AND REPLACEMENT • Install the pad pin plug 0. Pad pin plug: 3 Nm (0.3 m • kg, 2.2 ft • lb) 3. Inspect: • Brake fluid level Refer to “BRAKE FLUID LEVEL INSPEC- TION” section. 4.

  • Page 90

    INSP REAR BRAKE PAD INSPECTION AND REPLACEMENT • Remove the pad pin 6 and brake pads 7. • Connect the transparent hose 8 to the bleed screw 9 and place the suitable con- tainer under its end. • Loosen the bleed screw and push the cali- per piston in.

  • Page 91

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

  • Page 92

    INSP SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION EC368000 SPROCKETS INSPECTION 1. Inspect: • Sprocket teeth a Excessive wear → Replace. NOTE: Replace the drive, driven sprockets and drive chain as a set. DRIVE CHAIN INSPECTION 1. Measure: • Drive chain length (15 links) a Out of specification →...

  • Page 93

    INSP DRIVE CHAIN SLACK ADJUSTMENT 4. Check: • Drive chain stiffness a Clean and oil the chain and hold as illus- trated. Stiff → Replace drive chain. 5. Install: • Drive chain 1 • Joint 2 • Master link clip 3 CAUTION: Be sure to install the master link clip to the direction as shown.

  • Page 94

    INSP FRONT FORK INSPECTION 3. Adjust: • Drive chain slack Drive chain slack adjustment steps: • Loosen the axle nut 1 and locknuts 2. • Adjust chain slack by turning the adjusters To tighten →Turn adjuster 3 counter- clockwise. To loosen → Turn adjuster 3 clockwise and push wheel forward.

  • Page 95

    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: • Protector • Dust seal 1 NOTE: Use a thin screw driver, and be careful not to damage the inner fork tube and dust seal.

  • Page 96

    FRONT FORK COMPRESSION DAMPING FORCE INSP ADJUSTMENT Extent of adjustment: Maximum Minimum Fully turned in 20 clicks out (from position maximum position) • STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position.

  • Page 97: Rear Shock Absorber Inspection

    INSP REAR SHOCK ABSORBER INSPECTION Extent of adjustment: Maximum Minimum 20 clicks out Fully turned in (from maximum position position) • STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position.

  • Page 98

    REAR SHOCK ABSORBER SPRING PRELOAD INSP ADJUSTMENT REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT 1. Elevate the rear wheel by placing the suit- able stand under the engine. 2. Remove: • Rear frame 3. Loosen: • Locknut 1 4. Adjust: • Spring preload By turning the adjuster 2.

  • Page 99: Rear Shock Absorber Rebound Damping Force Adjustment

    REAR SHOCK ABSORBER REBOUND INSP DAMPING FORCE ADJUSTMENT EC36N014 REAR SHOCK ABSORBER REBOUND DAMPING FORCE ADJUSTMENT 1. Adjust: • Rebound damping force By turning the adjuster 1. Stiffer a → Increase the rebound damp- ing force. (Turn the adjuster 1 in.) Softer b →...

  • Page 100

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

  • Page 101

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

  • Page 102

    TIRE PRESSURE CHECK/SPOKES INSPECTION AND INSP TIGHTENING/WHEEL INSPECTION EC36Q000 TIRE PRESSURE CHECK 1. Measure: • Tire pressure Out of specification → Adjust. Standard tire pressure: 100 kPa (1.0 kgf/cm , 15 psi) NOTE: • Check the tire while it is cold. •...

  • Page 103

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

  • Page 104

    INSP STEERING HEAD INSPECTION AND ADJUSTMENT • Tighten the ring nut 3 using ring nut wrench 4. NOTE: • Apply the lithium soap base grease on the thread of the steering shaft. • Set the torque wrench to the ring nut wrench so that they form a right angle.

  • Page 105

    INSP STEERING HEAD INSPECTION AND ADJUSTMENT Steering shaft nut: 145 Nm (14.5 m • kg, 105 ft • lb) Handlebar upper holder: 28 Nm (2.8 m • kg, 20 ft • lb) Pinch bolt (handle crown): 23 Nm (2.3 m • kg, 17 ft • lb) Number plate: 7 Nm (0.7 m •...

  • Page 106

    INSP LUBRICATION LUBRICATION È Use Yamaha cable lube or equivalent on these To ensure smooth operation of all compo- areas. nents, lubricate your machine during setup, É Use SAE 10W-30 motor oil or suitable chain after break-in, and after every race.

  • Page 107

    INSP ELECTRICAL/SPARK PLUG INSPECTION EC370000 ELECTRICAL EC371001 SPARK PLUG INSPECTION 1. Remove: • Spark plug 2. Inspect: • Electrode 1 Wear/damage → Replace. • Insulator color 2 Normal condition is a medium to light tan color. Distinctly different color → Check the engine condition.

  • Page 108

    INSP IGNITION TIMING CHECK IGNITION TIMING CHECK 1. Remove: • Timing plug 1 2. Attach: • Timing light To the ignition coil lead (orange lead 1). Timing light: YM-33277-A/90890-03141 3. Adjust: • Engine idling speed Refer to “IDLE SPEED ADJUSTMENT”. 4.

  • Page 109

    SEAT, FUEL TANK AND SIDE COVERS EC400000 ENGINE EC4R0000 SEAT, FUEL TANK AND SIDE COVERS 1 Seat removal 2 Fuel tank removal Extent of removal: 3 Side covers removal 4 Number plate removal Extent of removal Order Part name Q’ty Remarks SEAT, FUEL TANK AND SIDE COVERS REMOVAL...

  • Page 110

    SEAT, FUEL TANK AND SIDE COVERS REMOVAL POINTS Side cover 1. Remove: • Bolt (side cover) • Side cover (left) 1 • Side cover (right) 2 NOTE: Draw the side cover downward to remove it because its claws a are inserted in the air fil- ter case.

  • Page 111: Exhaust Pipe And Silencer

    EXHAUST PIPE AND SILENCER EC4S0000 EXHAUST PIPE AND SILENCER È Except for USA 1 Silencer removal 2 Exhaust pipe removal Extent of removal: Extent of removal Order Part name Q’ty Remarks EXHAUST PIPE AND SILENCER REMOVAL Preparation for removal Side cover (right) Refer to “SEAT, FUEL TANK AND SIDE COVERS”...

  • Page 112

    EXHAUST PIPE AND SILENCER INSPECTION Exhaust pipe and silencer 1. Inspect: • Gasket 1 Damage → Replace. ASSEMBLY AND INSTALLATION Exhaust pipe and silencer 1. Install: • Gasket • Exhaust pipe 1 • Nut (exhaust pipe) 2 13 Nm (1.3 m · kg, 9.4 ft · lb) •...

  • Page 113

    RADIATOR EC450001 RADIATOR 1 Radiator removal Extent of removal: Extent of removal Order Part name Q’ty Remarks RADIATOR REMOVAL Preparation for removal Drain the coolant. Refer to “COOLANT REPLACEMENT” section in the CHAPTER 3. Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE COVERS”...

  • Page 114

    RADIATOR EC456000 HANDLING NOTE WARNING 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 radi- ator cap by the following procedure: Place a thick rag, like a towel, over the radi- ator cap, slowly rotate the cap counter-...

  • Page 115

    RADIATOR 3. Install: • Radiator breather hose 1 • Radiator (right) 2 10 Nm (1.0 m · kg, 7.2 ft · lb) Refer to “CABLE ROUTING DIAGRAM” section in the CHAPTER 2. 4. Install: • Panel 1 • Bolt (radiator panel upper) 2 10 Nm (1.0 m ·...

  • Page 116

    CARBURETOR CARBURETOR 4 Nm (0.4 m kg, 2.9 ft • • 2 Nm (0.2 m kg, 1.4 ft • • 11 Nm (1.1 m kg, 8.0 ft • • 4 Nm (0.4 m kg, 2.9 ft • • 3 Nm (0.3 m kg, 2.2 ft •...

  • Page 117

    CARBURETOR CARBURETOR DISASSEMBLY 1 Carburetor disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks CARBURETOR DISASSEMBLY Breather hose Valve lever housing cover Screw (throttle shaft) Throttle valve Needle holder Jet needle Cover Spring Diaphragm (accelerator pump) Float chamber Leak jet Pilot screw Refer to “REMOVAL POINTS”.

  • Page 118

    CARBURETOR Extent of removal Order Part name Q’ty Remarks Main jet Needle jet Spacer Pilot jet Starter jet Push rod Pull the push rod. Throttle shaft assembly Push rod link lever assembly Pilot air jet Cold starter plunger 4 - 10...

  • Page 119

    CARBURETOR EC466020 HANDLING NOTE CAUTION: Do not loosen the screws {TPS (throttle position sensor)} 1 except when changing the TPS (throttle position sensor) due to failure because it will cause a drop in engine performance. REMOVAL POINTS Pilot screw 1. Remove: •...

  • Page 120

    CARBURETOR 2. Inspect: • Main jet 1 • Pilot jet 2 • Needle jet 3 • Starter jet 4 • Pilot air jet 5 • Leak jet 6 Damage → Replace. Contamination → Clean. NOTE: • Use a petroleum based solvent for cleaning. Blow out all passages and jets with com- pressed air.

  • Page 121

    CARBURETOR EC464511 Float height 1. Measure: • Float height a Out of specification → Adjust. Float height: 8.0 mm (0.31 in) Measurement and adjustment steps: • Hold the carburetor in an upside down position. NOTE: • Slowly tilt the carburetor in the opposite direction, then take the measurement when the needle valve aligns with the float arm.

  • Page 122

    CARBURETOR Starter plunger 1. Inspect: • Cold starter plunger 1 • Hot starter plunger 2 Wear/damage → Replace. Accelerator pump 1. Inspect: • Diaphragm (accelerator pump) 1 • Spring 2 • Cover 3 • O-ring 4 • Push rod 5 Tears (diaphragm)/damage →...

  • Page 123

    CARBURETOR 3. Install: • Spring 1 1 • Lever 1 2 To lever 2 3. NOTE: Make sure the spring 1 fits on the stopper a of the lever 2. 4. Install: • Spring 2 1 To lever 2 2. 5.

  • Page 124

    CARBURETOR 8. Install: • Throttle shaft assembly 1 • Plain washer (metal) 2 • Plain washer (resin) 3 • Valve lever 4 NOTE: • Apply the fluorochemical grease on the bear- ings. • Fit the projection a on the throttle shaft assembly into the slot b in the TPS (throttle position sensor).

  • Page 125

    CARBURETOR 11. Install: • Needle valve 1 • Float 2 • Float pin 3 NOTE: • After installing the needle valve to the float, install them to the carburetor. • Check the float for smooth movement. 12. Install: • Pilot screw 1 •...

  • Page 126

    CARBURETOR 14. Install: • Diaphragm (accelerator pump) 1 • Spring 2 • O-ring 3 • Cover 4 • Hose holder (drain hose) 5 • Screw (cover) 6 NOTE: Install the diaphragm (accelerator pump) with its mark a facing the spring. 15.

  • Page 127

    CARBURETOR Accelerator pump timing adjustment Adjustment steps: NOTE: In order for the throttle valve height a to achieve the specified value, tuck under the throttle valve plate 1 the rod 2 etc. with the same outer diameter as the specified value. Throttle valve height: 1.30 mm (0.051 in) •...

  • Page 128

    CARBURETOR 4. Tighten: • Screw (air cleaner joint) 1 3 Nm (0.3 m · kg, 2.2 ft · lb) • Screw (carburetor joint) 2 3 Nm (0.3 m · kg, 2.2 ft · lb) 5. Install: • Throttle cable (pull) 1 4 Nm (0.4 m ·...

  • Page 129

    CAMSHAFTS CAMSHAFTS CYLINDER HEAD COVER 1 Cylinder head cover removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CYLINDER HEAD COVER REMOVAL Preparation for removal Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE COVERS” section. Carburetor Refer to “CARBURETOR”...

  • Page 130

    CAMSHAFTS CAMSHAFTS 1 Camshaft removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CAMSHAFTS REMOVAL Timing plug Straight plug Tensioner cap bolt Timing chain tensioner Gasket Refer to “REMOVAL POINTS”. Bolt (camshaft cap) Camshaft cap Clip Exhaust camshaft Intake camshaft 4 - 22...

  • Page 131

    CAMSHAFTS REMOVAL POINTS Camshaft 1. Remove: • Timing plug 1 • Straight plug 2 2. Align: • “I” mark With stationary pointer. Checking steps: • Turn the crankshaft counterclockwise with a wrench. • Align the “I” mark a on the rotor with the stationary pointer b on the crankcase cover.

  • Page 132

    CAMSHAFTS 6. Remove: • Clips • Exhaust camshaft 1 • Intake camshaft 2 NOTE: Attach a wire 3 to the timing chain to prevent it from falling into the crankcase. INSPECTION Camshaft 1. Inspect: • Cam lobes Pitting/scratches/blue discoloration → Replace.

  • Page 133

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

  • Page 134

    CAMSHAFTS Decompression system 1. Check: • Decompression system Checking steps: • Check that the decompressor cam 1 moves smoothly. • Check that the decompressor lever pin 2 projects from the camshaft. Timing chain tensioner 1. Check: • While pressing the tensioner rod lightly with fingers, use a thin screwdriver 1 and wind the tensioner rod up fully clock- wise.

  • Page 135

    CAMSHAFTS • Fit the timing chain 3 onto both camshaft sprockets and install the camshafts on the cylinder head. NOTE: The camshafts should be installed onto the cylinder head so that the exhaust cam sprocket punch mark c and the intake cam sprocket punch mark d align with the sur- face of the cylinder head.

  • Page 136

    CAMSHAFTS • With the rod fully wound and the chain ten- sioner UP mark a facing upward, install the gasket 1 and the chain tensioner 2, and tighten the bolt 3 to the specified torque. Bolt (timing chain tensioner): 10 Nm (1.0 m • kg, 7.2 ft • lb) •...

  • Page 137: Cylinder Head

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

  • Page 138

    CYLINDER HEAD INSPECTION Cylinder head 1. Eliminate: • Carbon deposits (from the combustion chambers) Use a rounded scraper. NOTE: Do not use a sharp instrument to avoid damag- ing or scratching: • Spark plug threads • Valve seats 2. Inspect: •...

  • Page 139

    CYLINDER HEAD ASSEMBLY AND INSTALLATION 1. Install: • Timing chain guide (front) 1 • Dowel pin 2 • Cylinder head gasket 3 • Cylinder head 4 NOTE: While pulling up the timing chain, install the timing chain guide (front) and cylinder head. 2.

  • Page 140

    CYLINDER HEAD • Remove the bolts. • Again apply the molybdenum disulfide grease on the threads and contact sur- faces of the bolts and on both contact sur- faces of the plain washers. • Retighten the bolts. NOTE: Tighten the bolts to the specified torque in two or three steps in the proper tightening sequence as shown.

  • Page 141: Valves And Valve Springs

    VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS 1 Valve removal Extent of removal: Extent of removal Order Part name Q’ty Remarks VALVES AND VALVE SPRINGS REMOVAL Preparation for removal Cylinder head Refer to “CYLINDER HEAD” section. Valve lifter Use special tool.

  • Page 142

    VALVES AND VALVE SPRINGS REMOVAL POINTS Valve lifter and valve cotter 1. Remove: • Valve lifters 1 • Pads 2 NOTE: Identify each lifter 1 and pad 2 position very carefully so that they can be reinstalled in their original place. 2.

  • Page 143

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

  • Page 144

    VALVES AND VALVE SPRINGS Valve guide remover: Intake: 4.5 mm (0.18 in) YM-4116/90890-04116 Exhaust: 5.0 mm (0.20 in) YM-4097/90890-04097 Valve guide installer: Intake: YM-4117/90890-04117 Exhaust: YM-4098/90890-04098 Valve guide reamer: Intake: 4.5 mm (0.18 in) YM-4118/90890-04118 Exhaust: 5.0 mm (0.20 in) YM-4099/90890-04099 NOTE: After replacing the valve guide reface the...

  • Page 145

    VALVES AND VALVE SPRINGS 5. Measure: • Runout (valve stem) Out of specification → Replace. Runout limit: 0.01 mm (0.0004 in) NOTE: • When installing a new valve always replace the guide. • If the valve is removed or replaced always replace the oil seal.

  • Page 146

    VALVES AND VALVE SPRINGS 9. Lap: • Valve face • Valve seat NOTE: After refacing the valve seat or replacing the valve and valve guide, the valve seat and valve face should be lapped. Lapping steps: • Apply a coarse lapping compound to the valve face.

  • Page 147

    VALVES AND VALVE SPRINGS Valve spring 1. Measure: • Valve spring free length a Out of specification → Replace. Free length (valve spring): Intake: 37.03 mm (1.46 in) <Limit>: 36.03 mm (1.42 in) Exhaust: 37.68 mm (1.48 in) <Limit>: 36.68 mm (1.44 in) 2.

  • Page 148

    VALVES AND VALVE SPRINGS ASSEMBLY AND INSTALLATION 1. Apply: • Molybdenum disulfide oil Onto the valve stem and valve stem seal. 2. Install: • Valves 1 • Valve spring seats 2 • Valve stem seals 3 • Valve springs 4 •...

  • Page 149

    VALVES AND VALVE SPRINGS 5. Install: • Adjusting pad 1 • Valve lifter 2 NOTE: • Apply the engine oil on the valve lifters. • Apply the molybdenum disulfide oil on the valve stem end. • Valve lifter must turn smoothly when rotated with a finger.

  • Page 150: Cylinder And Piston

    CYLINDER AND PISTON CYLINDER AND PISTON CYLINDER AND PISTON 1 Cylinder removal 2 Piston removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CYLINDER AND PISTON REMOVAL Preparation for removal Cylinder head Refer to “CYLINDER HEAD” section. Bolt (cylinder) Cylinder Gasket...

  • Page 151

    CYLINDER AND PISTON REMOVAL POINTS Piston 1. Remove: • Piston pin clips 1 • Piston pin 2 • Piston 3 NOTE: • Put identification marks on each piston head for reference during reinstallation. • Before removing each piston pin, deburr the clip groove and pin hole area.

  • Page 152

    CYLINDER AND PISTON 95.00 ~ 95.01 mm Cylinder bore “C” (3.7402 ~ 3.7406 in) Taper limit “T” 0.05 mm (0.002 in) Out of round “R” 0.05 mm (0.002 in) “C” = Maximum D “T” = (Maximum D or D – (Maximum D or D “R”...

  • Page 153

    CYLINDER AND PISTON Piston ring 1. Measure: • Ring side clearance Use a feeler gauge 1. Out of specification → Replace the piston and rings as a set. NOTE: Clean carbon from the piston ring grooves and rings before measuring the side clearance. Side clearance: Standard <Limit>...

  • Page 154

    CYLINDER AND PISTON Piston pin 1. Inspect: • Piston pin Blue discoloration/grooves → Replace, then inspect the lubrication system. 2. Measure: • Piston pin-to-piston clearance Measurement steps: • Measure the outside diameter (piston pin) If out of specification, replace the piston pin.

  • Page 155

    CYLINDER AND PISTON 2. Position: • Top ring • 2nd ring • Oil ring Offset the piston ring end gaps as shown. a Top ring end b 2nd ring end c Oil ring end (upper) d Oil ring e Oil ring end (lower) 3.

  • Page 156

    CLUTCH CLUTCH CLUTCH 1 Push rod and push lever removal 2 Push pod 1 disassembly Extent of removal: 3 Friction plate and clutch plate removal 4 Clutch housing removal Extent of removal Order Part name Q’ty Remarks CLUTCH REMOVAL Preparation for removal Drain the engine oil.

  • Page 157

    CLUTCH Extent of removal Order Part name Q’ty Remarks Clutch plate Friction plate Use special tool. Look washer Refer to “REMOVAL POINTS”. Clutch boss Thrust washer Clutch housing Push lever 4 - 49...

  • Page 158

    CLUTCH EC493000 REMOVAL POINTS EC483211 Clutch boss 1. Remove: • Nut 1 • Lock washer 2 • Clutch boss 3 NOTE: Straighten the lock washer tab and use the clutch holding tool 4 to hold the clutch boss. È É Clutch holding tool: YM-91042/90890-04086 È...

  • Page 159

    CLUTCH EC484500 Friction plate 1. Measure: • Friction plate thickness Out of specification → Replace friction plate as a set. Measure at all four points. Friction plate thickness: 2.92 ~ 3.08 mm (0.115 ~ 0.121 in) <Limit>: 2.8 mm (0.110 in) EC484600 Clutch plate 1.

  • Page 160

    CLUTCH EC4A5000 ASSEMBLY AND INSTALLATION Push lever 1. Install: • Push lever 1 • Bolt (push lever) 10 Nm (1.0 m · kg, 7.2 ft · lb) NOTE: • Apply the lithium soap base grease on the oil seal lip. •...

  • Page 161

    CLUTCH 3. Bend the lock washer 1 tab. 4. Install: • Friction plate 1 • Clutch plate 2 NOTE: • Install the clutch plates and friction plates alternately on the clutch boss, starting with a friction plate and ending with a friction plate. •...

  • Page 162

    CLUTCH 7. Install: • Pressure plate 1 8. Install: • Clutch spring • Bolt (clutch spring) 8 Nm (0.8 m · kg, 5.8 ft · lb) NOTE: Tighten the bolts in stage, using a crisscross pattern. 9. Install: • Gasket (clutch cover) 1 •...

  • Page 163

    OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) 1 Oil filter removal 2 Water pump removal Extent of removal: 3 Crankcase cover (right) removal Extent of removal Order Part name...

  • Page 164

    OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) Extent of removal Order Part name Q’ty Remarks Oil hose Kick starter Crankcase cover (right) Gasket Dowel pin/O-ring Impeller Plain washer Impeller shaft Refer to “REMOVAL POINTS”. Oil seal 1 Oil seal 2 Bearing 4 - 56...

  • Page 165

    OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) REMOVAL POINTS EC4G3110 Impeller shaft 1. Remove: • Impeller 1 • Plain washer 2 • Impeller shaft 3 NOTE: Hold the impeller shaft on its width across the flats a with spanners, etc. and remove the impeller.

  • Page 166

    OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) EC4H4600 Bearing 1. Inspect: • Bearing Rotate inner race with a finger. Rough spot/seizure → Replace. EC444400 Oil seal 1. Inspect: • Oil seal Wear/damage → Replace. ASSEMBLY AND INSTALLATION EC4G5110 Oil seal 1.

  • Page 167

    OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) EC4G5220 Impeller shaft 1. Install: • Impeller shaft 1 • Plain washer 2 • Impeller 3 14 Nm (1.4 m · kg, 10 ft · lb) NOTE: • Take care so that the oil seal lip is not dam- aged or the spring does not slip off its posi- tion.

  • Page 168

    OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) Kick crank 1. Install: • Kick starter 1 • Plain washer • Bolt (kick starter) 33 Nm (3.3 m · kg, 24 ft · lb) NOTE: Install the kick starter so that the kick starter is as vertical as possible with the distance a between the kick starter and the frame being 5 mm (0.20 in) or more.

  • Page 169

    OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT) 2. Install: • Water pump housing 1 • Bolt (water pump housing) 2 10 Nm (1.0 m · kg, 7.2 ft · lb) • Plain washer 3 • Coolant drain bolt 4 10 Nm (1.0 m ·...

  • Page 170

    BALANCER BALANCER BALANCER 1 Balancer drive gear 2 Balancer Extent of removal: Extent of removal Order Part name Q’ty Remarks BALANCER REMOVAL Preparation for removal Clutch housing Refer to “CLUTCH” section. Crankcase cover (right) Refer to “OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)”...

  • Page 171

    BALANCER REMOVAL POINTS Balancer drive gear and balancer driven gear 1. Straighten the lock washer tab. 2. Loosen: • Nut (primary drive gear) 1 • Nut (balancer) 2 NOTE: Place an aluminum plate a between the teeth of the balancer drive gear 3 and driven gear Balancer 1.

  • Page 172

    BALANCER ASSEMBLY AND INSTALLATION Balancer, balancer drive gear and balancer driven gear 1. Install: • Balancer 1 NOTE: When installing the balancer shaft, align the center of the balancer shaft weight a along the line connecting the centers of the crank- shaft and balancer shaft.

  • Page 173: Oil Pump

    OIL PUMP OIL PUMP OIL PUMP 1 Oil pump removal 2 Oil pump disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks OIL PUMP REMOVAL AND DIS- ASSEMBLY Preparation for removal Clutch housing Refer to “CLUTCH” section. Crankcase cover (right) Refer to “OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)”...

  • Page 174

    OIL PUMP Extent of removal Order Part name Q’ty Remarks Washer Oil pump drive shaft Rotor housing 4 - 66...

  • Page 175

    OIL PUMP INSPECTION Oil pump 1. Inspect: • Oil pump drive gear • Oil pump driven gear • Rotor housing • Oil pump cover Cracks/wear/damage → Replace. 2. Measure: • Tip clearance a Between the inner rotor 1 and the outer rotor 2.

  • Page 176

    OIL PUMP 2. Install: • Outer rotor 1 1 NOTE: Apply the engine oil on the outer rotor 1. 3. Install: • Oil pump cover 1 • Screw (oil pump cover) 2 2 Nm (0.2 m · kg, 1.4 ft · lb) •...

  • Page 177: Kick Axle And Shift Shaft

    KICK AXLE AND SHIFT SHAFT KICK AXLE AND SHIFT SHAFT KICK AXLE AND SHIFT SHAFT 1 Kick axle removal 2 Kick axle disassembly Extent of removal: 3 Shift shaft removal 4 Segment removal Extent of removal Order Part name Q’ty Remarks KICK AXLE AND SHIFT SHAFT REMOVAL...

  • Page 178

    KICK AXLE AND SHIFT SHAFT Extent of removal Order Part name Q’ty Remarks Roller Shift guide Refer to “REMOVAL POINTS”. Shift lever assembly Shift lever Pawl Pawl pin Spring Bolt (stopper lever) Stopper lever Torsion spring Segment Refer to “REMOVAL POINTS”. 4 - 70...

  • Page 179

    KICK AXLE AND SHIFT SHAFT REMOVAL POINTS EC4B3101 Kick axle assembly 1. Remove: • Kick axle assembly 1 NOTE: Unhook the torsion spring 2 from the hole a in the crankcase. EC4C3101 Shift guide and shift lever assembly 1. Remove: •...

  • Page 180

    KICK AXLE AND SHIFT SHAFT EC4B4400 Shift shaft 1. Inspect: • Shift shaft 1 Bend/damage → Replace. • Spring 2 Broken → Replace. EC4C4100 Shift guide and shift lever assembly 1. Inspect: • Shift guide 1 • Shift lever 2 •...

  • Page 181

    KICK AXLE AND SHIFT SHAFT EC4B5111 Stopper lever 1. Install: • Torsion spring 1 • Stopper lever 2 • Bolt (stopper lever) 3 10 Nm (1.0 m · kg, 7.2 ft · lb) NOTE: Align the stopper lever roller with the slot on segment.

  • Page 182

    KICK AXLE AND SHIFT SHAFT EC4C5301 Shift shaft 1. Install: • Roller 1 • Collar 2 • Torsion spring 3 • Shift shaft 4 NOTE: Apply the engine oil on the roller and shift shaft. 2. Install: • Shift pedal 1 •...

  • Page 183

    KICK AXLE AND SHIFT SHAFT 3. Install: • 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. Install: • Kick axle assembly 1 •...

  • Page 184: Cdi Magneto

    CDI MAGNETO EC4L0000 CDI MAGNETO Extent of removal: CDI magneto removal Extent of removal Order Part name Q’ty Remarks CDI MAGNETO REMOVAL Preparation for removal Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE COVERS” section. Bolt [radiator (left)] Refer to “RADIATOR”...

  • Page 185

    CDI MAGNETO EC4L3000 REMOVAL POINTS EC4L3101 Rotor 1. Remove: • Nut (rotor) 1 • Plain washer Use the rotor holding tool 2. Rotor holding tool: YU-1235/90890-01235 2. Remove: • Rotor 1 Use the flywheel puller 2. Flywheel puller: YM-1189/90890-01189 NOTE: When installing the flywheel puller, turn it counterclockwise.

  • Page 186

    • Apply the sealant to the grommet of the CDI magneto lead. • Tighten the screws using the T30 bit. ® Quick gasket ACC-QUICK-GS-KT YAMAHA Bond No. 1215: 90890-85505 2. Install: • Woodruff key 1 • Rotor 2 NOTE: • Clean the tapered portions of the crankshaft and rotor.

  • Page 187

    CDI MAGNETO 4. Connect: • CDI magneto lead Refer to “CABLE ROUTING DIAGRAM” section in the CHAPTER 2. 5. Install: • Dowel pin • Gasket [crankcase cover (left)] • Crankcase cover (left) 1 • Hose holder (cylinder head breather hose) 2 •...

  • Page 188: Engine Removal

    ENGINE REMOVAL EC4M0000 ENGINE REMOVAL Extent of removal Order Part name Q’ty Remarks ENGINE REMOVAL Preparation for removal Hold the machine by placing the WARNING suitable stand under the frame. Support the machine securely so there is no danger of it falling over. Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE COVERS”...

  • Page 189

    ENGINE REMOVAL 1 Engine removal Extent of removal: Extent of removal Order Part name Q’ty Remarks Engine skid plate (front) Neutral switch Oil hose Chain cover Nut (drive sprocket) Lock washer Refer to “REMOVAL POINTS”. Drive sprocket Clip Bolt (brake pedal) Brake pedal Engine upper bracket (right) Engine upper bracket (left)

  • Page 190

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

  • Page 191

    ENGINE REMOVAL EC4M5000 ASSEMBLY AND INSTALLATION Engine installation 1. Install: • Engine 1 Install the engine from right side. • Pivot shaft 2 85 Nm (8.5 m · kg, 61 ft · lb) • Engine mounting bolt (lower) 3 69 Nm (6.9 m · kg, 50 ft · lb) •...

  • Page 192

    ENGINE REMOVAL 2. Install: • Lock washer 1 • Nut (drive sprocket) 2 75 Nm (7.5 m · kg, 54 ft · lb) NOTE: Tighten the nut while applying the rear brake. 3. Bend the lock washer tab to lock the nut. 4.

  • Page 193: Crankcase And Crankshaft

    CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT 1 Crankcase separation 2 Crankshaft removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CRANKCASE SEPARATION Preparation for removal Engine Refer to “ENGINE REMOVAL” section. Piston Refer to “CYLINDER AND PISTON” sec- tion.

  • Page 194

    CRANKCASE AND CRANKSHAFT Extent of removal Order Part name Q’ty Remarks Crankcase (right) Refer to “REMOVAL POINTS”. Crankcase (left) Oil strainer Oil delivery pipe 2 Crankshaft Use special tool. Refer to “REMOVAL POINTS”. 4 - 86...

  • Page 195

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

  • Page 196

    CRANKCASE AND CRANKSHAFT REMOVAL POINTS Crankcase 1. Separate: • Crankcase (right) • Crankcase (left) Separation steps: • Remove the crankcase bolts, hose guide and clutch cable holder. NOTE: Loosen each bolt 1/4 of a turn at a time and after all the bolts are loosened, remove them.

  • Page 197

    CRANKCASE AND CRANKSHAFT Crankshaft 1. Remove: • Crankshaft 1 Use the crankcase separating tool 2. Crankcase separating tool: YU-1135-A/90890-01135 CAUTION: Do not use a hammer to drive out the crankshaft. Crankshaft bearing 1. Remove: • Bearing 1 NOTE: • Remove the bearing from the crankcase by pressing its inner race.

  • Page 198

    CRANKCASE AND CRANKSHAFT EC4N4201 Crankshaft 1. Measure: • Runout limit a • Small end free play limit b • Connecting rod big end side clearance c • Crank width d Out of specification → Replace. Use the dial gauge and a thickness gauge.

  • Page 199

    CRANKCASE AND CRANKSHAFT EC4N5000 ASSEMBLY AND INSTALLATION Crankshaft bearing 1. Install: • Bearing • Bearing stopper • Bolt (bearing stopper) 10 Nm (1.0 m · kg, 7.2 ft · lb) • Screw (bearing stopper) 10 Nm (1.0 m · kg, 7.2 ft · lb) •...

  • Page 200

    10 Nm (1.0 m · kg, 7.2 ft · lb) 4. Apply: • 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. 4 - 92...

  • Page 201

    CRANKCASE AND CRANKSHAFT 5. Install: • Dowel pin 1 • O-ring 2 • Crankcase (right) To crankcase (left). NOTE: • Fit the crankcase (right) onto the crankcase (left). Tap lightly on the case with soft ham- mer. • When installing the crankcase, the connect- ing rod should be positioned at TDC (top dead center).

  • Page 202

    TRANSMISSION, SHIFT CAM AND SHIFT FORK TRANSMISSION, SHIFT CAM AND SHIFT FORK TRANSMISSION, SHIFT CAM AND SHIFT FORK 1 Shift fork, shift cam, main axle and drive axle removal Extent of removal: Extent of removal Order Part name Q’ty Remarks TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVAL Preparation for removal...

  • Page 203

    TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H3000 REMOVAL POINTS Shift fork, shaft cam and transmission 1. Remove: • Shift forks • Shift cam • Main axle • Drive axle NOTE: • Tap lightly on the transmission drive axle and shift cam with a soft hammer to remove. •...

  • Page 204

    TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H4801 Shift fork, shift cam and segment 1. Inspect: • Shift fork 1 Wear/damage/scratches → Replace. 2. Inspect: • Shift cam 1 • Segment 2 Bend/wear/damage → Replace. 3. Check: • Shift fork movement Unsmooth operation →...

  • Page 205

    TRANSMISSION, SHIFT CAM AND SHIFT FORK 2. Install: • 2nd wheel gear (25T) 1 • Collar 2 • 3rd wheel gear (23T) 3 • 4th wheel gear (21T) 4 • 1st wheel gear (27T) 5 • O-ring 6 To drive axle 7. NOTE: •...

  • Page 206

    TRANSMISSION, SHIFT CAM AND SHIFT FORK 5. Install: • Shift fork 1 (L) 1 • Shift fork 2 (R) 2 • Shift cam 3 To main axle and drive axle. NOTE: • Apply the molybdenum disulfide oil on the shift fork grooves. •...

  • Page 207: Front Wheel And Rear Wheel

    CHAS FRONT WHEEL AND REAR WHEEL EC500000 CHASSIS EC590000 FRONT WHEEL AND REAR WHEEL EC598000 FRONT WHEEL 1 Front wheel removal 2 Wheel bearing removal Extent of removal: 3 Brake disc removal Extent of removal Order Part name Q’ty Remarks FRONT WHEEL REMOVAL WARNING Preparation for removal...

  • Page 208

    CHAS FRONT WHEEL AND REAR WHEEL EC598100 REAR WHEEL 1 Rear wheel removal 2 Wheel bearing removal Extent of removal: 3 Brake disc removal Extent of removal Order Part name Q’ty Remarks REAR WHEEL REMOVAL WARNING Preparation for removal Hold the machine by placing the Support the machine securely so there is no suitable stand under the engine.

  • Page 209

    CHAS FRONT WHEEL AND REAR WHEEL EC593000 REMOVAL POINTS EC523101 Rear wheel 1. Remove: • Wheel 1 NOTE: Push the wheel forward and remove the drive chain 2. EC513201 Wheel bearing (if necessary) 1. Remove: • Bearing 1 NOTE: Remove the bearing using a general bearing puller 2.

  • Page 210

    CHAS FRONT WHEEL AND REAR WHEEL EC514200 Wheel axle 1. Measure: • 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 211

    CHAS FRONT WHEEL AND REAR WHEEL EC595000 ASSEMBLY AND INSTALLATION Front wheel 1. Install: • Bearing (left) 1 • Spacer 2 • Bearing (right) 3 • Oil seal 4 NOTE: • Apply the lithium soap base grease on the bearing and oil seal lip when installing. •...

  • Page 212

    CHAS FRONT WHEEL AND REAR WHEEL 5. Install: • Wheel axle 1 NOTE: Apply the lithium soap base grease on the wheel axle. 6. Install: • Nut (wheel axle) 1 105 Nm (10.5 m · kg, 75 ft · lb) 7.

  • Page 213

    CHAS FRONT WHEEL AND REAR WHEEL Rear wheel 1. Install: • Bearing (right) 1 • Circlip 2 • Spacer 3 • Bearing (left) 4 • Oil seal 5 NOTE: • Apply the lithium soap base grease on the bearing and oil seal lip when installing. •...

  • Page 214

    CHAS FRONT WHEEL AND REAR WHEEL 4. Install: • Collar 1 NOTE: Apply the lithium soap base grease on the oil seal lip. 5. Install: • Wheel NOTE: Install the brake disc 1 between the brake pads 2 correctly. 6. Install: •...

  • Page 215

    CHAS FRONT WHEEL AND REAR WHEEL 9. Adjust: • Drive chain slack a Drive chain slack: 48 ~ 58 mm (1.9 ~ 2.3 in) Refer “DRIVE CHAIN SLACK ADJUSTMENT” section in the CHAPTER 10. Tighten: • Nut (wheel axle) 1 125 Nm (12.5 m ·...

  • Page 216: Front Brake And Rear Brake

    CHAS FRONT BRAKE AND REAR BRAKE EC5A0000 FRONT BRAKE AND REAR BRAKE EC5A8000 FRONT BRAKE 1 Brake hose removal 2 Caliper removal Extent of removal: 3 Master cylinder removal Extent of removal Order Part name Q’ty Remarks FRONT BRAKE REMOVAL WARNING Preparation for removal Hold the machine by placing the...

  • Page 217

    CHAS FRONT BRAKE AND REAR BRAKE EC5A8100 REAR BRAKE 1 Master cylinder removal 2 Brake hose removal Extent of removal: 3 Caliper removal Extent of removal Order Part name Q’ty Remarks REAR BRAKE REMOVAL WARNING Preparation for removal Hold the machine by placing the Support the machine securely so there is no suitable stand under the engine.

  • Page 218

    CHAS FRONT BRAKE AND REAR BRAKE EC5A8200 CALIPER DISASSEMBLY È Front É Rear 1 Front caliper disassembly 2 Rear caliper disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks CALIPER DISASSEMBLY Pad pin Brake pad Pad support Caliper piston Dust seal Refer to “REMOVAL POINTS”.

  • Page 219

    CHAS FRONT BRAKE AND REAR BRAKE EC5A8300 MASTER CYLINDER DISASSEMBLY È Front É Rear 1 Front master cylinder disassembly 2 Rear master cylinder disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks MASTER CYLINDER DISAS- SEMBLY Master cylinder cap Diaphragm Reservoir float Master cylinder boot...

  • Page 220

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

  • Page 221

    CHAS FRONT BRAKE AND REAR BRAKE EC533402 È Piston seal kit 1. Remove: • Dust seal 1 • Piston seal 2 NOTE: Remove the piston seals and dust seals by pushing them with a finger. CAUTION: Never attempt to pry out piston seals and É...

  • Page 222

    CHAS FRONT BRAKE AND REAR BRAKE 4. Inspect: È É • Master cylinder piston 1 • Master cylinder cup 2 Wear/damage/score marks → Replace master cylinder kit. È Front É Rear EC534214 È É Caliper 1. Inspect: • Caliper cylinder inner surface a Wear/score marks →...

  • Page 223

    CHAS FRONT BRAKE AND REAR BRAKE EC5A5800 È Caliper piston 1. Clean: • Caliper • Piston seal • Dust seal • Caliper piston Clean them with brake fluid. 2. Install: • Piston seal 1 • Dust seal 2 É WARNING Always use new piston seals and dust seals.

  • Page 224

    CHAS FRONT BRAKE AND REAR BRAKE 2. Install: • Caliper 1 • Bolt (caliper) 2 23 Nm (2.3 m · kg, 17 ft · lb) 3. Tighten: • Pad pin 3 18 Nm (1.8 m · kg, 13 ft · lb) 4.

  • Page 225

    CHAS FRONT BRAKE AND REAR BRAKE 3. Install: • Caliper 1 • Rear wheel 2 Refer to “FRONT WHEEL AND REAR WHEEL” section. 4. Tighten: • Pad pin 3 18 Nm (1.8 m · kg, 13 ft · lb) 5. Install: •...

  • Page 226

    CHAS FRONT BRAKE AND REAR BRAKE 4. Install: È [Front] • Master cylinder kit 1 • Plain washer 2 • Circlip 3 • Master cylinder boot 4 To master cylinder 5. [Rear] • Master cylinder kit 1 • Push rod 2 •...

  • Page 227

    CHAS FRONT BRAKE AND REAR BRAKE 2. Install: • Brake lever 1 • Bolt (brake lever) 2 6 Nm (0.6 m · kg, 4.3 ft · lb) • Nut (brake lever) 3 6 Nm (0.6 m · kg, 4.3 ft · lb) NOTE: Apply the lithium soap base grease on the brake lever sliding surface, bolt and contacting...

  • Page 228

    CHAS FRONT BRAKE AND REAR BRAKE 4. Install: • Pin 1 • Plain washer 2 • Cotter pin 3 NOTE: After installing, check the brake pedal height. Refer to “REAR BRAKE ADJUSTMENT” sec- tion in the CHAPTER 3. Front brake hose 1.

  • Page 229

    CHAS FRONT BRAKE AND REAR BRAKE 4. Pass the brake hose through the cable guide 1. 5. Install: • Copper washer 1 • Brake hose 2 • Union bolt 3 30 Nm (3.0 m · kg, 22 ft · lb) WARNING Always use new copper washers.

  • Page 230

    CHAS FRONT BRAKE AND REAR BRAKE 2. Install: • Brake hose holder 1 • Screw (brake hose holder) 2 1 Nm (0.1 m · kg, 0.7 ft · lb) CAUTION: After installing the brake hose holders, make sure the brake hose does not contact the spring (rear shock absorber).

  • Page 231

    CHAS FRONT BRAKE AND REAR BRAKE 2. Air bleed: • Brake system Refer to “BRAKE SYSTEM AIR BLEED- ING” section in the CHAPTER 3. 3. Inspect: • Brake fluid level Fluid at lower level → Fill up. Refer to “BRAKE FLUID LEVEL INSPEC- TION”...

  • Page 232: Front Fork

    CHAS FRONT FORK EC550000 FRONT FORK 1 Front fork removal Extent of removal: Extent of removal Order Part name Q’ty Remarks FRONT FORK REMOVAL WARNING Preparation for removal Hold the machine by placing the Support the machine securely so there is no suitable stand under the engine.

  • Page 233

    CHAS FRONT FORK EC558000 FRONT FORK DISASSEMBLY 1 Oil seal removal 2 Damper assembly removal Extent of removal: Extent of removal Order Part name Q’ty Remarks FRONT FORK DISASSEMBLY Adjuster Drain the fork oil. Use special tool. Refer to “REMOVAL POINTS”. Fork spring Dust seal Stopper ring...

  • Page 234

    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. CAUTION: To prevent an accidental explosion of air, following instructions should observed: • The front fork with a built-in piston rod has a very sophisticated internal con- struction and is particularly sensitive to foreign material.

  • Page 235

    CHAS FRONT FORK Adjuster 1. Drain the outer tube of its front fork oil at its top. 2. Loosen: • Adjuster 1 3. Remove: • Adjuster 1 NOTE: • While compressing the inner tube 2, set the cap bolt ring wrench 4 between the inner tube and locknut 3.

  • Page 236

    CHAS FRONT FORK Base valve 1. Remove: • 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 237

    CHAS FRONT FORK Base valve 1. Inspect: • Base valve 1 Wear/damage → Replace. Contamination → Clean. • O-ring 2 Wear/damage → Replace. • Bush 3 Wear/damage → Replace base valve. • Spring 4 Damage/fatigue → Replace base valve. • Air bleed screw 5 Wear/damage →...

  • Page 238

    CHAS FRONT FORK EC554600 Outer tube 1. Inspect: • Outer tube 1 Score marks/wear/damage → Replace. Adjuster 1. Inspect: • Adjuster 1 • O-ring 2 Wear/damage → Replace. EC555000 ASSEMBLY AND INSTALLATION Front fork assembly 1. Wash the all parts in a clean solvent. 2.

  • Page 239

    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 240

    CHAS FRONT FORK 9. Tighten: • 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 241

    CHAS FRONT FORK 13. Check: • Damper assembly smooth movement Tightness/binding/rough spots → Repeat the steps 2 to 12. 14. Install: • Dust seal 1 • Stopper ring 2 • Oil seal 3 • Oil seal washer 4 • Slide metal 5 To inner tube 6.

  • Page 242

    CHAS FRONT FORK 17. Install: • Slide metal 1 • 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: • Oil seal 1 NOTE: Press the oil seal into the outer tube with fork seal driver 2.

  • Page 243

    CHAS FRONT FORK 21. Check: • Inner tube smooth movement Tightness/binding/rough spots → Repeat the steps 14 to 20. 22. Measure: • Distance a Out of specification → Turn into the lock- nut. Distance a: 19 mm (0.75 in) or more Between damper assembly 1 bottom and locknut 2 bottom.

  • Page 244

    CHAS FRONT FORK 26. Install: • Push rod 1 • Copper washer 2 • Adjuster 3 To damper assembly 4. NOTE: • While compressing the inner tube 5, set the cap bolt ring wrench 7 between the inner tube and locknut 6. •...

  • Page 245

    CHAS FRONT FORK 29. Install: • Adjuster 1 55 Nm (5.5 m · kg, 40 ft · lb) To inner tube. 30. Fill: • Front fork oil 1 From outer tube top. Recommended oil: Suspension oil “S1” Standard oil amount: 260 cm (9.15 Imp oz, 8.79 US oz) *270 cm...

  • Page 246

    CHAS FRONT FORK 32. Install: • Protector guide 1 Installation 1. Install: • Front fork 1 NOTE: • Temporarily tighten the pinch bolts (under bracket). • Do not tighten the pinch bolts (handle crown) yet. 2. Tighten: • Damper assembly 1 30 Nm (3.0 m ·...

  • Page 247

    CHAS FRONT FORK 4. Tighten: • Pinch bolt (handle crown) 1 23 Nm (2.3 m · kg, 17 ft · lb) • Pinch bolt (under bracket) 2 20 Nm (2.0 m · kg, 14 ft · lb) CAUTION: Tighten the under bracket to specified torque.

  • Page 248

    CHAS HANDLEBAR EC5B0000 HANDLEBAR 1 Handlebar removal Extent of removal: Extent of removal Order Part name Q’ty Remarks HANDLEBAR REMOVAL Preparation for removal Number plate Remove the clamp portion only. Hot starter cable Disconnect at the lever side. Hot starter lever holder Clutch cable Disconnect at the lever side.

  • Page 249

    CHAS HANDLEBAR EC5B3000 REMOVAL POINTS EC5B3100 Master cylinder 1. Remove: • Master cylinder bracket 1 • Master cylinder 2 CAUTION: • Do not let the master cylinder hang on the brake hose. • Keep the master cylinder cap side hori- zontal to prevent air from coming in.

  • Page 250

    CHAS HANDLEBAR EC5B5000 ASSEMBLY AND INSTALLATION Handlebar 1. Install: • Handlebar 1 • Handlebar holder 2 • Bolt (handlebar holder) 3 28 Nm (2.8 m · kg, 20 ft · lb) NOTE: • The upper handlebar holder should be installed with the punched mark a forward. •...

  • Page 251

    CHAS HANDLEBAR 3. Install: • Grip (right) 1 • Collar 2 Apply the adhesive on the tube guide 3. NOTE: • Before applying the adhesive, wipe off grease or oil on the tube guide surface a with a lacquer thinner. •...

  • Page 252

    CHAS HANDLEBAR 6. Install: • Throttle cable cap 1 • Screw (throttle cable cap) 2 4 Nm (0.4 m · kg, 2.9 ft · lb) WARNING After tightening the screws, check that the throttle grip 3 moves smoothly. If it does not, retighten the bolts for adjustment.

  • Page 253

    CHAS HANDLEBAR 9. Install: • “ENGINE STOP” button 1 • Clutch lever holder 2 • Bolt (clutch lever holder) 3 4 Nm (0.4 m · kg, 2.9 ft · lb) • Hot starter lever holder 4 • Bolt (hot starter lever holder) 5 4 Nm (0.4 m ·...

  • Page 254

    CHAS STEERING EC560000 STEERING 1 Under bracket removal 2 Bearing removal Extent of removal: Extent of removal Order Part name Q’ty Remarks STEERING REMOVAL WARNING Preparation for removal Hold the machine by placing the Support the machine securely so there is no suitable stand under the engine.

  • Page 255

    CHAS STEERING EC563000 REMOVAL POINTS EC563202 Ring nut 1. Remove: • Ring nut 1 Use the ring nut wrench 2. Ring nut wrench: YU-33975/90890-01403 WARNING Support the steering shaft so that it may not fall down. EC563300 Bearing (lower) 1. Remove: •...

  • Page 256

    CHAS STEERING Bearing and bearing race 1. Wash the bearings and bearing races with a solvent. 2. Inspect: • Bearing 1 • 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 257

    CHAS STEERING 4. Install: • 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 INSPEC- TION AND ADJUSTMENT” section in the CHAPTER 3. 5.

  • Page 258

    CHAS STEERING 9. Install: • 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: • Front fork top end a Front fork top end (standard) a: Zero mm (Zero in) 12.

  • Page 259

    CHAS SWINGARM EC570000 SWINGARM 1 Swingarm removal Extent of removal: Extent of removal Order Part name Q’ty Remarks SWINGARM REMOVAL WARNING Preparation for removal Hold the machine by placing the Support the machine securely so there is no suitable stand under the engine. danger of it falling over.

  • Page 260

    CHAS SWINGARM EC578000 SWINGARM DISASSEMBLY 1 Swingarm disassembly 2 Connecting rod removal and disassembly Extent of removal: 3 Relay arm removal and disassembly Extent of removal Order Part name Q’ty Remarks SWINGARM DISASSEMBLY Refer to “REMOVAL POINTS”. Relay arm Connecting rod Collar Oil seal Thrust bearing...

  • Page 261

    CHAS SWINGARM EC573000 REMOVAL POINTS 1. Remove: • Cap (left) 1 NOTE: Remove with a slotted-head screwdriver inserted under the mark a on the cap (left). EC573200 Bearing 1. Remove: • Bearing 1 NOTE: Install the bearing by pressing its outer race. EC574010 INSPECTION Wash the bearings, bushes, collars, and cov-...

  • Page 262

    CHAS SWINGARM Connecting rod 1. Inspect: • Bearing 1 • Collar 2 Free play exists/unsmooth revolution/rust → Replace bearing and collar as a set. 2. Inspect: • Oil seal 3 Damage → Replace. EC575000 ASSEMBLY AND INSTALLATION Bearing and oil seal 1.

  • Page 263

    CHAS SWINGARM 3. Install: • Bearing 1 • Oil seal 2 To connecting rod. NOTE: • Apply the molybdenum disulfide grease on the bearing when installing. • Install the bearing by pressing it on the side having the manufacture’s marks or numbers. Installed depth of bearings a: 5 mm (0.20 in) Swingarm...

  • Page 264

    CHAS SWINGARM 3. Install: • Collar 1 To connecting rod 2. NOTE: Apply the molybdenum disulfide grease on the collar and oil seal lips. 4. Install: • Connecting rod 1 • Bolt (connecting rod) 2 • Plain washer 3 • Nut (connecting rod) 4 80 Nm (8.0 m ·...

  • Page 265

    CHAS SWINGARM 8. Install: • Bolt (connecting rod) 1 • Plain washer 2 • Nut (connecting rod) 3 NOTE: • Apply the molybdenum disulfide grease on the bolt. • Do not tighten the nut yet. 9. Install: • Bolt (rear shock absorber-relay arm) 1 •...

  • Page 266

    CHAS SWINGARM 13. Install: • Bolt [chain tensioner (lower)] 1 • Plain washer 2 • Collar 3 • Chain tensioner 4 • Nut [chain tensioner (lower)] 5 20 Nm (2.0 m · kg, 14 ft · lb) 14. Install: • Chain support 1 •...

  • Page 267: Rear Shock Absorber

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

  • Page 268

    CHAS REAR SHOCK ABSORBER Extent of removal Order Part name Q’ty Remarks Spring guide (upper) Spring (rear shock absorber) Bearing Refer to “REMOVAL POINTS”. 5 - 62...

  • Page 269

    1. Wear eye protection to prevent eye damage from escaping gas and/or metal chips. WARNING To dispose of a damaged or worn-out shock absorber, take the unit to your Yamaha dealer for this disposal procedure. 5 - 63...

  • Page 270

    CHAS REAR SHOCK ABSORBER EC583000 REMOVAL POINTS EC583320 Bearing 1. Remove: • Stopper ring (upper bearing) 1 NOTE: Press in the bearing while pressing its outer race and remove the stopper ring. 2. Remove: • Upper bearing 1 NOTE: Remove the bearing by pressing its outer race. 3.

  • Page 271

    CHAS REAR SHOCK ABSORBER EC585000 ASSEMBLY AND INSTALLATION EC585300 Bearing 1. Install: • Upper bearing 1 NOTE: Install the bearing parallel until the stopper ring groove appears by pressing its outer race. CAUTION: 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 272

    CHAS REAR SHOCK ABSORBER 2. Tighten: • Adjuster 1 3. Adjust: • Spring length (installed) a Spring length (installed) a: Standard Extent of length adjustment 248 mm (9.76 in) 240.5 ~ 258.5 mm *245 mm (9.65 in) (9.47 ~ 10.18 in) * For EUROPE NOTE: The length of the spring (installed) changes...

  • Page 273

    CHAS REAR SHOCK ABSORBER 2. Install: • Bush 1 • Collar 2 • Dust seal 3 NOTE: • Apply the molybdenum disulfide grease on the bearing. • Apply the lithium soap base grease on the bush, collars and dust seals. •...

  • Page 274: Electrical Components And Wiring Diagram

    – ELEC ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC600000 ELECTRICAL EC610000 ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC611000 ELECTRICAL COMPONENTS 1 “ENGINE STOP” button COLOR CODE 2 TPS (throttle position sensor) W .....White B...... Black Y ......Yellow 3 Neutral switch Br ....Brown B/L ....Black/Blue G .....

  • Page 275

    – ELEC MAP-CONTROLLED CDI UNIT MAP-CONTROLLED CDI UNIT A map-controlled, CDI ignition system is used in the YZ450F. The microcomputer in the CDI unit detects the engine speed and throttle position, thus determining the optimum ignition timing through the entire operating range. In this way, quick throttle response can be achieved according to various riding conditions.

  • Page 276: Ignition System

    – ELEC IGNITION SYSTEM EC620000 IGNITION SYSTEM INSPECTION STEPS Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure and for checking the spark plug which will not spark. Spark *Clean or replace Spark gap test spark plug.

  • Page 277

    – ELEC IGNITION SYSTEM SPARK GAP TEST È 1. Disconnect the ignition coil from spark plug. 2. Remove the ignition coil cap. 3. Connect the dynamic spark tester 1 (igni- tion checker 2) as shown. • Ignition coil 3 • Spark plug 4 È...

  • Page 278

    – ELEC IGNITION SYSTEM EC626002 IGNITION COIL INSPECTION 1. Remove the ignition coil cap. 2. Inspect: • Primary coil resistance Out of specification → Replace. Tester (+) lead → Orange lead 1 Tester (–) lead → Black lead 2 Primary coil Tester selector resistance position...

  • Page 279

    – ELEC IGNITION SYSTEM 2. Inspect: • Source coil 1 resistance Out of specification → Replace. Tester (+) lead → Brown lead 1 Tester (–) lead → Green lead 2 Source coil 1 Tester selector resistance position 720 ~ 1,080 Ω at Ω...

  • Page 280

    – ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM EC690000 TPS (THROTTLE POSITION SENSOR) SYSTEM 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 281

    – ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM HANDLING NOTE CAUTION: Do not loosen the screws {TPS (throttle position sensor)} 1 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...

  • Page 282

    – ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM 3. Inspect: • TPS coil variable resistance Check that the resistance in increased as the throttle grip is moved from the full close position to the full open position. Out of specification → Replace. Tester (+) lead →...

  • Page 283

    – ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM 4. Adjust: • Idle speed Refer to “IDLE SPEED ADJUSTMENT” section in the CHAPTER 3. 5. Insert the thin electric conductors 2 (lead) into the TPS coupler 1, as shown, and connect the tester to them. Tester (+) lead →...

  • Page 284

    – ELEC TPS (THROTTLE POSITION SENSOR) SYSTEM 8. Tighten: • Screw (TPS) 1 9. Stop the engine. EC694000 TPS INPUT VOLTAGE INSPECTION 1. Disconnect the TPS coupler. 2. Start the engine. 3. Inspect: • TPS input voltage Out of specification → Replace the CDI unit.

  • Page 285

    T U N SETTING EC700000 TUNING EC710000 ENGINE Carburetor setting • The air/fuel mixture will vary depending on atmospheric conditions. Therefore, it is nec- essary to take into consideration the air pres- sure, ambient temperature, humidity, etc., when adjusting the carburetor. •...

  • Page 286

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

  • Page 287

    T U N SETTING Effects of the setting parts on the throttle valve opening È Closed É Fully open È É 1 Pilot screw/pilot jet 2 Throttle valve cutaway 3 Jet needle 4 Main jet Main system The FLATCR carburetor has a primary main jet.

  • Page 288

    T U N SETTING Pilot system The FLATCR carburetor is manufactured with a pilot screw. The pilot screw adjustment ranges from fully closed throttle to 1/4 open throttle. Main jet adjustment The richness of the air-fuel mixture at full throt- tle can be set by changing the main jet 1.

  • Page 289

    T U N SETTING Pilot screw adjustment The richness of the air-fuel mixture with the throttle fully closed to 1/4 open can be set by turning the pilot screw 1. Turning in the pilot screw will make the mixture lean at low speeds, and turning it out will enrich it.

  • Page 290

    T U N SETTING Pilot jet adjustment The richness of the air-fuel mixture with the throttle open 1/4 or less can be set by adjust- ing the pilot jet 1. Standard pilot jet Effects of adjusting the pilot jet (reference) È...

  • Page 291

    T U N SETTING Jet needle adjustment The jet needle is adjusted by changing it. Standard jet needle NFLR The jet needle setting parts, having the same taper angle, are available in different straight portion diameters and in different taper starting positions.

  • Page 292

    T U N SETTING Leak jet adjustment (accelerator pump adjustment) The leak jet 1 is a setting part that adjusts the flow of fuel discharged by the accelerator pump. Since the accelerator pump operates only when throttle is open, the leak jet is used to adjust a fuel mixture ratio for quick throttle opening and is therefore different from other setting parts that adjust a fuel mixture for each...

  • Page 293

    T U N SETTING Carburetor setting parts Part name Size Part number Main jet Rich #178 4MX-14943-93 #175 4MX-14943-42 #172 4MX-14943-92 #170 4MX-14943-41 #168 4MX-14943-91 (STD) #165 4MX-14943-40 #162 4MX-14943-90 #160 4MX-14943-39 #158 4MX-14943-89 #155 4MX-14943-38 Lean #152 4MX-14943-88 Pilot jet Rich 4MX-14948-08 4MX-14948-07...

  • Page 294

    T U N SETTING Examples of carburetor setting depending on symptom Symptom Setting Checking Discoloration of spark plug → At full throttle Increase main jet calibration no. Hard breathing (Gradually) If tan color, it is in good condition. Shearing noise If cannot be corrected: Whitish spark plug Clogged float valve seat...

  • Page 295

    T U N 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 51/14 (3.643) reduction ratio <Requirement for selection of secondary gear reduction ratio> •...

  • Page 296

    T U N SETTING EC72N000 Drive and driven sprockets setting parts Part name Size Part number Drive sprocket 1 (STD) 9383E-14215 Driven sprocket 2 1C3-25447-00 1C3-25448-00 1C3-25449-00 1C3-25450-00 (STD) 1C3-25451-00 1C3-25452-00 EC721002 Tire pressure Tire pressure should be adjust to suit the road surface condition of the circuit.

  • Page 297

    T U N SETTING EC722011 Front fork setting The front fork setting should be made depend- ing on the rider’s feeling of an actual run and the circuit conditions. The front fork setting includes the following three factors: 1. Setting of air spring characteristics •...

  • Page 298

    T U N SETTING EC727020 Spring preload adjustment The spring preload is adjusted by installing the adjustment washer 1 between the spacer 2 and fork spring 3. CAUTION: Do not install three or more adjustment washers for each front fork. WARNING Always adjust each front fork to the same setting.

  • Page 299

    T U N SETTING 2. Use of stiff spring Generally a stiff spring gives a stiff riding feeling. Rebound damping tends become weaker, resulting in lack of a sense of contact with the road surface or in a vibrating handlebar. To set a stiff spring: •...

  • Page 300

    T U N SETTING EC72P000 Front fork setting parts • Adjustment washer 1 TYPE (thickness) PART NUMBER T = 2.3 mm (0.09 in) 1C3-23364-00 • 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...

  • Page 301

    T U N SETTING EC72C001 Choosing set length 1. Place a stand or block under the engine to put the rear wheel above the floor, and measure the length a between the rear wheel axle center and the rear fender hold- ing bolt.

  • Page 302

    T U N SETTING EC72G001 Setting of spring after replacement After replacement, be sure to adjust the spring to the set length [sunken length 90 ~ 100 mm (3.5 ~ 3.9 in)] and set it. 1. Use of soft spring •...

  • Page 303

    T U N SETTING EC72Q000 Rear shock absorber setting parts • 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 5UN-22212-10 Green/1 SOFT 5UN-22212-20 Red/1 5UN-22212-30 Black/1 *STD 5UN-22212-40 Blue/1 5UN-22212-50...

  • Page 304: Suspension Setting

    T U N SETTING EC72H002 Suspension setting • Front fork NOTE: • 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. •...

  • Page 305

    T U N SETTING • Rear shock absorber NOTE: • If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure given in the same chart. • Adjust the rebound damping in 2-click increments or decrements. •...

  • Page 306

    YAMAHA MOTOR CO., LTD. PRINTED ON RECYCLED PAPER PRINTED IN JAPAN 2004.06-1.9×1 CR 2500 SHINGAI IWATA SHIZUOKA JAPAN...

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