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Yamaha SR125 1997 Service Manual

Yamaha sr125'97 3mw-ae1 service manual.
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   Summary of Contents for Yamaha SR125 1997

  • Page 3 EB000000 SR125 SERVICE MANUAL 1996 by Yamaha Motor Co., Ltd. 1st Edition, September 1996 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Co., Ltd. is expressly prohibited.
  • Page 4 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 mo- torcycle has a basic understanding of the mechanical ideas and the procedures of motorcycle repair.
  • Page 5: How To Use This Manual

    YP002000 HOW TO USE THIS MANUAL MANUAL ORGANIZATION This manual consists of chapters for the main categories of subjects. (See “Illustrated symbols”) 1st title 1 : This is the title of the chapter with its symbol on 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 6 EB003000 ILLUSTRATED SYMBOLS Illustrated symbols 1 to 9 are designed as SPEC thumb tabs to indicate the chapter’s number INFO and content. 1 General information 2 Specifications INSP 3 Periodic inspection and adjustment 4 Engine 5 Carburation 6 Chassis CARB CHAS 7 Electrical 8 Troubleshooting...
  • Page 7 INDEX GENERAL INFORMATION INFO SPECIFICATIONS SPEC PERIODIC INSPECTION AND INSP ADJUSTMENT ENGINE OVERHAUL CARBURATION CARB CHASSIS CHAS ELECTRICAL ELEC TROUBLESHOOTING TRBL SHTG...
  • Page 9: Table Of Contents

    CHAPTER 1. GENERAL INFORMATION MOTORCYCLE IDENTIFICATION ....... FRAME SERIAL NUMBER .
  • Page 11: General Information

    MOTORCYCLE IDENTIFICATION INFO YP100000 GENERAL INFORMATION MOTORCYCLE IDENTIFICATION SR100020 FRAME SERIAL NUMBER The frame serial number 1 is stamped into the right side of the frame. EB100030 ENGINE SERIAL NUMBER The engine serial number 1 is stamped into the crankcase. NOTE: Designs and specifications are subject to change without notice.
  • Page 12: Important Information

    6. Keep all parts away from any source of fire. NB101010 REPLACEMENT PARTS 1. Use only genuine Yamaha parts for all re- placements. 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 13: Lock Washers/plates And Cotter Pins

    IMPORTANT INFORMATION INFO EB101030 LOCK WASHERS/PLATES AND COTTER PINS 1. Replace all lock washers/plates and cotter pins after removal. Bend lock tabs along the bolt or nut flats after the bolt or nut has been tightened to specification. EB101040 BEARINGS AND OIL SEALS Install bearings and oil seals so that the manufacturer’s marks or numbers are visible.
  • Page 14: Checking Of Connections

    CHECKING OF CONNECTIONS INFO EB801000 CHECKING OF CONNECTIONS 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. 4. Pull the lead to check that it will not come off. 5.
  • Page 15: How To Use The Conversion Table

    HOW TO USE THE CONVERSION TABLE INFO EB201000 HOW TO USE THE CONVERSION TABLE All specification data in this manual are listed in Sl and METRIC UNITS. Use this table to convert METRIC unit data to IMPERIAL unit data. METRIC MULTIPLIER ** mm 0.03937 ** in...
  • Page 16: Special Tools

    SPECIAL TOOLS INFO EB102000 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. When placing an order, refer to the list provided below to avoid any mistakes.
  • Page 17 SPECIAL TOOLS INFO Tool No. Tool name/Usage Illustration 90890-03079 Thickness gauge This tool is used to measure the valve clearance. 90890-03081 Compression gauge 90890-04082 Adaptor These tools are used to measure the engine compression. 90890-03112 Pocket tester These instruments are invaluable for checking the electrical system.
  • Page 18 This tool is used for removing and installing the lifter and for lapping the valve. 90890-06754 Ignition checker This instrument is necessary for checking the ignition system components. 90890-85505 Yamaha bond No.1215 This sealant (bond) is used for crankcase mating surface, etc.
  • Page 19 CHAPTER 2. SPECIFICATIONS GENERAL SPECIFICATIONS ........MAINTENANCE SPECIFICATIONS .
  • Page 21: Specifications

    SPEC GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model SR125 Model code: 3MW6 Dimensions: Overall length 1,915 mm Overall width 775 mm Overall height 1,080 mm Seat height 745 mm Wheelbase 1,280 mm Minimum ground clearance 155 mm Minimum turning radius 2,100 mm Basic weight: With oil and full fuel tank 113 kg...
  • Page 22: General Specifications

    SPEC GENERAL SPECIFICATIONS Model SR125 Carburetor: Type/quantity Y24P/1 Manufacturer TEIKEI Spark plug: Type DR8EA Manufacturer 0.6 X 0.7 mm Spark plug gap Clutch type: Wet, multiple-disc Transmission: Primary reduction system Spur gear Primary reduction ratio 73/22 (3.318) Secondary reduction system Chain drive Secondary reduction ratio 49/14 (3.500)
  • Page 23 SPEC GENERAL SPECIFICATIONS Model SR125 Brake: Front brake type Single disc brake operation Right hand operation Rear brake type Drum brake operation Right foot operation Suspension: Front suspension Telescopic fork Rear suspension Swingarm Shock absorber: Front shock absorber Coil spring/Oil damper Rear shock absorber Coil spring/Oil damper Wheel travel:...
  • Page 24: Maintenance Specifications

    SPEC MAINTENANCE SPECIFICATIONS MAINTENANCE SPECIFICATIONS ENGINE Item Standard Limit Cylinder head: Warp limit 0.03 mm Cylinder: 57.00 X 57.02 mm Bore size 57.1 mm Taper limit 0.05 mm Out of round limit 0.01 mm Camshaft: Cam dimensions 36.537 X 36.637 mm Intake “A”...
  • Page 25 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit 6.000 X 6.012 mm Guide inside diameter 6.042 mm 6.000 X 6.012 mm 6.042 mm 0.010 X 0.037 mm Stem-to-guide clearance 0.08 mm 0.025 X 0.052 mm 0.10 mm Stem runout limit 0.03 mm 0.9 X 1.1 mm Valve seat width 1.6 mm...
  • Page 26 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Crankshaft: 55.95 X 56.00 mm Crank width “A” Runout limit “C” 0.03 mm 0.35 X 0.65 mm Big end side clearance “D” 1.0 mm 0.010 X 0.025 mm Big end radial clearance 0.8 X 1.0 mm Small end free play “F”...
  • Page 27 SPEC MAINTENANCE SPECIFICATIONS TIGHTENING TORQUES ENGINE Tightening Thread torque Part to be tightened Part name Q’ty Remarks size size mSkg Cylinder head blind plug Screw Cylinder head and cylinder Bolt Cylinder head Bolt (Timing chain side) Cam sprocket cover Screw Valve cover Bolt Plate...
  • Page 28 SPEC MAINTENANCE SPECIFICATIONS Tightening Thread torque Part to be tightened Part name Q’ty Remarks size size mSkg Drive sprocket Bolt Shift cam (Segment) Screw Shift pedal Bolt Pick up coil Screw Neutral switch Screw Stator coil Screw Starter motor Screw...
  • Page 29 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Tightening sequence Cylinder head Crankcase...
  • Page 30 SPEC MAINTENANCE SPECIFICATIONS CHASSIS Item Standard Limit Steering system: Steering bearing type Ball bearing No./size of steel balls (upper) 22 pcs. 0.1875 in (lower) 19 pcs. 0.251 in Front suspension: Front fork travel 120 mm Fork spring free length 326.1 mm 321 mm Fitting length 311.1 mm...
  • Page 31 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Front brake: Type Single disc Disc outside diameter 267 mm Disc thickness 4 mm 3.5 mm Pad thickness (inner) 6.2 mm 0.8 mm (outer) 6.2 mm 0.8 mm Master cylinder inside diameter 12.7 mm Caliper cylinder 1 inside diameter 30.16 mm Caliper cylinder 2 inside diameter...
  • Page 32 SPEC MAINTENANCE SPECIFICATIONS TIGHTENING TORQUES CHASSIS Tightening torque Part to be tightened Thread size Remarks mSkg Handle crown and front fork Handle crown and steering shaft Handlebar holder (under and upper) Steering ring nut Refer to NOTE Master cylinder and cap (front brake) Handlebar under holder and nut Master cylinder (front brake) Brake hose union bolt (front brake)
  • Page 33 656 X 984 Ω at 20_C/ Pickup coil resistance/color Red – White 624 X 936 Ω at 20_C/ Source coil resistance/color Brown – Green C.D.I. unit model/manufacturer 4WP/YAMAHA Ignition coil: Model/ manufacturer 2JN/YAMAHA Minimum spark gap 6 mm 0.32 X 0.48 Ω at 20_C Primary winding resistance 5.68 X 8.52 kΩ...
  • Page 34 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Starter relay: Model/manufacturer MS5D-191/JIDECO Amperage rating 100 A 3.9 X 4.7 Ω at 20_C Coil winding resistance Horn: Model/manufacturer YF-12/NIKKO Maximum amperage 2.5 A Flasher relay: Type Condenser type Model/manufacturer FR2204/MITUBA Flasher frequency 85 cycle/min Circuit breaker: Type Fuse...
  • Page 35: General Torque Specifications

    SPEC GENERAL TORQUE SPECIFICATIONS GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasten- ers with standard I.S.O. pitch threads. Torque General torque specifications for special components or as- specifications semblies are included in the applicable sections (Nut) (Nut) (Bolt) (Bolt) mSkg of this book.
  • Page 36: Lubrication Point And Grade Of Lubricant

    Valve stem/valve guide (IN, EX) Valve stem end (IN, EX) Rocker arm shaft Cam and bearing (camshaft) Rocker arm inner surface Crankcase mating surfaces Yamaha bond No.1215 O-ring (all) Starter idle gear thrust surfaces Starter clutch (outer/roller) Starter wheel gear inner surface Push rod...
  • Page 37 SPEC LUBRICATION POINT AND GRADE OF LUBRICANT CHASSIS Lubrication Point Symbol Steering head pipe bearing (upper/lower) Front wheel oil seal lips (left/right) Rear wheel oil seal lips (left/right) Rear wheel hub Rear brake shoe plate, camshaft and pivoting pin Pivoting points (brake pedal shaft and frame) Sidestand sliding surface/mounting bolt Pivoting point (centerstand) Tube guide (throttle grip) inner surface...
  • Page 38: Lubrication Diagram

    SPEC LUBRICATION DIAGRAM LUBRICATION DIAGRAM 1 Rocker arm (IN) 2 Rocker shaft 3 Rocker arm (EX) 4 Camshaft 5 Oil pump 6 Push lever 2-18...
  • Page 39 SPEC LUBRICATION DIAGRAM 1 Oil pump 2 Oil filter 3 Crankshaft 4 Main axle 5 Drive axle 6 Oil strainer 2-19...
  • Page 40 SPEC CABLE ROUTING CABLE ROUTING 1 Front brake switch lead Clutch switch coupler A Clamp the handlebar switch 2 Brake hose Handlebar switch lead (left) lead, (left and right), front brake 3 Handlebar switch lead (right) Front flasher lead (left) switch lead, clutch switch lead to 4 Throttle cable Horn lead...
  • Page 41 SPEC CABLE ROUTING 1 Clamp A Align the clamp to the white tape 2 Wireharness on the wireharness 3 High tension cord B Pass the clutch cable through 4 Collar the outside of the throttle cable. 5 Ignition coil C Pass the brake hose and throttle 6 Ground lead cable through the slit of the 7 Ignition coil lead...
  • Page 42: Cable Routing

    SPEC CABLE ROUTING 1 Neutral switch lead Rectifier/ Regulator A Clamp the speedometer cable to 2 Pickup coil lead Thermostatic switch the steering bracket and pass 3 C.D.I. unit Throttle cable the cable to the cable holder. 4 Rear flasher lead (right) Clutch cable B Pass the brake hose through the 5 Rear flasher lead (left)
  • Page 43 SPEC CABLE ROUTING 1 Air filter case 2 Battery 3 Swingarm 4 Battery breather pipe 5 Lid 6 Air filter case drain pipe A Pass the air filter case drain pipe inside the swingarm. 2-23...
  • Page 44 SPEC...
  • Page 45 CHAPTER 3. PERIODIC INSPECTIONS AND ADJUSTMENTS INTRODUCTION ..........PERIODIC MAINTENANCE/LUBRICATION INTERVALS .
  • Page 47: Chapter 3. Periodic Inspections And Adjustments

    Repair if necessary. Rear shock Check operation / oil leakage. absorber Repair if necessary. It is recommended that these items be serviced by a Yamaha dealer. Medium weight wheel bearing grease. (bearing type) ***: Lithium soap base grease. (bush type)
  • Page 48 Check specific gravity. Battery Check breather pipe for proper operation. Correct if necessary. It is recommended that these items be serviced by a Yamaha dealer. **: Medium weight wheel bearing grease. (bearing type) ***: Lithium soap base grease. (bush type) NOTE: Brake fluid replacement: 1.
  • Page 49: Side Cover, Seat And Fuel Tank

    INSP SIDE COVER, SEAT AND FUEL TANK SIDE COVER, SEAT AND FUEL TANK Order Job name/Part name Q’ty Remarks Side cover, seat and fuel tank Remove the parts in order. removal Side cover (left) Side cover (right) Seat NOTE: Fuel pipe Disconnect the fuel pipe, set the fuel cock lever “OFF”...
  • Page 50: Engine

    INSP VALVE CLEARANCE ADJUSTMENT SR03004 ENGINE VALVE CLEARANCE ADJUSTMENT NOTE: Valve clearance adjustment should be made with the engine cool, at room temperature. When the valve clearance is to be measured or adjusted, the piston must be at Top Dead Cen- ter (T.D.C.) on the compression stroke.
  • Page 51: Idling Speed Adjustment

    VALVE CLEARANCE ADJUSTMENT/ INSP IDLING SPEED ADJUSTMENT 5. Adjust: : Valve clearance *************************************** Adjustment steps: : Loosen the locknut 1 . : Turn the adjuster 3 in or out with the valve ad- justing tool 2 until specified clearance is ob- tained.
  • Page 52: Throttle Cable Adjustment

    IDLING SPEED ADJUSTMENT/ INSP THROTTLE CABLE ADJUSTMENT 3. Check: : Engine idling speed Out of specification ! Adjust. Engine idling speed: 1,250 1,350 r/min 4. Adjust: : Engine idle speed *************************************** Adjustment steps: : Turn the pilot screw 1 until it is lightly seated. : Turn the pilot screw out by the specified num- ber of turns.
  • Page 53: Spark Plug Inspection

    THROTTLE CABLE ADJUSTMENT/ INSP SPARK PLUG INSPECTION : Loosen the locknut 1 on the throttle cable. : Turn the adjuster 2 in or out until specified free play is obtained. Turning in ! Free play is increased. Turning out ! Free play is decreased. : Tighten the locknut.
  • Page 54: Ignition Timing Check

    SPARK PLUG INSPECTION/ INSP IGNITION TIMING CHECK 5. Install: : Spark plug 18 Nm (1.8 m:kg) NOTE: Before installing a spark plug, clean the gasket surface and plug surface. YP303052 IGNITION TIMING CHECK NOTE: Prior to checking the ignition timing, check all electrical connections related to the ignition system.
  • Page 55: Compression Pressure Measurement

    INSP COMPRESSION PRESSURE MEASUREMENT SR303060 COMPRESSION PRESSURE MEASUREMENT NOTE: Insufficient compression pressure will result in performance loss. 1. Check: : Valve clearance Out of specification ! Adjust. Refer to “VALVE CLEARANCE ADJUST- MENT” section. 2. Start the engine and let it warm up for several minutes.
  • Page 56: Engine Oil Level Inspection

    COMPRESSION PRESSURE MEASUREMENT/ INSP ENGINE OIL LEVEL INSPECTION Compression pressure (at sea lev- el): Standard: 1,200 kPa (12.0 Kg/cm , 12 bar) Minimum: 1,100 kPa (11.0 Kg/cm , 11 bar) *************************************** Measurement steps: : Crank the engine with the throttle wideopen until the reading on the compression gauge stabilizes.
  • Page 57: Engine Oil Replacement

    ENGINE OIL LEVEL INSPECTION/ INSP ENGINE OIL REPLACEMENT CAUTION: : Do not put in any chemicals additives or use oils with a grade of CD a or higher. : Be sure not to use oils labeled “ENERGY CONSERVING II” b or higher. Engine oil also lubricates the clutch and additives could cause clutch slippage.
  • Page 58 INSP ENGINE OIL REPLACEMENT 6. Install: S Drain plug 43 Nm (4.3 mSkg) NOTE: Inspect the O-ring. If it is damaged, replace it with a new one. CAUTION: Before reinstalling the drain plug, do not for- get to fit the O-ring, compression spring and oil strainer.
  • Page 59: Timing Chine Tensioner Adjustment

    TIMING CHAINE TENSIONER ADJUSTMENT/ INSP CLUTCH ADJUSTMENT SR******* TIMING CHAINE TENSIONER ADJUSTMENT 1. Remove: S Cap 1 2. Check: S Rod Check the rod end 1 is flush with the adjust- er end 2 . Not flush ! Adjust. 3. Adjust: S Timing chine tension *************************************** Adjustment steps:...
  • Page 60: Air Filter Cleaning

    CLUTCH ADJUSTMENT/ INSP AIR FILTER CLEANING 2. Adjust: S Clutch cable free play *************************************** Adjustment steps: Crankcase side S Make sure that the adjuster 1 and locknut 2 are fully tightened. S Loosen the locknut 2 . S Turn the adjuster 1 in or out until the specified free play is obtained.
  • Page 61: Exhaust System Inspection

    AIR FILTER CLEANING/ INSP EXHAUST SYSTEM INSPECTION 2. Inspect: S Air filter element 1 Damage ! Replace. 3. Clean: S Air filter element Use solvent to clean the element. NOTE: After cleaning, remove the remaining solvent by squeezing the element. CAUTION: Do not twist the filter element when squeez- ing it.
  • Page 62 INSP EXHAUST SYSTEM INSPECTION 2. Check: S Tightening torque Bolt 12 Nm (1.2 mSkg) 20 Nm (2.0 mSkg) 3-16...
  • Page 63: Chassis

    FRONT BRAKE ADJUST MENT/ INSP REAR BRAKE ADJUSTMENT EB304002 CHASSIS FRONT BRAKE ADJUSTMENT 1. Check: : Brake lever free play a Out of specification ! Adjust. Free play (Brake lever): 5 mm at brake lever end 2. Adjust: : Brake lever free play *************************************** Adjustment steps: : Loosen the locknut 1 .
  • Page 64 INSP REAR BRAKE ADJUSTMENT 2. Adjust: S Brake pedal height *************************************** Adjustment steps: S Loosen the locknut 1 . S Turn the adjuster 2 in or out until the specified pedal height is obtained. Turning in ! Pedal height is decreased. Turning out ! Pedal height is increased.
  • Page 65: Brake Fluid Level Inspection

    INSP BRAKE FLUID LEVEL INSPECTION EB304020 BRAKE FLUID LEVEL INSPECTION 1. Stand the motorcycle on a level surface. NOTE: S Make sure the motorcycle is upright when in- specting the brake fluid level. S Stand the motorcycle on its centerstand if it has one.
  • Page 66: Brake Pad Inspection

    BRAKE PAD INSPECTION/BRAKE SHOE INSPECTION/ INSP BRAKE LIGHT SWITCH ADJUSTMENT EB304030 BRAKE PAD INSPECTION 1. Operate the brake lever. 2. Inspect: : Brake pad (front) Wear indicators 1 almost touch the brake disc ! Replace the brake pads as a set. Refer to “FRONT BRAKE”...
  • Page 67: Air Bleeding

    INSP AIR BLEEDING EB304070 AIR BLEEDING (HYDRAULIC BRAKE SYSTEM) WARNING Bleed the brake system whenever: S The system is disassembled. S A brake hose is loosened or removed. S The brake fluid level is very low. S Brake operation is faulty. Loss of braking performance may occur if the brake system is not properly bled.
  • Page 68: Drive Chain Slack Adjustment

    AIR BLEEDING/ INSP DRIVE CHAIN SLACK ADJUSTMENT j. Tighten the bleed screw. Bleed screw: 6 Nm (0.6 mSkg) NOTE: If bleeding is difficult, it may be necessary to let the brake fluid settle for a few hours. Repeat the bleeding procedure when the tiny bubbles in the brake system have disappeared.
  • Page 69 INSP DRIVE CHAIN SLACK ADJUSTMENT 1. Check: S Drive chain slack Out of specification ! Adjust. Drive chain slack: 35 mm a Check window b Adjustable limit c Usable limit d Usable range 2. Adjust: S Drive chain slack A Standard B Useful limit *************************************** Adjustment steps:...
  • Page 70: Steering Head Inspection

    INSP STEERING HEAD INSPECTION SR304130 STEERING HEAD INSPECTION WARNING Securely support the motorcycle so that there is no danger of it falling over. 1. Stand the motorcycle on a level surface. NOTE: Stand the motorcycle on its centerstand. 2. Elevate the front wheel by placing a suitable stand under the engine.
  • Page 71: Front Fork Inspection

    FRONT FORK INSPECTION/ INSP REAR SHOCK ABSORBER ADJUSTMENT EB304140 FRONT FORK INSPECTION WARNING Securely support the motorcycle so that there is no danger of it falling over. 1. Stand the motorcycle on a level surface. 2. Check: S Inner tube Scratches/damage ! Replace.
  • Page 72: Tire Inspection

    REAR SHOCK ABSORBER ADJUSTMENT/ INSP TIRE INSPECTION Adjustment numbers: Standard Minimum Maximum CAUTION: S Never turn the adjuster beyond the maxi- mum or minimum setting. S Always adjust each shock absorber to the same setting. *************************************** EB304171 TIRE INSPECTION 1. Measure: S Tire inflation pressure Out of specification ! Adjust.
  • Page 73 Ltd. for this model. No guarantee concern- ing handling characteristics can be given if a tire combination other than one ap- proved by Yamaha is used on this motor- cycle. The front and rear tires should al- ways be by the same manufacturer and of the same design.
  • Page 74: Spoke Inspection And Tightening

    SPOKE INSPECTION AND TIGHTENING/ INSP WHEEL INSPECTION EB304190 SPOKE INSPECTION AND TIGHTENING 1. Inspect: S Spokes 1 Bending/damage ! Replace. Loose spoke ! Retighten. 2. Tighten: S Spokes NOTE: Be sure to tighten the spokes before and after break-in. Nipple: 2 Nm (0.2 mSkg) EB304180 WHEEL INSPECTION...
  • Page 75: Electrical

    INSP BATTERY INSPECTION EB305001 ELECTRICAL BATTERY INSPECTION 1. Remove: S Side covers (left and right) Refer to “SIDE COVER, SEAT AND FUEL TANK” section. 2. Inspect: S Electrolyte level Electrolyte level should be between the up- per 1 and lower 2 level marks. Electrolyte level is too low ! Add electrolyte to proper level.
  • Page 76 INSP BATTERY INSPECTION *************************************** Replace the battery if: S Battery voltage will not rise to a specific value or bubbles fail to rise during charging. S Sulphation of one or more cells occurs, (as in- dicated by the plates turning white, or material accumulating in the bottom of the cell).
  • Page 77: Fuse Inspection

    INSP BATTERY INSPECTION/FUSE INSPECTION 7. Install: : Battery 8. Connect: : Battery leads CAUTION: Connect the positive lead 1 first and then connect the negative lead 2 . 9. Connect: : Breather hose Be sure the hose is properly attached and routed.
  • Page 78: Headlight Beam Adjustment

    FUSE INSPECTION/ INSP HEADLIGHT BEAM ADJUSTMENT 3. Replace: S Blown fuse *************************************** Replacement steps: S Turn off the main switch. S Install a new fuse with the proper current rat- ing. S Turn on switches to verify operation of related electrical devices.
  • Page 79 CHAPTER 4. ENGINE OVERHAUL ENGINE REMOVAL ..........EXHAUST PIPE, STARTING MOTOR AND WIRE READ .
  • Page 80 BALANCER GEAR ..........4-37 BALANCER DRIVEN GEAR REMOVAL .
  • Page 81: Engine Overhaul

    ENGINE REMOVAL EB400000 ENGINE OVERHAUL ENGINE RE MOVAL EXHAUST PIPE, STARTING MOTOR AND WIRE READ 12 Nm (1.2 m:kg) 20 Nm (2.0 m:kg) Order Job name/Part name Q’ty Remarks Exhaust pipe, starting motor and Remove the parts in order. wire read removal Refer to “SIDE COVER, SEAT AND Side cover, seat and fuel tank FUEL TANK”...
  • Page 82: Carburetor, Clutch Cable And Drive Chain

    ENGINE REMOVAL CARBURETOR, CLUTCH CABLE AND DRIVE CHAIN 65 Nm (6.5 m:kg) 7 Nm (0.7 m:kg) 10 Nm (1.0 m:kg) 8 Nm (0.8 m:kg) Order Job name/Part name Q’ty Remarks Carburetor, clutch cable and drive Remove the parts in order. chain removal Carburetor Refer to “CARBURETOR”...
  • Page 83: Engine

    ENGINE REMOVAL ENGINE 33 Nm (3.3 m:kg) 33 Nm (3.3 m:kg) 33 Nm (3.3 m:kg) 33 Nm (3.3 m:kg) 33 Nm (3.3 m:kg) Order Job name/Part name Q’ty Remarks Engine removal Remove the parts in order. Securely support the motorcycle so Engine stay (top) there is no danger of it falling over.
  • Page 84: Cam Sprocket Cover

    CYLINDER HEAD CYLINDER HEAD CAM SPROCKET COVER 10 Nm (1.0 m:kg) 18 Nm (1.8 m:kg) 2 Nm (0.2 m:kg) 7 Nm (0.7 m:kg) 10 Nm (1.0 m:kg) Order Job name/Part name Q’ty Remarks Cam sprocket cover removal Remove the parts in order. Side cover, seat and fuel tank Refer to “SIDE COVER SEAT AND FUEL TANK REMOVAL”...
  • Page 85: Cylinder Head

    CYLINDER HEAD CYLINDER HEAD 22 Nm (2.2 m:kg) 20 Nm (2.0 m:kg) 5 Nm (0.5 m:kg) 60 Nm (6.0 m:kg) 30 Nm (3.0 m:kg) Order Job name/Part name Q’ty Remarks Cylinder head removal Remove the parts in order. Timing chain tensioner cap/O-ring Timing chain tensioner assembly Refer to “CYLINDER HEAD REMOVAL/ Cam sprocket/Timing chain...
  • Page 86: Cylinder Head Removal

    CYLINDER HEAD T401030 CYLINDER HEAD REMOVAL 1. Align: : Slit a on the magneto (with stationary pointer b on the crank case cover) NOTE: Turn the crank shaft counterclockwise with a wrench and align the “I” mark c with the cylinder head match mark d when the piston is at TDC on the compression stroke.
  • Page 87: Cylinder Head Inspection

    CYLINDER HEAD 5. Remove: : Cylinder head NOTE: : Loosen the nuts in their proper loosening sequence. : Start by loosening each nut 1/2 turn until all are loose. YP402000 CYLINDER HEAD INSPECTION 1. Eliminate: : Carbon deposits (from combustion chambers) Use a rounded scraper.
  • Page 88: Cylinder Head Installation

    CYLINDER HEAD SR******** CYLINDER HEAD INSTALLATION 1. Install: : Dowel pins 1 : Gasket 2 : Gasket (cylinder head) 3 2. Install: : Cylinder head M8 (1 22 Nm (2.2 m:kg) M8 (5 20 Nm (2.2 m:kg) NOTE: : apply engine oil onto the nut threads. : Tighten the bolts starting with the lowest numbered one.
  • Page 89 CYLINDER HEAD 4. Install: : Plate washer : Bolt (timing chain) : Timing chain tensioner assembly 5. Tighten: : Bolt (timing chain) 60 Nm (6.0 m:kg) NOTE: Install the bolt while holding the magneto mounting bolt with a wrench. 6. Check: : Magneto rotor slit Align the stationary pointer with the crank- case cover (left).
  • Page 90: Cam Shaft And Rocker Arms

    CAM SHAFT AND ROCKER ARMS CAM SHAFT AND ROCKER ARMS 14 Nm (1.4 m:kg) 14 Nm (1.4 m:kg) 8 Nm (0.8 m:kg) Order Job name/Part name Q’ty Remarks Cam shaft and rocker arm removal Remove the parts in order. Cylinder head Refer to the “CYLINDER HEAD”...
  • Page 91: Rocker Arm And Rocker Arm Shaft Removal

    CAM SHAFT AND ROCKER ARMS SR****** ROCKER ARM AND ROCKER ARM SHAFT REMOVAL 1. Remove: : Camshaft 1 : Collar (camshaft) 2 NOTE: Use 10 mm bolt 3 to remove the camshaft. 2. Remove: : Rocker arm shaft (intake) : Rocker arm shaft (exhaust) NOTE: Attach a rocker arm shaft puller bolt 1 and weight 2 to the rocker arm shaft and slide out...
  • Page 92: Rocker Arms And Rocker Arm Shafts Inspection

    CAM SHAFT AND ROCKER ARMS YP402060 ROCKER ARMS AND ROCKER ARM SHAFTS INSPECTION 1. Inspect: : Rocker arm shafts : Rocker arms Wear/Pitting/Scratches/Blue discoloration ! Replace. *************************************** Inspection steps: : Inspect the two contact areas on the rocker arms for signs of unusual wear. : Rocker arm shaft hole.
  • Page 93 CAM SHAFT AND ROCKER ARMS 2. Apply: : Molybdenum disulfide oil (onto the rocker arm and rocker arm shaft) Molybdenum disulfide oil 3. Install: : Rocker arm : Rocker arm shaft 1 NOTE: : Apply engine oil onto the outside of the rocker arm shaft and apply molybdenum disulfide oil onto the inside of the rocker arm.
  • Page 94: Valves And Valve Springs

    VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS Order Job name/Part name Q’ty Remarks Valves and valve springs removal Remove the parts in order. Cylinder head Refer to “CYLINDER HEAD” section. Rocker arm, Camshaft Refer to “CAMSHAFT AND ROCKER ARMS” section. Valve cotters Refer to “VALVES AND VALVE SPRINGS REMOVAL/INSTALLATION”...
  • Page 95: Valves And Valve Springs Removal

    VALVES AND VALVE SPRINGS YP401150 VALVES AND VALVE SPRINGS REMOVAL 1. Remove: : Valve cotters 1 NOTE: Attach a valve spring compressor and attach- ment 2 between the valve spring retainer and cylinder head to remove the valve cotters. CAUTION: Do not compress so much as to avoid dam- age to the valve spring.
  • Page 96 VALVES AND VALVE SPRINGS : Install the new valve guide using a valve guide installer 2 and valve guide remover 1 . : After installing the valve guide, bore the valve guide using a valve guide reamer 3 to obtain proper stem-to-guide clearance.
  • Page 97: Valve Seats Inspection

    VALVES AND VALVE SPRINGS EB402020 VALVE SEATS INSPECTION 1. Eliminate: : Carbon deposits (from the valve face and valve seat) 2. Inspect: : Valve seats Pitting/wear ! Reface the valve seat. 3. Measure: : Valve seat width a Out of specification ! Reface the valve seat. Valve seat width: Intake: 1.1 mm...
  • Page 98: Valves And Valve Springs Installation

    VALVES AND VALVE SPRINGS : Apply molybdenum disulfide oil to the valve stem. : Install the valve into the cylinder head. : Turn the valve until the valve face and valve seat are evenly polished, then clean off all compound. Valve lapper: 90890-04101 NOTE:...
  • Page 99 VALVES AND VALVE SPRINGS 2. Apply: : Molybdenum disulfide oil (onto the valve stem 3 and oil seal 2 ) Molybdenum disulfide oil 3. Install: : Valve spring seat 1 : Valve stem seat 2 : Valve 3 (into the cylinder head) : Valve spring 4 : Spring retainer 5 NOTE:...
  • Page 100: Cylinder And Piston

    CYLINDER AND PISTON CYLINDER AND PISTON Order Job name/Part name Q’ty Remarks Cylinder and piston removal Remove the parts in order. Cylinder head Refer to “CYLINDER HEAD” section. Timing chain guide (exhaust side) Cylinder/O-ring O-ring Refer to “PISTON RINGS, PISTON AND Dowel pin CYLINDER INSTALLATION”...
  • Page 101: Piston And Piston Rings Removal

    CYLINDER AND PISTON YP****** PISTON AND PISTON RINGS REMOVAL 1. Remove: : Piston pin circlip 1 : Piston pin 2 : Piston 3 NOTE: Before removing the piston pin circlip, cover the crankcase opening with a clean towel or rag to prevent the circlip from falling into the crankcase cavity.
  • Page 102 CYLINDER AND PISTON Cylinder bore “C” 57.00 57.02 mm Taper limit “T” 0.05mm Out of round “R” 0.01mm “C” = Maximum D “T” = (Maximum D or D ) – (Maximum D or D “R” = (Maximum D or D –...
  • Page 103: Piston Ring Inspection

    CYLINDER AND PISTON EB402110 PISTON RING INSPECTION 1. Measure: : Side clearance Out of specification ! Replace the piston and the piston rings as a set. NOTE: Eliminate the carbon deposits from the piston ring grooves and rings before measuring the side clearance.
  • Page 104: Piston Pin Inspection

    CYLINDER AND PISTON EB402120 PISTON PIN INSPECTION 1. Inspect: : Piston pin Blue discoloration/grooves ! Replace, then inspect the lubrication system. 2. Measure: : Piston pin-to-piston clearance *************************************** Measurement steps: : Measure the piston pin outside diameter a . If out of specification, replace the piston pin. Outside diameter (piston pin): 14.978 14.992 mm...
  • Page 105 CYLINDER AND PISTON 2. Install: : Piston 1 : Piston pin 2 : Piston pin clip 3 NOTE: : Apply engine oil onto the piston pins. : The “!” mark a on the piston must face the exhaust side of the cylinder. : Before installing the piston pin clip, cover the crankcase opening with a clean rag to prevent the piston pin clip from falling into the crank-...
  • Page 106: Clutch

    CLUTCH CLUTCH CRANKCASE COVER (RIGHT) 45 Nm (4.5 m:kg) 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Crankcase cover (right) removal Remove the parts in order. Drain the engine oil Refer to “ENGINE OIL REPLACEMENT” section in CHAPTER 3. Foot rest (right) Clutch cable Crankcase cover (right)
  • Page 107: Clutch

    CLUTCH CLUTCH 70 Nm (7.0 m:kg) 8 Nm (0.8 m:kg) 12 Nm (1.2 m:kg) 6 Nm (0.6 m:kg) Order Job name/Part name Q’ty Remarks Remove the parts in order. Clutch removal Refer to “ENGINE REMOVAL” section. Sprocket cover Clutch springs Pressure plate Refer to “CLUTCH INSTALLATION”...
  • Page 108 CLUTCH 70 Nm (7.0 m:kg) 8 Nm (0.8 m:kg) 12 Nm (1.2 m:kg) 6 Nm (0.6 m:kg) Order Job name/Part name Q’ty Remarks Push lever axle Refer to “CLUTCH INSTALLATION” sec- Torsion spring tion. Circlip Oil seal Nut/Washer Refer to “CLUTCH INSTALLATION” sec- Push rod #1/O-ring tion.
  • Page 109: Clutch Removal

    CLUTCH SR401061 CLUTCH REMOVAL 1. Remove: : Nut 1 (clutch boss) : Lock washer 2 : Clutch boss 3 Straighten the lock washer tab 2 . NOTE: Loosen the clutch boss nut 1 while holding the clutch boss with a clutch holding tool 4 . Clutch holding tool: 90890-04086 SR402181...
  • Page 110: Push Rod Inspection

    CLUTCH 6. Measure: : Free length (clutch spring) a Out of specification ! Replace the clutch springs as a set. Free length (clutch spring): 34.5 mm <Lilmit: 32.9 mm> 7. Inspect: : Dogs on the primary driven gear 1 Scoring/wear/damage ! Deburr or re- place.
  • Page 111 CLUTCH 3. Install: :Lock washer 1 : Nut 2 (clutch boss) 70 Nm (7.0 m:kg) NOTE: Install the clutch boss nut 2 while holding the clutch boss with a clutch holding tool 3 . Clutch holding tool: 90890-04086 4. Bend: : Lock washer tab (along a flat side of the end) 5.
  • Page 112 CLUTCH 9. Check: : Push lever position Push the push lever assembly in the arrow direction and make sure that match marks are be aligned ! Adjust. a Match mark on the push lever assembly b Match mark on the crankcase 10.
  • Page 113: Oil Pump

    OIL PUMP OIL PUMP 50 Nm (5.0 m:kg) 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Oil pump removal Remove the parts in order. Clutch Refer to “CLUTCH” section. Refer to “PRIMARY DRIVE GEAR Lock washer REMOVAL/INSTALLATION” section. Primary drive gear Oil pump cover Oil pump assembly...
  • Page 114 OIL PUMP 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Oil pump disassembly Disassemble the parts in order. Oil pump housing 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Dowel pin Oil pump driven gear Dowel pins...
  • Page 115: Primary Drive Gear Removal

    OIL PUMP SR401070 PRIMARY DRIVE GEAR REMOVAL NOTE: Straighten the lock washer tab. 1. Remove: : Nut (primary drive gear) 1 : Lock washer 2 : Primary drive gear 3 NOTE: Place a folded aluminium plate or copper wash- er a between the teeth of the balancer drive gear 4 and balancer driven gear 5 .
  • Page 116: Oil Pump Installation

    OIL PUMP SR404010 OIL PUMP INSTALLATION 1. Lubricate: : Oil delivery passage (crankcase right) : Oil pump assembly Recommended lubricant: Engine oil SR404140 PRIMARY DRIVE GEAR INSTALLATION 1. Install: : Primary drive gear 1 : Lock washer 2 : Nut (primary drive gear) 3 50 Nm (5.0 m:kg) NOTE: : Place a folded aluminium plate or copper...
  • Page 117: Balancer Gear

    BALANCER GEAR BALANCER GEAR 50 Nm (5.0 m:kg) Order Job name/Part name Q’ty Remarks Balancer gear removal Remove the parts in order. Clutch Refer to “CLUTCH” section. Primary drive gear Refer to “OIL PUMP” section. Refer to “BALANCER DRIVEN GEAR Nut/Lock washer REMOVAL/BALANCER GEAR Balancer driven gear...
  • Page 118 BALANCER GEAR SR****** BALANCER DRIVEN GEAR REMOVAL NOTE: Straighten the lock washer tab. 1. Remove: : Nut (balancer driven gear) 1 : Lock washer 2 : Balancer driven gear 3 NOTE: Place a folded aluminium plate or copper wash- er a between the teeth of the balancer drive gear 4 and balancer driven gear 3 .
  • Page 119 BALANCER GEAR SR****** BALANCER GEAR INSTALLATION 1. Install: : Balancer driven gear 1 NOTE: Install the balancer driven gear, then mesh the balancer driven gear match mark a and ba- lancer drive gear assembly match mark b . 2. Install: : Lock washer 1 : Nut (balancer drive gear) 2 50 Nm (5.0 m:kg)
  • Page 120: Shift Shaft And Segment

    SHIFT SHAFT AND SEGMENT SHIFT SHAFT AND SEGMENT 12 Nm (1.2 m:kg) Order Job name/Part name Q’ty Remarks Shift shaft and segment removal Remove the parts in order. Clutch Refer to “CLUTCH” section. Shift pedal Refer to “ENGINE REMOVAL” section. Shift shaft Plate washer Torsion spring...
  • Page 121 SHIFT SHAFT AND SEGMENT 12 Nm (1.2 m:kg) Order Job name/Part name Q’ty Remarks Screw Segment Refer to “SEGMENT INSTALLATION” Dowel pins (short length) section. Dowel pins (long length) Reverse the removal procedure for installation. 4-41...
  • Page 122: Shift Shaft Removal

    SHIFT SHAFT AND SEGMENT SR****** SHIFT SHAFT REMOVAL 1. Remove: : Shift shaft assembly 1 NOTE: Push the shift lever arm 2 and the stopper lever 3 to the arrow direction and remove them from the segment. T402200 SHIFT SHAFT INSPECTION 1.
  • Page 123: Sift Shaft Installation

    SHIFT SHAFT AND SEGMENT 2. Install: : Segment 1 NOTE: Fit the dowel pin 2 (long length) on the seg- ment to the locating hole a on the sift cam and install the segment. 3. Tighten: : Screw 1 12 Nm (1.2 m:kg) SR****** SIFT SHAFT INSTALLATION 1.
  • Page 124: Cdi Magneto And Starter Clutch

    CDI MAGNETO AND STARTER CLUTCH CDI MAGNETO AND STARTER CLUTCH CRANKCASE COVER (LEFT) 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Crankcase cover (left) removal Remove the parts in order. Drain the engine oil Refer to “ENGINE OIL REPLACEMENT” section in CHAPTER 3.
  • Page 125: Pickup Coil And Stator Coil

    CDI MAGNETO AND STARTER CLUTCH PICKUP COIL AND STATOR COIL 3 Nm (0.3 m:kg) 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Pickup coil and stator coil removal Remove the parts in order. Clamp (stator coil) Clamp (pickup coil) Pickup coil Stator coil Reverse the removal procedure for...
  • Page 126: Cdi Magneto Removal

    CDI MAGNETO AND STARTER CLUTCH CDI MAGNETO AND STARTER CLUTCH 30 Nm (3.0 m:kg) 50 Nm (5.0 m:kg) Order Job name/Part name Q’ty Remarks CDI magneto and starter clutch Remove the parts in order. removal CDI magneto Refer to “CDI MAGNETO REMOVAL/INSTALLATION”...
  • Page 127: Starter Clutch Inspection

    CDI MAGNETO AND STARTER CLUTCH YP401081 C.D.I. MAGNETO REMOVAL 1. Remove: : Bolt 1 (magneto) : Plain washer 2 NOTE: : Loosen the bolt (magneto) 1 while holding the rotor with a sheave holder 3 . : Do not allow the sheave holder to touch the projection on the magneto.
  • Page 128: Starter Clutch Installation

    CDI MAGNETO AND STARTER CLUTCH 3. Inspect: : Starter wheel gear (contacting surface) Pitting/Wear/Damage ! Replace. SR****** STARTER CLUTCH INSTALLATION 1. Install: : Starter clutch assembly 1 30 Nm (3.0 m:kg) 2. Unloosen the starter clutch assembly by us- ing the center punch. 3.
  • Page 129 CDI MAGNETO AND STARTER CLUTCH 3. Tighten: : CDI magneto assembly 1 50 Nm (5.0 m:kg) NOTE: Tighten the bolt while holding the CDI magneto assembly with the sheave holder 2 . Sheave holder: 90890-01701 4-49...
  • Page 130: Crank Case And Crankshaft Crankcase

    CRANKCASE AND CRANK SHAFT CRANK CASE AND CRANKSHAFT CRANKCASE 8 Nm (0.8 m:kg) 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Crankcase separation Remove the parts in order. Engine Refer to “ENGINE REMOVAL” section. Cylinder head Refer to “CYLINDER HEAD” section. Cylinder and piston Refer to “CYLINDER AND PISTON”...
  • Page 131 CRANKCASE AND CRANK SHAFT 8 Nm (0.8 m:kg) 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Timing chain Crankcase Refer to “CRANKCASE SEPARATION/INSTALLATION” section. Dowel pins Reverse the removal procedure for installation. 4-51...
  • Page 132: Crankshaft And Balancer Weight

    CRANKCASE AND CRANK SHAFT CRANKSHAFT AND BALANCER WEIGHT Order Job name/Part name Q’ty Remarks Crankshaft and balancer weight Remove the parts in order. removal Balancer weight Refer to “BALANCER WEIGHT Crankshaft assembly INSTALLATION” seciton. Dowel pin Refer to “PLUNGER SEAL Plunger seal REMOVAL/INSTALLATION”...
  • Page 133: Crankcase Separation

    CRANKCASE AND CRANK SHAFT SR401132 CRANKCASE SEPARATION 1. Remove: : Crankcase screws NOTE: : The numbers embossed on the crankcase in- dicate the tightening sequence. Loosen the screws in decreasing numerical order (see numbers on the illustration). : Loosen each screw 1/4 turn at a time and re- move them after all are loose.
  • Page 134: Crankshaft Inspection

    CRANKCASE AND CRANK SHAFT T****** CRANKSHAFT INSPECTION 1. Measure: : Crankshaft runout Out of specification ! Replace crankshaft and/or bearing. NOTE: Measure the crankshaft runout with the crank- shaft assembly turning slowly. Runout limit: 0.03 mm 2. Measure: : Big end side clearance Out of specification ! Replace big end bear- ing, crank pin and/or connecting rod.
  • Page 135: Plunger Seal Installation

    1. Clean all the gasket mating surface and crankcase mating surface thoroughly. 2. Apply: : Sealant (onto the crankcase mating surfaces) Yamaha bond No.1215: 90890-85505 NOTE: DO NOT ALLOW any sealant to come in con- tact with the oil gallery a .
  • Page 136: Transmission, Shift Cam And Shift Fork

    TRANSMISSION SIFT CAM AND SHIFT FORK TRANSMISSION, SHIFT CAM AND SHIFT FORK Order Job name/Part name Q’ty Remarks Transmission, shift cam and Remove the parts in order. shift fork removal Crankcase separating Refer to “CRANKCASE AND CRANKSHAFT” section. Shift fork guide bar 2 (short length) Shift fork guide bar 1 (long length) Refer to “TRANSMISSION, SHIFT CAM Shift cam...
  • Page 137 TRANSMISSION SIFT CAM AND SHIFT FORK DRIVE AXLE AND MAIN AXLE Order Job name/Part name Q’ty Remarks Drive axle and main axle Disassemble the parts in order. disassembly Second wheel gear First wheel gear Fifth wheel gear Circlip/washer Third wheel gear Forth wheel gear Drive axle Second pinion gear...
  • Page 138: Shift Fork Shift Cam Inspection

    TRANSMISSION SIFT CAM AND SHIFT FORK SR****** TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVAL 1. Install: : O-Ring 1 To the drive sprocket groove. 2. Remove: : Drive axle assembly 1 : Main axle assembly 2 Remove them at same the time. T402190 SHIFT FORK SHIFT CAM INSPECTION 1.
  • Page 139: Transmission, Shift Cam And Shift Fork Installation

    TRANSMISSION SIFT CAM AND SHIFT FORK 4. Check: : Shift fork movement (on the guide bar) Unsmooth operation ! Replace the shift fork and the guide bar. NOTE: When damaged the shift fork and mission gear, replace the facing each gear as set. SR****** TRANSMISSION, SHIFT CAM AND SHIFT FORK INSTALLATION...
  • Page 141 CHAPTER 5. CARBURETION CARBURETOR ..........CARBURETOR ASSEMBLY .
  • Page 143 CARB CARBURETOR EB600000 CARBURETION CARBURETOR Order Job name/Part name Q’ty Remarks Carburetor removal Remove the parts in order. Side cover Refer to “SIDE COVER, SEAT AND Seat FUEL TANK” section in CHAPTER 3. Fuel tank NOTE: Heater unit lead Disconnect the cable from wireharness. NOTE: Carburetor joint clamp screw Loosen.
  • Page 144 CARB CARBURETOR Order Job name/Part name Q’ty Remarks Carburetor disassembly Disassemble the parts in order. Throttle cable Throttle valve assembly Throttle valve spring Mixing chamber top/O-ring Drain screw assembly Float chamber Gasket (float chamber) Float pin/float Needle valve assembly Refer to “CARBURETOR ASSEMBLY” Main jet section.
  • Page 145 CARB CARBURETOR Order Job name/Part name Q’ty Remarks Pilot screw assembly Refer to “CARBURETOR ASSEMBLY” Pilot jet section. Throttle stop screw assembly Starter plunger assembly Screw/gasket Heater unit/washer Reverse the disassembly procedure for assembly.
  • Page 146 CARB CARBURETOR SR****** CARBURETOR ASSEMBLY CAUTION: : Do not use a wire for cleaning. : Before assembling, wash all parts in clean petroleum based solvent. : Always use a new gasket. 1. Install: : Pilot jet 1 : Pilot screw assembly 2 Pilot screw (turn out): 2 turns out 2.
  • Page 147 CARB CARBURETOR YP600060 FUEL LEVEL ADJUSTMENT 1. Measure: : Fuel level a Out of specification ! Adjust. Fuel level: 3.5 mm below the float chamber line *************************************** Measurement and adjustment steps: : Place the motorcycle on a level surface. : Put a garage jack under the engine to ensure that the carburetors are positioned vertically.
  • Page 148 CARB...
  • Page 149 CHAPTER 6. CHASSIS FRONT WHEEL AND BRAKE DISC ......FRONT WHEEL DISASSEMBLY .
  • Page 150 STEERING INSTALLATION ........6-42 REAR SHOCK ABSORBER AND SWINGARM .
  • Page 151: Chapter 6. Chassis

    CHAS FRONT WHEEL AND BRAKE DISC EB700000 CHASSIS FRONT WHEEL AND BRAKE DISC 20 Nm (2.0 m:kg) 59 Nm (5.9 m:kg) 23 Nm (2.3 m:kg) Order Job name/Part name Q’ty Remarks Front wheel and brake disc removal Remove the parts in order. WARNING Securely support the motorcycle so there is no danger of it falling over.
  • Page 152 CHAS FRONT WHEEL AND BRAKE DISC Order Job name/Part name Q’ty Remarks Front wheel disassembly Disassemble the parts in order. Oil seal Refer to “FRONT WHEEL ASSEMBLY” section. Bearing Spacer Refer to “FRONT WHEEL Spacer flange DISASSEMBLY/ASSEMBLY” section. Bearing Reverse the disassembly procedure for reassembly.
  • Page 153: Front Wheel Disassembly

    CHAS FRONT WHEEL AND BRAKE DISC T****** FRONT WHEEL DISASSEMBLY 1. Remove: : Bearings 1 : Spacer Remove the bearings using a general bear- ing puller 2 . CAUTION: Handle the wheel with care not to damage the brake disc. If the brake disc is damaged, replace.
  • Page 154: Brake Disc Inspection

    CHAS FRONT WHEEL AND BRAKE DISC 5. Measure: : Front wheel runout Over the specified limits ! Replace. Front wheel runout limits: Radial 1 : 2.0 mm Lateral 2 : 2.0 mm 6. Inspect: : Front wheel bearings Bearings allow free play in the wheel hub or the wheel does not turn smoothly ! Replace.
  • Page 155: Front Wheel Installation

    CHAS FRONT WHEEL AND BRAKE DISC CAUTION: Do not strike the inner race of balls of the bearing. Contact should be made only with the outer race. 2. Install: : Brake disc 1 23 Nm (2.3 m:kg) NOTE: Tighten the bolts (brake disc) in stage using a crisscross pattern.
  • Page 156: Wheel Static Balance Adjustment

    CHAS FRONT WHEEL AND BRAKE DISC 4. Tighten: : Front wheel axle 59 Nm (5.9 m:kg) : Axle pinch bolt 20 Nm (2.0 m:kg) CAUTION: Before tightening the wheel axle, stroke the front fork several times to check for proper fork operation.
  • Page 157 CHAS FRONT WHEEL AND BRAKE DISC 4. Adjust: : Wheel static balance *************************************** Adjusting steps: : Install a balancing weight 1 on the rim exactly opposite to the heavy spot “X”. NOTE: Start with the smallest weight. : Turn the wheel so that the heavy spot is 90_ : Check that the heavy spot is at rest there.
  • Page 158: Front Brake

    CHAS FRONT BRAKE FRONT BRAKE BRAKE PAD 23 Nm (2.3 m:kg) Order Job name/Part name Q’ty Remarks Brake pad removal Remove the parts in order. Bolt (caliper support bolt) Refer to “BRAKE PAD REPLACEMENT” Brake pads section. Pad support Reverse the removal procedure for installation.
  • Page 159: Brake Pad Replacement

    CHAS FRONT BRAKE SR702010 BRAKE PAD REPLACEMENT NOTE: It is not necessary to disassemble the brake cal- iper and brake hose to replace the brake pads. 1. Remove: : Bolt (caliper support bolt) 1 Move the direction brake caliper 2 to the ar- row mark.
  • Page 160: Master Cylinder

    CHAS FRONT BRAKE MASTER CYLINDER 2 Nm (0.2 m:kg) 9 Nm (0.9 m:kg) 30 Nm (3.0 m:kg) Order Job name/Part name Q’ty Remarks Master cylinder removal Remove the parts in order. Drain the brake fluid Rear view mirror (right) Brake lever/compression spring Brake switch Union bolt Plate washer...
  • Page 161 CHAS FRONT BRAKE Order Job name/Part name Q’ty Remarks Master cylinder disassembly Disassemble the parts in order. Rubber boots Circlip Refer to “MASTER CYLINDER Master cylinder kit ASSEMBLY” section. Spring Reverse the disassembly procedure for reassembly. 6-11...
  • Page 162: Master Cylinder Inspection

    CHAS FRONT BRAKE YP702040 MASTER CYLINDER INSPECTION 1. Inspect: : Master cylinder piston 1 Wear/scratches ! Replace the master cyl- inder kit. : Master cylinder cup 2 Cracks/damage ! Replace. 2. Inspect: : Master cylinder Scratches/wear/damage ! Replace the master cylinder assembly. 3.
  • Page 163: Master Cylinder Installation

    CHAS FRONT BRAKE 2. Install: : Circlip 1 Install the circlip securely into the master cyl- inder groove. : Rubber boot 2 YP****** MASTER CYLINDER INSTALLATION 1. Install: : Master cylinder 1 : Master cylinder bracket 2 9 Nm (0.9 m:kg) CAUTION: Install the master cylinder bracket 2 with the “UP”...
  • Page 164 CHAS FRONT BRAKE WARNING : Use only designated quality brake fluid: Otherwise, the rubber seals may deterio- rate, causing leakage and poor brake per- formance. : Refill with the same type of brake fluid:mix- ing fluids may result in a harmful chemical reaction and lead to poor performance.
  • Page 165: Caliper

    CHAS FRONT BRAKE CALIPER 30 Nm (3.0 m:kg) 40 Nm (4.0 m:kg) 23 Nm (2.3 m:kg) Order Job name/Part name Q’ty Remarks Caliper removal Remove the parts in order. Drain teh brake fluid Brake hose holder Union bolt Plain washer Refer to “CALIPER INSTALLATION”...
  • Page 166 CHAS FRONT BRAKE 6 Nm (0.6 m:kg) Order Job name/Part name Q’ty Remarks Caliper disassembly Disassemble the parts i order. Brake pad Refer to “BRAKE PAD” section. Caliper piston Dust seal Refer to “BRAKE CALIPER DISASSEMBLY/ASSEMBLY” section. Piston seal Bleed screw/Cap Reverse the disassembly procedure for reassembly.
  • Page 167: Brake Caliper Disassembly

    CHAS FRONT BRAKE SR****** BRAKE CALIPER DISASSEMBLY NOTE: Before disassembling either brake caliper, drain the brake fluid from the brake hose, mas- ter cylinder, brake caliper and reservoir tank. 1. Remove: : Brake caliper pistons : Caliper piston seals/dust seals *************************************** Removal steps: : Use a piece of wood 1 to secure the smaller...
  • Page 168: Caliper Installation

    CHAS FRONT BRAKE 1. Install: : Piston seals 1 : Dust seal 2 WARNING Always use new caliper piston seals. 2. Install: : Caliper piston 1 Apply brake fluid to the outer surface and install. YP****** CALIPER INSTALLATION 1. Install: : Caliper 1 40 Nm (4.0 m:kg) : Caliper support bolt 2...
  • Page 169 CHAS FRONT BRAKE WARNING : Use only the designated quality brake fluid: other brake fluids may deteriorate the rubber seals, causing leakage and poor brake performance. : Refill with the same type of brake fluid: mixing brake fluids may result in a harmful chemical reaction and lead to poor brake performance.
  • Page 170: Rear Wheel, Rear Brake And Drive Chain

    CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN REAR WHEEL, REAR BRAKE AND DRIVE CHAIN REAR WHEEL AND REAR BRAKE 40 Nm (4.0 m:kg) 65 Nm (6.5 m:kg) 20 Nm (2.0 m:kg) Order Job name/Part name Q’ty Remarks Rear wheel and rear brake removal Remove the parts in order.
  • Page 171 CHAS REAR WHEEL REAR BRAKE AND DRIVE CHAIN 40 Nm (4.0 m:kg) 65 Nm (6.5 m:kg) 20 Nm (2.0 m:kg) Order Job name/Part name Q’ty Remarks Rear wheel assembly Collar Shoe plate Nut (driven sprocket) Circlip Refer to “REAR WHEEL ASSEMBLY” Washer section.
  • Page 172 CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN Order Job name/Part name Q’ty Remarks Rear wheel disassembly Disassemble the parts in order. Bearing Collar Refer to “REAR WHEEL Spacer DISASSEMBLY/ASSEMBLY” section. Oil seal Bearing Reverse the disassembly procedure for reassembly. 6-22...
  • Page 173 CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN 9 Nm (0.9 m:kg) Order Job name/Part name Q’ty Remarks Brake shoe plate disassembly Disassemble the parts in order. Brake shoe kit Tension springs Refer to “BRAKE SHOE PLATE Cam lever ASSEMBLY” section. Indicator plate Camshaft Reverse the disassembly procedure for...
  • Page 174: Drive Chain

    CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN DRIVE CHAIN 65 Nm (6.5 m:kg) 10 Nm (1.0 m:kg) 7 Nm (0.7 m:kg) 8 Nm (0.8 m:kg) Order Job name/Part name Q’ty Remarks Drive chain removal Remove the parts in order. Chain case Refer to “REAR WHEEL, REAR BRAKE AND DRIVE CHAIN”...
  • Page 175: Rear Wheel Disassembly

    CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN T****** REAR WHEEL DISASSEMBLY 1. Remove: : Bearings 1 : Spacer 2 : Collar 3 Refer to “FRONT WHEEL”. SR701020 REAR WHEEL INSPECTION 1. Inspect: : Rear wheel axle : Rear wheel : Rear wheel bearings : Oil seals Refer to “FRONT WHEEL”.
  • Page 176: Drive Chain Inspection

    CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN 5. Inspect: : Cam shaft face T701020 DRIVE CHAIN INSPECTION 1. Inspect: : Drive chain stiffness Stiffness ! Clean and lubricate or replace. 2. Inspect: : Drive chain 1 : Driven sprocket 2 More than 1/2 tooth a wear ! Replace the drive chain.
  • Page 177: Brake Shoe Plate Assembly

    CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN 4. Clean: : Drive chain Put it in kerosene, and brush off as much dirt as possible. Then remove the drive chain from the kerosene and dry it. Drive chain lubricant: Engine oil SR****** BRAKE SHOE PLATE ASSEMBLY 1.
  • Page 178: Rear Wheel Assembly

    CHAS REAR WHEEL, REAR BRAKE AND DRIVE CHAIN SR****** REAR WHEEL ASSEMBLY 1. Install: : Bearing 1 : Spacer 2 : Collar 3 : Bearing 4 NOTE: : Apply the lithium soap base grease on the bearing and oil seal lip when installing. : Use a socket that matches the outside diame- ter of the race of the bearing.
  • Page 179: Front Fork

    CHAS FRONT FORK FRONT FORK 48 Nm (4.8 m:kg) 30 Nm (3.0 m:kg) 40 Nm (4.0 m:kg) Order Job name/Part name Q’ty Remarks Front fork removal Remove the parts in order. Front wheel Refer to “FRONT WHEEL AND BRAKE DISC” section. Brake hose holder Caliper Front fender...
  • Page 180 CHAS FRONT FORK 65 Nm (86.5 m:kg) Order Job name/Part name Q’ty Remarks Front fork disassembly Disassemble the parts in order. Cap bolt/O-ring Collar/washer NOTE: Fork spring Drain the fork oil. Dust cover Retaining clip Refer to “FRONT FORK Washer (oil seal) DISASSEMBLY/ASSEMBLY”...
  • Page 181: Front Fork Disassembly

    CHAS FRONT FORK SR****** FRONT FORK DISASSEMBLY 1. Remove: : Cap bolt 1 : Collar 2 : Washer 3 : Fork spring 4 2. Remove: : Dust cover 1 : Retaining clip 2 (using a slotted-head screwdriver) : Washer (oil seal) 3 CAUTION: Take care not to scratch the inner tube.
  • Page 182: Front Fork Assembly

    CHAS FRONT FORK 2. Measure: : Fork spring a Front fork spring free length: 326.1 mm <Wear limit> 321 mm Over the specified limit ! Replace. 3. Inspect: : Rod assembly 1 Bends/damage ! Replace. CAUTION: : The front fork has a built-in piston rod and a very sophisticated internal construction which are particularly sensitive to foreign material.
  • Page 183 CHAS FRONT FORK 2. Install: : Piston metal 1 : Oil seal 2 Use the fork seal driver weight 3 and the at- tachment 4 . NOTE: Before installing the oil seal 2 , apply lithium soap base grease onto the oil seal lips. CAUTION: Make sure that the oil seal numbered side faces upward.
  • Page 184: Front Fork Installation

    CHAS FRONT FORK 7. Measure: : Oil level a Out of specification ! Adjust. Oil level: 165 mm (from the top of the inner tube fully compressed and without the fork spring) NOTE: Hold the fork in an upright position. 8.
  • Page 185: Handlebar

    CHAS HANDLEBAR HANDLEBAR 9 Nm (0.9 m:kg) 20 Nm (2.0 m:kg) Order Job name/Part name Q’ty Remarks Handlebar removal Remove the parts in order. Headlight assembly NOTE: Handlebar switch lead (left and right), Disconnect the connector. front brake switch lead and clutch switch lead Master cylinder bracket Master cylinder...
  • Page 186 CHAS HANDLEBAR 9 Nm (0.9 m:kg) 20 Nm (2.0 m:kg) Order Job name/Part name Q’ty Remarks Handlebar switch (left) Grip (left) Refer to “HANDLEBAR REMOVAL” section. Lever holder (left) Upper holder Refer to “HANDLEBAR INSTALLATION” Handlebar section. Reverse the removal procedure for installation.
  • Page 187: Handlebar Removal

    CHAS HANDLEBAR YP****** HANDLEBAR REMOVAL 1. Remove: : Grip (Left) *************************************** Removal steps: : Remove the grip end (left). : Blow with compressed air between the hadle- bar and adhesive side of the grip to remove. *************************************** YP704020 HANDLEBAR INSPECTION 1.
  • Page 188 CHAS HANDLEBAR 3. Install: : Master cylinder 1 : Master cylinder bracket 2 9 Nm (0.9 m:kg) NOTE: Install the master cylinder bracket with the “UP” mark facing upward. 4. Adjust: : Throttle cable free play : Brake operation. Refer to “THROTTLE CABLE ADJUST- MENT/BRAKE LEVER ADJUSTMENT”...
  • Page 189: Steering

    CHAS STEERING STEERING UNDER BRACKET 40 Nm (4.0 m:kg) 1st step: 38 Nm (3.8 m:kg) 2nd step: 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Under bracket removal Remove the parts in order. Front fork Refer to “FRONT FORK” section. Handlebar Refer to “HANDLEBAR”...
  • Page 190 CHAS STEERING 40 Nm (4.0 m:kg) 1st step: 38 Nm (3.8 m:kg)2nd step: 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Ball race (upper) Ball Refer to “STEERING REMOVAL/ Ball INSTALLATION” section. Ball race (center) Ball race (lower) Reverse the removal procedure for installation.
  • Page 191: Steering Removal

    CHAS STEERING YP704010 STEERING REMOVAL WARNING : Securely support the motorcycle so that there is no danger of it falling over. : Stand the motorcycle on a level surface. 1. Remove: : Ring nut 1 Use a exhaust and steering nut wrench 2 . Exhaust and steering out wrench: 90890-01268 WARNING...
  • Page 192 CHAS STEERING EB704030 STEERING INSTALLATION Reverse the “REMOVAL” procedure. Note the following points. 1. Lubricate: : Bearings (upper and lower) : Ball races Recommended lubricant Lithium-soap base grease 2. Install: : Ring nut 1 7 Nm (0.7 m:kg) Refer to “STEERING HEAD INSPECTION” section in CHAPTER 3.
  • Page 193: Rear Shock Absorber And Swingarm

    CHAS REAR SHOCK ABSORBER AND SWINGARM REAR SHOCK ABSORBER AND SWINGARM 40 Nm (4.0 m:kg) 45 Nm (4.5 m:kg) 20 Nm (2.0 m:kg) 30 Nm (3.0 m:kg) Order Job name/Part name Q’ty Remarks Rear shock absorber and swingarm Remove the parts in order. removal Rear wheel Refer to “REAR WHEEL, REAR BRAKE...
  • Page 194 CHAS REAR SHOCK ABSORBER AND SWINGARM T***** SWINGARM INSPECTION 1. Inspect: : Swingarm side play Free play exists ! Check side clearance. : Swingarm up and down movement Unsmooth movement/bending/rough spots ! Grease or replace bearings, solid bushes and collars. 6-44...
  • Page 195 CHAPTER 7. ELECTRICAL ELECTRICAL COMPONENTS ........SWITCH INSPECTION .
  • Page 197: Chapter 7. Electrical

    ELEC ELECTRICAL COMPONENTS EB800000 ELECTRICAL ELECTRICAL COMPONENTS Horn Neutral relay C.D.I. unit Flasher relay Thermo switch Main switch Sidestand switch Starter relay Rear brake switch Rectifier/ Regulator Neutral switch Battery Spark plug cap Fuse holder assembly Ignition coil...
  • Page 198: Switch Inspection

    ELEC SWITCH INSPECTION YP-N SWITCH INSPECTION INSPECTION STEPS Using pocket tester, check switches for continu- ity between their terminals to determine wheth- er they are correctly connected. Replace the switch component if any of the combinations does not produce the correct reading.
  • Page 199: Switch Continuity Inspection

    ELEC SWITCH INSPECTION SWITCH CONTINUITY INSPECTION Refer to “SWITCH INSPECTION” and check for continuity between lead terminals. Poor connection, no continuity ! Correct or replace. * The coupler locations are circled. Clutch switch Engine stop switch Thermo switch Turn switch Start switch Dimmer switch Rear brake switch...
  • Page 200: Ignition System

    ELEC IGNITION SYSTEM EB802000 IGNITION SYSTEM CIRCUIT DIAGRAM C.D.I. magneto Main switch Engine stop switch C.D.I. unit Ignition coil Spark plug Sidestand switch...
  • Page 201: Troubleshooting

    ELEC IGNITION SYSTEM SR802010 TROUBLESHOOTING IF THE IGNITION SYSTEM FAILS TO OPERATE. (NO SPARK OR INTERMITTENT SPARK) Procedure Check: 1. Spark plug 6. Source coil resistance 2. Ignition spark gap 7. Main switch 3. Spark plug cap resistance 8. Engine stop switch 4.
  • Page 202 ELEC IGNITION SYSTEM YP***** 2. Ignition spark gap S Disconnect the spark plug cap from the spark plug. S Connect the ignition checker as shown. Spark plug cap S Turn the main switch to “ON”. S Check the ignition spark gap S Check the spark by pushing the starter switch, and increase the spark gap until a misfire occurs.
  • Page 203 ELEC IGNITION SYSTEM YP***** Tester (+) lead ! 4. Ignition coil resistance Orange Terminal S Disconnect the ignition coil connector from Tester (–) lead ! the wireharness. Ground Terminal S Connect the pocket tester (Ω 1) to the ignition coil. S Check if the primary coil has the specified re- sistance.
  • Page 204 ELEC IGNITION SYSTEM YP****** 5. Pickup coil resistance S Disconnect the pickup coil coupler from the wireharness. S Connect the pocket tester (Ω 100) to the pickup coil coupler. Tester (+) lead ! White Terminal Tester (–) lead ! Red Terminal S Check the pickup coil has the specified re- sistance.
  • Page 205 ELEC IGNITION SYSTEM YP***** NO CONTINUITY 8. Engine stop switch Refer to “SWITCH INSPECTION” section. Replace the handlebar switch (right). CONTINUITY YP***** NO CONTINUITY 9. Sidestand switch Refer to “SWITCH INSPECTION” section. Replace the sidestand switch CONTINUITY YP***** 10.Wiring connection POOR CONNECTIONS S Check the connection of the entire ignition system.
  • Page 206: Electric Starting System

    ELEC ELECTRIC STARTING SYSTEM EB80300 ELECTRIC STARTING SYSTEM CIRCUIT DIAGRAM Starter relay Battery Fuse Main switch Engine stop switch Start switch Clutch switch Sidestand switch Neutral relay Neutral switch Starter motor 7-10...
  • Page 207: Starting Circuit Operation

    ELEC ELECTRICAL STARTING SYSTEM SR****** STARTING CIRCUIT OPERATION The starting circuit on this model consists of the starter motor, starter relay, and the neutral relay. If the engine stop switch and the main switch are both closed, the starter motor can operate only if: The transmission is in neutral (the neutral relay is closed).
  • Page 208: Troubleshooting

    ELEC ELECTRICAL STARTING SYSTEM YP803020 TROUBLESHOOTING IF THE STARTER MOTOR FAILS TO OPERATE. Procedure Check: 1. Fuse 7. Engine stop switch 2. Battery 8. Neutral switch 3. Starter motor 9. Sidestand switch 4. Starter relay 10. Clutch switch 5. Neutral relay 11.
  • Page 209 ELEC ELECTRICAL STARTING SYSTEM YP****** 3. Starter motor WARNING S Connect the battery positive terminal and starter motor cable using a jumper S A wire used as a jumper lead must have the lead equivalent capacity as that of the battery S Check the starter motor operation.
  • Page 210 ELEC ELECTRICAL STARTING SYSTEM YP****** 5. Neutral relay S Remove the relay from the frame. S Connect the pocket tester (Ω 100) to the Battery and the relay connecter. Tester (+) lead ! Terminal 1 Tester (–) lead ! Terminal 3 Battery (+) lead ! Terminal 2 Battery (–) lead !
  • Page 211 ELEC ELECTRICAL STARTING SYSTEM YP****** NO CONTINUITY 10.Clutch switch Refer to “SWITCH INSPECTION” section. Replace the clutch switch. CONTINUITY YP****** NO CONTINUITY 11. Start switch Refer to “SWITCH INSPECTION” section. Replace the handlebar switch (right). CONTINUITY YP****** 12.Wiring connection POOR CONNECTION S Check the connections of the entire starting system.
  • Page 212: Starter Motor

    ELEC ELECTRICAL STARTING SYSTEM STARTER MOTOR 7 Nm (0.7 m:kg) Order Job name/Part name Q’ty Remarks Starter motor removal Remove the parts in order. Drain the engine oil Refer to “ENGINE OIL REPLACEMENT” section in CHAPTER 3. Crankcase cover (right) Refer to “CLUTCH REMOVAL”...
  • Page 213 ELEC ELECTRICAL STARTING SYSTEM YP803034 Inspection and repair 1. Inspect: : Commutator Dirt ! Clean it with #600 grit sandpaper. 2. Measure: : Commutator diameter a Commutator wear limit: 27 mm Out of specification ! Replace the starter motor 3. Measure: : Mica undercut a Mica undercut: 0.7 mm...
  • Page 214 ELEC ELECTRICAL STARTING SYSTEM 6. Measure: : Brush spring force Fatigue/out of specification ! Replace as a set. Brush spring force: 540 X 660 g 7. Inspect: : Oil seal Wear/damage ! Replace. YP****** Assembly Reverse the “Disassembly” procedure. Note the following points. 1.
  • Page 215: Charging System

    ELEC CHARGING SYSTEM YP804000 CHARGING SYSTEM CIRCUIT DIAGRAM C.D.I. magneto Rectifier/ Regulator Battery Fuse 7-19...
  • Page 216: Troubleshooting

    ELEC CHARGING SYSTEM YP804010 TROUBLESHOOTING IF THE BATTERY IS NOT CHARGED Procedure Check: 1. Fuse 4. Stator coil resistance 2. Battery 5. Wiring system (entire charging system) 3. Charging voltage NOTE: Remove the following parts before trouble- Use the special tools specified in the trouble- shooting.
  • Page 217 ELEC CHARGING SYSTEM YP****** 3. Charging voltage S Connect the engine tachometer to the spark plug lead. S Connect the pocket tester (DC20V) to the battery. Tester (+) lead ! Battery (+) terminal Tester (–) lead ! Battery (–) terminal Right side S Measure the battery terminal voltage.
  • Page 218 ELEC CHARGING SYSTEM YP****** 5. Wiring connection POOR CONNECTION Check the entire charging system for connec- tions. Refer to “CIRCUIT DIAGRAM” section. Correct. CORRECT Replace the rectifier/regulator. 7-22...
  • Page 219: Lighting System

    ELEC LIGHTING SYSTEM EB804000 LIGHTING SYSTEM CIRCUIT DIAGRAM Battery Fuse Main switch High beam indicator light Meter light Tail/ Brake light Auxiliary light Lights switch Dimmer switch Headlight 7-23...
  • Page 220: Troubleshooting

    ELEC LIGHTING SYSTEM YP805010 TROUBLESHOOTING IF THE HEADLIGHT, AUXILIARY LIGHT, HIGH BEAM INDICATOR LIGHT, TAILLIGHT AND/OR METER LIGHT FAIL TO COME ON. Procedure Check: 1. Fuse 4. Lights switch 2. Battery 5. Dimmer switch 3. Main switch 6. Wiring connection (entire lighting system) NOTE: Remove the following parts before trouble- Use the special tools specified in the trouble-...
  • Page 221: Lighting System Check

    ELEC LIGHTING SYSTEM NO CONTINUITY YP****** 4. Lights switch Refer to “SWITCH INSPECTION” section. Replace the handlebar switch (left). CONTINUITY YP****** NO CONTINUITY 5. Dimmer switch Refer to “SWITCH INSPECTION” section. CONTINUITY Replace the handlebar switch (left). YP****** 6. Wiring connection POOR CONNECTIONS S Check the connections of the entire lighting system.
  • Page 222 ELEC LIGHTING SYSTEM S Turn the main switch to on position. S Turn the lights switch to on position. S Turn the dimmer switch to low beam or high OUT OF SPECIFICATION beam. S Check for voltage (12 V) on the lead at bulb socket connectors.
  • Page 223 ELEC LIGHTING SYSTEM YP805022 3. The taillight fails to come on. NO CONTINUITY 1. Bulb and bulb socket Refer to “SWITCH INSPECTION” section. Replace the bulb and/or bulb socket. CONTINUITY 2. Voltage : Connect the pocket tester (DC20V) to the bulb socket connector.
  • Page 224: Signal System

    ELEC SIGNAL SYSTEM EB806000 SIGNAL SYSTEM CIRCUIT DIAGRAM Battery Rear brake switch Fuse Front flasher lights Main switch Flasher relay Thermo switch Horn Heater unit Horn switch Neutral indicator light Turn switch Turn indicator light (left) Turn indicator light (right) Neutral switch Rear flasher lights Tail/ Brake light...
  • Page 225: Troubleshooting

    ELEC SIGNAL SYSTEM YP806010 TROUBLESHOOTING IF THE FLASHER LIGHT, BRAKE LIGHT AND/OR INDICATOR LIGHT FAIL TO COME ON. IF THE HORN FAILS TO SOUND. Procedure Check: 1. Fuse 3. Main switch 2. Battery 4. Wiring connection (entire signal system) NOTE: S Remove the following parts before trouble- S Use the special tools in the troubleshooting shooting.
  • Page 226 ELEC SIGNAL SYSTEM YP****** 4. Wireharness S Check the connections of the entire signal POOR CONNECTION system. Refer to “CIRCUIT SYSTEM WIRING DIA- GRAM” section. Correct. CORRECT Check condition of each of the signal sys- tem’s circuits. Refer to “SIGNAL SYSTEM CHECK” section. 7-30...
  • Page 227: Signal System Check

    ELEC SIGNAL SYSTEM YP806020 SIGNAL SYSTEM CHECK 1. If the horn fails to sound. NO CONTINUITY 1. Horn switch Refer to “SWITCH INSPECTION” section. Replace the left handlebar switch (left). CONTINUITY 2. Voltage : Connect the pocket tester (DC20V) to the horn lead.
  • Page 228 ELEC SIGNAL SYSTEM YP806022 2. If the brake light fails to come on: NO CONTINUITY 1. Bulb and bulb socket Refer to “SWITCH INSPECTION” section. Replace the bulb and/or bulb socket. CONTINUITY NO CONTINUITY 2. Brake switch (Front/Rear) Refer to “SWITCH INSPECTION” section. Replace brake switch.
  • Page 229 ELEC SIGNAL SYSTEM YP806023 3. If the flasher light and/or turn indicator light fails to blink. NO CONTINUITY 1. Bulb and bulb socket Refer to “SWITCH INSPECTION” section. Replace the bulb and/or bulb socket. CONTINUITY NO CONTINUITY 2. Turn switch Refer to “SWITCH INSPECTION”...
  • Page 230 ELEC SIGNAL SYSTEM 5. Voltage S Connect the pocket tester (DC20V) to the bulb socket connector. At flasher light (left) Tester (+) lead ! Chocolate lead Tester (–) lead ! Black terminal At flasher light (right) Tester (+) lead ! Dark green lead Tester (–) lead ! Black terminal OUT OF SPECIFICATION S Turn the main switch to on.
  • Page 231 ELEC SIGNAL SYSTEM 3. Voltage S Connect the pocket tester (DC20V) to the fuel gauge coupler. Tester (+) lead ! Brown terminal Tester (–) lead ! Sky blue terminal S Turn the main switch to on position. OUT OF SPECIFICATION S Select the gear position in neutral.
  • Page 232 ELEC SIGNAL SYSTEM 2. Heater unit resistance S Remove the heater unit from the carburetor. S Connect the pocket tester (Ω 1) to the heater unit. Tester (+) lead ! Terminal Tester (–) lead ! Terminal S Check the heater unit for specificated resis- tance.
  • Page 233 CHAPTER 8. TROUBLE SHOOTING STARTING FAILURE/HARD STARING ......POOR IDLE SPEED PERFORMANCE ......POOR MEDIUM AND HIGH SPEED PERFORMANCE .
  • Page 235 TRBL STARTING FAILURE/HARD STARTING SHTG EB90000 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 inspection, adjustment and replacement of parts.
  • Page 236: Poor Idle Speed Performance

    TRBL POOR IDLE SPEED PERFORMANCE SHTG IGNITION SYSTEM Battery Ignition system : Improperly charged battery : Faulty C.D.I. unit : Faulty battery : Faulty pick up coil : Broken magneto woodruff key Fuse : Burnt out, improper connection Switch : Faulty main switch Spark plug : Improper plug gap : Faulty “ENGINE STOP”...
  • Page 237: Poor Medium And High Speed Performance

    TRBL POOR MEDIUM AND HIGH SPEED PERFORMANCE SHTG EB902000 POOR MEDIUM AND HIGH SPEED PERFORMANCE POOR MEDIUM AND HIGH SPEED PERFORMANCE Refer to “STARTING FAILURE/HARD STARTING” section. (Fuel system, electrical system, compres- sion system and valve train) Carburetor Air filter : Improperly adjusted fuel level : Clogged air filter element : Clogged main nozzle...
  • Page 238: Clutch Slipping/dragging

    TRBL FAULTY CLUTCH/FAULTY GEAR SHIFTING SHTG EB904000 EB903000 CLUTCH SLIPPING/DRAGGING FAULTY GEAR SHIFTING CLUTCH SLIPPING HARD SHIFTING Clutch Refer to “CLUTCH DRAGGING”. : Improperly adjusted clutch cable SHIFT PEDAL DOES NOT MOVE : Loose clutch spring Shift shaft : Fatigued clutch spring : Improperly adjusted shift rod : Worn friction plate/clutch plate : Bent shift shaft...
  • Page 239: Faulty Brake

    TRBL OVER HEATING/FAULTY BRAKE SHTG SR905000 SR906001 OVER HEATING OR OVER-COOL- FAULTY BRAKE POOR BRAKING EFFECT Front brake OVER HEATING : Worn brake pad Ignition system : Worn brake disc : Improper spark plug gap : Air in brake fluid : Improper spark plug heat range : Leaking brake fluid : Faulty C.D.I.
  • Page 240: Front Fork Malfunction

    TRBL FRONT FORK MALFUNCTION/INSTABLE HANDLING SHTG SR907000 SR908000 FRONT FORK MALFUNCTION INSTABLE HANDLING OIL LEAKAGE INSTABLE HANDLING : Bent, damaged or rusty inner tube Handlebars : Damaged or cracked outer tube : Improperly installed or bent : Damaged oil seal lip : Loose handlebar tightening bolt : Loose hexagon bolt Steering...
  • Page 241: Starter Motor Does Not Operate

    TRBL STARTER MOTOR DOES NOT OPERATE SHTG SR****** STARTER MOTOR DOES NOT OPERATE STARTER MOTOR DOES NOT OPERATE Battery : Insufficient battery capacity : Faulty battery Fuse : Burnt out, improper connection Switch : Faulty main switch : Faulty starter switch : Faulty clutch switch : Faulty neutral switch : Faulty sidestand switch...
  • Page 242: Faulty Signal And Lighting System

    TRBL FAULTY SIGNAL AND LIGHTING SYSTEM SHTG YP909000 FAULTY SIGNAL AND LIGHTING SYSTEM HEADLIGHT DARK FLASHER BLINKS SLOWER : Improper bulb : Faulty flasher relay : Too many electric accessories : Insufficient battery capacity : Hard charging (nearly discharged) : Faulty rectifier/regulator : Improper bulb : Faulty battery : Faulty main and/or turn switch...
  • Page 243 SR125 ’97 WIRING DIAGRAM 1 C.D.I. magneto 2 Rectifier / Regulator 3 Starter relay 4 Battery 5 Fuse 6 Main switch 7 Thermo switch 8 Heater unit 9 Handlebar switches (right) Engine stop switch Start switch C.D.I. unit Ignition coil Spark plug Clutch switch Sidestand switch...

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