Yingang YG125-23 Maintenance Manual Download Page 39

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YG125-23Maintenance ManualFuel system

Fuel system

Maintenance notice

Disassembly and assembly of fuel tank

Troubleshooting

Removal and installation of air filter

Removal and installation of fuel tank

Removal and installation of carburetor

Maintenance notice

This section introduces the knowledge related to the fuel system.

CAUTION



Pay special attention to fire prevention while dealing with gasoline!

Take care of the mounting position of such sealing members as the O-ring while removing various parts of the fuel system.

While reassembling, always use new sealing members such as an O-ring.

Technical specifications

Throat opening diameter

Φ16mmequivalent

Idle speed

1500r/min

150 r/min

Throttle handle free stroke

～

3mm

Troubleshooting



Engine ignition is ok, but it does not start

No fuel or insufficient fuel in the fuel tank

Too much fuel enters the cylinder;

Air filter is clogged;

Spark plug fails;

Fuel tube does not flow well;

Fuel quality problem (containing moisture);

Fuel is stored too long;

Fuel pump failure;

Injector failure (clogged)

Summary of Contents for YG125-23

Page 1: ...describes various constituting parts of the motorcycle respectively Chapter 19 contains the electrical system diagram The standard maintenance procedures maintenance precautions and general maintenance knowledge are not covered in this manual Any user or maintenance personnel who needs the above information may refer to the related materials All materials charts and various data as well as perform...

Page 2: ...ystem 79 87 9 Crankcase crankshaft and Shift mechanism 88 104 10 Frame and exhaust system 105 109 11 Front wheel front overhang and steering stem 110 121 12 Rear wheel and rear overhang 122 127 13 General remarks of electrical system 128 14 Power supply system 129 131 15 Starting system 132 134 16 Illumination signal system 135 140 17 Electrical starting control system 141 144 18 Engine management...

Page 3: ...ition Bar Tool About Motorcycle Maintenance Maintenance Period Table Technical Data of Main Performance Symbol Descriptions Standard Torque Values Engine Number Position Photo of Complete Vehicle Frame Number Position Engine Number Position Engine Number Frame Number ...

Page 4: ...nd components After reassembling check whether all the spare parts are mounted properly by means of turning moving and operating them 4 To disassemble and assemble a motorcycle special service tools SST and general purpose tools must be used in accordance with relevant regulations 5 The specified or equivalent lubricating grease oil must be applied to or refilled into the specified locations 6 Whe...

Page 5: ...aking or bending Make sure the terminals are not too long or are falling off The connector shall be fully inserted in place For a connector with lock confirm whether the lock is completely fixed Make sure the harness is not falling off Make sure the plastic jacket of the connector is securely covering the connector without scaling off 11 Before connecting a connector make sure the sleeve is not br...

Page 6: ...he vehicle body The wire harness shall be incapable of passing through the position contacting a bolt a screw head or any front part The wire harness shall not be slackened or be forcibly pulled If the wire harness has to contact the edge or sharp corner parts the contacting part shall be protected with hose or adhesive tape In case of a wire harness with garland it shall be reliably harnessed Do ...

Page 7: ...nance manual after understanding the explanations in the instruction manual 16 Do not drop or throw the parts and components 17 In case of rust on the terminals carry out connection operation after disposing it with abrasive paper etc 18 Do not forcibly twist or forcefully bend the cable Because a deformed or damaged cable is the cause of bad operation and damage Rust must be eliminated Have you l...

Page 8: ...ng 120 70 12 120 70 12 Normally loaded 225kPa Normally loaded 225kPa Single disc type ModelΦ220 Single disc type ModelΦ190 9L 92 Engine Mode Cylinder bore Stroke Cylinder displacement Compression ratio Max power Max torque Valve clearance cold Valve driving gear Air filter Cooling method Lubrication method Engine oil grade Engine oil charge volume Engine oil filter element Electricmotor starting I...

Page 9: ...Sequence I N Ⅱ Ⅲ Ⅳ V Electrical system Electric generator Accumulator capacity Power supply system Fusible cutout Spark plug Spark plug gap Ignition coil type Fuel supply mode Ignition mode Ignition advance angle Ignition timing Front lamp Turn lamp Stop Rear position lamp permanent magnet DC magneto 12V7A h DC power supply and the electric generator is only used to recharge the accumulator 15A 10...

Page 10: ...3 6 8 12 LOCTITE 648 Stator leads pressure plate bolt 2 6 8 12 LOCTITE 648 Spark Plug 1 12 18 25 Pensioner plate fastening bolt 1 6 7 10 Vehicle body Item Quantity Thread diameter mm Torque value N m Thread locker Front wheel spindle 1 14 50 60 Front vibration damper plate 1 10 30 40 Real wheel spindle nut 1 16 60 90 Rear fork shaft nut 1 14 50 60 Engine hanging bolt 3 10 30 40 4 8 20 30 Steering ...

Page 11: ...otorized gun special power tool for mantling dismantling bolt and nut Pawl socket for mantling dismantling oil filtering element nut and clutch nut A and B bolt socket for mantling dismantling A and B bolt and exhaust muffler bolt Adaptor electric special tool for cross hexagon gun tip Valve adjusting socket for valve clearance adjustment Socket for mantling dismantling nuts andbolts Cutting plier...

Page 12: ...re the clearance of piston cylinder valve etc Micrometer to measure the dimensions of piston piston pin etc Dial gauge to measure the wheel bouncing cylinder inner diameter etc Cylinder barometer to measure the cylinder pressure Wrench measure tighteness of ad bolt Vernia caliper measure size of rear wheel hub internal diameter Tire barometer to measure the tire pressure ...

Page 13: ...ut and bolt fastening I I I I Wheel tire I I I I Steering column bearing I I I I Steering backstay cable Inspect every 5000km driving and replace every 10000km driving Maintenance shall be carried out to the motorcycle in a specified period The meanings of various symbols in the list are as follows I Carry out inspection cleaning adjustment lubrication or replacement C Cleaning R Replacement A Adj...

Page 14: ...se general purpose tools Tightening torque of 50 N m Use suggested engine oil Use the mixtures of engine oil and molybdenum disulfide Use thread locker Use sealant Use lithium base grease 1 Measures to be prompted during operating inspecting and maintaining 2 Special instructions or disposal measures given to prevent motorcycle from being damaged 3 Special instructions or measures given to avoid s...

Page 15: ...il its quality scale must reach Grade SG and its viscosity shall be selected according to the accompanying diagram depending upon region and air temperature changes While replacing lubricating oil fully discharge the original lubricating oil in the crankcase and clean it up with washing kerosene and then refill fresh lubricating oil as per regulations The lubricating oil inside the engine must be ...

Page 16: ... in the above diagram besides applying dedicated lubricating oil for chain to the driving chain apply lithium base grease to all other positions All lubricating oils not specified for use in this manual shall be ordinary common lubricating oil All sliding surfaces and cables not shown in this diagram shall be coated with lubricating oil or lubricating grease Lubrication of Control Lines Regular lu...

Page 17: ...alLubrication system 15 Engine Lubrication System Diagram Crankshaft oil through Spindle oil through Countershaft oil through Camshaft oil through Cylinder head oil through Cylinder oil through Oil filter Oil pump Oil strainer ...

Page 18: ...oil drain plug and discharge the waste engine oil and then clean the oil drain plug engine oil strainer engine oil filter etc Finally insert the oil drain plug Unscrew the oil filter plug and slowly refill 1 0L new engine oil of the specified trademark into the crankcase then insert the oil filter plug Left crankcase body oil through Cylinder block cylinder head camshaft bearing seat and a camshaf...

Page 19: ...teps according to the method of Replacement of Lubricating Oil Cleaning and Replacement of Lubricating Oil Filter Remove the engine oil filter cover to detach the engine oil filter element clean the filter cover and filter element with cleaning agent and then mount the clean engine oil element Replace with a new one as required Check for damage of the engine oil filter cover and its O shaped seali...

Page 20: ...embly and assembly of oil pump etc Steps for oil pump removal 1 Remove the oil drain plug to drain the engine oil inside the crankcase 2 Loosen the right crankcase cover connecting bolts to detach the right crankcase cover components 3 Use the clutch push rod extractor to remove the clutch push rod assembly use the fixing tool to prevent the clutch and the primary driving gear from rotating loosen...

Page 21: ...be replaced with new ones 6 Remember to refill engine oil after all these are completed CAUTION The clutch retaining nut must be screwed up to the specified tightening torque must be applied to prevent the nut from getting loose Disassembly and assembly of oil pump Disassemble and assemble oil pump according to the following diagram While assembling the rotor shall be coated with engine oil While ...

Page 22: ... to the sense organs of human being The way is simple and easy to use it is used wide in motorcycle maintenance Testing examination method This way is a way that test the size of part and change of geometric form with gauge and instrument and make contrast to the allowed limit with the data to confirm the technologic state of part The accuracy of this way is high but before test should check the p...

Page 23: ...rcycle according to the contents hereof before using it Technical specifications Throttle bar free stroke 1 3mm Recommended spark plug CPR8EA 9 Spark plug gap 0 7 0 9mm Valve clearance cold IN 0 06 0 08mm EX 0 06 0 08mm Idle speed 1500 150 rpm Cylinder pressure 0 8MPa 300rpm Driving chain tension 10 20mm Rear brake pedal free stroke 20 30mm Front brake operating handle free stroke 10 20mm Clutch o...

Page 24: ...et is in good condition To mount the spark plug manually screw up the spark plug first and then tighten it with a socket wrench Put on the spark plug cap Lubricating oil Park the motorcycle on a flat surface let the engine stop for 2 3 minutes and check to see whither the oil level is in between the upper and lower line the oil gauge if the engine oil level is under the lower scale line refill the...

Page 25: ...m is abnormal should check electronic ignition high voltage coil charging on the generator and trigger coil etc After properly timing pull off the tensioner locking key and coat the mixture of engine oil and molybdenum disulfide on the tensioner to make it tensioned mount the sprocket retaining plate and retaining bolt Cylinder pressure When the engine fails to start or is difficult to start or wh...

Page 26: ...ound Dah Dah it indicates insufficient tension of the chain tensioner replace it with a new one To replace the chain tensioner Unscrew the 2 M6 16 socket cap screw to remove the sealing washer and detach the old chain tensioner Take care not let the sealing washer and so on fall into the crankcase Insert the tensioner 4locking key into the tail end of the newchain tensioner turn and retract the fr...

Page 27: ...tion but rock arms will move apparently when flywheel rotate a small angle the flywheel is not in the compressing stroke but exhaust intake stroke In this case continuously turn the flywheelclockwise for 360 degrees to the top dead center position of the compressing stroke where the valve clearance can be adjusted Afterwards check the valve clearance by inserting a clearance gage into the gap betw...

Page 28: ...led by an ECU Since the intake flow at idle speed has been properly adjusted upon delivery do not adjust the idle speed adjusting screw as desired In case the idle speed is unsteady zero or too high find out the possible causes with the troubleshooting method for the EMS system and eliminate the trouble Under the monitoring of the maintaining and diagnostic instrument check whether the ignition ad...

Page 29: ...protective rubber lagging Coarse adjustment If the fine adjustment is not satisfying separate the throttle control line with throttle valve body and unscrew the retaining nut B to make adjust the free stroke in a larger range Screw up the retaining but B after the adjustment Check whether the throttle can turn smoothly from full open to full close at any position If there is clogging adjust or rep...

Page 30: ...p the handle or completely push down quickly screw the deflating valve bolt with the torque being 7 9 N m 6 Mount the brake cylinder cover with the sealinggasket flattened and replace with new sealing gasket as required 7 After refilling check the oil cup hydraulic brake hose and all connecting pieces for leakage Notice 1 The brake fluid shall be DOT 4 non petroleum base brake fluid The brake flui...

Page 31: ...eds to be changed Please go to the designated special maintenance station And it is better to use the parts from our company Caution Please change the brake shoe in time if it has been touched the wear limit Otherwise it would cause accidents by the lack of strength Substitution of the brake pads Press the brake caliper towards the brake disc and put the brake piston back into its basic position R...

Page 32: ...djust it according to the following overhauling content The content is the free stroke of clutch control handle general is 10 20mm some venial need adjust the adjusting screw of declutch mechanism Check the clutch operating handle free stroke Clutch operating handle free stroke 10 20mm Adjusting methods Fine adjustment Pull open the rubber lagging unscrew the retaining nut and turn the adjusting n...

Page 33: ...ion 10 20mm If the chain is too loose or too tight make adjustment Adjusting methods Unscrew the rear wheel spindle nut and turn the adjusting bolt on the chain adjuster until the specified tension is achieved and then fasten the rear wheel spindle nut and check the flexibility for free rotation of the rear wheel and the consistency of the front and rear wheels Warning The rear wheel spindle nut m...

Page 34: ...ss than 12V recharge it with a charge power supply Seriously corroded conductor connectors of the battery shall be replaced Installation of accumulator Installation is in the reverse order of removal While connecting the poles connect the positive pole first Warning 1 In this model both the startup and EMS system are completely powered with accumulator Therefore it is quite important to ensure suf...

Page 35: ...he buckle strip While installing the rear brake spring shall be reliably hooked with the pin hole on the rear brake lamp switch After replacement adjustment shall still be carried out to the rear brake lamp switch Replacement of Fuse Set the ignition switch to OFF position The specified fuse tube of 15A 10A should be used for main fuse replacement and a 10A fuse tube for FAI injection nozzle Open ...

Page 36: ...stall new bulb in opposite order as below Taillight bulb 13 5V 1 2 2W Front and rear lamp bulb Loosen the screws remove the Tail lights If the Tail lights are not bright only new Tail lights will be replaced Front and rear lamp bulb12V4W Steering stem bearing Lift the motorcycle with a jack or other support with the front wheel being apart from the ground surface and check whether the steering han...

Page 37: ... up to the specified torques Rear suspension Forcibly press the rear end of the seat cushion with the rear suspension and check the rear fork spindle sleeve for abrasion or damage If it is damaged replace it Check whether the whole suspension assembly is mounted securely and whether it is damaged or deformed Bolts nuts and fasteners All the bolts nuts and fasteners shall be screwed up as per the m...

Page 38: ...YG125 23Maintenance ManualFuel system 41 4 Fuel system ...

Page 39: ...g position of such sealing members as the O ring while removing various parts of the fuel system While reassembling always use new sealing members such as an O ring Technical specifications Throat opening diameter Φ16mmequivalent Idle speed 1500r min 150 r min Throttle handle free stroke 1 3mm Troubleshooting Engine ignition is ok but it does not start 1 No fuel or insufficient fuel in the fuel ta...

Page 40: ...nstallation procedures are the removal procedures in reverse order While installing note that the wiring of the fuel pump control wire shall be in strict accordance with the wiring diagram Avoid fuel line contamination Removal and installation of air filter Refer to the section Inspection and Adjustment Air Filter It is unnecessary to remove the air cleaner assy from the frame when performing main...

Page 41: ...move throttle body including the fuel injector Installation steps The installation procedures are the removal procedures in reverse order While installing the locating slot must be aligned with the locating lobe of throttle body Warning Donot further disassemble the removed throttle body in case several sensors on it need to be changed proceed under the instruction of an EMS system technician ...

Page 42: ...uch dust deposit on the filtering element The engine is difficult to start Insufficient engine output Poor performance of engine during idle run Excessive fuel consumption The exhaust muffler pipe fumes strongly black C1ean the filtering element c1ean The filtering element is fractured or chipped Engine air suction noise is toooud Replace the filtering element ...

Page 43: ...YG125 23 Maintenance ManualRemoval and installation of engine 46 5 Removal and installation of engine ...

Page 44: ...ing oil To maintain the heat engine parts including cylinder head cylinder body piston etc it is necessary to remove the coverings fuel tank throttle body air filter assembly etc To remove the engine s right crankcase cover for maintenance it is necessary to remove the rear brake pedal To remove the engine s left front cover for maintenance it is necessary to remove the gear shift pedal left rear ...

Page 45: ...e pole of the battery 2 Remove bracket from left and right 3 Remove clutch cable 4 Remove the magnetic motor gear display line and hit the line wire 5 Remove engine cycle tube 6 Remove muffler front part 7 Remove the magnet motor to connect the cable Drive sprocket 8 Remove the gear shift pedal and left rear cover 9 Remove the high voltage wire ...

Page 46: ... the rear fork backwards Loosen the nut and remove the lower hanging bolt Move the engine slowly from the right Installation of engine The installation of engine is in the reverse order of removal of engine During installation note that the wiring of cable shall be in strict accordance with the wiring diagram Remove the 4 engine bracket and the frame connecting bolt Remove the 2 front suspension b...

Page 47: ...YG125 23 Maintenance ManualCylinder Head Cylinder and Piston 52 6 Cylinder head cylinder and piston Cylinder head cover Cylinder head Cylinder ...

Page 48: ...e assembling coat engine oil and molybdenum disulfide lubricant on the protruding surface of the camshaft for preliminary lubrication Be careful not to damage the cylinder wall and piston Technical specifications maintenance benchmark Item Standard value Maintenancelimit value Camshaft Camshaft lift IN 5 15mm 5 21mm Camshaft lift EX 5 0mm 5 06mm Cylinder head Planeness 0 03mm 0 05mm Valve spring I...

Page 49: ...mm Connecting rod small end Internal diameter φ13 013mm φ13 028mm φ13 028mm Clearance with piston pin 0 013mm 0 033mm 0 033mm Piston ring First ring gap clearance 0 015mm 0 05mm 0 05mm Second ring gap clearance 0 015mm 0 05mm 0 05mm First ring side clearance 0 002mm 0 013mm 0 013mm Second ring side clearance 0 002mm 0 013mm 0 013mm Oil ring side clearance 0 002mm 0 013mm 0 013mm Key torque values ...

Page 50: ...der piston ring worn Black smoke from exhaust 1 Valve guide worn 2 Oil shield leaked or damaged 3 Cylinder piston piston ring worn 4 Piston ring clearance too big 5 Piston ring incorrectly installed 6 Piston or cylinder wall scratched or scuffed Excessive noise 1 Incorrect valve adjustment 2 Valve jammed or valve spring broken 3 Camshaft worn or damaged 4 Timing chain too long worn or damaged 5 Ti...

Page 51: ...drop the location pin into the crankcase To mount the cylinder head cover 1 Turn the crankshaft so that the piston is at the upper dead point of the compression stroke 2 Remember to confirm the location pin 3 Mount the cylinder head cover and the sealing gasket 4 Mount the cylinder head connecting bolt tightening torque is 12N m 5 Confirm the valve clearance and make adjustment with a valve cleara...

Page 52: ... pins 6 Remove the camshaft bearings 7 Strip the timing chain from the timing driven sprocket and remove the timing driven sprocket 8 Remove the camshaft Caution Do not drop the timing chain into the crankcase To mount the camshaft 1 Turn the crankshaft so that the piston is at the upper dead point of the compression stroke and the scale line I on the rotor is aligned with the triangular indicatio...

Page 53: ...st the valve clearance 7 Connect the phase sensor and mount the eyehole cover and upper eyehole cover in turn Caution When the tensioner is not tensioned never turn the crankshaft for fear of interlocking the teeth while timing Camshaft inspection Check the camshaft for abrasion damage oil through jamming etc and check whether the decompressor flying block can rotate and return smoothly Measure th...

Page 54: ...Precautions for installation 1 Confirm the location pin clean all parts and components and check whether the cylinder head oil through is unobstructed clean and free of leak 2 Replace new cylinder head gasket 3 The tightening torque of cylinder bolt is 45N m Warning The cylinder head bolt must be fully screwed up to the tightening torque of 45N m and carry out 100 torque inspection Disassembly and...

Page 55: ...ocedure Quantity Remarks 1 cylinder block 1 2 Cylinder head gasket 1 Coat the mixture of engine oil and molybdenum disulfide on the stem while assembling 3 Cylinder body gasket 1 Coat the mixture of engine oil and molybdenum disulfide on the stem while assembling 4 Dowel Pin 2 5 cylinder head 1 Assemble with sparse end facing up 6 spark plug 1 Assemble with sparse end facing up 7 Gas CAM shaft sea...

Page 56: ... Maintenance limit φ4 53mm Measure the valve stem diameter Maintenance limit IN φ5 15mm EX φ5 15mm Measure the width of the valve contacting surface Maintenance limit 1 7mm Measure the free length of the valve spring Maintenance limit Internal spring 35 00mm External spring 42 00mm Calculate the clearance between the valve stem and valve guide Maintenance limit IN 0 09mm EX 0 10mm Cylinder To remo...

Page 57: ...the piston slide gage seat Cylinder inspection Check the cylinder for abrasion or damage and check the cylinder wall for scratch Check the cylinder wall for deformation and use the edge ruler and clearance gauge to inspect the planeness of the cylinder s joining surface Maintenance limit 0 05mm Measure the cylinder internal diameter The measurement shall be made at three positions top middle and b...

Page 58: ...mshaft See Installation of camshaft 6 Mount the cylinder head cover See Installation of cylinder head cover Notice Assemble the piston with the top side with the marker facing exhaust side Do not drop the piston pin retainer into the crankcase Disassembly and assembly of piston Disassemble and assemble piston according to the following diagram While assembling let the side with marker face the top...

Page 59: ...t reverse the mounting position of the first ring ATG marker and second ring A marker No Procedure Quantity Remarks Sequence of disassembling Assembling is in the reverse order of disassembling 1 Crank rod assembly 1 2 Piston 1 3 Piston ring 2 4 Piston pin 1 5 Piston pin circlip 2 With the side with marker face the top of ...

Page 60: ...m Measure the clearance between the piston ring and the piston groove before removing the piston ring Maintenance limit First ring Second ring 0 12mm Oil ring 0 40mm Mount the piston rings into the cylinder respectively and measure the gap clearance Maintenance limit First ring 0 65mm Second spring 0 7mm Measure the piston pin external diameter Clearance gauge Maintenance limit φ12 98mm Work out t...

Page 61: ...YG125 23 Maintenance ManualClutch and Right crankcase cover 70 Clutch and Right crankcase cover Clutch Right crankcase cove Engine ...

Page 62: ...arts and components with cleaning agent and dry them with compressed air To assemble the clutch loosen the clutch spring and coat engine oil on the clutch disc in case of replacing new clutch the clutch disc must be soaked in oil for over 24 hours before being assembled Be careful not to damage the crankshaft seal on the right crankcase cover Technical specifications maintenance benchmark Item Sta...

Page 63: ...dle pressure 1 Clutch cable galling damaged or dirty 2 Clutch push rod damaged or jammed Hard clutch operation There is burr on clutch housing chute Shift lever can t return 1 Return spring cracked or slipped 2 Transmission shaft plate convenes with crankcase or crankcase cover Vehicle moves slowly upon firmly grabbing the handle 1 Excessive handle free stroke 2 Clutch plate deformed or bent Hard ...

Page 64: ... right crankcase cover connecting bolt 5 Take out the right crankcase cover component 6 Take out the right crankcase cover sealing paper gasket To install the right crankcase cover 1 Confirm the location pin clean up the residual sealing paper gaskets on the right crankcase and right crankcase cover 2 Replace with a new right crankcase cover sealing paper gasket 3 Mountthe right crankcase cover 4 ...

Page 65: ...direction of the clutch operating lever Mount the clutch operating lever rear brake return spring cotter pin rear brake lamp switch etc 6 Refill engine oil Notice Do not scrape the crankshaft oil seal Assemble only when the rack side of the clutch push rod faces the crankshaft ...

Page 66: ...er 1 2 Right crankcase cover sealing paper gasket 2 Replace it with a new one while assembling 3 clutch push rod 1 4 rubber ring 1 5 Oil Level Gauge 1 6 lever return spring 1 7 elastic cylindrical pin 1 8 clutch lever 1 9 Bolt M6 40 8 Replace it with a new one as required 10 Bolt M6 32 3 11 Bolt M6 35 1 12 Clutch zip plate 1 13 Right crankcase cover sealing paper gasket 1 Replace it with a new one...

Page 67: ...sher 4 Remove the clutch 5 Remove the clutch washer To install the clutch 1 Mount the clutch washer with the sabotage side facing the main shaft right bearing 2 Mount the clutch 3 Mount the butterfly washer and retaining nut M18 Note to assemble with the protruding side of the butterfly nut washer facing outside 4 Use the fastening tool to clamp the primary driving and driven gear and screw up the...

Page 68: ...er 6 Assemble the right crankcase cover by turning the clutch push rod until its rack side faces the crankshaft See Installation of right crankcase cover Warning Thread retaining adhesive LOCTITE243 must be coated on the clutch retaining nut M18 while assembling with the tightening torque being 120N m Right crankcase cover ...

Page 69: ...1 12 Clutch spring 4 13 Clutch plate 1 14 Bolt m6 25 4 Disassemble and assemble of clutch Disassemble and assemble the clutch according to the following diagram While removing the clutch lift plate alternatively loosen the 6connecting bolts to avoid damage of cracking due to uneven force of the clutch spring While mounting the clutch lift plate alternatively loosen the 6 connecting bolts to the sp...

Page 70: ...r Installation is in the reverse order of removal 1 clutch bush 1 Tightening torque 12N m 2 clutch assembly 1 3 Nut M14 1 1 4 Flat washer 1 5 Deepgroove ballbearing 1 Gum base soaking oil while assembling 6 Clutch out cover 1 7 Clutch lug washer 1 8 Clutch center bush 1 9 Clutchfriction plate 5 10 clutch driven plate 4 Assemble with the sub stage side facing inwards 11 Clutch platen 1 12 Clutch sp...

Page 71: ...of each clutch disc Maintenance limit 2 8mm 3 Check the clutch plate for distortion and check the planners with a clearance gauge Maintenance limit 0 20mm 4 Measure the thickness of each clutch plate The thickness is 1 4mm 5 Measure the free length of the clutch spring Maintenance limit 41 3mm Clutch plate planners measurement Clutch plate thickness measurement Outside micrometer Inspection Are th...

Page 72: ...YG125 23Maintenance ManualMagneto and starting system 79 8 Magneto and starting system Engine Double linked Gear Rotor assembly Left front cover Idle gear Disk gear Double linked gear cover ...

Page 73: ...parts coat the mixture of engine oil and molybdenum disulfide onto the left crank journal as the initial lubrication Do not dent the seal surface and do not damage the stator coil Technical specifications maintenance benchmark Item Standard value Maintenance limit value Disk gear Disk gear external diameter φ51 67 φ51 7 φ51 57 One way device outer body One way device outer body internal diameter φ...

Page 74: ...ear cover and separate the magneto lead connector with the main cable 2 Unscrew the oil drain plug to drain the engine lubricating oil inside the engine 3 Remove the double linked gear cover connecting bolts 4 Remove the left front cover Left front cover sealing paper gasket Left front cover Left rear pla te Gear shift pedal Draining engine oil ...

Page 75: ...8 while assembling the magneto stator connecting bolt In case of O ring aging prolonging or deforming replace it Notice Do not dent the seal surface and do not damage the stator coil No Procedure Quantity Remarks Removing order Installation is in the reverse order of removal 1 stator module 1 2 Bolt M5 27 1 Replace it with a new one as required 3 Nut M14 1 25 1 4 rotor assembly 1 5 Bolt M6x16 1 6 ...

Page 76: ...ouble linked gear etc 3 Use the rotor fastening tool to fasten the rotor and remove the fastening nut M12 and plain washer 4 Use the rotor extractorto extract the rotor 5 Remove the rotor assembly washer disk gear needle bearing disk gear washer Notice Do not let the semicircular key drop into the crankcase Double linked Gear Rotor fastening tool Rotor extracto Disk gear Disk gear washer ...

Page 77: ... screw while assembling with the tightening torque being 10 14N m No Procedure Quantity Remarks Removing order Installation is in the reverse order of removal 1 Screw M8 16 6 Use thread retaining adhesive LOCTITE 648 while assembling with the tightening torque being 25N m 2 One way device outer body 1 3 One way device 1 Be careful of the assembling direction 4 Armature 1 M8 16 Armature One way dev...

Page 78: ...ead retaining adhesive LOCTITE648 to the fastening nut M12 use the rotor fastening tool to fasten the rotor and screw up the nut M12 to the torque of 45N m 4 To install the double linked gear The Washerand the double linked gear is assembled into the left crankcase 5 To install the left front cover Clean the sealing paper gasket remaining on the left crankcase and left front cover replace with new...

Page 79: ...ing clockwise flexibly relative to the rotor Use the thread retaining adhesive LOCTITE 648 while assembling the pressure plate bolt Warning Thread retaining adhesive LOCTITE243 must be applied to the rotor retaining nut M12 while assembling with the tightening torque being 45N m Check 1 Check the spline gear of output shaft of the starting motor for defect squeezing deforming etc 2 Check the idle ...

Page 80: ...3Maintenance ManualMagneto and starting system 87 6 Measure the disk gear diameter the maintenance limit φ42 084mm 7 Measure the washer thickness the maintenance limit 0 4mm Outside micrometer Vernier calipers ...

Page 81: ...23Maintenance ManualCrankcase crankshaft and Shift mechanism 88 9 Crankcase crankshaft and Shift mechanism Right hand crankcase body Crankshaft Gearshift drum Counter shaft Main shaft Left hand crankcase body ...

Page 82: ...e removed 1 Right hand crankcase clutch gear shifter 2 Cylinder head cover camshaft cylinder head cylinder and piston See Cylinder head cylinder and piston 3 Left front cover rotor assembly electrical starting transmission system See Magneto and electrical starting system 4 Driving drive sprocket shift switch Before assembling clean all parts and components with cleaning agent and dry them with co...

Page 83: ...1 Shift fork bent or damaged 2 Shift fork shaft bent 3 Gearshift drum badly machined or bearing shifted 4 Driving driven shaft bearings shifted Gear shift trouble 1 Shift fork bent or damaged 2 Shift fork shaft bent 3 Gearshift drum guiding slot worn or damaged 4 Clutch improperly adjusted 5 Locking plate bend or fray 6 Five star plate assy broken 7 Pin broken or slip off Gear shaft cannot return ...

Page 84: ...e left right hand crankcase body by inserting such tools as screwdrivers into the mould closing face To mount the crankcase 1 Place the right hand crankcase on the assembly operating table and assemble the internal parts and components of the crankcase including crankshaft balance shaft driving driven shaft gearshift drum shift fork etc 2 Clean up the left and right crankcase box surface put the n...

Page 85: ...over rotor assembly electrical starting transmission system driving drive sprocket etc Refer to the related sections 6 Mount the assembled engine onto the frame and engine oil to complete the assembly of the complete vehicle Notice To close the crankcase use your hand s to gently press it in place or use a Bakelite hammer to strike it gently Never strike it forcibly Mount the mould closing bolt ...

Page 86: ... Right hand crankcase 1 2 Pin 1 3 Pad 1 4 O ring 1 5 engine oil filter net 1 6 Release oil bolt 1 7 Pad 1 8 Left hand crankcase 1 9 O ring 1 10 Double head bolt 1 11 Main gear plate 1 12 Bolt M6 16 1 13 Pin 10 14 2 14 BOLT FLGM6 40 7 15 BOLT FLGM6 45 1 16 BOLT FLGM6 70 7 Disassembly and assembly of left hand crankcase Disassemble and assemble the left hand crankcase according to the following diag...

Page 87: ...il seal facing inwards No Procedure Quantity Remarks Removing order Installation is in the reverse order of removal 1 Left hand crankcase 1 Apply engine oil while assembling 2 Crankshaft bearing 6203 1 Apply engine oil while assembling 3 Driving shaft bearing 6006 1 Let the oil seal side face inward and apply engine oil while assembling 4 Balance shaft bearing 6301 13 C3 1 Apply engine oil while a...

Page 88: ... inwards No Procedure Quantity Remarks Removing order Installation is in the reverse order of removal 1 Right hand crankcase 1 2 Balance shaft bearing 6302 1 Apply engine oil while assembling 3 Driving shaft bearing 62 22 C3 1 Let the oil seal side face inward and apply engine oil while assembling 4 Gear shift shaft oil seal 18x34x5 1 Apply engine oil while assembling 5 Driven shaft bearing 60 18R...

Page 89: ...y operating table and use a high power electric drier to heat the right crankcase body crankshaft bearing until the temperature at the inner circle of the bearing reaches 106 and then assemble the crankshaft 2 Use a high power electric drier to heat the right crankcase body balance shaft bearing until the temperature at the inner circle of the bearing reaches 106 and then assemble the balance shaf...

Page 90: ...chanism 97 Removal and installation of crankshaft and balance shaft No Procedure Quantity Remarks Removing order Installation is in the reverse order of removal 1 Left hand crankcase 1 2 Crankshaft 1 3 Balance shaft 1 4 Right hand crankcase 1 4 3 2 1 Knock pin ...

Page 91: ...the reverse order of disassembling 1 Balance shaft 1 Apply engine oil while assembling 2 Driving gear 1 Apply engine oil while assembling 3 Pad 1 Apply engine oil while assembling 4 Driven plate 1 5 Buffer rubber 1 Apply engine oil while assembling 6 Driven gear 1 Apply engine oil while assembling 7 Spring 1 Apply engine oil while assembling 8 WASHER 1 Apply engine oil while assembling 9 WASHER 1 ...

Page 92: ...imit Ф20 063mm 2 Measure the crankshaft radial run out Maintenance limit 0 10mm 3 Measure the connecting rod big end radial clearance Maintenance limit 0 06mm 4 Measure the connecting rod large end side clearance the maintenance limit 0 80mm 5 Measure the left hand crank journal Maintenance limit Ф29 87mm 6 Check whether the balance shaft supplementary tooth spring fails and whether the balance sh...

Page 93: ...ance shaft on the assembly operating table and the driving driven shaft and assemble the them together 2 Assemble the shift fork with 3 Mount the gearshift drum 4 Change the O shaped sealing ring mount the shift fork and check whether the driving driven shaft can rotate freely 5 Mount the shift arm 6 Replace it with a new paper pad assembly one while assembling mount the left hand crankcase See In...

Page 94: ...il while assembling 2 Pad 6 14 1 1 3 Bolt M6 28 2 4 Shift show 1 5 Shift show trigger 1 6 Shift fork 1 Apply engine oil while assembling 7 Shift fork right 1 Apply engine oil while assembling 8 driving shaft 1 Apply engine oil while assembling 9 driven shaft 1 Apply engine oil while assembling 10 Warping spring 1 11 Bolt M8 28 1 12 gearshift drum 1 Apply engine oil while assembling 13 Shift plant ...

Page 95: ...moval of left hand crankcase cover See Removal of left hand crankcase cover 2 Remove the unloaded rotor assembly left crankcase assembly See Removal of left hand crankcase cover 3 If only remove unloading gear arm is not required to remove unloading gear drum assembly can be directly drawn outward shift arm combination To mount the shift mechanism 1 Mount the gearshift arm combination Driving driv...

Page 96: ...oil seal guide to protect oil seal 3 Mount the rotor assembly See Mount of left hand crankcase cover 4 Mount the left hand crankcase cover See Mount of right crankcase cover Warning Thread retaining adhesive LOCTITE243 must be applied to the rotor retaining nut M12 while assembling with the tightening torque being 45N m ...

Page 97: ...YG125 23Maintenance ManualFrame and exhaust system 106 10 Frame and exhaust system ...

Page 98: ...omponent Trouble symptom of motorcycle Repair method Frame The frame is deformed or broken The frame is deformed or broken Running off tracking Calibrate or replace frame Main stand Deformation or fractured Deformation or fractured Effect of parking Replace the main stand Return spring is fractured Main stand impossible to return Effect of parking Replace the return spring Covering parts Broken Br...

Page 99: ...h plug to remove the headlamp Remove the meter assembly total of 3 connecting bolts To mount the coverings headlamp and meter The installation of the coverings headlamp and meter is in the reverse order of removal During installation do not scratch the coverings or damage the bulb Notice During removal and installation do not scratch the outer surface of coverings or break the bucklemortise Seat c...

Page 100: ... the nut Remove turn the connecting wire Remove the signal lights Replace the new signal light LED Do not remove the replacement bulb The order in which the signal light are installed is reversed Front and rear lamp bulb12V1 5W LED Taillight Taillight bulb Loosen the screws Remove the rear lights Replace the new taillights LED Do not remove the replacement bulb The order in which the tail lights a...

Page 101: ...r Installation is in the reverse order of removal The muffler seal gasket at the engine s exhaust port shall be replaced with a new one While mounting apply sealants at the joining part of the exhaust pipe and the muffler and fasten the bolts of the exhaust port and muffler support after the joint anchor ear bolt is screwed up otherwise air leakage may occur Notice Proceed with the operation after...

Page 102: ...YG125 23 Maintenance ManualFront wheel front overhang and steering stem 110 11 Front wheel front suspension device and steering stem ...

Page 103: ... torque values Front wheel spindle 50N m 60N m Steering handle set bolt20 30N m Front fork vertical pipe cap nut50 60N m Upper lower connection plate set bolt8 12N m Brake disc fastening nut20 30N m Troubleshooting Steering unstable 1 Vertical pipe bearing failure 2 Tire pressure insufficient 3 Tire damaged 4 Wheel bush damaged Driving directions to the side or not to walk in a straight line 1 Lef...

Page 104: ...le The steel cable The clutch is slipping or not fullydisconnected Replace control steel cable Rear brake pedal The free stroke is over small The clutch is not fully disconnected Readjust the free stoke The free stoke is over big Disoperation of rear brake Readjust the free stoke For the damage form fault symptom and repair method of front wheel Component description Damage form Trouble symptom of...

Page 105: ...Piston rod Over worn or damaged Over soft at front shock cylinder Replace piston rod Piston ring is over worn ordamaged Over soft at front shock cylinder Replace piston ring Oil sealing Cut edge is over Worn or damaged or aged Leakage from oil seal Leakage at front shock absorber Replace oil seal Shock oil Insufficient oil amount or too little Insufficient shock oil or too little Over soft of fron...

Page 106: ...rake lose effect exhaust front brake oil way oil pipe is broken oil leakage from oil pipe brake lose effect replace oil pipe frontbrake oil pipe is clogged oil pipe is clogged brake lose effect clean or replace oil pipe wall is broken or cocked brake lose effect replace front brake caliper wall is over worn brake lose effect replace front brake caliper front brake caliperis broken oil leakage from...

Page 107: ...rol line Remove the right combination switch Remove the right brake cylinder body Remove the clutch control line and disassemble the connection of the clutch switch leads and the main cable Remove the left combination switch Loosen the retaining bolt and remove the clutch handle holder Brake switch Remove the upper lower body Throttle control line Right combination switch Remove the right brake cy...

Page 108: ...olt at the connection board and then the bolt at direction of the tube up to the torque of 20 30N m 4 Do not mount the throttle cable in the opposite direction of the feeder on the right handle otherwise the handle may rotate incorrectly while refueling 5 Upon installation adjust the throttle control line Upon installation check whether the cable and wiring is in accordance with the wiring diagram...

Page 109: ...Place the front wheel spindle on the V holder and measure the deflection of the wheel spindle with a dial gauge if the reading is no less than 0 2mm replace the front wheel spindle Front wheel bearing inspection Place the front wheel on the calibration table inspect the rim s deflection and then manually rotate the wheel and measure its deflection value with a dial gauge if the reading is no less ...

Page 110: ...nip the front brake handle While installing the front brake caliper apply the thread retaining adhesive LOCTITE 243 with the tightening torque being 20 30N m Check 1 Dismantle oil drain bolt and check bolt whether or not is loose 2 Drain off absorber oil and check quality whether or not is turned 3 Take off dust sleeve circlip and oil seal to check edge whether or not is worn and circlip is distor...

Page 111: ...eter to check whether or not is it worn 8 Measure free length of absorber spring and check it whether or not is distorted 245mm 9 Check length of return spring to check it whether or not is distored 24mm 10 Fill absorber oil per standard Oiling quantity 90 2ml the brand is CN1 shock absorber oil injected before the strict filtering does not allow water sand and other foreign bodies into the ...

Page 112: ...Installation is in the reverse order of removal While installing the steering stem adjust the adjusting nut and inspect it by turning it left and right and moving it up and down to ensure no vertical play and flexible rotating laterally Tighten the cap nut to the required torque of 60 70N m Front brake Front brake caliper inspection 1 Dismantle front brake caliper bolt 2 Operating brake if the wea...

Page 113: ...stead drive it after holding and releasing the front brake handle until the brake strip and the brake disc are well engaged Front brake disc inspection Measure the thickness of the brake disc with an outside micrometer if the thickness is no more than 3mm replace the front brake disc Measure the runout of the brake disc with a dial gauge maintanence limit 0 2mm utside micrometer ...

Page 114: ...YG125 23 Maintenance ManualRear wheel and rear suspension device 122 12 Rear wheel and rear suspension device ...

Page 115: ...r damper reliably stand the motorcycle from under the engine a jack or other supports Key torque values Real wheel spindle nut 50 60N m Rear fork shaft nut 50 60N m Troubleshooting Rear wheel shimmy 1 Rim bent 2 Rear wheel bearing worn 3 Low tire pressure 4 Regulator differs between left and right 5 Wheel bush damaged Wheel hard to rotate 1 Wheel bearing or bush damaged 2 Wheel incorrectly mounted...

Page 116: ...description Damage form Trouble symptom ofcomponent Trouble symptom of motorcycle Repair method Sprocket and cam sprocket Gear is over wor Drive chain has abnormal sound drive chain is easy to fall out Replace sprocket and cam sprocket Drive chain Too dirty or poor lubrication Drive chain has abnormal sound Clean and lubricate the chain Improper chain tightness Chain is over tight Drive chain has ...

Page 117: ...d that the left and right scale lines of the chain adjuster are consistent and then fasten the rear wheel spindle nut to the required tightening torque of 60 90N m Warning The rear wheel spindle must be firmly screwed up to the required torque of 60 70N m Rear wheel spindle inspection Place the rear wheel spindle on the V holder and measure the deflection of the wheel spindle with a dial gauge if ...

Page 118: ...rear fork shaft from the left side 3 Remove the rear damper and rear fork connecting bolt 4 Take out the rear fork backwards To install the rear fork Installation is in the reverse order of removal While installing the rear fork shaft make sure that the end covers shall be aligned and that the tightening torque of the rear fork shaft retaining nut is 50 60N m Warning The rear fork retaining nut mu...

Page 119: ...d check rear absorber Remove the bolt connecting the frame Remove the bolt connecting the rear fork To install the rear damper Installation is in the reverse order of removal While installing use the upper hole for the lower installation of the damper Notice Before removing the damper the tightening torque of the bolt connecting the frame is 30 40N m and the tightening torque of the bolt connectin...

Page 120: ...where the removal is convenient first following the principle of searching from easy to difficulty Both the parameter detection method and the parts replacement method are acceptable However if the parts replacement method is used you should confirm whether or not overload has occurred in the line as this may damage the new spare parts 7 A multimeter must be permanently available for the circuit i...

Page 121: ...ems The main contents include recharging charge storing and discharging YG125 23 power supply features large power supply capacity as high as more than 250W It comprises the following parts and components Magneto Variable voltage rectifier Accumulator Combined ignition switch Various fuses Circuit schematic drawing Overview Major parts and components Circuit schematic drawing Major faults diagnosi...

Page 122: ...llow wire whether is short circuit or broken circuit by millimeter 3 Open left cover to check magneto coil whether is burned or loose 4 Dismantle magneto bolt and replace magneto coil 5 Dismantle starting clutch and replace magnetic case 6 Check plate electrode whether is damaged 7 check connector socket of rectifier and measure output voltage by multimeter to 13 0 13 3 v 8 Check fuse pipe whether...

Page 123: ...e accumulator s terminal voltage is less then 12V The vehicle has been stored for too long and the accumulator has discharged automatically Charging circuit fails in the complete vehicle Accumulator fails to store charge Recharge it with DC voltage stabilizing charger Check the charging circuit Replace accumulator Accumulatorcharges insufficiently After the engine is started the meter s voltage al...

Page 124: ...ion of shift position switch side stand switch and clutch switch then press down the start button to power on the relay start the engine to drive the idle gear and starter gear thus enabling the engine to enter its operating cycle for normal ignition fuel injection and combustion The system consists of the following components Starting motor Starting relay Accumulator Start switch and flameout swi...

Page 125: ...k fuse whether is burned 6 Check positive and negative pole of battery whether contact well 7 Check relay whether is damaged 8 Check magneto coil whether contact well Check the closure of the circuit with the instrument 9 Check electrical starting switch whether contact well 10 Turn on electrical starting button to check whether is rusted or energize 11 Turn on flameout switch to check it whether ...

Page 126: ...ace clutch switch Connect the line or replace the left switch Connect the line or replace the left switch Replace the starting relay Repair or replace main cable Starting motor doesn t rotate there is the sound of relay suction however the motor doesn t rotate Accumulator voltage too low Heavy line connector lug slackened Motor open circuit failure Open circuit between the terminal contacts of the...

Page 127: ...les and people to dodge by the flash of the turn lamp while driving at night it shall inform of its presence by the tail lamp s front rear position lamp and illuminate the number on the license plate while braking it shall illuminate the brake lamp to inform the vehicle behind of its braking deceleration The flash of the turn lamp is controlled by a switch and a flasher and the illuminations of ot...

Page 128: ...YG125 23 Maintenance ManualIllumination signal system 136 Circuit schematic drawing ...

Page 129: ...whether is charged 5 Check fuse whether is burned 6 Take off headlamp switch socket to check whether there is current 7 Remove the headlamp bolt check the cable connection current 8 Notice Circuit is normal replace the new headlamp assembly check headlamp whether it light 9 Dismantle taillight bolt to check lamp case whether is damaged 10 Check the front rear brake switch work circuit check item b...

Page 130: ... of electrical horn to check it whether is damaged 15 Check neutral socket whether contact well 16 Signal lamp control systems Check flasher whether is burned or plug is loose Turn on signal indication switch left handle to check switch whether is rusted or lose contact Check steering signal indication lamp socket whether lose contact or bulb is burned 17 Fuel level sensor Check fuel sensor failed...

Page 131: ...YG125 23 Maintenance ManualIllumination signal system 139 Major parts and components ...

Page 132: ...Related lines of the main cable are open Connect the fuse or replace it Repair or replace the left switch Replace bulb Re plug Repair or replace main cable Brake lamp does not illuminate Corresponding fuse is not connected or is blown Front brake lamp switch failed Rear brake lamp switch failed Bulb failure Line failure Connect the fuse or replace it Replace front brake lamp switch Adjust and repl...

Page 133: ... The complete vehicle information theYG125 23displays include vehicle speed engine speed fuel indicator Neutral indicator turn indication high beam indication total subtotal mileage traveled and EFI Indicator Constituting parts and components include Combination meter Turn lamp Vehicle speed sensor Fuel level sensor Shift position switch Signal switch ECU Circuit schematic drawing Overview Major p...

Page 134: ... turn indicator 3 Meter reading and usage 1 Speedometer Indicate motorcycle speed Km h Do not exceed legal rate limiting to assure safe riding 2 Odometer Indicate riding distance Km 3 Turn indicator R right turn twinkle when turn to right Green L left turn twinkle when turn to left Green 4 Headlight high beam indicator light on when Far light is switched on 5 Neutral indicator It is lit up when in...

Page 135: ...check electrical start whether energize 2 Check fuse whether is burned 3 Dismantle headlamp holder to check holder whether there is current 4 Dismantle meter bolt to check it whether is loose or damaged 5 Dismantle meter bolt and odometer cable to check bolt whether is damaged or loose 6 Take off meter to check odometer tachometer and fuel meter whether are damaged ...

Page 136: ...ication failure Line poorly plugged or open circuit Meter failed ECU failed Re plug or repair Replace meter Replace ECU Fuel level indication failure No indication while there is fuel Having indication while there is no fuel Fuel sensor failed or float is blocked Meter failed Line poorly plugged open or short circuit Replace fuel sender Replace meter Re plug or repair Meter backlight source doesn ...

Page 137: ... handled Through the engine and actuators on the vehicle ignition coil fuel injector Idle speed control valve and so on the fuel and fire are exactly controlled and corrected with closed loop For production conformity corrected fuelling in order to match up to the difference of vehicles due to the inconformity of components System composition 1 Sensor Intake air pressure sensor load information in...

Page 138: ...YG125 23 Maintenance ManualEngine management system 146 Major parts and components ...

Page 139: ...YG125 23 Maintenance ManualEngine management system 147 ...

Page 140: ...ect the connectors 3 Make sure the temperature of the ECU is below 80 4 The fuel pressure is much high about 250kPa so please do not disassemble the fuel pipe arbitrariliy If have to pleae release the pressure at first and make sure the operation is dilivered in the ventilated environment by the the professional mantenance persons 5 When disassmeble the fuel pump from the pump make sure the power ...

Page 141: ...lant Oil Temperature Sensor Circuit Low Voltage KsDGDM_CoolantShortLow P0118 Coolant Oil Temperature Sensor Circuit High Voltage or Open KsDGDM_CoolantShortHigh Throttle Position Sensor TPS P0122 TPS Circuit Low Voltage or Open KsDGDM_TPS_ShortLow P0123 TPS Circuit High Voltage KsDGDM_TPS_ShortHigh Oxygen Sensor P0131 O2S 1 Circuit Low Voltage KsDGDM_O2_1_ShortLow P0132 O2S 1 Circuit High Voltage ...

Page 142: ...emperature Yes Setp 5 No Next 3 Remove the connector and use the multimeter to check whether the resistance between pin B and D is reasonable according to the temperature Yes Step 5 No Next 4 Remove the connector and check whether the voltage between pin B and D is about 5V Yes Next No Check harness 5 Check whether the following pins are short battery J2 8 J2 10 of the ECU and pin C D of the conne...

Page 143: ... use the multimeter to check whether the resistance between pin A and C of the sensor is reasonable according to the temperature Yes Step 5 No Next 4 Use the multimeter to measure whether the voltage between A and C is about 5V Yes Next No Check the harness 5 check whether the following pins are short to gound or open J2 10 J2 14 of the ECU and pin C and D of the sensor Yes Harness issue No Next 6...

Page 144: ...o Next 3 Open the throttle to 100 slowly check whether the data of throttle opening goes to between 90 100 Yes Step 5 No Next 4 Repeat Step 3 check whether the data jumps when open the throttle slowly Yes Change the sensor No Next 5 Remove the connector and check whether the following pins are short to battery J2 12 J2 16 of ECU and pin A and C of the sensor Yes Harness issue No Next 6 Use multime...

Page 145: ...k whether voltage of the relay feeder ear is about 12V Yes Change the pump No Next 3 Check whether the feeder ear is short to ground or open Yes Harness issue No Help Malfcode P0351 Information Cylinder 1 Ignition Coil Malfunction ITEM OPERATION RESULT NEXT STEP 1 Connect the diagnostic tool and ignition on next 2 Remove the connector and check whether the voltage of pin is about 12V Yes Step 4 No...

Page 146: ...l quality 5 Change the ECU and repeat the test if the issue is gone then the root cause is the ECU Or change the old one back to check the root cause ITEM OPERATION RESULT NEXT STEP Engine cannot start Check whether the voltage of the battery is around 8 12V Yes Next No Change the battery Crank the engine and check whether the voltage is above 8V Yes Next No Change the battery Check whether the st...

Page 147: ...s blocked and whether the intake pipe leaks Yes Intake system maintenance No Next Whether there is carbon deposit at the throttle body and bypass channel Yes Clean the TB No Next Check whether the IACV works well Yes Next No Check the IACV Check whethe the fuel pressure is about 250kPa Yes Next No Check the pump Check whether the injeoctor is blocked Yes Clean or change the injector No Next Make s...

Page 148: ...k plug Yes Next No Change the sprk plug Check whether the cylinder pressure is normal Yes Next No Check the engine Check whether the exhaust pipe is blocked or not No help Yes maintenance Backfire Pull out the spark plug check whether the sparkover is normal Yes Next No Check the ignition system Check whether the timing is right Yes Next No Adjust the timing Check whether there is leakage of the v...

Page 149: ...YG125 23Maintenance ManualElectrical System Diagram 157 19 Electrical System Diagram ...

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