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BT49QT-28 MODEL 

SERVICE MANUAL 

 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

Summary of Contents for BT49QT-28

Page 1: ...BT49QT 28 MODEL SERVICE MANUAL ...

Page 2: ...NG AIR FOIL 18 Ⅱ DISSEMBLING AND INSPECTING CYLINDER HEAD HOOD 18 Ⅲ DISSEMBLING AND INSPECTING CYLINDER HEAD AND VALVE 18 Ⅳ DISSEMBLING AND INSPECTING CYLINDER AND PISTON 20 Ⅴ DISSEMBLING AND INSPECTING KICK STARTER 22 Ⅵ DISSEMBLING AND INSPECTING STEPLESS TRANSMISSION SYSTEM 23 Ⅶ DISSEMBLING AND INSPECTING ELECTRIC STARTER 25 Ⅷ DISSEMBLING AND INSPECTING MAGNETO AND ELECTRIC FITTINGS 27 Ⅸ DISSEMB...

Page 3: ...CHAPTER FIVE ELECTRIC PART TROUBLESHOOTING SECTION ONE ELECTRIC PART COMMON TROUBLES AND TROUBLE DETECTION 54 SECTION TWO DETAILED DESCRIPTIONS OF ELECTRIC ASSEMBLIES AND PARTS SERVICE 56 Ⅰ PRECAUTIONS IN ELECTRIC CIRCUIT SERVICE 56 Ⅱ POWER CHARGING SYSTEM SERVICE 56 Ⅲ IGNITION SYSTEM SERVICE 62 Ⅳ ELECTRIC STARTING SYSTEM SERVICE 68 Ⅴ LIGHTING AND SIGNAL SYSTEM SERVICE 69 Ⅵ CIRCUIT DIAGRAM 74 ...

Page 4: ...laden mass 249 kg Front tire pressure 250KPa Fuel tank capacity 4 5 0 5L Rear tire pressure 250KPa Max speed 45Km h Engine Type 1E40QMA Lubricate method Pressure spray Stroke 2 Lubricant brand SAE15W 40SF Bore stroke 40 0mm 39 2mm Gasoline brand 90 or above Cylinder capacity 49cm3 Clutch type Automatic acentric Compression ratio 7 5 0 1 1 Transmission type Nonpolar Max torque N m r min 4 9 6500 St...

Page 5: ...estrict the length of riding time to avoid long time running of the engine Replace engine oil at short intervals so that metal chips caused in the running in period can be discharged It is recommended to replace engine oil for 3 times during the running in period 2 Routine Maintenance Routine maintenance is the basis of all kinds of maintenances It refers to the daily maintenance including cleanin...

Page 6: ...em I I I I I I I I I I I I Drive belt I Suspension I I I Tire I I I Steering rod bearing I I I Screws and bolts of parts I I Notes 1 I Inspect and when necessary clean lubricate supplement modify or replace A adjust C clean R replace T tighten 2 Effect periodic maintenance according to the instructions in the user s manual 3 When the mileage exceeds the range specified in the schedule repeat the m...

Page 7: ...e parts and to obtain specified tightening torques 4 Cleaning Cleaning is needed where call for cleanliness and tidiness Cleaning operations include all the means and measures taken to remove dust contamination metal chips oily stains and carbon deposits that might lead to pipe clogging or reduction in motorcycle performance Cleaning measures are washing carbon deposit removing rubbing cleaning an...

Page 8: ... 6mm The main adjusting position is beside the carburetor Remove rear store case inner cover Adjust by loosening the fastening nut and turning the adjusting nut Fine adjustment is effected on the side of the throttle grip Effected adjustment is by removing the dust cover loosening the tightening nut and turning the adjusting nut ...

Page 9: ...arlier Remove 7 screws of air filter Remove strainer cover Take out the strainer Immerse foam strainer in gasoline and wash it to remove dust and impurities by gripping and pressing Press gasoline out of the foam Soak the cleaned foam with engine oil press out or throw out engine oil to leave it moist with oil Mount VI BRAKE BLOCKS INSPECTION Grip the brake lever and check the wear tear indicator ...

Page 10: ...ton back into caliper Brake Blocks Replacement Brake blocks must be replaced when it is worn to the limit of use It is not necessary to remove brake oil pipe when replacing brake blocks Brake blocks must be replaced as a set Remove the brake block pins by means of a hexagon wrench Take out the old brake blocks and mount a set of new brake blocks Effect mounting in an order reversed to that of dism...

Page 11: ... so as to prevent jamming of brake blocks If brake blocks are jammed pry it with screwdriver and push piston back into caliper Brake Blocks Replacement The same as the replacement of the front brake blocks Brake Disc Inspection The same as the inspection of the front brake disc VIII FRONT AND REAR SHOCK ABSORBER INSPECTION 1 Front Shock Absorber Tighten front brake lever press front shock absorber...

Page 12: ...leakage Do not use wheel rims in the following cases Bruise of wheel rim face contacting tire bead ring exceeds 0 5mm in depth and 1 0mm in width Tire Inspection Inspect if there is fissure or iron nail in the tire In one of the following conditions tires must be replaced instead of repair Puncture of tire by a foreigner matter 6mm in diameter or tire fissure Layered tire Chunking of tread Damaged...

Page 13: ...ire 130 60 13 Inspect if front wheel nut is loose Inspect if rear wheel nut is loose If loose tighten them to specified torques Torques front wheel nut 60N m rear wheel nut 120N m X STEERING STEM INSPECTION Swing handlebar right and left to see if there is interference such as wire or other things Turn front wheel to see that handlebar is easy in operation In case of any difficulty in operation in...

Page 14: ...h designated or equivalent greases Parts must be tightened and their performances inspected at their positions when mounted The battery s negative terminal must be disconnected before operation Make sure that tools such as wrenches are not in contact with the frame At the completion of operations reconfirm correct connections and fastenings The positive terminal must be connected first in case of ...

Page 15: ...om turning or moving parts Do not damage the covering of wire bunches In case of wire bunch defects remedy it with insulating bands Wire bunches must not be covered with mounted parts Do not twist or bend cables by force Deformed or damaged cables would result in poor rotation or damage Ⅲ Ⅲ Ⅲ Ⅲ SPECIFIED TORQUES Torques at important positions and standard torques of other positions are as follows ...

Page 16: ...t 4 M 7 16 18 Valve adjusting bolt 2 M 5 9 Chain tensioner bolt 1 M 6 10 Leaking oil bolt 2 M 8 10 12 Clutch outside wheel fixing bolt 1 M 10 40 Magneto rotor fixing bolt 1 M 10 40 Left crankshaft bolt 1 M 12 55 Spark plug 1 M 10 12 Oil pump driven gear bolt 1 M 6 10 Chain tensioner bolt M8 8 1 M 8 6 Rear driving combination bolt 7 M 8 20 22 Brake pad fixing bolt 1 M 8 10 Cyclinder head fixing bol...

Page 17: ...olt nut M6 10 Bolt nutM8 21 5 Bolt nut M10 35 Bolt nut M12 55 Screw M5 4 Screw M6 9 Flange bolt nut M6 12 Flange bolt nut M8 27 Flange bolt nut M10 40 Ⅳ Ⅳ Ⅳ Ⅳ Tools Tools Number Flywheel disassemble ware Z01 Valve adjusting gripe Z01 Spark plug spring guide Z03 ...

Page 18: ...kable deformation of steering stem due to outside impact Refer to Front Fork Service Over tightening of steering stem top ball bearing retainer Damaged or broken ball bearing Reduced tire air Refer to Front Wheel Service Rear Wheel Service Deflected steering stem Imbalance of right and left shock absorbers Refer to Front Shock Absorber Service Bent front fork Refer to Front Fork Service Bent front...

Page 19: ...ous or worn brake caliper piston Inability of brake caliper normal sliding Worn main cylinder piston seal ring Viscous or worn main cylinder piston Contaminated main cylinder Stiff brake lever Clogged narrow brake system Clogged narrow liquid passage Viscous worn brake caliper Inability of brake caliper normal sliding Worn seal ring of brake caliper piston Viscous or worn main cylinder piston Resi...

Page 20: ...eel mounting Refer to Front Wheel Service Roundness error of wheel rim Deformation of wheel rim Inadequate tire pressure Front wheel oscillation Deformed wheel rim Refer to Front Wheel Service Loose front wheel bearing Poor tire Poor axle locking Soft front shock absorber Spring fatigue Refer to Front Shock Absorber Service Rear wheel oscillation Deformed wheel rim Refer to Rear Wheel Service Poor...

Page 21: ...to align the corresponding parts of hoods When mounting body cover parts avoid pressing wires cables or pipes I FRONT WHEEL SERVICE Front Wheel Dismounting Support the body bottom to lift front wheel Remove the left and right rubber cap Loosen and remove the front axle nut Take out the front axle and remove transmission gearbox front axle bush and the small axle bush Remove front wheel Remove brak...

Page 22: ...ction Remove front wheel bearing and dust cover Turn bearing inner race to inspect sliding Replace it with a new one in case of no sliding or damage or loosening of outer race Front Wheel Bearing Replacement Dismounting Remove front wheel bearing by means of a bearing remover take out spacer Mounting Apply grease to the bearing Drive in left bearings Mount spacer Drive in right bearings Bearings m...

Page 23: ...not use brake oils of different specifications or impure brake oils Prevent brake oil from dripping onto rubber plastic or painted parts Brake Oil Exhausting Place main cylinder at a level place remove oil reservoir cover and diaphragm Connect a hose to oil exhaust valve loosen exhaust valve grip and release brake lever till oil is exhausted Brake Oil Replenishing Lock exhaust valve Replenish oil ...

Page 24: ...ain Brake Oil Tank Dismounting and Mounting Dismounting Exhaust brake oil from front brake system Take out brake switch plug from main cable Remove bracket bolts from handlebar Remove main cylinder Remove brake oil pipe from main cylinder Prevent brake oil from splashing to rubber plastic or painted surfaces Cover the above mentioned parts with a cloth Remove brake light switch and brake lever Rem...

Page 25: ...brake lever axis pin Mount brake lever and brake switch Mount main cylinder main cylinder bracket and lock them Mount brake oil pipe Connect brake light switch cable with switch Replenish brake oil and exhaust air in brake system Ⅲ Ⅲ Ⅲ Ⅲ FRONT SHOCK ABSORBER SERVICE Dismounting Remove front brake calliper Remove front fender mounting screws and remove front fender Remove front wheel Remove front b...

Page 26: ... Remove bolt bush and nut Remove handlebar Remove steering stem set nut Remove upper bearing cup upper bearing top and bearing set Support the body bottom to lift front wheel Remove front shock absorber together with front wheel Remove steering stem from head tube The removing of the bottom bearing cup bearing top and bearing set is the same as the removing of the upper series Do not damage steeri...

Page 27: ...ng cup bearing ball set bottom bearing top on the bottom of steering stem Pass steering stem through head tube Apply grease to top bearing cup and bearing top Mount in order upper bearing cup bearing ball set and upper bearing top on the upper part of steering stem and fasten them Torque 15 N m Turn front fork right and left to effect close contact of bearing balls Loosen upper bearing top to torq...

Page 28: ... switch Remove left handlebar switch Remove left grip from handlebar Remove two bolts of front brake maincylinder and remove brake main cylinder Remove connectors of right handlebar switch Remove 2 screws of right handlebar switch Remove right handlebar switch Remove throttle cable from throttle grip Remove throttle grip from handlebar Remove handlebar bolt bush and nut from handlebar Remove handl...

Page 29: ...ft grip Mount covering parts of front head cover and rear head cover Confirm easy rotation of throttle grip When mounting left grip apply a thin film of adhesive to contacting face and then mount grip in a turning manner Ⅵ Ⅵ Ⅵ Ⅵ REAR WHEEL SERVICE Dismounting Remove 2 mounting bolts of rear wheel fender Remove 2 mounting bolts and 2 mounting nuts of exhaust muffler and remove exhaust muffler Remov...

Page 30: ...fasten lower mounting bolt Mount exhaust muffler Fasten exhaust muffler connecting nuts and bolts Torque Exhaust muffler connecting nut 12N m Exhaust muffler mounting bolt 35N m Ⅶ Ⅶ Ⅶ Ⅶ REAR BRAKE SERVICE DISK BRAKE Rear brake service is the same with front brake service Ⅷ Ⅷ Ⅷ Ⅷ REAR SHOCK ABSORBER SERVICE Dismounting Remove motorcycle body covering parts Remove upper mounting bolt connecting rear...

Page 31: ... oil seal for oil leakage inspect buffer bar and spring for deformation and other parts for damage and loosening Mounting Mount rear shock absorber Torque upper mounting bolt 40N m lower mounting bolt 25N m Mount motorcycle body covering parts ...

Page 32: ...r battery charging Poor contact Poor charging system Poor adjusting rectifier Breakage of power current Poor contact of battery wire Poor contact in charging system Poor contact or short circuit in ignition system Poor contact or short circuit in light system Poor power supply Poor contact of wire or connector wire breakage or short circuit Poor adjusting rectifier Poor AC generator Sparkless spar...

Page 33: ...or contact or breakage of wire Poor starting motor Refer to Electric Starting System Service Feeble starting motor Inadequate battery charging Poor contact of wire Jamming of starting motor or pinion by foreign matter Engine refuses to start with starting motor running Poor starting motor pinion Reversed running of starting motor Poor battery No switching between high beam and low beam when hightl...

Page 34: ...ferent colors are to be connected they should be connected with wires with a sleeve of the same color near the terminal 9 Connectors of the same color and the same number of wires should be connected 10 When measuring terminal voltage and resistance with a gauge the probe should be inserted from behind the connector Waterproof connector tester should be inserted from the front of the terminal II P...

Page 35: ...take out storage battery Remove negative wire and then positive wire When removing positive terminal tools should not contact motorcycle body otherwise short circuit shall occur which causes spark that shall easily ignite gasoline and damage storage battery Mounting is effected in an order reversed to that of dismounting To prevent short circuit please connect negativeterminal first before connect...

Page 36: ...ery might be very high and charging can not be effected at a common charging voltage 16 17V In such a case charging can be effected at a higher voltage by adjusting charging voltage to 25V maximum under the supervision of a ammeter In 5 minutes when current reaches standard value voltage must be adjusted back to standard value for continued charging In case current does not change after 5 minutes ...

Page 37: ...f there is short circuit in main switch or main wire Charging Inspection Inspect by means of a circuit tester with storage battery fully charged Mount fully charged storage battery on preheated Engine Connect an ammeter between storage battery terminals Remove main fuse and connect an ammeter between terminals Connect engine to tachometer Start engine gradually raise its speed and measure limiting...

Page 38: ...V Storage battery overcharging or overdischarging Damaged voltage adjusting part of voltage adjusting rectifier Start engine measure charging voltage and charging current Voltage 11 1 16 8V Current 0 5 0 51A Note 1 Normally voltage does not rise much with the rise of engine speed In case of remarkable risee of voltage with an engine speed of 5000r min and a voltage of 40V it is abnormal Note 2 The...

Page 39: ...During inspection do not touch the metal part of circuit tester as human body resistance shall affect the accuracy of measurement readings Inspect with a standard circuit tester Consumption of dry battery in circuit tester shall affect measurement readings In case of abnormality inspect battery capacity In case of abnormal resistance between terminals replace voltage adjusting rectifier 4 AC Gener...

Page 40: ... 2 Poor main switch 3 Poor CDI connector 4 Breakage or poor contact of CDI earthing wire 5 Poor ignition and charging coils measure maximum voltage 6 Poor trigger coil measure maximum voltage 7 Poor contact of high voltage wire 8 Poor CDI abnormal in 1 7 with sparkless spark plug Sparkless spark plug with normal voltage of ignition coil 1 Poor spark plug or leakage in secondary ignition coil 2 Poo...

Page 41: ...essary to adjust ignition time c Disconnection drooping or impact of ignition CDI sysstem is the cause of trouble Dismounting should be effected with special care d Most of the causes of trouble are those of connectors and plugs Before service inspect connectors to ensure sound contact e Inspect for the correct heat value of spark plugs Improper spark plugs are the main causes of ill running or bu...

Page 42: ...ted on cylinder head Remove middle cover Connect ignition coil wire Distributor is connected between primary coil terminal black yellow and motorcycle earthling Start starting motor or tread on starting rod and measure ignition coil primary side maximum voltage Connecting method positive terminal connected togreen wire and negative terminal connected to black yellow wire Minimum voltage 95V and ab...

Page 43: ...ty at both ends indicates poor ignition and charging coils Please refer to trouble detection chart for inspection Trigger Coil Note Mount spark plug on cylinder head inspect at normal compression pressure Remove CDI connector 6P connect high voltage distributor between trigger coil at wire terminal blue yellow terminal and green terminal Actuate electric starting motor or tread on starting rod mea...

Page 44: ...ction loosening or corrosion Inspection items Terminal Main switch Main switch Black white motorcycle earthing Conductive with main switch at OFF Ignition and charging coils Black red motorcycle earthing 400 800Ω Trigger coil Blue yellow motorcycle earthing 50 200Ω Primary ignition coil Black yellow green 0 21Ω 10 Secondary ignition coil Green spark plug cover not including spark plug cover 3 1kΩ ...

Page 45: ...ard value 3 1kΩ 10 20 5 5 5 5 Trigger Coil Inspection of trigger coil can be effected on engine Remove motorcycle cover Remove trigger coil wire connector Measure resistance between engine side wire blue yellow terminal and earthing Standard value 50 200Ω 20 In case measured value exceeds standard value replace AC generator 6 Ignition and Charging Coil It is not necessary to remove coil while coil...

Page 46: ...r keeps running when starting switch is released Idle speed too low Starting motor speed too low Inadequate storage battery Poor connection of wire Starting Relay Actuation Inspection Remove motorcycle cover Main switch is set at ON Inspect if there is a clicking sound when starting motor button is pressed This sound indicates normality In case there is no sound Inspect starting relay voltage Insp...

Page 47: ...e is introduced conductivity between relay storage battery starting motor terminal should be normal V LIGHTING AND SIGNAL SYSTEM SERVICE Troubles Causes Burnt bulb in lighting system Partial damage of voltage adjusting rectifier All direction lights are off Inadequate charging Flashing relay failure Damaged direction lights switch Circuit failure One direction light is not on and one does not flas...

Page 48: ...hould be 12V 18W 2 Front Direction Light Bulb Replacement Remove 2 plus screws Remove direction light cover Remove bulb Effect mounting in an order reversed to that of dismounting 3 Taillight and Rear Direction Light Taillight and Rear Direction Light Bulb Replacement Remove motorcycle guard cover Remove taillight hood set screw Removee taillight hood Remove bulbs of taillight and direction light ...

Page 49: ...und Horn Increase horn current turn out adjusting screw counterclockwise at 1 6 turn a time 2 3A No sound Horn Replace horn 3A No sound Horn Decrease horn current turn in adjusting screw 1 6 turn a time 10A 0A No sound Inadequate power Inspect power supply when voltage 10V adjust horn in above mentioned manner Remove front head cover Remove horn wire Connect horn wire with storage battery Horn sou...

Page 50: ...46 6 Handlebar Switch Remove handlebar switch connector Inspect conductivity between connector terminals Headlight Switch Starting Switch Horn Switch ...

Page 51: ...47 Direction Light Switch Lighting Lamps Switching Switch Brake Switch Remove instrument hood Remove brake switch wire There should be conductivity between two wires while brake bar is gripped ...

Page 52: ...48 Ⅵ Ⅵ Ⅵ Ⅵ Circuit Diagram ...

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