Yamaha YFM50S Service Manual
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Yamaha YFM50S Service Manual

Yamaha YFM50S Service Manual

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YFM50S
SERVICE MANUAL
LIT-11616-17-13
5YF-28197-10

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  • Page 1 YFM50S SERVICE MANUAL LIT-11616-17-13 5YF-28197-10...
  • Page 2 EBS00001 YFM50S SERVICE MANUAL ©2003 by Yamaha Motor Corporation, U.S.A. First Edition, April 2003 All rights reserved. Any reproduction or unauthorized use without the written permission of Yamaha Motor Corporation, U.S.A. is expressly prohibited. Printed in U.S.A. LIT-11616-17-13...

  • Page 3: Important Information

    EBS00002 NOTICE This manual was produced by the Yamaha Motor Company primarily for use by Yamaha dealers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual, so it is assumed that anyone who uses this book to perform maintenance and repairs on Yamaha machine has a basic understanding of the mechanical ideas and the procedures of machine repair.

  • Page 4: How To Use This Manual

    EBS00004 HOW TO USE THIS MANUAL MANUAL ORGANIZATION This manual consists of chapters for the main categories of subjects. (See “symbols”) 1st title 1: This is the title of the chapter with its symbol in the upper right corner of each page. 2nd title 2: This title indicates the section of the chapter and only appears on the first page of each section.

  • Page 5: General Information

    EBS00005 SYMBOLS The following symbols are not relevant to SPEC every machine. INFO Symbols 1 to 9 indicate the subject of each chapter. 1 General information 2 Specifications 3 Periodic checks and adjustments 4 Engine 5 Carburetor 6 Drive train 7 Chassis CARB DRIV...

  • Page 6: Table Of Contents

    EBS00007 TABLE OF CONTENTS GENERAL INFORMATION INFO SPECIFICATIONS SPEC PERIODIC CHECKS AND ADJUSTMENTS ENGINE CARBURETOR CARB DRIVE TRAIN DRIV CHASSIS CHAS – ELECTRICAL ELEC TROUBLESHOOTING TRBL SHTG...
  • Page 7 CONTENTS CHAPTER 1 GENERAL INFORMATION MACHINE IDENTIFICATION................1-1 VEHICLE IDENTIFICATION NUMBER .............1-1 MODEL LABEL..................1-1 IMPORTANT INFORMATION ................. 1-2 PREPARATION FOR REMOVAL AND DISASSEMBLY......1-2 REPLACEMENT PARTS................1-2 GASKETS, OIL SEALS AND O-RINGS ............ 1-2 LOCK WASHERS/PLATES AND COTTER PINS ........1-3 BEARINGS AND OIL SEALS ..............
  • Page 8 OIL FLOW DIAGRAMS ................. 2-20 CABLE ROUTING ..................2-22 CHAPTER 3 PERIODIC CHECKS AND ADJUSTMENTS INTRODUCTION....................3-1 PERIODIC MAINTENANCE/LUBRICATION ..........3-1 SEAT, FENDERS AND FUEL TANK .............. 3-2 SEAT AND FRONT PANEL ..............3-2 FRONT FENDER ..................3-3 REAR FENDER AND FOOTREST BOARDS ...........3-4 FUEL TANK....................
  • Page 9 ELECTRICAL SYSTEM................. 3-33 CHECKING AND CHARGING THE BATTERY........3-33 CHECKING THE FUSE................3-37 CHAPTER 4 ENGINE ENGINE ......................4-1 EXHAUST PIPE/MUFFLER, BREATHER HOSE AND LEADS ....4-1 ENGINE MOUNTING BOLTS ..............4-2 REMOVING THE ENGINE ................ 4-4 INSTALLING THE ENGINE............... 4-4 CYLINDER HEAD.................... 4-5 REMOVING THE CYLINDER HEAD............4-7 CHECKING THE CAMSHAFT SPROCKET..........4-8 CHECKING THE TAPPET COVERS...
  • Page 10 CLUTCH ......................4-33 REMOVING THE CLUTCH ..............4-35 REMOVING THE PRIMARY DRIVE GEAR ..........4-35 CHECKING THE FRICTION PLATES.............4-35 CHECKING THE CLUTCH PLATES ............4-36 CHECKING THE CLUTCH SPRINGS.............4-36 CHECKING THE CLUTCH HOUSING ............4-36 CHECKING THE CLUTCH BOSS............4-37 CHECKING THE PRESSURE PLATE ............4-37 CHECKING THE CLUTCH BALLS............

  • Page 11: Chassis

    CHAPTER 5 CARBURETOR CARBURETOR....................5-1 DISASSEMBLING THE CARBURETOR........... 5-4 CHECKING THE CARBURETOR ............. 5-4 ASSEMBLING THE CARBURETOR............5-6 INSTALLING THE CARBURETOR ............5-6 MEASURING AND ADJUSTING THE FUEL LEVEL ........5-7 CHAPTER 6 DRIVE TRAIN TROUBLESHOOTING..................6-1 CHECKING NOISES ................. 6-2 TROUBLESHOOTING CHART ..............6-4 REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT ......6-5 REAR AXLE/FINAL DRIVE ASSEMBLY...........
  • Page 12 FRONT AND REAR BRAKES................. 7-6 FRONT BRAKE ..................7-6 REAR BRAKE ................... 7-7 REMOVING THE BRAKES ............... 7-9 CHECKING THE BRAKE SHOE PLATES ..........7-9 CHECKING THE BRAKE SHOES............. 7-9 CHECKING THE BRAKE DRUMS ............7-10 INSTALLING THE FRONT BRAKES ............7-11 INSTALLING THE REAR BRAKE ............

  • Page 13: Electrical

    CHAPTER 8 ELECTRICAL ELECTRICAL COMPONENTS................ 8-1 CHECKING SWITCH CONTINUITY..............8-2 CHECKING THE SWITCHES................8-3 CHECKING THE BULBS AND BULB SOCKETS .......... 8-4 TYPES OF BULBS ..................8-4 CHECKING THE CONDITION OF THE BULBS ........8-4 CHECKING THE CONDITION OF THE BULB SOCKETS .......8-6 IGNITION SYSTEM ..................
  • Page 14 POOR IDLE SPEED PERFORMANCE ............9-2 POOR IDLE SPEED PERFORMANCE.............9-2 POOR MEDIUM AND HIGH-SPEED PERFORMANCE........9-2 POOR MEDIUM AND HIGH-SPEED PERFORMANCE ......9-2 FAULTY DRIVE TRAIN ................... 9-3 FAULTY GEAR SHIFTING................9-4 HARD SHIFTING..................9-4 SHIFT LEVER DOES NOT MOVE ............9-4 JUMPS OUT GEAR................... 9-4 CLUTCH SLIPPING/DRAGGING..............

  • Page 15: General Information

    MACHINE IDENTIFICATION INFO EBS00009 GENERAL INFORMATION MACHINE IDENTIFICATION EBS00010 VEHICLE IDENTIFICATION NUMBER The vehicle identification number 1 is stamped into the left side of the frame. EBS00011 MODEL LABEL The model label 1 is affixed to the frame. This information will be needed to order spare parts.

  • Page 16: Important Information

    5. Keep all parts away from any source of fire. EBS00014 REPLACEMENT PARTS 1. Use only genuine Yamaha parts for all replacements. Use oil and grease recom- mended by Yamaha for all lubrication jobs. Other brands may be similar in function and appearance, but inferior in quality.

  • Page 17: Lock Washers/Plates And Cotter Pins

    IMPORTANT INFORMATION INFO EBS00016 LOCK WASHERS/PLATES AND COTTER PINS After removal, replace all lock washers/plates 1 and cotter pins. After the bolt or nut has been tightened to specification, bend the lock tabs along a flat of the bolt or nut. EBS00017 BEARINGS AND OIL SEALS Install bearings and oil seals so that the manu-...

  • Page 18: Checking The Connections

    IMPORTANT INFORMATION INFO EBS00019 CHECKING THE CONNECTIONS Check the leads, couplers, and connectors for stains, rust, moisture, etc. 1. Disconnect: • lead • coupler • connector 2. Check: • lead • coupler • connector Moisture → Dry with an air blower. Rust/stains →...

  • Page 19: Special Tools

    SPECIAL TOOLS INFO EBS00021 SPECIAL TOOLS The following special tools are necessary for complete and accurate tune-up and assembly. Use only the appropriate special tools; this will help prevent damage caused by the use of inappropriate tools or improvised techniques. Special tools may differ by shape and part number from country to country.
  • Page 20 SPECIAL TOOLS INFO Tool No. Tool name/Function Illustration Axle nut wrench (36 mm) 90890-01422 YM-37132 This tool is needed to loosen or tighten the rear axle nut. Ring nut wrench 90890-01430 YM-38404 This tool is needed to loosen and tighten the final gear case bearing retainer.
  • Page 21 SPECIAL TOOLS INFO Tool No. Tool name/Function Illustration Valve spring compressor Compressor Valve spring compressor attachment 90890-04019 YM-04019 Attachment 90890-04108 This tool is needed to remove and install YM-04108 the valve assemblies. Universal joint holder Holder Universal joint holder attachment 90890-04062 YM-04062 Attachment...
  • Page 22 SPECIAL TOOLS INFO Tool No. Tool name/Function Illustration Yamaha bond No. 1215 ® Sealant (Quick Gasket Bond 90890-85505 Sealant ACC-11001-05-01 This sealant (bond) is used on crankcase mating surfaces, etc. 27-mm hexagon wrench YM-01363 This tool is needed to loosen and tighten the middle driven pinion gear bearing retainer.

  • Page 23: Spec

    SPEC GENERAL SPECIFICATIONS EBS01001 SPECIFICATIONS GENERAL SPECIFICATIONS Item Standard Model code 5YF1 Dimensions Overall length 1,537 mm (60.5 in) Overall width 825 mm (32.5 in) Overall height 915 mm (36.0 in) Seat height 618 mm (24.3 in) Wheelbase 1,030 mm (40.6 in) Minimum ground clearance 70 mm (2.76 in) Minimum turning radius...
  • Page 24 SPEC GENERAL SPECIFICATIONS Item Standard Fuel Type Unleaded gasoline only Fuel tank capacity 6.8 L (1.50 Imp gal, 1.80 US gal) Fuel reserve amount 0.9 L (0.20 Imp gal, 0.24 US gal) Carburetor Type/quantity VM16SH/1 Manufacturer MIKUNI Spark plug Type/manufacturer CR7HS/NGK Spark plug gap 0.6 ~ 0.7 mm (0.024 ~ 0.028 in)
  • Page 25 SPEC GENERAL SPECIFICATIONS Item Standard Brake Front brake type Drum brake operation Right hand operation Rear brake type Drum brake operation Left hand operation Suspension Front suspension Leading arm Rear suspension Swingarm Shock absorber Front shock absorber Coil spring/oil damper Rear shock absorber Coil spring/oil damper Wheel travel...

  • Page 26: Engine Specifications

    SPEC ENGINE SPECIFICATIONS EBS01002 ENGINE SPECIFICATIONS Item Standard Limit Cylinder head Warp limit ---- 0.05 mm (0.002 in) Cylinder Bore size 39.000 ~ 39.005 mm 39.105 mm (1.5354 ~ 1.5356 in) (1.5396 in) Taper limit ---- 0.05 mm (0.002 in) Maximum out-of-round ---- 0.01 mm...
  • Page 27 SPEC ENGINE SPECIFICATIONS Item Standard Limit Rocker arm/rocker arm shaft Rocker arm inside diameter 10.000 ~ 10.015 mm ---- (0.3937 ~ 0.3943 in) Rocker arm shaft outside diameter 9.981 ~ 9.991 mm ---- (0.3930 ~ 0.3933 in) Rocker-arm-to-rocker-arm-shaft clearance 0.009 ~ 0.034 mm 0.08 mm (0.0004 ~ 0.0013 in) (0.0031 in)
  • Page 28 SPEC ENGINE SPECIFICATIONS Item Standard Limit Stem-to-guide clearance 0.010 ~ 0.037 mm 0.08 mm (0.0004 ~ 0.0015 in) (0.0031 in) 0.025 ~ 0.052 mm 0.10 mm (0.0010 ~ 0.0020 in) (0.0039 in) Stem runout limit ---- 0.02 mm (0.0008 in) Valve seat width 0.9 ~ 1.1 mm 1.6 mm...
  • Page 29 SPEC ENGINE SPECIFICATIONS Item Standard Limit Piston Piston to cylinder clearance 0.025 ~ 0.045 mm 0.15 mm (0.0010 ~ 0.0018 in) (0.0059 in) Piston size “D” 38.960 ~ 38.975 mm ---- (1.5339 ~ 1.5344 in) Measuring point “H” 5.0 mm (0.20 in) ---- Oversize 39.5 mm (1.56 in)
  • Page 30 SPEC ENGINE SPECIFICATIONS Item Standard Limit Oil ring Dimensions (B × T) 2.0 × 2.0 mm ---- (0.0787 × 0.0787 in) End gap (installed) 0.20 ~ 0.70 mm ---- (0.0079 ~ 0.0276 in) Crankshaft Crank width “A” 40.20 ~ 40.25 mm ---- (1.5827 ~ 1.5846 in) Runout limit C1...
  • Page 31 SPEC ENGINE SPECIFICATIONS Item Standard Limit Clutch plate 1 Thickness 1.4 mm (0.055 in) ---- Quantity ---- Maximum warpage ---- 0.06 mm (0.002 in) Clutch plate 2 Thickness 1.2 ~ 1.6 mm (0.047 ~ 0.063 in) ---- Quantity ---- Maximum warpage ---- 0.06 mm (0.002 in)
  • Page 32 SPEC ENGINE SPECIFICATIONS Item Standard Limit Oil pump Oil pump type Trochoid ---- Inner-rotor-to-outer-rotor-tip clearance 0.05 ~ 0.07 mm 0.15 mm (0.002 ~ 0.003 in) (0.006 in) Outer-rotor-to-oil-pump-housing clearance 0.013 ~ 0.036 mm 0.106 mm (0.0005 ~ 0.0014 in) (0.0042 in) Oil-pump-housing-to-inner-rotor-and-outer- 0.06 ~ 0.10 mm 0.17 mm...

  • Page 33: Chassis Specifications

    SPEC CHASSIS SPECIFICATIONS EBS01003 CHASSIS SPECIFICATIONS Item Standard Limit Front suspension Shock absorber travel 60 mm (2.36 in) ---- Optional spring ---- Rear suspension Shock absorber travel 58 mm (2.28 in) ---- Optional spring ---- Front wheel Type Panel wheel ---- 7 ×...

  • Page 34: Electrical Specifications

    Advanced timing (B.T.D.C.) 30°/5,000 r/min ---- Advancer type Electrical (analogue) ---- C.D.I. Magneto model/manufacturer F2FM/YAMAHA ---- 264 ~ 396 Ω at 20 °C (68 °F)/ Pickup coil resistance/color ---- White/Red—White/Blue 304 ~ 456 Ω at 20 °C (68 °F)/ Source coil resistance/color ---- Black/Red—Green/White...
  • Page 35 SPEC ELECTRICAL SPECIFICATIONS Item Standard Limit Electric starter system Type Constant mesh ---- Starter motor Model/manufacturer ADB4A5/DENSO ---- Output 0.2 kW ---- 0.029 ~ 0.035 Ω at 20 °C (68 °F) Armature coil resistance ---- Brush overall length 6.0 mm (0.24 in) 3.5 mm (0.14 in) Spring force...

  • Page 36: Tightening Torques

    SPEC TIGHTENING TORQUES EBS01005 TIGHTENING TORQUES ENGINE TIGHTENING TORQUES Tightening torque Thread Part to be tightened Part name Q’ty Remarks size Nm m · kg ft · lb Cylinder head (exhaust pipe) Stud bolt Intake and exhaust tappet cover — Camshaft sprocket cover Screw Cylinder head...

  • Page 37: Chassis Tightening Torques

    SPEC TIGHTENING TORQUES Tightening torque Thread Part to be tightened Part name Q’ty Remarks size Nm m · kg ft · lb Neutral switch — Spark arrester tailpipe Screw Purging bolt Bolt EBS01006 CHASSIS TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Remarks Nm m ·...
  • Page 38 SPEC TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Remarks Nm m · kg ft · lb Final gear oil drain plug Final gear case bearing retainer Final drive pinion gear and bearing Rear axle housing bearing retainer 11.0 NOTE: ®...

  • Page 39: How To Use The Conversion Table

    HOW TO USE THE CONVERSION TABLE/ SPEC GENERAL TIGHTENING TORQUE SPECIFICATIONS EBS00022 EBS00023 HOW TO USE THE CONVERSION GENERAL TIGHTENING TORQUE TABLE SPECIFICATIONS All specification data in this manual are listed This chart specifies tightening torques for stan- in SI and METRIC UNITS. dard fasteners with a standard ISO thread Use this table to convert METRIC unit data to pitch.

  • Page 40: Lubrication Points And Lubricant Types

    Shift shaft Shift shaft washer Middle driven pinion gear, universal joint yoke, drive shaft, coupling gear, final drive pinion gear splines Final drive pinion gear, ring gear Sealant ® (Quick Gasket Crankcase mating surface Yamaha Bond No.1215 2 - 18...
  • Page 41 SPEC LUBRICATION POINTS AND LUBRICANT TYPES Lubrication points Lubricant Sealant ® (Quick Gasket Final gear case and rear axle housing mating surface Yamaha Bond No.1215 2 - 19...

  • Page 42: Oil Flow Diagrams

    SPEC OIL FLOW DIAGRAMS EBS00026 OIL FLOW DIAGRAMS 1 Camshaft 2 Crankshaft 3 Main axle 4 Drive axle 2 - 20...
  • Page 43 SPEC OIL FLOW DIAGRAMS 1 Oil pump 2 Oil strainer 2 - 21...

  • Page 44: Cable Routing

    SPEC CABLE ROUTING EBS00028 CABLE ROUTING 1 Rear brake cable 0 Wire harness H Left front brake cable 2 Throttle cable A Negative battery lead I Engine stop switch (frame) 3 Fuel tank breather hose B Rectifier/regulator 4 Carburetor air vent hose C Engine stop switch lead 5 Final gear case breather hose (frame end)
  • Page 45 SPEC CABLE ROUTING È Route the rear brake cable to the right of the Ë Align the white tape of the wire harness with the steering stem. bracket. É Pass the carburetor air vent hose through the hole Ì 200 mm (7.87 in) Í...
  • Page 46 SPEC CABLE ROUTING Ñ Fasten the carburetor air vent hose with a plastic band. Be sure to not pinch the hose. Install the plastic band with the buckle facing backward and the end inward. Ò Route the cables under the frame. Ó...
  • Page 47 SPEC CABLE ROUTING 1 Rear brake cable B Fuel tank breather hose 2 Wire harness C Throttle cable 3 Ignition coil D Front brake cables 4 Handlebar switch lead 5 Rear brake switch lead 6 Neutral indicator light lead 7 Main switch 8 C.D.I.
  • Page 48 SPEC CABLE ROUTING È 80 mm (3.15 in) Ë Fasten the rear brake cable and wire harness É Fasten the rear brake cable, wire harness, near the ignition coil with a plastic locking tie. Ì Do not fasten the main switch lead. crankcase breather hose, and final gear case Í...
  • Page 49 SPEC CABLE ROUTING 1 Rear brake switch 2 Rear brake cable 3 Left front brake cable 4 Right front brake cable 5 Throttle cable 6 Fuel tank breather hose 7 Negative battery lead 8 Main fuse 9 Positive battery lead 0 Handlebar switch 2 - 27...
  • Page 50 SPEC CABLE ROUTING È Fasten the negative battery lead with the plastic holder. É To starter motor Ê Pass the leads through the hole. Ë To wire harness Ì To starter relay Í Fasten the handlebar switch lead and rear brake switch lead with a plastic band. Î...
  • Page 51 SPEC CABLE ROUTING 1 Throttle cable È Route the front brake cables to the left of the 2 Fuel tank breather hose steering stem. Route the left front brake cable to 3 Rear brake cable the right of the air filter joint. Route the right front 4 Handlebar switch lead brake cable to the left of the air filter joint.

  • Page 52: Chk Adj

    • Check specific gravity. Battery* • Check breather hose for correct routing. • Correct if necessary. Since these items require special tools, data and technical skills, have a Yamaha dealer perform the service. EBS00032 WARNING Indicates a potential hazard that could result in serious injury or death.

  • Page 53: Seat, Fenders And Fuel Tank

    SEAT, FENDERS AND FUEL TANK EBS00033 SEAT, FENDERS AND FUEL TANK SEAT AND FRONT PANEL Order Job/Part Q’ty Remarks Removing the seat and front panel Remove the parts in the order listed. Seat NOTE: Pull back the seat lock lever, than pull up on the rear of the seat.

  • Page 54: Front Fender

    SEAT, FENDERS AND FUEL TANK EBS00037 FRONT FENDER 7 Nm (0.7 m kg, 5.1 ft • • 7 Nm (0.7 m kg, 5.1 ft • • Order Job/Part Q’ty Remarks Removing the front fender Remove the parts in the order listed. Seat and front panel Refer to “SEAT AND FRONT PANEL”.

  • Page 55: Rear Fender And Footrest Boards

    SEAT, FENDERS AND FUEL TANK EBS00039 REAR FENDER AND FOOTREST BOARDS 7 Nm (0.7 m kg, 5.1 ft • • 7 Nm (0.7 m kg, 5.1 ft • • 7 Nm (0.7 m kg, 5.1 ft • • 7 Nm (0.7 m kg, 5.1 ft •...
  • Page 56 SEAT, FENDERS AND FUEL TANK 7 Nm (0.7 m kg, 5.1 ft • • 7 Nm (0.7 m kg, 5.1 ft • • 7 Nm (0.7 m kg, 5.1 ft • • 7 Nm (0.7 m kg, 5.1 ft • •...

  • Page 57: Fuel Tank

    SEAT, FENDERS AND FUEL TANK EBS00042 FUEL TANK Order Job/Part Q’ty Remarks Removing the fuel tank Remove the parts in the order listed. Seat and front panel Refer to “SEAT AND FRONT PANEL”. Front fender Refer to “FRONT FENDER”. Fuel hose Disconnect.

  • Page 58: Engine

    ADJUSTING THE TIMING CHAIN TENSIONER EBS00046 ENGINE ADJUSTING THE TIMING CHAIN TENSIONER 1. Remove: • C.D.I. magneto cover • camshaft sprocket cover Refer to “CYLINDER HEAD” in chapter 4. 2. Remove: • cap nut 1 3. Loosen: • locknut 2 •...

  • Page 59: Adjusting The Valve Clearance

    ADJUSTING THE TIMING CHAIN TENSIONER/ ADJUSTING THE VALVE CLEARANCE 5. Install: • camshaft sprocket cover • C.D.I. magneto cover Refer to “CYLINDER HEAD” in chapter 4. ADJUSTING THE VALVE CLEARANCE NOTE: • The valve clearance must be adjusted when the engine is cool to the touch. •...
  • Page 60 ADJUSTING THE VALVE CLEARANCE NOTE: • When the piston is at the Top Dead Center (TDC) on the compression stroke, there should be clearance between the valve stem tips and their respective adjusting screws. • Be sure to align the alignment mark 3 on the camshaft sprocket with the alignment mark 4 on the cylinder head.

  • Page 61: Adjusting The Engine Idling Speed

    ADJUSTING THE VALVE CLEARANCE/ ADJUSTING THE ENGINE IDLING SPEED 4. Install: • camshaft sprocket cover • exhaust tappet cover • intake tappet cover • C.D.I. magneto cover Refer to “CYLINDER HEAD” in chapter 4. EBS00051 ADJUSTING THE ENGINE IDLING SPEED 1.

  • Page 62: Adjusting The Throttle Lever Free Play

    ADJUSTING THE ENGINE IDLING SPEED/ ADJUSTING THE THROTTLE LEVER FREE PLAY 6. Adjust: • throttle lever free play Refer to “ADJUSTING THE THROTTLE LEVER FREE PLAY”. Throttle lever free play 1.5 ~ 5.0 mm (0.06 ~ 0.20 in) EBS00052 ADJUSTING THE THROTTLE LEVER FREE PLAY NOTE: Engine idling speed should be adjusted prop-...

  • Page 63: Adjusting The Speed Limiter

    ADJUSTING THE SPEED LIMITER EBS00053 ADJUSTING THE SPEED LIMITER The speed limiter keeps the carburetor throttle from becoming fully-opened even when the throttle lever is applied to the maximum posi- tion. Screwing in the adjuster stops the engine speed from increasing. 1.

  • Page 64: Checking The Spark Plug

    CHECKING THE SPARK PLUG EBS00057 CHECKING THE SPARK PLUG 1. Remove: • spark plug 2. Check: • spark plug type Incorrect → Change. Standard spark plug CR7HS/NGK 3. Check: • electrode 1 Wear/damage → Replace. • insulator 2 Abnormal color → Replace. Normal color is a medium-to-light tan color.

  • Page 65: Checking The Ignition Timing

    CHECKING THE IGNITION TIMING EBS00058 CHECKING THE IGNITION TIMING NOTE: Engine idling speed and throttle cable free play should be adjusted properly before checking the ignition timing. 1. Remove: • C.D.I. magneto cover Refer to “C.D.I. MAGNETO” in chapter 4. 2.

  • Page 66: Measuring The Compression Pressure

    MEASURING THE COMPRESSION PRESSURE EBS00061 MEASURING THE COMPRESSION PRESSURE NOTE: Insufficient compression pressure will result in a loss of performance. 1. Measure: • valve clearance Out of specification → Adjust. Refer “ADJUSTING VALVE CLEARANCE”. 2. Start the engine, warm it up for several min- utes, and then turn it off.

  • Page 67: Measuring The Compression Pressure

    MEASURING THE COMPRESSION PRESSURE M MMM M MMM M MMM M MMM M MMM a. Set the main switch to “ON”. b. With the throttle wide open, crank the engine until the reading on the compression gauge stabilizes. WARNING To prevent sparking, ground the spark plug lead before cranking the engine.

  • Page 68: Checking The Engine Oil Level

    CHECKING THE ENGINE OIL LEVEL EBS00064 CHECKING THE ENGINE OIL LEVEL 1. Place the machine on a level surface. 2. Check: • engine oil level Oil level should be between the maximum a mark and minimum b mark. Oil level low → Add oil to the proper level. NOTE: Do not screw the dipstick 1 in when checking the oil level.

  • Page 69: Changing The Engine Oil

    CHANGING THE ENGINE OIL EBS00068 CHANGING THE ENGINE OIL 1. Start the engine, warm it up for several min- utes, and then turn it off. 2. Place a container under the engine oil drain bolt. 3. Remove: • dipstick 1 •...

  • Page 70: Cleaning The Air Filter Element

    CLEANING THE AIR FILTER ELEMENT EBS00071 CLEANING THE AIR FILTER ELEMENT NOTE: There is a check hose 1 at the bottom of the air filter case. If dust and/or water collects in this hose, clean the air filter element and air fil- ter case.

  • Page 71: Cleaning The Spark Arrester

    CLEANING THE AIR FILTER ELEMENT/ CLEANING THE SPARK ARRESTER b. Squeeze the excess solvent out of the ele- ment and let it dry. CAUTION: Do not twist or wring out the element. This could damage the foam material. c. Apply engine oil to the element. d.
  • Page 72 CLEANING THE SPARK ARRESTER c. Tap the tailpipe lightly with a soft-face ham- mer or suitable tool, then use a wire brush to remove any carbon deposits from the spark arrester portion of the tailpipe and the inner contact surfaces of the muffler. d.

  • Page 73: Chassis

    CHECKING THE FRONT AND REAR BRAKE SHOES/ ADJUSTING THE FRONT BRAKE CHASSIS È EBS00079 CHECKING THE FRONT AND REAR BRAKE SHOES 1. Operate the brake. 2. Check: • wear indicator 1 Reaches the wear limit line 2 → Replace the brake shoes as a set. Refer to “FRONT AND REAR BRAKES”...

  • Page 74: Adjusting The Rear Brake

    ADJUSTING THE REAR BRAKE EBS00084 ADJUSTING THE REAR BRAKE NOTE: Before adjusting the rear brake, the rear brake linings should be checked. CAUTION: Proper lever free play is essential to avoid excessive brake drag. 1. Place the machine on a level surface. 2.

  • Page 75: Checking The Final Gear Oil Level

    CHECKING THE FINAL GEAR OIL LEVEL/ CHANGING THE FINAL GEAR OIL EBS00101 CHECKING THE FINAL GEAR OIL LEVEL 1. Place the machine on a level surface. 2. Remove: • dipstick 1 3. Check: • final gear oil level Oil level should be between the maximum a and minimum b marks.

  • Page 76: Checking The Swingarm Dust Boot

    CHANGING THE FINAL GEAR OIL/ CHECKING THE SWINGARM DUST BOOT 6. Fill: • final gear case Total amount 0.12 L (0.11 Imp qt, 0.13 US qt) Recommended oil SAE80 API “GL-4” Hypoid gear CAUTION: Take care not to allow foreign material to enter the final gear case.

  • Page 77: Checking The Steering System

    CHECKING THE STEERING SYSTEM EBS00107 CHECKING THE STEERING SYSTEM 1. Place the machine on a level surface. 2. Check: • steering shaft bushings and bearings Move the handlebar up and down, and/or back and forth. Excessive play → Replace the steering shaft bushings and or bearings.

  • Page 78: Adjusting The Toe-In

    ADJUSTING THE TOE-IN EBS00108 ADJUSTING THE TOE-IN 1. Place the machine on a level surface. 2. Measure: • toe-in Out of specification → Adjust. Toe-in 0 ~ 10 mm (0 ~ 0.39 in) M MMM M MMM M MMM M MMM M MMM NOTE: Before measuring the toe-in, make sure that...

  • Page 79: Checking The Front And Rear Shock Absorbers

    ADJUSTING THE TOE-IN/CHECKING THE FRONT AND REAR SHOCK ABSORBERS M MMM M MMM M MMM M MMM M MMM a. Mark both tie-rods ends. This reference point will be needed during adjustment. b. Loosen the locknuts (tie-rod end) 1 of both tie-rods.

  • Page 80: Checking The Tires

    • TIRE CHARACTERISTICS 1) Tire characteristics influence the han- dling of ATVs. The tires listed below have been approved by Yamaha Motor Co., Ltd. for this model. If other tire com- binations are used, they can adversely affect your machine’s handling charac- teristics and are therefore not recom- mended.
  • Page 81 CHECKING THE TIRES 1. Measure: • tire pressure Out of specification → Adjust. NOTE: • The low-pressure tire gauge 1 is included as standard equipment. • If dust or the like is stuck to this gauge, it will not provide the correct readings. Therefore, take two measurements of the tire’s pressure and use the second reading.

  • Page 82: Checking The Wheels

    CHECKING THE TIRES/ CHECKING THE WHEELS 2. Check: • tire surfaces Wear/damage → Replace. Tire wear limit a Front and rear: 3 mm (0.12 in) WARNING It is dangerous to ride with a worn-out tire. When tire wear is out of specification, replace the tire immediately.

  • Page 83: Checking And Lubricating The Cables

    CHECKING AND LUBRICATING THE CABLES/LUBRICATING THE LEVERS, STEERING SHAFT AND STEERING KNUCKLES EBS00117 CHECKING AND LUBRICATING THE CABLES WARNING A damaged cable sheath may cause corro- sion and interfere with the cable move- ment. An unsafe condition may result so replace a damaged cable as soon as possi- ble.

  • Page 84: Electrical System

    CHECKING AND CHARGING THE BATTERY EBS00119 ELECTRICAL SYSTEM CHECKING AND CHARGING THE BATTERY WARNING Batteries generate explosive hydrogen gas and contain electrolyte which is made of poisonous and highly caustic sulfuric acid. Therefore, always follow these preventive measures: • Wear protective eye gear when handling or working near batteries.
  • Page 85 CHECKING AND CHARGING THE BATTERY 3. Remove: • battery 4. Check: • electrolyte level The electrolyte level should be between the minimum level mark a and the maximum level mark b. Below the minimum level mark → Add dis- tilled water to the proper level. CAUTION: Add only distilled water.
  • Page 86 CHECKING AND CHARGING THE BATTERY • Do not use a high-rate battery charger. They force a high-amperage current into the battery quickly and can cause battery overheating and battery plate damage. • If it is impossible to regulate the charging current on the battery charger, be careful not to overcharge the battery.
  • Page 87 CHECKING AND CHARGING THE BATTERY 7. Check: • battery breather hose and battery vent Obstruction → Clean. Damage → Replace. 8. Install: • battery 9. Connect: • battery breather hose 1 CAUTION: When checking the battery, make sure the battery breather hose is properly installed and routed correctly.

  • Page 88: Checking The Fuse

    CHECKING THE FUSE EBS00121 CHECKING THE FUSE CAUTION: To avoid a short circuit, always set the main switch to “OFF” when checking or replacing a fuse. 1. Remove: • seat Refer to “SEAT, FENDERS AND FUEL TANK”. • fuse holder 1 2.
  • Page 89 CHECKING THE FUSE d. If the fuse immediately blows again, check the electrical circuit. Amperage Items Q’ty rating Main Reserve WARNING Never use a fuse with an amperage rating other than that specified. Improvising or using a fuse with the wrong amperage rat- ing may cause extensive damage to the electrical system, cause the ignition sys- tems to malfunction and could possibly...

  • Page 90: Eng

    ENGINE EBS00198 ENGINE ENGINE EXHAUST PIPE/MUFFLER, BREATHER HOSE AND LEADS 25 Nm (2.5 m kg, 18 ft • • 10 Nm (1.0 m kg, 7.2 ft • • Order Job/Part Q’ty Remarks Removing the exhaust pipe/muffler, Remove the parts in the order listed. breather hose and leads Rear fender Refer to “SEAT, FENDERS AND FUEL...

  • Page 91: Engine Mounting Bolts

    ENGINE EBS00205 ENGINE MOUNTING BOLTS 33 Nm (3.3 m kg, 24 ft • • 33 Nm (3.3 m kg, 24 ft • • Order Job/Part Q’ty Remarks Removing the engine mounting Remove the parts in the order listed. bolts Carburetor Refer to “CARBURETOR”...
  • Page 92 ENGINE 33 Nm (3.3 m kg, 24 ft • • 33 Nm (3.3 m kg, 24 ft • • Order Job/Part Q’ty Remarks Upper engine mounting nut/bolt Refer to “INSTALLING THE ENGINE”. Engine assembly Dust boot Refer to “REMOVING THE ENGINE” and “INSTALLING THE ENGINE”.

  • Page 93: Removing The Engine

    ENGINE REMOVING THE ENGINE 1. Remove: • metal clamps NOTE: After removing the metal clamps, slide the dust boot 1 towards the swingarm. EBS00207 INSTALLING THE ENGINE 1. Install: • dust boot 1 NOTE: Before mounting the engine assembly, install the dust boot onto the middle driven gear bear- ing housing.

  • Page 94: Cylinder Head

    CYLINDER HEAD EBS00218 CYLINDER HEAD Order Job/Part Q’ty Remarks Removing the cylinder head Remove the parts in the order listed. Carburetor assembly Refer to “CARBURETOR” in chapter 5. Exhaust pipe/muffler Refer to “ENGINE”. C.D.I. magneto cover Refer to “C.D.I. MAGNETO”. Spark plug lead Spark plug Camshaft sprocket cover...
  • Page 95 CYLINDER HEAD Order Job/Part Q’ty Remarks Exhaust side timing chain guide Cylinder head gasket Dowel pin For installation, reverse the removal pro- cedure. 4 - 6...

  • Page 96: Removing The Cylinder Head

    CYLINDER HEAD EBS00220 REMOVING THE CYLINDER HEAD 1. Align: • “T” mark on the rotor (with the stationary pointer on the crank- case) M MMM M MMM M MMM M MMM M MMM a. Turn the crankshaft counterclockwise with a wrench.

  • Page 97: Checking The Camshaft Sprocket

    CYLINDER HEAD 4. Remove: • bolts • nuts • cylinder head 1 NOTE: Working in a crisscross pattern, loosen each nut 1/4 of a turn. EBS00224 CHECKING THE CAMSHAFT SPROCKET 1. Check: • camshaft sprocket Wear/damage → Replace the camshaft sprocket and timing chain as a set.

  • Page 98: Checking The Cylinder Head

    CYLINDER HEAD EBS00230 CHECKING THE CYLINDER HEAD 1. Eliminate: • combustion chamber carbon deposits (with a rounded scraper) NOTE: Do not use a sharp instrument to avoid damag- ing or scratching: • spark plug bore threads • valve seats 2. Check: •...

  • Page 99: Installing The Cylinder Head

    CYLINDER HEAD EBS00233 INSTALLING THE CYLINDER HEAD 1. Install: • cylinder head 1 • nuts • bolts NOTE: Tighten the nuts in two stages and a crisscross pattern. 2. Install: • camshaft sprocket M MMM M MMM M MMM M MMM M MMM a.
  • Page 100 CYLINDER HEAD i. If the marks are aligned, temporarily tighten the camshaft sprocket bolt. If the marks are not aligned, change the meshing position of the camshaft sprocket and timing chain. L LLL L LLL L LLL L LLL L LLL 3.

  • Page 101: Camshaft, Rocker Arms And Valves

    CAMSHAFT, ROCKER ARMS AND VALVES EBS00235 CAMSHAFT, ROCKER ARMS AND VALVES Order Job/Part Q’ty Remarks Removing the camshaft, rocker Remove the parts in the order listed. arms and valves Cylinder head Refer to “CYLINDER HEAD”. Intake manifold Rocker arm shaft Refer to “REMOVING THE ROCKER Rocker arm ARMS AND CAMSHAFT”...
  • Page 102 CAMSHAFT, ROCKER ARMS AND VALVES Order Job/Part Q’ty Remarks Valve guide For installation, reverse the removal pro- cedure. 4 - 13...

  • Page 103: Removing The Rocker Arms And Camshaft

    CAMSHAFT, ROCKER ARMS AND VALVES EBS00237 REMOVING THE ROCKER ARMS AND CAMSHAFT 1. Loosen: • locknuts • adjusters 2. Remove: • intake rocker arm shaft • exhaust rocker arm shaft • intake rocker arm • exhaust rocker arm NOTE: Remove the rocker arm shafts with the slide hammer bolt 1 and weight 2.

  • Page 104: Checking The Camshaft

    CAMSHAFT, ROCKER ARMS AND VALVES 2. Remove: • valve cotters NOTE: Attach a valve spring compressor 1 and attachment 2 between the valve spring retainer and the cylinder head to remove the valve cotters. Valve spring compressor P/N. YM-04019, 90890-04019 Valve spring compressor attach- ment P/N.
  • Page 105 CAMSHAFT, ROCKER ARMS AND VALVES 2. Check: • rocker arm shaft Blue discoloration/excessive wear/pitting/ scratches → Replace or check the lubrica- tion system. 3. Check: • camshaft lobe Excessive wear → Replace the camshaft. 4. Measure: • rocker arm inside diameter a Out of specification →...

  • Page 106: Checking The Valves And Valve Springs

    CAMSHAFT, ROCKER ARMS AND VALVES EBS00240 CHECKING THE VALVES AND VALVE SPRINGS 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. Stem-to-guide clearance Intake 0.010 ~ 0.037 mm (0.0004 ~ 0.0015 in)
  • Page 107 CAMSHAFT, ROCKER ARMS AND VALVES 3. Check: • valve face Pitting/wear → Grind the face. • valve stem end Mushroom shape or diameter larger than the body of the stem → Replace. 4. Measure: • margin thickness a Out of specification → Replace. Margin thickness Intake 0.5 ~ 0.9 mm...
  • Page 108 CAMSHAFT, ROCKER ARMS AND VALVES 8. Measure: • valve seat width a Out of specification → Reface the valve seat. Valve seat width Intake 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in) <Limit>: 1.6 mm (0.063 in) Exhaust 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in) <Limit>: 1.6 mm (0.063 in) M MMM...
  • Page 109 CAMSHAFT, ROCKER ARMS AND VALVES b. Apply molybdenum disulfide oil to the valve stem. c. Install the valve into the cylinder head. d. Turn the valve until the valve face and valve seat are evenly polished, then clean off all of the compound.

  • Page 110: Installing The Valves And Valve Springs

    CAMSHAFT, ROCKER ARMS AND VALVES 12.Measure: • spring tilt a Out of specification → Replace. Spring tilt limit Inner 2.5°/1.4 mm (2.5°/0.06 in) EBS00241 INSTALLING THE VALVES AND VALVE SPRINGS 1. Apply: • molybdenum disulfide oil (onto the valve stem and valve stem seal) 2.

  • Page 111: Installing The Camshaft And Rocker Arms

    CAMSHAFT, ROCKER ARMS AND VALVES EBS00243 INSTALLING THE CAMSHAFT AND ROCKER ARMS 1. Install: • camshaft 1 NOTE: Install the camshaft groove a facing down. 2. Apply: • engine oil (onto the rocker arm shafts) 3. Install: • rocker arms 1 •...

  • Page 112: Cylinder And Piston

    CYLINDER AND PISTON EBS00245 CYLINDER AND PISTON Order Job/Part Q’ty Remarks Removing the cylinder and piston Remove the parts in the order listed. Cylinder head Refer to “CYLINDER HEAD”. Cylinder Refer to “INSTALLING THE CYLINDER”. Cylinder gasket Dowel pin Piston pin clip Piston pin Refer to “REMOVING THE PISTON”...

  • Page 113: Removing The Piston

    CYLINDER AND PISTON EBS00247 REMOVING THE PISTON 1. Remove: • piston pin clips 1 • piston pin 2 • piston 3 NOTE: Before removing each piston pin, deburr the clip groove and pin hole area. If the piston pin groove is deburred and the piston pin is still difficult to remove, use the piston pin puller 4.
  • Page 114 CYLINDER AND PISTON 39.000 ~ 39.005 mm Cylinder bore “C” (1.5354 ~ 1.5356 in) Taper limit “T” 0.05 mm (0.002 in) Out-of-round “R” 0.01 mm (0.0004 in) “C” = maximum of D “T” = maximum of D or D – maximum of D or D “R”...

  • Page 115: Checking The Piston Rings

    CYLINDER AND PISTON EBS00250 CHECKING THE PISTON RINGS 1. Measure: • piston ring side clearance Out of specification → Replace the piston and piston rings as a set. NOTE: Before measuring the piston ring side clear- ance, eliminate any carbon deposits from the piston ring grooves and piston rings.

  • Page 116: Checking The Piston Pin

    CYLINDER AND PISTON EBS00251 CHECKING THE PISTON PIN 1. Check: • piston pin Blue discoloration/grooves → Replace the piston pin and then check the lubrication system. 2. Measure: • piston pin outside diameter a Out of specification → Replace the piston pin.

  • Page 117: Installing The Piston

    CYLINDER AND PISTON EBS00252 INSTALLING THE PISTON 1. Install: • piston rings (onto the piston) NOTE: • Be sure to install the piston rings so that the manufacturer’s marks numbers located on the upper side of the rings. • Lubricate the piston and piston rings liberally with engine oil.

  • Page 118: Installing The Cylinder

    CYLINDER AND PISTON EBS00253 INSTALLING THE CYLINDER 1. Install: • cylinder NOTE: Install the cylinder with one hand while com- pressing the piston rings with the other hand. CAUTION: • Be careful not to damage the timing chain damper during installation. •...

  • Page 119: C.d.i. Magneto

    C.D.I. MAGNETO EBS00256 C.D.I. MAGNETO Order Job/Part Q’ty Remarks Removing the C.D.I. magneto Remove the parts in the order listed. Rear fender Refer to “SEAT, FENDERS AND FUEL TANK” in chapter 3. Shift lever Refer to “INSTALLING THE SHIFT LEVER”. C.D.I.

  • Page 120: Removing The C.d.i. Magneto Rotor

    C.D.I. MAGNETO EBS00259 REMOVING THE C.D.I. MAGNETO ROTOR 1. Remove: • C.D.I. magneto rotor nut • washer NOTE: • While holding the C.D.I. magneto rotor 1 with the sheave holder 2, loosen the rotor nut. • Do not allow the sheave holder to touch the projection on the rotor.

  • Page 121: Installing The C.d.i. Magneto Rotor

    C.D.I. MAGNETO EBS00268 INSTALLING THE C.D.I. MAGNETO ROTOR 1. Install: • woodruff key • C.D.I. magneto rotor NOTE: • Before installing the rotor, clean the outside of the crankshaft and the inside of the rotor. • After installing the rotor, check that the rotor rotates smoothly.

  • Page 122: Clutch

    CLUTCH EBS00291 CLUTCH Order Job/Part Q’ty Remarks Removing the clutch Remove the parts in the order listed. Engine oil Drain. Refer to “CHANGING THE ENGINE OIL” in chapter 3. C.D.I. magneto cover Refer to “C.D.I. MAGNETO”. Clutch cover Refer to “REMOVING THE CLUTCH” and “INSTALLING THE CLUTCH”.
  • Page 123 CLUTCH Order Job/Part Q’ty Remarks Clutch plate 1 Clutch plate 2 Friction plate 2 Thrust weight plate Clutch ball Refer to “INSTALLING THE CLUTCH”. Thrust plate Clutch boss Clutch boss one-way cam Primary driven gear/clutch housing Spacer Primary drive gear Refer to “REMOVING THE PRIMARY DRIVE GEAR”...

  • Page 124: Removing The Clutch

    CLUTCH EBS00297 REMOVING THE CLUTCH 1. Remove: • clutch cover NOTE: Loosen each screw 1/4 of a turn at a time, in stages and in a crisscross pattern. After all of the screws are fully loosened, remove them. 2. Loosen: •...

  • Page 125: Checking The Clutch Plates

    CLUTCH EBS00301 CHECKING THE CLUTCH PLATES The following procedure applies to all of the clutch plates. 1. Check: • clutch plate Damage → Replace the clutch plates as a set. 2. Measure: • clutch plate warpage (with a surface plate and thickness gauge Out of specification →...

  • Page 126: Checking The Clutch Boss

    CLUTCH EBS00304 CHECKING THE CLUTCH BOSS 1. Check: • clutch boss splines • clutch boss cam groove • clutch boss one-way cam Damage/pitting/wear → Replace the clutch boss and clutch boss one-way cam as a set. NOTE: Pitting on the clutch boss splines will cause erratic clutch operation.

  • Page 127: Installing The Primary Drive Gear

    CLUTCH EBS00310 INSTALLING THE PRIMARY DRIVE GEAR 1. Tighten: • primary drive gear nut 1 50 Nm (5.0 m · kg, 36 ft · lb) NOTE: Place an aluminum plate 2 between the teeth of the primary driven gear/clutch housing 3 and primary drive gear 4.
  • Page 128 CLUTCH 3. Install: • friction plate 2 1 • clutch plates 2 2 • friction plates 1 (with black color marking) • clutch plate 1 4 5 thrust weight plate a silver section NOTE: Install the clutch plates and friction plates alter- nately on the clutch boss, starting and ending with a friction plate.
  • Page 129 CLUTCH 5. Install: • clutch housing 1 NOTE: Make sure that the primary driven gear teeth and primary drive gear teeth mesh correctly. 6. Install: • clutch boss one-way cam 1 • clutch boss 2 NOTE: Align section a of the clutch boss one-way cam with section b of the clutch boss and then install the primary driven gear/clutch housing.
  • Page 130 CLUTCH 9. Install: • thrust weight plate 1 • friction plate 2 2 • clutch plates 2 3 • friction plates 1 4 • clutch plate 1 5 • pressure plate 6 a silver section NOTE: Install the clutch plates and friction plates alter- nately on the clutch boss, starting and ending with a friction plate.

  • Page 131: Starter Clutch And Oil Pump

    STARTER CLUTCH AND OIL PUMP EBS00315 STARTER CLUTCH AND OIL PUMP Order Job/Part Q’ty Remarks Removing the starter clutch and oil Remove the parts in the order listed. pump Clutch assembly Refer to “CLUTCH”. Starter idle gear assembly Starter wheel gear Starter clutch assembly Spacer Oil pump drive gear...
  • Page 132 STARTER CLUTCH AND OIL PUMP EBS00316 Order Job/Part Q’ty Remarks Disassembling the oil pump Remove the parts in the order listed. Oil pump housing cover Oil pump shaft Inner rotor Outer rotor Oil pump housing For assembly, reverse the disassembly procedure.

  • Page 133: Checking The Starter Clutch

    STARTER CLUTCH AND OIL PUMP EBS00263 CHECKING THE STARTER CLUTCH 1. Check: • starter clutch rollers 1 Cracks/damage → Replace. 2. Check: • starter clutch screws 1 Loose → Replace with a new one, and clinch the end of the screw. Starter clutch screw 10 Nm (1.0 m ·...

  • Page 134: Checking The Oil Pump

    STARTER CLUTCH AND OIL PUMP 4. Check: • starter idle gear teeth 1 • starter wheel gear teeth 2 Burrs/clips/roughness/wear → Replace. 5. Check: • starter wheel gear contacting surface a Damage/pitting/wear → Replace. EBS00330 CHECKING THE OIL PUMP 1. Check: •...
  • Page 135 STARTER CLUTCH AND OIL PUMP 3. Measure: • inner-rotor-to-outer-rotor-tip clearance a • outer-rotor-to-oil-pump-housing clearance • oil-pump-housing-to-inner-rotor-and-outer- rotor clearance c Out of specification → Replace the oil pump. 1 Inner rotor 2 Outer rotor 3 Oil pump housing Inner-rotor-to-outer-rotor-tip clearance 0.05 ~ 0.07 mm (0.002 ~ 0.003 in) <Limit>: 0.15 mm (0.006 in) Outer-rotor-to-oil-pump-housing...

  • Page 136: Shift Shaft

    SHIFT SHAFT SHIFT SHAFT Order Job/Part Q’ty Remarks Removing the shift shaft Remove the parts in the order listed. Clutch assembly Refer to “CLUTCH”. Shift shaft Stopper lever Dowel pin For installation, reverse the removal pro- cedure. 4 - 47...

  • Page 137: Checking The Shift Shaft

    SHIFT SHAFT EBS01018 CHECKING THE SHIFT SHAFT 1. Check: • shift shaft 1 Bends/damage/wear → Replace. • shift shaft spring 2 Damage/wear → Replace. EBS01019 CHECKING THE STOPPER LEVER 1. Check: • stopper lever 1 • stopper lever spring 2 Bends/damage →...

  • Page 138: Crankcase

    CRANKCASE EBS00319 CRANKCASE Order Job/Part Q’ty Remarks Removing the timing chain and sep- Remove the parts in the order listed. arating the crankcase Engine Refer to “ENGINE”. Cylinder head Refer to “CYLINDER HEAD”. Cylinder and piston Refer to “CYLINDER AND PISTON”. C.D.I.

  • Page 139: Crankcase Bearings

    CRANKCASE EBS00321 CRANKCASE BEARINGS 8 Nm (0.8 m kg, 5.8 ft • • Order Job/Part Q’ty Remarks Removing the crankcase bearings Remove the parts in the order listed. Crankshaft Refer to “CRANKSHAFT”. Transmission Refer to “TRANSMISSION”. Middle driven pinion gear Refer to “MIDDLE GEAR”.

  • Page 140: Separating The Crankcase

    CRANKCASE EBS00333 SEPARATING THE CRANKCASE 1. Separate: • right crankcase • left crankcase M MMM M MMM M MMM M MMM M MMM a. Remove the crankcase screws. NOTE: • Loosen each screw 1/4 of a turn at a time and after all the screws are loosened, remove them.

  • Page 141: Checking The Bearings And Oil Seals

    CRANKCASE EBS00339 CHECKING THE BEARINGS AND OIL SEALS 1. Check: • bearings Clean and lubricate, then rotate the inner race with a finger. Roughness → Replace. 2. Check: • oil seals Damage/wear → Replace. EBS00338 CHECKING THE CRANKCASE 1. Thoroughly wash the case halves in a mild solvent.

  • Page 142: Assembling The Crankcase

    CRANKCASE EBS00341 ASSEMBLING THE CRANKCASE 1. Apply: ® • sealant (Quick Gasket ) or Yamaha bond No. 1215 1 (to the mating surfaces of both case halves) ® Sealant (Quick Gasket P/N. ACC-11001-05-01 Yamaha bond No. 1215 P/N. 90890-85505 2. Install: •...

  • Page 143: Crankshaft

    CRANKSHAFT EBS00326 CRANKSHAFT Order Job/Part Q’ty Remarks Removing the crankshaft Remove the parts in the order listed. Crankcase Separate. Refer to “CRANKCASE”. Crankshaft Refer to “INSTALLING THE CRANK- SHAFT”. For installation, reverse the removal pro- cedure. 4 - 54...

  • Page 144: Checking The Crankshaft

    CRANKSHAFT EBS00361 CHECKING THE CRANKSHAFT 1. Measure: • crank width a Out of specification → Replace the crank- shaft. Crank width 40.20 ~ 40.25 mm (1.5827 ~ 1.5846 in) 2. Measure: • side clearance d Out of specification → Replace the crank- shaft.

  • Page 145: Transmission

    TRANSMISSION EBS00345 TRANSMISSION Order Job/Part Q’ty Remarks Removing the transmission Remove the parts in the order listed. Crankcase Separate. Refer to “CRANKCASE”. Main axle/1st pinion gear Shift fork guide bar Shift fork Refer to “REMOVING THE TRANSMIS- SION” and “INSTALLING THE TRANS- Drive axle/middle drive pinion gear MISSION”.

  • Page 146: Removing The Transmission

    TRANSMISSION REMOVING THE TRANSMISSION 1. Remove: • shift fork guide bar 1 • shift fork 2 • drive axle/middle drive pinion gear assem- bly 3 • shift drum 4 NOTE: Remove the shift fork guide bar, shift fork, drive axle/middle drive gear assembly, and shift drum from the crankcase together.

  • Page 147: Checking The Shift Drum

    TRANSMISSION EBS01103 CHECKING THE SHIFT DRUM 1. Check: • shift drum grooves Damage/scratches/wear → Replace the shift drum assembly. • shift drum segment 1 Damage/wear → Replace the shift drum assembly. EBS00354 CHECKING THE TRANSMISSION 1. Measure: • main axle runout (with a centering device and dial gauge 1) Out of specification →...

  • Page 148: Installing The Transmission

    TRANSMISSION EBS00357 INSTALLING THE TRANSMISSION 1. Install: • shift drum 1 • drive axle/middle drive pinion gear assem- bly 2 • shift fork 3 • shift fork guide bar 4 NOTE: • The embossed marks on the shift fork should face towards the left of the engine.

  • Page 149: Middle Gear

    MIDDLE GEAR EBS00363 MIDDLE GEAR Order Job/Part Q’ty Remarks Removing the middle gear Remove the parts in the order listed. Crankcase Separate. Refer to “CRANKCASE”. Drive axle/middle drive pinion gear Refer to “TRANSMISSION”. assembly Middle drive gear shim Middle driven gear shim Refer to “SELECTING MIDDLE DRIVEN GEAR SHIMS”.

  • Page 150: Removing The Middle Driven Shaft

    MIDDLE GEAR EBS00366 REMOVING THE MIDDLE DRIVEN SHAFT 1. Remove: • universal joint M MMM M MMM M MMM M MMM M MMM a. Remove the circlips. b. Place the universal joint in a press. c. With a suitable diameter pipe 1 beneath the yoke 2, press the bearings 3 into the pipe as shown.

  • Page 151: Checking The Pinion Gears

    MIDDLE GEAR 3. Remove: • bearing housing assembly 1 M MMM M MMM M MMM M MMM M MMM a. Clean the outside of the middle driven shaft. b. Place the middle driven shaft onto a hydrau- lic press. CAUTION: •...

  • Page 152: Selecting Middle Driven Gear Shims

    MIDDLE GEAR 2. Check: • O-ring Damage → Replace. • bearings Pitting/damage → Replace. 3. Check: • universal joint movement Roughness → Replace universal joint. EBS00370 SELECTING MIDDLE DRIVEN GEAR SHIMS When the drive and driven gear, bearing hous- ing assembly and/or crankcase replaced, be sure to adjust the gear shim 1.

  • Page 153: Installing The Middle Driven Shaft

    MIDDLE GEAR EBS00373 INSTALLING THE MIDDLE DRIVEN SHAFT 1. Install: • bearing retainer M MMM M MMM M MMM M MMM M MMM a. Secure the bearing housing edge in the vise with a clean rag 1. NOTE: ® Apply locking agent (LOCTITE ) to the threads of bearing retainer.
  • Page 154 MIDDLE GEAR 3. Install: • universal joint M MMM M MMM M MMM M MMM M MMM a. Install the yoke into the universal joint. b. Apply wheel bearing grease to the bearings. c. Install the bearing 1 onto the yoke. CAUTION: Check each bearing.

  • Page 155: Measuring The Middle Gear Backlash

    MIDDLE GEAR EBS00376 MEASURING THE MIDDLE GEAR BACKLASH 1. Measure: • middle gear lash Middle gear lash 0.17 ~ 0.31 mm (0.007 ~ 0.012 in) M MMM M MMM M MMM M MMM M MMM a. Temporarily install the drive axle/middle drive pinion gear assembly and middle driven pinion gear.

  • Page 156: Carb

    CARB CARBURETOR EBS00141 CARBURETOR CARBURETOR 7 Nm (0.7 m kg, 5.1 ft • • Order Job/Part Q’ty Remarks Removing the carburetor Remove the parts in the order listed. Fuel overflow hose Carburetor air vent hose Fuel hose Carburetor assembly Carburetor top cover Throttle cable Spring Refer to “INSTALLING THE CARBURE-...
  • Page 157 CARB CARBURETOR EBS00144 Order Job/Part Q’ty Remarks Disassembling the carburetor Remove the parts in the order listed. NOTE: Before disassembling the carburetor, make sure to note the number of times the pilot screw is turned out from the seated position to its set position. Throttle stop screw Float chamber Pilot jet...
  • Page 158 CARB CARBURETOR Order Job/Part Q’ty Remarks Float Refer to “ASSEMBLING THE CARBURE- TOR”. Needle valve For assembly, reverse the disassembly procedure. 5 - 3...

  • Page 159: Disassembling The Carburetor

    CARB CARBURETOR EBS00146 DISASSEMBLING THE CARBURETOR NOTE: Before disassembling the carburetor, make sure to note the number of times the pilot screw is turned out from the seated position to its set position. EBS00148 CHECKING THE CARBURETOR 1. Check: • carburetor body •...
  • Page 160 CARB CARBURETOR 4. Check: • piston valve 1 Scratches/wear/damage → Replace. 5. Check: • carburetor top cover 1 • spring 2 Cracks/damage → Replace. 6. Check: • jet needle 1 • main jet 2 • needle jet 3 • pilot jet 4 •...

  • Page 161: Assembling The Carburetor

    CARB CARBURETOR EBS00150 ASSEMBLING THE CARBURETOR NOTE: Before assembling the carburetor, make sure to turn out the pilot air screw the same number of times, as noted before disassembly, from the seated position to the set position. CAUTION: • Before reassembling, wash all of the parts in a clean petroleum based solvent.

  • Page 162: Measuring And Adjusting The Fuel Level

    CARB CARBURETOR EBS00154 MEASURING AND ADJUSTING THE FUEL LEVEL 1. Measure: • fuel level a Out of specification → Adjust. Fuel level (below the float chamber mating surface) 4.0 ~ 5.0 mm (0.16 ~ 0.20 in) M MMM M MMM M MMM M MMM M MMM...

  • Page 163: Driv

    DRIV TROUBLESHOOTING EBS00155 DRIVE TRAIN TROUBLESHOOTING The following conditions may indicate damaged shaft drive components: Symptoms Possible Causes 1. A pronounced hesitation or “jerky” move- A. Bearing damage. ment during acceleration deceleration or B. Improper gear lash. sustained speed. (This must not be con- C.

  • Page 164: Checking Noises

    DRIV TROUBLESHOOTING EBS00156 CHECKING NOISES 1. Investigate any unusual noises. M MMM M MMM M MMM M MMM M MMM a. A “rolling rumble” noise during coasting, acceleration, or deceleration. The noise increases with rear wheel speed, but it does not increase with higher engine or transmis- sion speeds.
  • Page 165 DRIV TROUBLESHOOTING 3. Check: • oil leakage M MMM M MMM M MMM M MMM M MMM a. Clean the entire machine thoroughly, then dry it. b. Apply a leak-localizing compound or dry powder spray to the shaft drive. c. Road test the machine for the distance nec- essary to locate the leak.

  • Page 166: Troubleshooting Chart

    DRIV TROUBLESHOOTING EBS00157 TROUBLESHOOTING CHART When basic condition “a” and “b” exist, check the following points: Check the wheel and hub nuts for tightness. Torque to specification. (Refer to “FRONT AND REAR WHEELS” in chapter 7.) Check the rear brake adjustment. Adjust per instructions.

  • Page 167: Rear Axle/Final Drive Assembly And Drive Shaft

    REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT EBS00178 REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT Order Job/Part Q’ty Remarks Removing the rear axle/final drive Remove the parts in the order listed. assembly and drive shaft Rear wheels Refer to “FRONT AND REAR WHEELS” in chapter 7.
  • Page 168 REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT Order Job/Part Q’ty Remarks Rear axle/final drive assembly Refer to “REMOVING THE REAR AXLE/ FINAL DRIVE ASSEMBLY” and Drive shaft “INSTALLING THE REAR AXLE/FINAL Coupling gear DRIVE ASSEMBLY”. For installation, reverse the removal pro- cedure.

  • Page 169: Rear Axle/Final Drive Assembly

    REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT EBS00179 REAR AXLE/FINAL DRIVE ASSEMBLY Order Job/Part Q’ty Remarks Disassembling the rear axle/final Remove the parts in the order listed. drive assembly Rear axle housing Rear axle housing bearing retainer Refer to “DISASSEMBLING THE REAR AXLE HOUSING”...

  • Page 170: Removing The Nuts

    REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT REMOVING THE NUTS 1. Place the machine on a level surface. 2. Loosen: • nuts 1 NOTE: • Apply the rear brake lever so that the rear axle does not turn, when loosening the nuts. •...

  • Page 171: Disassembling The Rear Axle Housing

    REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT EBS00181 DISASSEMBLING THE REAR AXLE HOUSING 1. Remove: • rear axle housing bearing retainer NOTE: Use a ring nut wrench 1. Ring nut wrench P/N. YM-38404, 90890-01430 EBS00181 DISASSEMBLING THE FINAL GEAR CASE 1.

  • Page 172: Checking The Rear Axle

    REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT EBS00190 CHECKING THE REAR AXLE 1. Check: • rear axle runout a Out of specification → Replace. WARNING Do not attempt to straighten a bent axle. Rear axle runout limit 1.5 mm (0.06 in) EBS00191 CHECKING THE DRIVE SHAFT 1.

  • Page 173: Assembling The Final Gear Case

    REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT EBS00195 ASSEMBLING THE FINAL GEAR CASE 1. Install: • final drive pinion gear assembly • spacer 1 • bearing • final gear case bearing retainer 80 Nm (8.0 m · kg, 58 ft · lb) Use a ring nut wrench 2.

  • Page 174: Installing The Rear Axle/Final Drive Assembly

    No. 1215 to the mating surfaces of the swingarm and the final gear case. ® Sealant (Quick Gasket P/N. ACC-11001-05-01 Yamaha bond No. 1215 P/N. 90890-85505 b. Temporarily install the rear axle/final drive assembly 1 on the swingarm 2. The bolts and nuts should be temporarily tightened.

  • Page 175: Installing The Nuts

    REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE DRIV SHAFT EBS00397 INSTALLING THE NUTS 1. Tighten: • nuts 1, 2 M MMM M MMM M MMM M MMM M MMM a. Check if the rear brake assembly is installed on the rear axle housing. If the rear brake assembly is not installed, refer to “FRONT AND REAR BRAKES”...

  • Page 176: Chas

    CHAS FRONT AND REAR WHEELS EBS00378 CHASSIS FRONT AND REAR WHEELS FRONT WHEELS Order Job/Part Q’ty Remarks Removing the front wheels Remove the parts in the order listed. Place the machine on a level surface. WARNING Securely support the machine so there is no danger of it falling over.

  • Page 177: Rear Wheels

    CHAS FRONT AND REAR WHEELS EBS00379 REAR WHEELS Order Job/Part Q’ty Remarks Removing the rear wheels Remove the parts in the order listed. Place the machine on a level surface. WARNING Securely support the machine so there is no danger of it falling over. The following procedure applies to both of the rear wheels.

  • Page 178: Checking The Wheels

    CHAS FRONT AND REAR WHEELS EBS00383 CHECKING THE WHEELS The following procedure applies to both of the front and rear wheels. 1. Check: • wheel 2. Measure: • wheel runout Over the specified limit → Replace the wheel or check the wheel bearing play 1. Wheel runout limit Radial 2: 2.0 mm (0.08 in) Lateral 3: 2.0 mm (0.08 in)

  • Page 179: Checking The Rear Wheel Hubs

    CHAS FRONT AND REAR WHEELS WARNING Eye protection is recommended when using striking tools. c. To install the wheel bearings, reverse the above sequence. Use a socket that matches outside diameter of bearing outer race to drive in bearing. CAUTION: Do not strike the center race or balls of the bearing.

  • Page 180: Installing The Wheels

    CHAS FRONT AND REAR WHEELS EBS00391 È INSTALLING THE WHEELS The following procedure applies to both of the front and rear wheels. 1. Install: • wheel NOTE: The arrow mark 1 on the tire must point in the direction of rotation + of the wheel. È...

  • Page 181: Front And Rear Brakes

    CHAS FRONT AND REAR BRAKES EBS00437 FRONT AND REAR BRAKES FRONT BRAKE Order Job/Part Q’ty Remarks Removing the front brakes Remove the parts in the order listed. Front wheels Refer to “FRONT AND REAR WHEELS”. The following procedure applies to both of the front brakes.

  • Page 182: Rear Brake

    CHAS FRONT AND REAR BRAKES REAR BRAKE Order Job/Part Q’ty Remarks Removing the rear brake Remove the parts in the order listed. Refer to “FRONT AND REAR WHEELS”. Brake drum cover Refer to “REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT” in chapter 6.
  • Page 183 CHAS FRONT AND REAR BRAKES Order Job/Part Q’ty Remarks Rear brake cable (lever side) Rear brake switch Rear brake lever For installation, reverse the removal pro- cedure. 7 - 8...

  • Page 184: Removing The Brakes

    CHAS FRONT AND REAR BRAKES REMOVING THE BRAKES The following procedure applies to each brake. 1. Remove: • brake camshaft lever • brake shoe wear indicator • brake camshaft NOTE: When removing the brake camshaft lever, mark the position on the brake camshaft lever where it is aligned with the punch mark in the brake camshaft.

  • Page 185: Checking The Brake Drums

    CHAS FRONT AND REAR BRAKES 2. Check: • brake shoe lining surface Glazed areas → Remove. Use coarse sandpaper. NOTE: After using sandpaper, wipe off the polished particles with a cloth. 3. Measure: • brake shoe lining thickness a Out of specification → Replace. 1 Measuring points NOTE: Replace the brake shoes as a set if either is...

  • Page 186: Installing The Front Brakes

    CHAS FRONT AND REAR BRAKES 2. Check: È É • brake drum inner surface Oil/scratches → Remove. Use a rag soaked in lacquer thinner or solvent. Use an emery cloth (light Scratches and even polishing). È Front brake drum É Rear brake drum EBS00442 INSTALLING THE FRONT BRAKES The following procedure applies to both of the...

  • Page 187: Installing The Rear Brake

    CHAS FRONT AND REAR BRAKES 3. Install: • brake shoe plate 1 NOTE: When installing the brake shoe plate, align the groove a of the brake shoe plate with the pro- jection b of the steering knuckle. 4. Install: • front brake cable (drum side) •...
  • Page 188 CHAS FRONT AND REAR BRAKES 2. Install: • brake camshaft 1 • brake shoe wear indicator plate 2 • brake camshaft lever 9 Nm (0.9 m · kg, 6.5 ft · lb) NOTE: • Install the brake camshaft so its punch mark a is positioned as shown.

  • Page 189: Steering System

    CHAS STEERING SYSTEM EBS00444 STEERING SYSTEM HANDLEBAR Order Job/Part Q’ty Remarks Removing the handlebar Remove the parts in the order listed. Handlebar cover Refer to “SEAT, FENDERS AND FUEL TANK” in chapter 3. Handlebar grip Refer to “REMOVING THE HANDLEBAR GRIPS”...
  • Page 190 CHAS STEERING SYSTEM Order Job/Part Q’ty Remarks Upper handlebar holder Refer to “INSTALLING THE HANDLE- Handlebar BAR”. Lower handlebar holder For installation, reverse the removal pro- cedure. 7 - 15...

  • Page 191: Removing The Handlebar Grips

    CHAS STEERING SYSTEM EBS00447 REMOVING THE HANDLEBAR GRIPS 1. Remove: • handlebar grips 1 NOTE: Blow compressed air between the handlebar and handlebar grip, and gradually push the grip off the handlebar. EBS00445 REMOVING THE REAR BRAKE SWITCH 1. Remove: •...

  • Page 192: Installing The Handlebar

    CHAS STEERING SYSTEM EBS00449 INSTALLING THE HANDLEBAR 1. Install: • lower handlebar holder • handlebar • upper handlebar holders 20 Nm (2.0 m · kg, 14 ft · lb) NOTE: • Install the handlebar within 15° from the hori- zontal line shown in the illustration. •...

  • Page 193: Installing The Rear Brake Lever

    CHAS STEERING SYSTEM EBS00451 INSTALLING THE REAR BRAKE LEVER 1. Install: • rear brake lever 1 • handlebar switch 2 NOTE: • Install the rear brake lever within 10° from the horizontal line shown in the illustration. • After installing the rear brake lever, make sure the rear brake lever 1, handlebar switch 2, and handlebar grip 3 are in the positions shown in the illustration.

  • Page 194: Steering Stem

    CHAS STEERING SYSTEM EBS00454 STEERING STEM Order Job/Part Q’ty Remarks Removing the steering stem Remove the parts in the order listed. Front fender Refer to “SEAT, FENDERS AND FUEL TANK” in chapter 3. Handlebar Refer to “HANDLEBAR”. Lock washer Refer to “INSTALLING THE LOCK WASHER”.

  • Page 195: Removing The Steering Stem

    CHAS STEERING SYSTEM EBS00455 REMOVING THE STEERING STEM 1. Remove: • steering stem NOTE: When loosening each tie-rod end nut 1, hold the tie-rod ball joint with a 14-mm wrench 2. EBS00456 CHECKING THE STEERING STEM 1. Check: • steering stem Bends →...

  • Page 196: Tie-Rods And Steering Knuckles

    CHAS STEERING SYSTEM EBS00460 TIE-RODS AND STEERING KNUCKLES Order Job/Part Q’ty Remarks Removing the tie-rods and steering Remove the parts in the order listed. knuckles Front brakes Refer to “FRONT AND REAR BRAKES”. The following procedure applies to both of the tie-rods and steering knuckles. Tie-rod Refer to “REMOVING THE TIE-RODS”...

  • Page 197: Removing The Tie-Rods

    CHAS STEERING SYSTEM EBS00461 REMOVING THE TIE-RODS The following procedure applies to both of the tie-rods. 1. Remove: • tie-rod 1 NOTE: When removing the tie-rod, hold each tie-rod ball joint with a 14-mm wrench 2 and then loosen the tie-rod end nut. EBS00462 CHECKING THE TIE-RODS The following procedure applies to both of the...

  • Page 198: Installing The Tie-Rods

    CHAS STEERING SYSTEM EBS00465 INSTALLING THE TIE-RODS The following procedure applies to both of the tie-rods. 1. Install: • tie-rod 15 Nm (1.5 m · kg, 11 ft · lb) NOTE: • The tie-rod side which must be installed on the inside has grooves 1.

  • Page 199: Front Shock Absorber Assemblies And Front Swingarm

    FRONT SHOCK ABSORBER ASSEMBLIES AND FRONT CHAS SWINGARM EBS00468 FRONT SHOCK ABSORBER ASSEMBLIES AND FRONT SWINGARM Order Job/Part Q’ty Remarks Removing the front shock absorber Remove the parts in the order listed. assemblies and front swingarm Steering knuckles Refer to “STEERING SYSTEM”. Front shock absorber Front swingarm Refer to “REMOVING THE FRONT...

  • Page 200: Removing The Front Swingarm

    FRONT SHOCK ABSORBER ASSEMBLIES AND FRONT CHAS SWINGARM EBS00469 REMOVING THE FRONT SWINGARM 1. Check: • front swingarm free play M MMM M MMM M MMM M MMM M MMM a. Check the front swingarm side play È by moving it from side to side. If side play is noticeable, check the bush- ings.

  • Page 201: Rear Shock Absorber And Rear Swingarm

    CHAS REAR SHOCK ABSORBER AND REAR SWINGARM EBS00476 REAR SHOCK ABSORBER AND REAR SWINGARM Order Job/Part Q’ty Remarks Removing the rear shock absorber Remove the parts in the order listed. and swingarm C.D.I. magneto cover Refer to “C.D.I. MAGNETO” in chapter 4. Rear axle/final drive assembly Refer to “REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT”...

  • Page 202: Removing The Rear Swingarm

    CHAS REAR SHOCK ABSORBER AND REAR SWINGARM EBS00477 REMOVING THE REAR SWINGARM 1. Check: • swingarm free play M MMM M MMM M MMM M MMM M MMM a. Check the tightening torque of the pivot shaft. Pivot shaft 85 Nm (8.5 m · kg, 61 ft · lb) b.

  • Page 203: Checking The Rear Swingarm

    CHAS REAR SHOCK ABSORBER AND REAR SWINGARM EBS00479 CHECKING THE REAR SWINGARM 1. Check: • rear swingarm Bends/cracks/damage → Replace. 2. Check: • bushings Wear/damage → Replace. EBS00481 CHECKING THE DUST BOOT 1. Check: • dust boot 1 Damage → Replace. INSTALLING THE LOCK WASHER 1.

  • Page 204: Elec

    – ELEC ELECTRICAL COMPONENTS EBS00500 ELECTRICAL ELECTRICAL COMPONENTS 1 Main switch 8 Rectifier/regulator E Ignition coil 2 Neutral indicator light 9 Diode F C.D.I. unit 3 Rear brake switch 0 Starting circuit cut-off relay G Wire harness 4 Handlebar switch A Starter relay 5 Battery B Neutral switch...

  • Page 205: Checking Switch Continuity

    – ELEC CHECKING SWITCH CONTINUITY EBS01028 CHECKING SWITCH CONTINUITY Check each switch for continuity with the pocket tester. If the continuity reading is incor- rect, check the wiring connections and if nec- essary, replace the switch. CAUTION: Never insert the tester probes into the cou- pler terminal slots 1.

  • Page 206: Checking The Switches

    – ELEC CHECKING THE SWITCHES EBS01029 CHECKING THE SWITCHES Check each switch for damage or wear, proper connections, and also for continuity between the ter- minals. Refer to “CHECKING SWITCH CONTINUITY”. Damage/wear → Repair or replace. Improperly connected → Properly connect. Incorrect continuity reading →...

  • Page 207: Checking The Bulbs And Bulb Sockets

    – ELEC CHECKING THE BULBS AND BULB SOCKETS EBS01030 CHECKING THE BULBS AND BULB SOCKETS Check each bulb and bulb socket for damage or wear, proper connections, and also for con- tinuity between the terminals. Damage/wear → Repair or replace the bulb, bulb socket or both.
  • Page 208 – ELEC CHECKING THE BULBS AND BULB SOCKETS WARNING Since the headlight bulb gets extremely hot, keep flammable products and your hands away from the bulb until it has cooled down. CAUTION: • Be sure to hold the socket firmly when removing the bulb.

  • Page 209: Checking The Condition Of The Bulb Sockets

    – ELEC CHECKING THE BULBS AND BULB SOCKETS CHECKING THE CONDITION OF THE BULB SOCKETS The following procedure applies to all of the bulb sockets. 1. Check: • bulb socket (for continuity) (with the pocket tester) No continuity → Replace. Pocket tester P/N.

  • Page 210: Ignition System

    – ELEC IGNITION SYSTEM EBS00503 IGNITION SYSTEM CIRCUIT DIAGRAM ( BLACK ) ( BLACK ) W/R W/L W/L W/R ( GRAY ) ( GRAY ) B Y/R Y/R B R Y/R ( BLACK ) ( BLACK ) B/W B ( BLACK ) ( BLACK ) G/Y B 1 C.D.I.

  • Page 211: Troubleshooting

    – ELEC IGNITION SYSTEM EBS01045 EBS01032 TROUBLESHOOTING 1. Spark plug The ignition system fails to operate (no • Check the condition of the spark plug. spark or intermittent spark). • Check the spark plug type. • Measure the spark plug gap. Check: Refer to “CHECKING THE SPARK PLUG”...
  • Page 212 – ELEC IGNITION SYSTEM EBS01034 EBS01036 2. Ignition spark gap 3. Spark plug cap resistance • Disconnect the spark plug cap from the • Remove the spark plug cap from the spark spark plug. plug lead. • Connect the pocket tester (“Ω × 1k” range) •...
  • Page 213 – ELEC IGNITION SYSTEM EBS01038 EBS01041 4. Ignition coil resistance 5. Main switch • Disconnect the ignition coil connectors • Check the main switch for continuity. from the ignition coil terminals. Refer to “CHECKING THE SWITCHES”. • Connect the pocket tester (Ω × 1) to the •...
  • Page 214 – ELEC IGNITION SYSTEM EBS01040 EBS01099 7. Pickup coil resistance 8. Source coil resistance • Disconnect the C.D.I. magneto coupler • Disconnect the C.D.I. magneto coupler from the wire harness. from the wire harness. • Connect the pocket tester (Ω × 100) to the •...

  • Page 215: Electric Starting System

    – ELEC ELECTRIC STARTING SYSTEM EBS00506 ELECTRIC STARTING SYSTEM CIRCUIT DIAGRAM 2 Neutral switch 3 Main switch 5 Main fuse 6 Positive battery lead 7 Battery 8 Negative battery lead 9 Starter relay 0 Starter motor ( BLACK ) ( BLACK ) A Starting circuit cut-off relay E Diode W/R W/L...

  • Page 216: Starting Circuit Operation

    – ELEC ELECTRIC STARTING SYSTEM EBS00507 STARTING CIRCUIT OPERATION The starting circuit on this model consists of the starter motor, starter relay, starting circuit cut-off relay, rear brake switch and neutral switch. If the main switch is on and the engine È...

  • Page 217: Troubleshooting

    – ELEC ELECTRIC STARTING SYSTEM EBS01050 EBS01044 TROUBLESHOOTING 2. Battery The starter motor fails to turn. • Check the condition of the battery. Refer to “CHECKING AND CHARGING Check: THE BATTERY” in chapter 3. 1. main fuse 2. battery Specific gravity 3.
  • Page 218 – ELEC ELECTRIC STARTING SYSTEM EBS01053 Second step: 4. Starting circuit cut-off relay • Connect the pocket tester (Ω × 1) to the starting circuit cut-off relay coupler as First step: shown. • Disconnect the starting circuit cut-off relay • Measure the starting circuit cut-off relay for coupler from the wire harness.
  • Page 219 – ELEC ELECTRIC STARTING SYSTEM EBS01054 EBS01046 5. Starter relay 7. Neutral switch • Disconnect the starter relay coupler from • Check the neutral switch for continuity. the coupler. Refer to “CHECKING THE SWITCHES”. • Connect the pocket tester (Ω × 1) and bat- •...
  • Page 220 – ELEC ELECTRIC STARTING SYSTEM EBS01060 EBS01059 10.Diode 11.Wiring • Remove the diode from the coupler. • Check the entire starting system’s wiring. • Connect the pocket tester (Ω × 1) to the Refer to “CIRCUIT DIAGRAM”. diode terminals as shown. •...

  • Page 221: Starter Motor

    – ELEC STARTER MOTOR EBS01061 STARTER MOTOR Order Job/Part Q’ty Remarks Removing the starter motor Remove the parts in the order listed. Starter motor lead Ground lead Starter motor For installation, reverse the removal pro- cedure. Disassembling the starter motor Remove the parts in the order listed.

  • Page 222: Checking The Starter Motor

    – ELEC STARTER MOTOR EBS01064 CHECKING THE STARTER MOTOR 1. Check: • commutator Dirt → Clean with 600-grit sandpaper. 2. Measure: • commutator diameter a Out of specification → Replace the starter motor. Commutator wear limit 15.5 mm (0.61 in) 3.

  • Page 223: Assembling The Starter Motor

    – ELEC STARTER MOTOR 5. Measure: • brush length a Out of specification → Replace the brushes as a set. Brush length wear limit 3.5 mm (0.14 in) 6. Measure: • brush spring force Out of specification → Replace the brush springs as a set.

  • Page 224: Charging System

    – ELEC CHARGING SYSTEM EBS00516 CHARGING SYSTEM CIRCUIT DIAGRAM W/R W/L W/L W/R ( GRAY ) ( GRAY ) B Y/R Y/R B R Y/R ( BL ( BLACK ) B/W B ( BLACK ) 1 C.D.I. magneto 4 Rectifier/regulator 5 Main fuse 6 Positive battery lead 7 Battery...

  • Page 225: Troubleshooting

    – ELEC CHARGING SYSTEM EBS01065 EBS01043 TROUBLESHOOTING 1. Main fuse The battery is not being charged. • Check the main fuse for continuity. Refer to “CHECKING THE FUSE” in chap- Check: ter 3. 1. main fuse • Is the main fuse OK? 2.
  • Page 226 – ELEC CHARGING SYSTEM EBS01066 EBS01100 3. Charging voltage 4. Charging coil resistance • Connect the engine tachometer to the • Disconnect the C.D.I. magneto coupler spark plug lead. from the wire harness. • Connect the pocket tester (Ω × 1) to the •...

  • Page 227: Signal System

    – ELEC SIGNAL SYSTEM EBS00521 SIGNAL SYSTEM CIRCUIT DIAGRAM ( BLACK ) ( B W/R W/L W/L W/R ( GRAY ) ( GRAY ) B Y/R Y/R B R Y/R ( BLACK ) ( BLACK ) B/W B ( BLACK ) 2 Neutral switch ( BLACK ) 3 Main switch...

  • Page 228: Troubleshooting

    – ELEC SIGNAL SYSTEM EBS01073 EBS01044 TROUBLESHOOTING 2. Battery If the neutral indicator light fails to come • Check the condition of the battery. Refer to “CHECKING AND CHARGING THE BATTERY” in chapter 3. Check: 1. main fuse Specific gravity 2.

  • Page 229: Checking The Signaling System

    – ELEC SIGNAL SYSTEM EBS01075 3. Voltage CHECKING THE SIGNALING SYSTEM EBS01077 • Connect the pocket tester (DC 20 V) to the 1. The neutral indicator light fails to come on. neutral indicator light connectors (wire har- ness side) as shown. 1.

  • Page 230: Trbl Shtg

    TRBL STARTING FAILURE/HARD STARTING SHTG EBS00537 TROUBLESHOOTING NOTE: The following troubleshooting does not cover all the possible causes of trouble. It should be helpful, however, as a guide to troubleshooting. Refer to the relative procedure in this manual for check, adjustment and replacement of parts.

  • Page 231: Compression System

    TRBL STARTING FAILURE/HARD STARTING/POOR IDLE SPEED PERFORMANCE/POOR MEDIUM AND HIGH-SPEED PERFORMANCE SHTG COMPRESSION SYSTEM Cylinder and cylinder head Piston and piston rings • Loose spark plug • Improperly installed piston ring • Loose cylinder head or cylinder • Worn, fatigued or broken piston ring •...

  • Page 232: Faulty Drive Train

    TRBL FAULTY DRIVE TRAIN SHTG EBS00540 FAULTY DRIVE TRAIN The following conditions may indicate damaged shaft drive components: Symptoms Possible Causes 1. A pronounced hesitation or “jerky” move- A. Bearing damage. ment during acceleration, deceleration, or B. Improper gear lash. sustained speed.

  • Page 233: Faulty Gear Shifting

    FAULTY GEAR SHIFTING/CLUTCH SLIPPING/ TRBL DRAGGING/OVERHEATING SHTG EBS00541 FAULTY GEAR SHIFTING HARD SHIFTING Refer to “CLUTCH SLIPPING/DRAGGING—CLUTCH DRAGGING”. SHIFT LEVER DOES NOT MOVE JUMPS OUT GEAR Shift shaft Shift shaft • Bent shift shaft • Improperly adjusted shift shaft position Shift cam, shift forks •...

  • Page 234: Faulty Brake

    FAULTY BRAKE/SHOCK ABSORBER MALFUNCTION/ TRBL UNSTABLE HANDLING SHTG EBS00549 FAULTY BRAKE POOR BRAKING EFFECT Front and rear drum brake • Worn brake shoe lining • Worn brake drum • Oily or greasy brake shoe lining • Oily or greasy brake drum •...
  • Page 235 YAMAHA MOTOR CO., LTD. 2500 SHINGAI IWATA SHIZUOKA JAPAN PRINTED IN U.S.A.
  • Page 236 YFM50S WIRING DIAGRAM 1 C.D.I. magneto 2 Neutral switch 3 Main switch (BLACK) (BLACK) 4 Rectifier/regulator 5 Main fuse 6 Positive battery lead W/R W/L W/L W/R 7 Battery (GRAY) (GRAY) 8 Negative battery lead 9 Starter relay 0 Starter motor...

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