Yamaha YB50 Service Manual Download Page 95

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CARB

CARBURETOR

5-3

4. Remove:

•

throttle stop screw

(with spring,

washer and o-ring)

• pilot air screw

(with spring)

5. Remove:

• spring seat

• jet needle

• throttle valve

• throttle valve spring

EAS00485

CHECKING THE CARBURETOR

1. Check:

• carburetor body

Dirty

Clean

NOTE:

For cleaning, use a petrol based solvent. Clean
the pipes and jets with compressed air

2. Check:

• main jet

• needle jet

• pilot jet

Dirty

Clean

3. Check:

• needle valve

Wear/Dirty

Clean

• float

Damage

Change

• gasket Damage

Change

Summary of Contents for YB50

Page 1: ...2002 SERVICE MANUAL YN505RN AE1 ...

Page 2: ...MANUAL 2002 Yamaha Motor España S A First Edition September 2002 All rights reserved The reprinting or use of this material without the written authorisation of Yamaha Motor España S A is forbidden Printed in Spain ...

Page 3: ...tinually trying to improve all models which it manufactures Authorised Yamaha MBK agents will be notified of all significant modifications and changes in the specifications or procedures and these will appear where applicable in future editions of this manual PARTICULARLY IMPORTANT INFORMATION This material used the following notation s A danger symbol means ATTENTION BE CAREFUL YOUR SAFETY IS IN ...

Page 4: ... useful reference material which contains ample explanations of all disassembly repair assembly and inspection procedures A particularly important procedure is placed between a lines of asterisks with each procedu re preceded by IMPORTANT CHARACTERISTICS Data and special tools are put in a box preceded by a corresponding symbol A number within a circle indicates the number of a part and an alphabe...

Page 5: ...ar in the text Refill with fluid 10 Lubricant 11 Special tool 12 Tightening 13 Wear limit clearance 14 Engine speed 15 Ω V A Illustrated symbols 16 to 23 of detailed dia grams indicate the degree of lubricant and the location of the lubrication point 16 Apply engine oil 17 Apply gear oil 18 Apply molybdenum disulphide oil 19 Apply grease to wheel bearings 20 Apply grease with lightweight lithium s...

Page 6: ...FICATIONS INSP ADJ 3 PERIODIC INSPECTION AND ADJUSTMENTS ENG 4 GENERAL OVERHAUL OF ENGINE CARB 5 CARBURATION CHAS 6 CHASSIS ELEC 7 ELECTRICAL SYSTEM INDEX TRBL SHTG 8 TROUBLESHOOTING GENERAL INFORMATION GEN INFO 1 ...

Page 7: ...GEN INFO 1 ...

Page 8: ...E FRAME 1 1 ENGINE SERIAL NUMBER 1 1 IMPORTANT INFORMATION 1 2 CHANGE OF ALL PARTS 1 2 OIL SEALS AND O RINGS 1 2 SEALING WASHERS PLATE AND KEYS 1 2 BEARING AND OIL SEALS 1 2 CIRCLIPS 1 3 SPECIAL TOOLS 1 3 FOR SERVICING THE ENGINE 1 3 FOR SERVICING THE CHASSIS 1 5 FOR ELECTRICAL COMPONENTS 1 6 ...

Page 9: ...d EU0 Frame VTLSA15 according standard EU1 Frame VTLSA19 according Mofa Version ENGINE SERIAL NUMBER The engine serial number is stamped on the upper part of the rear left hand section of the gear box NOTE The first three digits of these numbers identify the model the remaining digits are the manu facturing number of the unit NOTE The designs and specification are subject to change without prior n...

Page 10: ...ply grease on the lips of seals SEALING WASHER PLATES AND KEYS 1 All washers plates and keys should be replaced when they are removed The loc king tabs should be folded along the flat parts of the bolts or nuts after correctly tigh tening them BEARINGS AND OIL SEALS 1 Install the bearings and oil seals with their manufacturer s marks or numbers facing outwards i e the printed letters should on the...

Page 11: ... the sharp edge is placed in the opposing direction to the thrust it receives See sectional view Axle SPECIAL TOOLS Appropriate special tools are needed to com plete and perfect assembly with accuracy Using correct tools will help to avoid damage caused by the use of incorrect tools or impro vised techniques FOR SERVICING THE ENGINE 1 Engine wheel holding tool 90890 01235 2 Engine wheel removal to...

Page 12: ...GEN INFO SPECIAL TOOLS 1 4 4 Pulley wheel clamp 90890 01701 5 Clutch spring compressor 90890 01337 6 Crankshaft installer crucible 90890 01274 7 Crankshaft installer bolt 90890 01275 ...

Page 13: ... 90890 01277 9 Spacer 90890 01411 FOR SERVICING THE CHASSIS 1 T shaped handle 2 90890 01326 Shock absorber rod support 90890 01294 A 2 Counterbalance for insertion of fork seals 90890 01184 3 Accessory for insertion of fork seals 90890 01186 ...

Page 14: ...GEN INFO SPECIAL TOOLS 1 6 4 Steering nuts wrench 90890 01403 FOR ELECTRICAL COMPONENTS 1 Pocket tester 90890 03112 2 Ignition tester 90890 06754 ...

Page 15: ......

Page 16: ...SPEC 2 ...

Page 17: ...SPEC CHAPTER 2 SPECIFICATIONS GENERAL SPECIFICATIONS 2 1 MAINTENANCE SPECIFICATIONS 2 3 ENGINE 2 3 CHASSIS 2 5 ELECTRICAL SYSTEM 2 6 CABLE ROUTING 2 7 ...

Page 18: ... 11 L Air filter Flue type Fuel Type Unleaded petrol Fuel tank capacity 6 5 L Carburettor Type Manufacturer PHVA DELLORTO PY12 1 GURTNER Spark plug 5AD y SA15 SA19 Type Manufacturer BR8HS N G K BPR4HS NGK Distance between electrodes 0 6 0 7 mm 0 6 0 7 mm Clutch type Dry automatic centrifugal Transmission Primary reduction system Helicoidal gearing Primary reduction ratio 52 13 4 00 Secondary reduc...

Page 19: ...absorber Spring oil shock absorber Rear shock absorber Spring oil shock absorber Travel of wheels Travel of front wheel 70 mm Travel of rear wheel 60 mm Electrical system Ignition system DC C D I Generating system Magnetic flywheel Battery type or model YB4C B Battery capacity 12V4AH Type of headlight Bulb type Bulb voltage quantity Headlamp 25W 25Wx2 Rear light brake 5 21W Indicator 10Wx4 Metre l...

Page 20: ...it 0 01 mm Piston Piston size 39 952 39 972 mm Measurement point 5 mm Piston clearance 0 034 0 047 mm First clearance 40 50 mm Piston ring Cross section 1 5 x 1 8 mm B x T Distance between ends installed 0 15 0 35 mm Limit 0 6 mm Lateral clearance 0 03 0 05 mm Crank shaft Width of crank shaft A 37 90 37 95 mm Deflection limit C 0 03 mm Connecting rod big end clearance D 0 2 0 5 mm Free play from s...

Page 21: ...Ratchet type Pedal friction force 150 250 g Air filter oil grade oil filter Oil for foam air filter 2T oil for air cooled engines Carburettor Type Manufacturer Quantity PHVA Dellorto 1 YP12 GURTNER 1 Main jet M J 78 5AD 65 SA15 74 5AD 62 SA15 60 SA19 Retaining position of jet needles J N A12 3 5 A20 3 5 B10A 2 3 B10A 2 3 L3035H 1 3 Main air jet M A I ø 1 5 ø 1 5 Pilot jet P J 36 5AD 36 SA15 38 5AD...

Page 22: ...ont wheel Alloy rim Type of rear wheel Alloy rim Size material of front wheel 12 x 3 5 aluminium Size material of rear wheel 12 x 3 5 aluminium Rim run out limit Vertical 1 0 mm Lateral 1 0 mm Front disc brake Type Single External diameter and disc thickness 190 0 x 3 5 mm Thickness of pads 4 mm Limit 0 8 mm Internal diameter of master cylinder 11 mm Internal diameter of calliper 30 16 mm Brake fl...

Page 23: ...ystem Charging output 0 4 A or more 3 000 rpm min 1 A or less 8 000 rpm min Charging coil resistance colour 4 8 7 2 Ω a 20 C 68 F Black White Lighting system Lighting output 12 V or more 3 000 rpm min 15 V or less 8 000 rpm min Lighting coil resistance colour 0 4 0 6 Ω a 20 C 68 F Yellow Red Black Battery Type YB4L B Capacity 12V4AH Specific gravity 1280 20 C Starter system Type Constant mesh type...

Page 24: ...osing cable 13 Oil hose 14 choke wire A Insert the seat closing cable through the frame orifice B Connect the oil tube to the carburettor C Splice the fuel pipe to the cock D Splice the fuel pipe to the carburettor E Press the earth cable and the starter motor together F Splice all the cables except the brake hose without tightening G Splice to the frame wire harness and throtle H Pass the brake c...

Page 25: ...il tank C D I A Splice the electrical installation to the frame B Splice the oil pipe to the tank C Connect the oil pipe to the pump D Splice the installation to the frame E Tighten the earth cable and the ignition coil together F Pass the speedometer cable through the guide G Fit the grommet in the small hole of the underbracket ...

Page 26: ...r assembly Accelerator cable Rear brake cable Choke cable Front brake hose A Do not pinch the accelerator cable when assembling the handlebar covers B Accelerator cable tensioner Cover after adjusting C Connect the brake switch cables in this area D Do not pass the brake pipe through the flan ge ...

Page 27: ...INSP ADJ 3 ...

Page 28: ... 3 9 CHANGE OF TRANSMISSION OIL 3 10 AUTOLUBE PUMP AIR BLEEDING 3 10 CLEANING AIR FILTER 3 10 CHASSIS 3 12 ADJUSTMENT OF FREE PLAY OF FRONT BRAKE LEVER 3 12 ADJUSTMENT OF FREE PLAY OF REAR BRAKE LEVER 3 12 INSPECTION OF BRAKE PADS 3 12 INSPECTION OF BRAKE SHOES 3 13 INSPECTION OF BRAKE FLUID LEVEL 3 13 AIR BLEEDING HYDRAULIC BRAKE SYSTEM 3 14 STEERING ADJUSTMENT 3 14 INSPECTION OF TYRES 3 15 WHEEL...

Page 29: ...heck runout and for damage 8 Tires Check tread depth and for damage Replace if necessary Check air pressure Correct if necessary 9 Wheel Check bearing for looseness or damage bearings 10 Steering bearings Check bearing play and steering for roughness Lubricate with lithium soap based grease Every 24 000 km 11 Chassis fasteners Make sure that all nuts bolts and screws are properly tightened 12 Cent...

Page 30: ...ST 3 2 REAR BODYWORK AND FOO TREST REMOVAL 1 Raise the seat 2 Remove Seat 3 Remove Battery cover 4 Remove Rear cover 5 Remove Side covers NOTE When the side covers are being removed unhook them from the catches and slide them outwards ...

Page 31: ... 3 6 Remove Footrest INSTALLATION When the foot support panel and the rear cover are being installed reverse the removal process Remember the following points 1 Install Side covers NOTE Match up the support and hole and then apply pressure ...

Page 32: ...eadlight NOTE Disconnect the headlight cable and indica tors 3 Remove Front lower fairing screws Carrier hook bolt Footrest lower cover screws 4 Remove Battery cover Battery fuse and starter relay Bottom footrest cover Footrest Bottom rear fairing NOTE Disconnect indicator cables Mudguards INSTALLATION Reverse the removal process NOTE After installing all plastic parts check that all hooks are pro...

Page 33: ...NSTALLATION Reverse the removal procedure Remember the following points 1 Install Front handlebar cover Rear handlebar cover NOTE When installing the rear cover check that the speedometer cables goes through its hou sing NOTE After installing the handlebar cover ensure that all the hooks are properly coupled ...

Page 34: ...sure that the central safety stand is being used 4 Join Inductive tachometer On the spark plug cable 5 Check Engine idling Outside specified value Adjust 6 Adjust Engine idling Adjustment steps Turn the accelerator stop screw outward or inwards until the specified idling is obtai ned OUTWARDS TURNS OF THE PILOT AIR SCREW DELLORTO GURTNER EU0 EU1 EU0 EU1 MOFA 1 1 2 1 4 2 1 8 1 8 1 1 8 1 7 8 1 7 8 I...

Page 35: ...twards until the specified free play is obtained Tighten the lock nuts NOTE If the free play cannot be adjusted adjust the cable on the side of the carburettor second step Second step Remove the cover Loosen the lock nut Turn the adjuster inwards or outwards until the specified free play is obtained Tighten the lock nut Install the cover s s WARNING After adjustment turn the handlebar to the right...

Page 36: ...olour Replace The normal colour is a light to medium coffee colour 3 Clean the spark plug with a spark plug cle aner or wire brush 4 Measure Distance between electrodes Use a thickness gauge Outside the specified value Correct 5 Tighten Spark plug Gap between electrodes 0 6 0 7 mm Spark plug 2 0 m kg Standard spark plug 5AD y SA15 BR8HS N G K for SA19 BRP4HS N G K ...

Page 37: ... oil or equivalent Total 1 2 L Visual inspection steps for engine oil level Place main switch in position h The OIL CAUTION indicator light is not lit Inspect for defective electric circuit bulbs etc The OIL CAUTION indicator light is lit Place the main switch in position f The OIL CAUTION indicator light is not lit The OIL CAUTION indicator light is lit Supply engine oil The OIL CAUTION indicator...

Page 38: ...smission oil Oil refill cap 2 Inspect Gasket drainage screw O ring refill cap Damaged Change 3 Install Gasket Drainage screw 4 Fill Transmission Case CLEANING AIR FILTER Carburettor side 1 Remove Air filter box assembly Drainage screw 18 Nm 1 8 m kg Transmission oil SE engine oil type SAE 30 or GL gear oil Caacity 0 11 L 4 2 ...

Page 39: ...inlet area of the air filter with cloths or rags 3 Inspect Damaged element Change 4 Clean Air filter Steps for cleaning air filter Wash the filter carefully but completely with solvent s s WARNING Never use solvents with a low flammability point such as petrol to clean the filter Such solvents may cause fire or explosions Clean off excess solvent from the filter and leave it to dry ATTENTION Do no...

Page 40: ...e Air in the system will reduce the braking capacity and may cause loss of control and accidents Inspect and bleed the system if it is necessary ADJUSTMENT OF FREE PLAY OF REAR BRAKE LEVER 1 Check Free play of rear brake lever a Outside specified value Adjust Steps for adjusting the free play of the rear brake lever Turn the adjuster inwards or outwards until the correct free play is obtained INSP...

Page 41: ... ATTENTION The fluid may corrode painted surfaces or plastic parts Always clean any spilt fluid immediately s s WARNING Only use fluid of the designated quality Otherwise the rubber seals may deterio rate due to leakages and poor performan ce of the brakes Refill with the same type of fluid The mix ture of fluids may cause a damaging che mical reaction which may cause the poor performance of the b...

Page 42: ...y apply the brake lever several times f Pull the lever inwards Keep it in this posi tion g Loosen the bleed screw and tighten the lever as far as it will go h Tighten the bleed screw when it has rea ched its limit afterwards loosen the lever i Repeat steps e to h until the air bubbles in the system have been removed j Add brake fluid to the correct level s s WARNING Check the brake operation after...

Page 43: ...install and thigten the upper ring nut to 7 5 m kg INSPECTION OF TYRES s s WARNING Do not try to use tubeless tyres in a wheel designed only for inner tube tyres This may cause damage to the tyre and perso nal injury due to a puncture 1 Measure Air pressure Outside specified value Adjust 2 Inspect Tyre surface Worn Damaged Change Thread depth Side wall Wear indicator Wheel Tyre Tube type Only imer...

Page 44: ... s WARNING Never try to make even the smallest repairs on wheels INSPECTION OF REAR FORK 1 Inspect Rear fork Bent Damaged Fork bar Change Oil leaks Seals Change Rough operation Fork assembly Change REAR SHOCK ABSORBER INSPECTION 1 Inspect Rear shock absorber Oil leaks Damage Replace 2 Check Coupling torque Upper nut 3 2 m kg Lower bolt 1 8 m kg ...

Page 45: ...ll ATTENTION Add only distilled water tap water contains minerals which are damaging to the battery 3 Inspect Battery terminals Dirty terminals Clean with a wire brush Bad connection Correct NOTE Once the terminals are clean apply a thin cover of grease 4 Check The density of the electrolyte Less than 1 280 Recharge the battery Charge current 0 3 Amps 10 Hrs Electrolyte density 1 280 at 20 C 68 F ...

Page 46: ... and is conse quently poisonous and very caustic Always follow the following preventive measures Avoid physical contact with the electroly te which can cause serious burns or per manent damage to sight Use protective glasses when handling batteries or working near them Antidote EXTERNAL SKIN Wash with water EYES Wash with water for 15 minutes and consult a doctor immediately Antidote INTERNAL Drin...

Page 47: ...the ignition and circuit Install a new fuse of the correct amperage Connect the switches to check the correct operation of the electrical device If the fuse blows immediately after check the circuit concerned s s WARNING Do not use fuses of a higher amperage than that recommended This can cause extensi ve damage to the electrical system and fire Description Amperage Quantity Principal 7A 1 ...

Page 48: ...just Headlamp vertically REPLACEMENT OF HEADLAMP BULB 1 Remove Front fairing 2 Disconnect Headlamp cables 3 Remove Headlamp bulb cover Headlamp bulb 4 Install When the front fairing is installed reverse the removal process To raise the beam Turn the screw inwards To lower the beam Turn the screw outwards ...

Page 49: ......

Page 50: ...ENG 4 ...

Page 51: ...9 CRANKCASE AND CRANKSHAFT 4 9 INSPECTION AND REPAIR 4 11 CYLINDER HEAD 4 11 CYLINDER AND PISTON 4 11 PISTON RINGS 4 13 PISTON PIN AND PISTON PIN BEARING 4 14 KICK STARTER 4 15 TRANSMISSION 4 16 AUTOLUBRICATION PUMP 4 16 CRANKSHAFT 4 16 PRIMARY PULLEY WHEEL 4 17 SECONDARY PULLEY WHEEL 4 18 TRAPEZOIDAL BELT 4 19 GEARS AND STARTER CLUTCH 4 19 ASSEMBLY AND ADJUSTMENT OF ENGINE 4 21 CRANKSHAFT AND CRA...

Page 52: ...nel See section in chapter 3 REAR BODYWORK AND FOOTREST CARBURETTOR 1 Remove Air filter box assembly 2 Disconnect Autochoke wire Trhottle cable 3 Remove Oil discharge tube Fuel supply tube Carburettor SILENCER ASSEMBLY 1 Remove Silencer assembly Ventilator cover 2 Loosen Rear axle nut NOTE When the rear wheel axle nut is loosened apply the rear brake 1 1 1 ...

Page 53: ... that the oil does not spill out 2 Remove Bolts trunk Overflow bowl rivets NOTE To remove the overflow bowl take off the fuel and oil caps and replace them immediately after removing the bowl 3 Disconnect Battery cable Starter motor cable Magnetic flywheel cable Spark plug pipe 4 Remove Rear brake cable 1 ...

Page 54: ...ENG ENGINE REMOVAL 4 3 ENGINE REMOVAL 1 Remove Rear shock absorber screw lower 2 Remove Engine assembly screw Engine Lift the frame and remove the engine 3 Place the frame on a suitable support ...

Page 55: ...over Cylinder head Cylinder head gasket NOTE Before loosening the cylinder head loosen the spark plug The position nuts of the cylinder head should be loosened by 1 2 a turn each time and then removed 2 Remove Cylinder Cylinder gasket PISTON PIN AND PISTON 1 Remove Piston pin clip NOTE Before removing the piston pin clip cover the crankcase with a clean cloth so that it does not accidentally fall ...

Page 56: ...ON Do not use a hammer to take out the pis ton pin KICKSTART SYSTEM 1 Remove Kickstart pedal Crankcase cover left 2 Remove Guide air filter Air filter 3 Remove Pedal gear NOTE When the pedal gear removed move the pedal axle 4 Unhook Return spring 5 Remove Circlip Flat washer Pedal axle ...

Page 57: ... Conical spring washer One way clutch Washer Fixed primary pulley wheel Shim Trapezoidal belt 4 Remove Hub Primary pulley wheel assembly SECONDARY PULLEY WHEEL 1 Remove Nut secondary pulley wheel NOTE Support the secondary pulley wheel using the pulley wheel clamp 2 Remove Clutch drum Secondary pulley wheel assembly Crankcase cover gasket Centring devices Engine wheel holding tool 90890 01235 Pull...

Page 58: ...pring compressor 6 Remove Clutch positioning nut 7 Remove Clutch assembly Clutch spring Spring seat Guide pins Secondary sliding pulley wheel STARTER SYSTEM 1 Remove Plate intermediate gearing Intermediate gearing Starter clutch assembly Washer Starter wheel gearing 2 Remove Bushing Bearing Washer Starter motor Pulley wheel clamp 90890 01701 Clutch spring compressor 90890 01337 ...

Page 59: ...Drive axle Flat washer Conical spring washer 3 Remove Oil seal Bearing Secondary pulley wheel axle MAGNETIC FLYWHEEL 1 Remove Nut rotor Flat washer NOTE Support the rotor to loosen the nut with the engine flywheel support tool 2 Remove Rotor Woodruff key Use the magnetic flywheel extractor Stator assembly Gasket Magnetic flywheel extractor 90890 01362 Engine flywheel support tool 90890 01235 ...

Page 60: ...sket CRANKCASE AND CRANKSHAFT 1 Remove Oil seal catch Screws crankcase NOTE Loosen each screw 1 4 of a turn and remove them after loosening them 2 Apply Crankcase separation tool NOTE Fully tighten the positioning nuts of the tool but ensure that the tool body is parallel with the box If necessary slightly loosen one of the screws to level the body of the tool Crankcase separation tool 90890 01135...

Page 61: ...MBLY THE ENGINE 4 10 3 Remove Crankcase right While pressure is applied strike alternati vely on the engine assembly hubs 4 Apply Crankcase separation tool 5 Remove Crankshaft Crankcase separation tool 90890 01135 ...

Page 62: ...a thickness cali bration on the cylinder head Measure the limit of the warping If the warping is outside the specified value rectify the cylinder head NOTE Turn the cylinder head several times to avoid removing too much material from one side CYLINDER AND PISTON 1 Eliminate Carbon deposits Use a rounded file 2 Inspect Cylinder wall Wear striping Rectify or change 3 Eliminate Carbon deposits From t...

Page 63: ...f cylinder C in parallel and at right angles to the crankshaft Then find the mean of the measurements If this is outside the specified value rectify or change the cylinder change the piston and the set of rings Second step Measure the diameter of the piston skirt P with a micrometer a 5 0 mm 0 20 in from the inner edge of the piston Wear Standard limit Inner diameter 40 0 mm 40 10 mm of cylinder C...

Page 64: ...STON RINGS 1 Measurement Lateral clearance Outside specified value Change the piston and or rings Use a thickness gauge 2 Install Piston rings on the cylinder Press the ring and the piston crown together Size of the piston P Standard 39 952 39 997 mm 1st Clearance 40 25 mm 2st Clearance 40 50 mm Clearance of piston to cylinder Inner diameter of cylinder C Diameter of piston skirt P Cylinder piston...

Page 65: ...ubrication system 2 Measure External diameter a Piston pin clip Outside specified value Change 3 Measure Clearance of piston pin to piston Outside specified value Change the piston Clearance of piston pin to piston 0 004 0 016 mm Limit 0 07 mm Standard Limit Top ring 0 15 0 35 mm 0 60 mm Second ring 0 15 0 35 mm 0 60 mm Clearance of piston pin to piston Size of inner diameter Piston pin b External...

Page 66: ...Inspect Pedal gear teeth Pedal pinion gear teeth Burrs Spalling Non uniformity Wear Change 2 Inspect Locking bolt pedal pinion gear and one way clutch Rounded edges Wear Change 3 Measure Spring tension pedal pinion gear Outside specified value Change Use a dynamometer Standard tension 150 250 gr ...

Page 67: ... operation may cause the pump to deviate from its factory adjust ment However this is very uncommon If incorrect operation is suspected inspect the following 1 Inspect Supply line Obstruction Apply air under pressure O ring Wear Damage Change 2 Inspect Drive gear teeth of the autolubrication pump Gear teeth driven by autolubrication pump Pitting Wear Damage Change CRANKSHAFT 1 Measurement Deflecti...

Page 68: ...ear Cracks Striping Damage Change 2 Check Free movement Insert the bushing in the primary sliding pulley wheel and check if there is free movement If it catches or there is excessive play Change the pulley wheel or the bushing 3 Measure External diameter roller Outside specified value Change External diameter roller 15 0 mm Limit 14 5 mm Deflection limit C 0 03 mm Clearance on big end side D 0 2 0...

Page 69: ...ring Damaged Change 3 Measure Free length of variator spring Outside specified value Change 4 Inspect Inner surface of the clutch hub Oil Striping Clean 5 Measure Internal diameter of the clutch hub a Outside specified value Change Free length of secondary pulley wheel 109 6 mm Limit 90 4 mm Oil Use a cloth dampened with dissolvent Striping Use sand paper polish lightly and uniformly Internal diam...

Page 70: ...ELT 1 Inspect Trapezoidal belt Cracks Wear Change NOTE Replace the trapezoidal belt if it is dirty with oil or grease 2 Measure Width of trapezoidal belt a Outside specified value Change STARTER CLUTCH AND GEARS 1 Inspect Starter clutch Press the conical pin in the direction of the arrow Rough operation Change the starter clutch assembly Width of trapezoidal belt 16 5 mm Wear limit 15 7 mm Thickne...

Page 71: ...ENG INSPECTION AND REPAIR 4 20 2 Inspect Starter wheel gear teeth Intermediate gear teeth Burrs Spalling Non uniformity Wear Change Bearing starter wheel gear Pitting Damage Change ...

Page 72: ...ND CRAKCASE Oil seal Oil seal catch Crankcase right Centring device Bearing Crankcase right Bearing Crankshaft pin Connecting rod 10 Crankcase left 11 Bearing 12 Engine mounting spacer 13 Crankcase left 14 Oil seal CRANKSHAFT A 37 90 37 95 mm C 0 03 mm D 0 2 0 5 mm F Limit 1 0 mm 0 4 0 8 mm ...

Page 73: ...nstallation tool 6 Install Right crankcase 7 Tighten Crankcase positioning screws NOTE Tighten the crankcase positioning screws in stages using a crossed method for tighte ning 8 Check Rotation of crankshaft Rough turning Repair 9 Install Oil seal catch plate Crankshaft installation tool 90890 01411 90890 01274 90890 01275 90890 01277 Yamaha N 1215 adhesive 90890 85505 Crankshaft installation tool...

Page 74: ...her Rotor assembly Charge coil Lighting coil Harnessing coil Stator plate Oil seal Gasket 10 Oil outlet pipe 11 Oil pipe 12 Bushing 13 Autolubrication pump 14 O ring 15 Elastic circlip 16 Oil pump drive gear 17 Pin AUTOLUBRICATION PUMP AND MAGNETIC FLYWHEEL ...

Page 75: ...nstall Autolubrication pump 4 Apply Grease with lithium soap base on the autolubrication pump gear FLYWHEEL MAGNETO 1 Install Seal 2 Apply Grease with lithium soap base on the oil reten 3 Pass the wheel cable through the crankca se orifice 4 Install Stator assembly 5 Install Key Magnetic wheel Flat washer Nut Screw autolubrication pump 0 4 m kg 15 cc Screw stator assembly 0 8 m kg ...

Page 76: ...OF ENGINE 4 25 TRANSMISSION Circlip Bearing Oil seal Drive axle Bearing Main axle Conical spring washer Flat washer Secondary pulley wheel axle 10 Bearing 11 Centring device 12 Seal 13 Transmission box cover 14 Bearing 15 Oil seal ...

Page 77: ...x cover 3 Install Circlip Oil seal NOTE Apply grease with lithium soap based on the oil seal lips 4 Check Rotation of secondary pulley wheel axle Rough rotation Repair 5 Apply SE type 10W30 engine oil on bearing of main axle and drive axle bearing 6 Install Drive axle Main axle Conical spring washer Flat washer 7 Install Gasket Conical pins Transmission box cover Screw box cover 0 9 m kg Flywheel ...

Page 78: ...MOT ASSEMBLY AND ADJUSTMENT OF ENGINE 4 27 STARTER SYSTEM Bushing Bearing Starter wheel gear Starter clutch Plate Axle Flat washer Intermediate gear O ring 10 Starter engine ...

Page 79: ...n the bearing Apply molybdenum disulphide oil on the pin starter clutch 2 Install Flat washer Intermediate gear Flat washer Plate intermediate gear NOTE Apply engine oil on the intermediate gear 3 Install Starter motor NOTE Apply grease with a lithium soap base on the o ring of the starter motor Screw intermediate gear plate 0 8 m kg Starter motor bolts 1 3 m kg ...

Page 80: ... belt 11 Guide pin 12 Secondary fixed pulley wheel 13 Conical washer 14 One way clutch 15 Washer 16 Fixed primary pulley wheel 17 Shim 18 Hub 19 Sliding primary pulley wheel 20 Rollers 21 Runner 22 Cam 23 Washer Apply assembly lube FREE LENGTH LIMIT OF VARIATOR 83 mm WASTE LIMIT OF CLUTCH HOUSING 107 4 mm WASTE LIMIT OF CLUTCH SHOES 1 0 mm TRAPEZOIDAL BELT WASTE LIMIT 15 7 mm VARIATOR ROLLER LIMIT...

Page 81: ...MOT ASSEMBLY AND ADJUSTMENT OF ENGINE 4 30 KICKSTART PEDAL Pedal axle Return spring Bushing Flat washer Elastic retainer Starter pedal Spring Pedal pinion gear 10 Nm 1 0 m kg 150 250 g ...

Page 82: ...iding pulley wheel NOTE Take care that the lips of the oil seals do not turn when the pulley wheel is installed 3 Apply Assembly grease on the torsion cam grooves and o rings 4 Check Sliding pulley wheel Faulty operation Repair 5 Install Clutch positioning bolt Use the clutch spring compressor 6 Tighten Clutch positioning nut Use the pulley wheel clamp Spanner 41 MM Clutch spring compressor 90890 ...

Page 83: ...LLEY WHEEL 1 Clean Surface of primary sliding pulley wheel Surface of primary fixed pulley wheel Hubs Rollers Roller races 2 Install Counterbalance Race Runner Hub 3 Check Operation of race Rough operation Repair 4 Install Primary pulley wheel assembly Hub 5 Install Trapezoidal belt NOTE The trapezoidal belt should be installed with the arrow facing towards the front Pulley wheel clamp 90890 01701...

Page 84: ...tightened primary pulley wheel support the magnetic flywheel using the engine wheel support tool 8 Adjust Trapezoidal belt Tense the trapezoidal belt by turning the primary pulley wheel several times 9 Install Fan KICKSTART PEDAL 1 Install Return spring Pedal axle Bushing Flat washer Elastic circlip Engine wheel support tool 90890 01235 Primary pulley wheel nut 3 3 m kg Screw fan 0 7 m kg ...

Page 85: ...ND ADJUSTMENT OF ENGINE 4 34 2 Hook on Return spring on pedal gear and hub 3 Install Pedal pinion gear 4 Install Crankcase cover 5 Install Kickstart pedal Screw crankcase cover 7 Nm 0 7 m kg Kickstart pedal 0 9 m kg ...

Page 86: ...n rings Piston 10 Piston pin 11 Circlips 12 Bearing SPARK PLUG MANUFACTURER TYPE NKG BR7HS GAP BETWEEN ELECTRODES 0 06 0 7 mm CLEARANCE FROM PISTON TO CYLINDER 0 034 0 047 mm Limit 0 1 mm BETWEEN ENDS INSTALLED Top ring 0 15 0 35 mm Limit 0 60 mm Second ring 0 15 0 35 mm Limit 0 60 mm LATERAL CLEARANCE Top ring 0 03 0 05 mm Limit 0 10 mm Second ring 0 03 0 05 mm Limit 0 10 mm ...

Page 87: ... point to the exhaust side Before installing the piston circlip cover the crankcase with a towel or clean cloth so that the circlip and other materials do not accidentally fall into the crankcase Always use new piston circlips CYLINDER AND CYLINDER HEAD 1 Install Cylinder gasket Use a new gasket 2 Check Piston rings NOTE Ensure that the ends of the rings are correctly coupled around the centring d...

Page 88: ...gasket 5 Install Cylinder head Spark plug Air protector NOTE The arrow EX from the cylinder head should point to the exhaust side Tighten the cylinder head positioning nuts in several steps using a cris cross pattern 6 Install Central stand Spring Axle Clasp Rubber washer Strap loop 7 Install Brake shoes Flat washer Rear wheel Cylinder head positioning screws 1 4 m kg spark plug 2 0 m kg ...

Page 89: ...gn the projection of the carburettor with the projections of the head Before installing the oil supply pipe fill it with oil 3 Install Oil pipe Oil supply pipe NOTE Pass the oil supply pipe and the oil pipe through as shown 4 Bleed the air Autolubrication pump Consult chapter 3 section BLEEDING OF AIR FROM THE AUTOLUBRICATION PUMP 5 Tighten Rear wheel axle nut NOTE When the rear wheel axle nut is ...

Page 90: ... Free play of accelerator cable See sec tion ADJUSTMENT OF FREE PLAY OF ACCELERATOR CABLE 9 Install Helmet carrier Overflow bowl Footrest Rear bodywork Rear cover Follow the reverse process to the removal procedure 10 Install Battery in its footrest housing 11 Connect Battery cables 12 Place Front cover Bolt silencer 2 6 m kg Bolt exhaust pipe 0 9 m kg 1 2 Positive cable to positive terminal of ba...

Page 91: ...CARB 5 ...

Page 92: ... CARBURETOR 5 2 CHECKING THE CARBURETOR 5 3 ASSEMBLING THE CARBURETOR 5 5 CHECKING THE AUTOCHOKE UNIT 5 6 INSTALLING THE CARBURETOR 5 7 FUEL COCK 5 7 CHECKING THE FUEL COCK 5 7 REED VALVE 5 8 REMOVING THE REED VALVE 5 8 CHECKING THE REED VALVE 5 8 INSTALLING THE REED VALVE 5 9 CARB ...

Page 93: ...ng Spring catch Throttle valve Jet needle Pilot air screw Throttle stop screw Needle jet Main jet Pilot jet 10 Float 11 Float gasket 12 Drain screw 13 Needle valve 14 Float chamber 15 Autochoke unit 13 11 14 10 12 carburetor dell orto carburetor gurtner 15 13 11 14 10 15 ...

Page 94: ...chapter 3 2 Drain fuel from drain screw 3 Disconnect autochoke lead coupler fuel hose vacuum hose oil delivery hose throttle cable with throttle valve clamp fixing clip 4 Remove carburetor DISASSEMBLING THE CARBURETOR 1 Remove float chamber 2 Remove float pin float needle valve 3 Remove pilot jet main jet needle jet ...

Page 95: ... needle throttle valve throttle valve spring EAS00485 CHECKING THE CARBURETOR 1 Check carburetor body Dirty Clean NOTE For cleaning use a petrol based solvent Clean the pipes and jets with compressed air 2 Check main jet needle jet pilot jet Dirty Clean 3 Check needle valve Wear Dirty Clean float Damage Change gasket Damage Change ...

Page 96: ...r screw jet needle starter plunger Wear Damage Change 7 Measure Float height a Outside specifications Check valve float and valve seat Steps for measuring the height of the float Assemble the valve float and axle on the carburettor body Turn the carburettor upside down Using a vernier caliper measure the distance between the plane of the bowl gasket wit hout the gasket and the upper part of the fl...

Page 97: ...s adjusted in the fac tory Do not try to modify it under any cir cumstances EAS00487 ASSEMBLING THE CARBURETOR The assembly of the carburetor is carried out following the reverse procedure to DISAS SEMBLY Bear in mind the following points CAUTION Before assembling the carburetor wash all of the parts in a petroleum based sol vent Always use new gaskets 1 Install jet needle clip throttle valve spri...

Page 98: ...r plunger is open air should come out of the other side of the starter air passage 3 Check autochoke unit a Connect the autochoke unit leads to a 12 0 V battery for five minutes b Connect a 3 3 mm hose to the starter air passage and blow into the hose Starter plunger Perform step 3 opens Starter plunger Replace the auto closes choke unit Positive batter lead yellow red Negtive battery lead black S...

Page 99: ...to chapter 3 REAR BODYWORK MUDGUARD section 3 Inspect fuel cock Steps for inspecting fuel cock Disconnect the fuel hose Place a receptacle under the end of the fuel hose Disconnect the vacum hose and suction to create a vacuum If the fuel comes out of the fuel hose as a result of applying a vacuum and stops when the vacuum is stopped the cock is in good condition If not clean or replace the vacuum...

Page 100: ...carburetor See section REMOVING THE CARBURE TOR 3 Remove carburetor joint reed valve assembly CHECKING THE REED VALVE 1 Inspect carburetor joint Damage Cracks Change reed valve Fatigue Cracks Change Inspection steps Visually inspect the reed valve If there is any doubt on how to seal apply suction on the carburettor side Leaks should be light or moderate ...

Page 101: ...lace the reed valve INSTALLING THE REED VALVE When the reed valve assembly is installed reverse the removal procedure Bear in mind the following points 1 Install gasket 2 Tighten tighten the bolts for reed valve NOTE Tighten each bolt gradually to avoid it being deformed Height of valve stopper 6 0 6 4 mm Clearance of reed valve Less than 0 2 mm Reed valve 11 Nm 1 1 m kg New ...

Page 102: ...CHAS 6 ...

Page 103: ...CALLIPER 6 6 INSPECTION AND REPAIR 6 7 ASSEMBLY OF CALLIPER 6 7 ASSEMBLY OF PUMP 6 8 REAR WHEEL 6 9 EXTRACTION 6 10 INSPECTION 6 10 ASSEMBLY 6 11 INSTALLATION 6 12 REAR FORK 6 13 EXTRACTION 6 14 DISASSEMBLY 6 14 INSPECTION 6 15 ASSEMBLY 6 16 INSTALLATION 6 18 HANDLEBAR AND STEERING 6 19 REMOVAL 6 20 INSPECTION 6 21 INSTALLATION 6 22 CHAS ...

Page 104: ... CHASSIS FRONT WHEEL Wheel axle Speedometer gear unit Bearing Spacer Hub Rim assembly Tyre Oil seal Spacer 10 Nut 11 Washer TYRE SIZE 120 70 12 RIM RUN OUT LIMIT Vertical 1 0 mm Lateral 1 0 mm WHEEL AXLE BEND LIMIT 0 25 mm ...

Page 105: ...of wheel axle Outside specified value Change s s WARNING Do not try to straighten a bent axle 2 Measure Run out of wheel Outside specified value Change 3 Inspect Wheel Cracks Marked Deformed Change 4 Inspect Wheel bearings Bearings allow play on the wheel hub or the wheel turns abruptly Change 5 Inspect Speedometer gear unit Wear Damage Change Bend limitof wheel axle 0 25 mm Run out limit Vertical...

Page 106: ...nit NOTE Ensure that the two projections in the gear unit are engaging with the flat surface of the gear unit 3 Install Front wheel NOTE Ensure that the projection torsion stopper of the casing of the gear unit is correctly positioned 4 Tighten Front wheel axle s s WARNING Ensure that the brake pipe is correctly positioned Recommended lubricant Grease with lithium soap base Front wheel axle 4 8 m ...

Page 107: ... spring Pad set Piston seal Piston Brake disc Master cylinder cap 10 Diaphragm 11 Hose 12 Brake pump assembly 13 Assembly plate 14 Copper washer 15 Assembly bolt 16 Brake light switch cable TYPE OF BRAKE FLUID DOT 3 or 4 WEAR LIMIT OF BRAKE PADS 0 8 mm WEAR LIMIT OF BRAKE DISC 3 0 mm ...

Page 108: ...fication Replace the brake pads as a set 4 Install brake pad shims onto the brake pads brake pads brake pad spring NOTE Always install new brake pads brake pad shims and a brake pad spring as a set a Connect a clear plastic hose tightly to the bleed screw Put the other end of the hose into an open container b Loosen the bleed screw and push the brake caliper pistons into the brake caliper with you...

Page 109: ...luid level Below the minimum level mark Add the recommended brake fluid to the proper level Refer to CHECKING THE BRAKE FLUID LEVEL in chapter 3 7 Check brake lever operation Soft or spongy feeling Bleed the brake system Refer to BLEEDING THE HYDRAULIC BRAKE SYSTEM in chapter 3 REMOVING THE BRAKE HOSE NOTE Before replacing the brake hose drain the brake fluid from the entire brake system 1 Remove ...

Page 110: ... 1 Install Brake hose Copper washers Assembly bolts Brake switch s s WARNING The correct positioning of the hose is essential to ensure the safe operation of the scooter See CABLE ROUTING Always use new copper washers 2 Ensure that the brake hose does not touch other parts accelerator cable installation cables etc by turning the handlebar to the left and right If it does touch correct this 1 2 3 4...

Page 111: ...ection of brake disc Outside specified value Inspect run out of wheel If the wheel is in good condition change the brake disc Brake disc thickness Outside specified value Change Maximum deflection 0 5 mm Minimum thickness 3 0 mm Bolt brake disc 2 0 m kg LOCTITE ...

Page 112: ... washer Return spring Brake shoe Brake cam Shoe axle Wear indicator 10 Brake lever Change Brake shoes and return spring as a set TYRE SIZE 130 70 12 BRAKE DRUM WEAR LIMIT 110 5 mm BRAKE SHOE WEAR LIMIT 2 0 mm WHEEL RUN OUT LIMIT Vertical 1 0 mm Lateral 1 0 mm ...

Page 113: ...oes Flat washer INSPECTION 1 Inspect Wheel See INSPECTION OF REAR WHEEL section 2 Measure Wheel run out See INSPECTION OF REAR WHEEL section 3 Check Wheel bearings Consult the INSPEC TION OF REAR WHEEL section 4 Inspect Brake shoes Crystallisation Polish with sand paper NOTE After using sand paper clean the polished particles with a cloth Rim run out limits Vertical 1 0 mm Lateral 1 0 mm ...

Page 114: ...re Bear in mind the following points 1 Install Brake cam NOTE Apply Grease with a lithium soap base on the brake cam and pin ATTENTION After installing the brake cam remove excess grease 2 Install Brake shoes Return spring NOTE Install with the mark outwards 3 Install Torsion spring Wear indicator Cam lever NOTE Align the projection of the wear indicator with the line as shown Align the punch mark...

Page 115: ...ocedure The following points should be remembered 1 Install Rear wheel Flat washer Nut 2 Install Silencer 3 Adjust Free play of rear brake lever See section in chapter 3 CHECKING FREE PLAY OF REAR BRAKE LEVER Bolt cam lever 0 7 m kg Nut Rear wheel axle 12 5 m kg Bolt exhaust pipe side 0 9 m kg Bolt silencer side 2 6 m kg ...

Page 116: ...g Cap O ring Dust guard Retainer Oil seal 10 Fork spring 11 Sliding metal 12 Shock absorber rod 13 Return spring 14 Bar 15 Oil lock piece 16 Outer tube 17 Front fork assembly right FREE LENGTH OF FORK SPRING LIMIT LEFT 226 mm RIGHT 226 mm FORK OIL CAPACITY 50 cc 1 cc GRADE 10 W oil fork or equivalent ...

Page 117: ... Consult FRONT BRAKE REMOVAL sec tion 3 Remove Front wheel See FRONT WHEEL REMOVAL SEC TION 4 Remove Mudguard front fairing See chapter 3 FRONT BODYWORK MUDGUARD 5 Loosen Positioning bolt fork 6 Remove Restraining ring FRONT FORK DISASSEMBLY 1 Remove Rubber cap Restraining ring Cap Fork spring 2 Drain Fork oil 3 Remove Mudguard Retainer 1 3 2 ...

Page 118: ...e left side Oil seal INSPECTION 1 Inspect Fork bar Outer tube Shock absorber rod Striping Warping Wear Damage Change s s WARNING Do not try to straighten a fork bar or an outer tube as this may dangerously wea ken the tube 2 Measure Fork spring Above specified limit Change 3 Inspect Oil lock piece O ring cover Wear Damage Change T handle 90890 01326 Support 90890 01294 A Free length of fork spring...

Page 119: ...ew Bolt shock absorber rod NOTE Tighten the bolt hydraulic rod while suppor ting the bar with the T handle and the sup port 2 Install Oil seal Use a counterbalance for installing fork seals and an adaptor NOTE Before installing the oil seal apply grease with a lithium soap base on the edges of same ATTENTION Ensure that the numbered side of the seal is facing upwards Bolt hydraulic rod 23 Nm 2 3 m...

Page 120: ...5 Install Fork spring Cover Restraining ring Rubber cap NOTE Before installing the cover apply grease to the o ring Couple the restraining ring correctly on the inner tube groove Each fork 50 cm3 10 W fork oil or equivalent after filling slowly pump the fork to distribute the oil Oil level 95 mm From the upper part of the inner fork tube totally compressed wit hout the spring ...

Page 121: ...ttach the stopper ring correctly on the inner tube groove 2 Tighten Positioning bolt lower bracket 3 Install Front wheel Brake calliper Clasp brake hose Speedometer cable See FRONT WHEEL section Front mudguard See chapter 3 section FRONT BODY WORK MUDGUARD Positioning bolt inner lever arm 30 Nm 3 0 m kg 22 ft lb Wheel axle 48 Nm 4 8 m kg 35 ft lb ...

Page 122: ...le grip Throttle grip guide Grip Nut Bolt Throttle cable Brake cable 10 Upper ring nut 11 Lock washer 12 Center ring nut 13 Rubber washer 14 Lower ring nut 15 Bearing cover 16 Upper bearing race 17 Bearing cage 18 Bearing race 19 Lower bracket 10 11 13 15 17 16 18 19 12 14 16 18 17 ...

Page 123: ...g See chapter 3 FRONT BODYWORK MUDGUARDS section 4 Remove Handlebar covers See chapter 3 HAND LEBAR COVER section NOTE Before completely removing the rear cover with the speedometer disconnect the spee dometer cable and the signalling and lighting system cables 5 Remove Front fork See REMOVAL OF FRONT FORK sec tion 6 Remove Brake pump support Brake pump Throttle grip 7 Remove Flange electrical ins...

Page 124: ...ng cover Lower bracket INSPECTION 1 Wash the bearing and race with solvent 2 Inspect Bearings Bearing race Pitted Damage Change Steps for replacing the bearing race Remove steering bearing races using a long rod and the hammer as shown Remove the bearing race from the shaft using a chisel and the hammer as shown Install the new mudguard and the guides Ring nut wrench for steering 90890 01403 ...

Page 125: ...d Cracks Damage Change 4 Inspect Handlebar Cracks Damage Change s s WARNING Do not try to straighten a bent handlebar since this can weaken it dangerously INSTALLATION Reverse the steps for disassembly and remo val The following points should be remembe red 1 Apply Wheel bearing grease on upper bearings and lower bearings 2 Install Lower bracket Lower ring nut Rubber washer Central ring nut Lock w...

Page 126: ...entral ring nut and hand tighten untill the lower and central ring nuts slots allignet 6 Install the lock washer 7 Supporting the lower and central ring nuts install and thigten the upper ring nut to 7 5 m kg 4 Install Handlebar Bolt Nut NOTE Match up the bolt on the tooth of the stee ring column 5 Install Flange NOTE Support electrical installation 6 Apply Grease with lithium soap base on the end...

Page 127: ...er with speedometer Front handlebar cover NOTE Connect the speedometer cables signalling and lighting systems ATTENTION Situate the speedometer cable through its housing in the rear cover 9 Install Front fork See INSTALLATION OF FRONT FORK SECTION 10 Install Front wheel See section INSTALLATION OF FRONT WHEEL 1 Bolt brake pump 0 9 m kg ...

Page 128: ......

Page 129: ...ELEC 7 ...

Page 130: ...STEM 7 4 TROUBLESHOOTING 7 5 CHARGING SYSTEM 7 10 CIRCUIT DIAGRAM 7 10 LOCATION AND REPAIR OF FAULTS 7 11 LIGHTING SYSTEM 7 13 CIRCUIT DIAGRAM 7 13 LOCATION AND REPAIR OF FAULTS 7 14 CHECKING OF LIGHTING SYSTEM 7 15 SIGNALLING SYSTEM 7 17 CIRCUIT DIAGRAM 7 17 LOCATION AND REPAIR OF BREAKDOWNS 7 18 CHECKING OF SIGNALLING SYSTEM 7 19 ELEC ...

Page 131: ...unit Engine oil level gauge Starter relay Fuel level gauge Battery Ignition coil ELECTRICAL SYSTEM ELECTRICAL COMPONENTS IGNITION COIL PRIMARY COIL RESISTANCE 0 56 0 84 Ω at 20 C 68 F SECONDARY COIL RESISTANCE 5 7 8 5 Ω at 20 C 68 F BATTERY SPECIFIC GRAVITY 1 280 ...

Page 132: ...ELEC ELECTRICAL COMPONENTS 7 2 Main switch seat lock Turn signal relay Rectifier regulator Horn ...

Page 133: ...TARTER SYSTEM 7 3 CDI magneto CDI Spark plug Main switch Fuse Battery Starter relay 10 Starter motor 11 START switch 24 Front brake switch 25 Rear brake switch 34 Ignition coil IGNITION AND STARTER SYSTEM CIRCUIT DIAGRAM ...

Page 134: ...Front brake switch 19 Rear brake switch B Pick up coil G To oil level switch R B LOCK OPEN OFF CHECK ON Br G B W DC CDI UNIT B W Br B 0 B W L B B Current which flows in the ignition control circuit Current which flows in the starter motor control circuit INDUCED COIL RESISTANCE 0 05 0 06 _ at 20 C 68 F BRUSH WEAR LIMIT 0 9 mm COMMUTATOR WEAR LIMIT 16 6 mm MICA LOWER CUT OFF 1 35 mm ...

Page 135: ...of spark plug Check distance between electrodes Consult chapter 3 INSPECTION OF SPARK PLUG CORRECT 2 Gap of the ignition spark plug Disconnect the spark plug pipe from the spark plug Connect the ignition tester as shown Spark plug pipe Spark gap Check spark gap Start the engine and increase the spark jump until ignition fails Minimum spark gap 6 0 mm OUTSIDE SPECIFIED VALUE OR NO SPARK INCORRECT D...

Page 136: ...coil Ignition coil Cable of tester Terminal orange Cable of tester Terminal ground Check if the primary coil has the specified resistance Primary coil resistance 0 56 0 84 Ω at 20 C 68 F Connect the pocket tester Ωx1k on the ignition bobbin Cable of tester Cable of spark plug Cable of tester Ground Check if the secondary coil has the speci fied resistance Secondary coil resistance 5 7 8 5 kΩ at 20...

Page 137: ... White blue Cable of tester Black Check if the pick up coil has the specified resistance Resistance of harnessing coil 250 370 Ω at 20 C 68 F SATISFIES THE SPECIFIED VALUE CORRECT 6 Connections Check the connections throughout the igni tion system for connections Consult the ELECTRICAL DIAGRAM sec tion Replace the CDI unit OUTSIDE SPECIFIED VALUE The pick up coil is defective replace it Correct ...

Page 138: ...OF THE BAT TERY section in chapter 3 CONTINUITY CORRECT Open circuit voltage 12 8 V or more at 20 C 68 F Check the operation of the starter motor 3 Starter motor Connect the positive terminal of the battery and the starter motor cable using a bridge cable STARTER MOTOR TURNS NO CONTINUITY The fuse is defective INCORRECT Clean the battery terminals Recharge or change battery STARTER MOTOR DOESN T T...

Page 139: ...t to see if there is continuity between Red and Brown 6 Starter switch Disconnect the coupler of the handlebar switch right from the installation Check the starter switch component to see if there is continuity between Blue White and Black CORRECT CORRECT 7 Connections Check the connections throughout the igni tion system See the ELECTRICAL DIAGRAM INCORRECT The main switch is defective change DOE...

Page 140: ...ELEC CHARGING SYSTEM 7 10 CHARGING SYSTEM CIRCUIT DIAGRAM Flywheel Magneto Fuse Battery Rectifier Regulator ...

Page 141: ...See chapter 3 section INSPECTION OF THE BATTERY CONTINUITY OUTSIDE SPECI FIED VALUE Open circuit voltage 12 8 V or more at 20 C 68 F 3 Charging voltage Connect the inductive tachometer on the spark plug cable Connect the pocket tester 20 V CC on the battery Cable of the tester Terminal Cable of the tester Terminal Start the engine and accelerate to 5 000 rpm min Check charging voltage Charging vol...

Page 142: ...the charge coil SATISFIES THE SPECIFIED VALUE 5 Connections Check the connections throughout the igni tion system Consult the ELECTRICAL DIAGRAM sec tion Cable of the tester White cable Cable of tester Yellow Red Cable Charge coil resistance 0 288 0 432 Ω at 20 C 68 F GOOD Change the rectifier regulator OUTSIDE SPECIFIED VALUE The charge coil is defective change BAD CONNECTION Correct ...

Page 143: ...ELEC LIGHTING SYSTEM 7 13 LIGHTING SYSTEM CIRCUIT DIAGRAM Flywheel 14 Light dinmer switch 16 Headlamp 21 Brake and rear light 27 Meter light ...

Page 144: ...n Place the switch k j in position j Check the switch component to see if there is continuity between Blue Yellow and Blue Green 2 Resistance of the lighting coil Disconnect the lighting coil coupler from the installation Connect the pocket tester Ωx1 on the lighting coils Measure the resistances of the lighting coil correct Cable of tester Yellow Red Cable of tester Ground Lighting coil resistanc...

Page 145: ...low or Green Cable of tester Black A When the switch k j intensity control is in position k B When the switch k j intensity control is in position j Place the main switch on f Start the engine Place the switch k j dimmer switch in position k or j Check if there is a voltage 12 V in the Green and Yellow cable in the connec tors of the bulb holder SATISFIES THE SPECIFIED VALUE 12 V The circuit is in...

Page 146: ...r 20 V AC on the bulb holder coupler Cable of the tester Blue terminal Cable of tester Black terminal Place the main switch on ON Check if there is a voltage 12 V in the Blue cable of the connector of the bulb holder The circuit is in good condition The circuit is in good condition SATISFIES THE SPECIFIED VALUE 12 V 1 Bulb and bulb holder Check the bulb and bulb holder for conti nuity 3 The rear l...

Page 147: ...tery 13 Horn 13 HORN switch 15 TURN switch 17 Front indicator light Left 18 Front indicator light Right 19 Rear indicator light Left 20 Rear indicator light Right 21 Tail light 22 Horn 23 Indicator relay 24 Front brake switch 25 Rear brake switch 26 Oil level switch 27 Motor lights 28 Fuel sensor ...

Page 148: ...nect the pocket tester Ωx1 on the fuses See INSPECTION OF FUSES in chapter 3 2 Battery Check the operation of the battery See section INSPECTION OF THE BAT TERY in chapter 3 CORRECT Open circuit voltage 12 8 V or more at 20 C 68 F SATISFIES THE SPECIFIED VALUE CORRECT 3 Main switch Disconnect the main switch coupler of the installation Check the switch component for continuity between Red and Brow...

Page 149: ...e installation and horn cable Check the switch component for continuity between Black and Red 2 Voltage Connect the pocket tester 20 V DC on the horn cable Cable of the tester Brown Cable of tester Frame earth Place the main switch on ON Check if there is a voltage 12 V in the brown cable of the horn terminal SATISFIES THE SPECIFIED VALUE 12 V CORRECT CORRECT BAD CONNECTION Repair INCORRECT The HO...

Page 150: ...pocket tester 20 V DC on the horn on the Pink terminal THE HORN DOES NOT SOUND Cable of tester Pink Cable of tester Earth of frame Place main switch on ON Check if there is a voltage 12 V in the Pink cable on the horn terminal Adjust the horn CONTINUITY 2 Brake switch Disconnect the brake switch cables from the installation Check the switch component for continuity between Brown and Green Yellow O...

Page 151: ... the switch component for continuity between Brown white and Chocolate and Brown White and Dark green Cable of tester Green Yellow Cable of tester Black Place the main switch on ON Activate the brake lever Check if there is a voltage 12 V on the Green Yellow cable of the bulb holder connector SATISFIES THE SPECIFIED VALUE 12 V CORRECT INCORRECT The brake switch is defective change OUTSIDE SPECIFIE...

Page 152: ...e flasher relay terminal Cable of tester White Brown Cable of tester Frame ground SATISFIES THE SPECIFIED VALUE 12V 4 Voltage Connect the pocket tester 20VDC on the flaster relay 5 Voltage Connect the pocket tester 20 V DC on the bulb holder receptacle On the indicator light left Cable of the tester Chocolate Cable of tester Frame ground On the indicator light right Cable of tester Dark Green Cabl...

Page 153: ...Oil level switch Remove the oil sump oil level switch Connect the pocket tester Ωx1 on the oil level switch Cable of tester Terminal Cable of tester Terminal Check the oil level measurer for continuity A Vertical position x x upwards B Reverse position x x Continuity x No continuity GOOD CONDITION 3 Voltage Connect the pocket tester 20 V DC on the bulb holder connector Cable of tester Gray Cable o...

Page 154: ...re harness side as shown Positive tester probe red yellow Negative tester probe black yellow L Y Br Ch Dg R B Gy GR BY Sb G LG Dg Ch L GR Y Gy R Br B BY Sb G RY RY LG R Y L G B Y 1 3 2 Set the main switch to ON Measure the voltage DC 12 V of red yellow on the multi function meter coupler wire harness side Is the voltage within specification Replace the speed sensor YES NO OUTSIDE SPECIFIED VALUE 4...

Page 155: ...ster probe black yellow L B R B Y R Y L G Set the main switch to ON Elevate the front wheel and slowly rotate it Measure the voltage DC 12 V of red yellow and black yellow With each full rotation of the front wheel the voltage rea ding should cycle from 0 V to 5 11V to 0 V to 5 11V etc Does the voltage reading cycle correctly Replace the speed sensor YES NO The circuit is OK ...

Page 156: ...LOC AVER 8 ...

Page 157: ...CHAPTER 8 LOCATION AND REPAIR OF BREAKDOWNS LOCATION AND REPAIR OF ENGINE BREAKDOWNS 8 1 ELECTRICAL SYSTEM 8 1 COMPRESSION SYSTEM 8 2 INLET AND EXHAUST SYSTEM 8 3 ELECTRICAL DIAGRAM YN50 LOC AVER ...

Page 158: ...LUG Excessive carbon deposits Damp electrodes Incorrect gap Broken SOURCE COIL The coils are broken PICK UP COIL The coils are broken Incorrect ignition distribution CDI UNIT CDI unit defective IGNITION COIL The primary and secondary coils are broken or defective The high voltage cable is defective The spark plug cap is defective ...

Page 159: ... 8 2 COMPRESSION SYSTEM FATIGUE CRACKS DEFECTIVE SEALING DAMAGE DAMAGE WEAR WEAR CRACKS DAMAGE INSUFFICIENT TIGHTENING TORQUE WEAR STRIPING WEAR CATCHING BREAKS CARBON DEPOSITS WARPING CARBON DEPOSITS DAMAGE WEAR DAMAGE DAMAGE ...

Page 160: ...EDLE Badly adjusted Average speed PILOT JET Obstructed Low range FLOAT Incorrect adjustment of fuel level Broken FUEL TANK CAP Obstructed FUEL PIPE Obstructed AIR FILTER ELEMENT Dirty or obstructed FUEL COCK Obstructed AIR SCREW Badly adjusted Idling and starting ACCELERATOR STOPPING SCREW Badly adjusted Idling and starting BOWL Accumulated dust and or water FLOAT VALVE Worn DAMP TYPE CARBURETTOR ...

Page 161: ...ghts relay 24 Front stop switch 25 Rear stop switch 26 Oil level switch 27 Instrument panel 28 Fuel sender 31 License light UK only 33 Auto choke 34 Ignition coil COLOUR CODE B BLACK R RED L BLUE G GREEN O ORANGE Y YELLOW P PINK BR BROWN CH CHOCOLATE SB SKY BLUE DG DARK GREEN W WHITE B BR BLACK BROWN B Y BLACK YELLOW B R BLACK RED B W BLACK WHITE G R GREEN RED G Y GREEN YELLOW BR W BROWN WHITE W R...

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Yamaha YB50, Service Manual

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