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Chapter I    Engine                                                       

 

CRANKCASE DISASSEMBLY 

 

GEAR SHIFT MECHANISM 

  Check the small spring locates on the 

gearshift arm to see if it’s too loose or 
not. 

  Check the stopper plate is loose or not. 

  Check the roller guide. 

 

Working diameter limit: 

    Replace if under 5.7mm 
 
 
 

  Check the inside diameter of the forks. 

 

Working diameter limit: 

    Replace if over 13.04mm 
 
 

  Check the outside diameter of the forks. 

 

Working diameter limit: 

    Replace if over 12.96mm 
 
 
 
 

  Check the fork ear thickness applied to 

gear shaft area. 

 

Working diameter limit: 

    Replace if under 4.50mm 
 
 
 
 
 
 
 

  Check the shift drum grooves for wear, 

  especially at the points. 
 
 
 
 
 
 
 

 

 

 
 
 
 

 
 
 
 
 
 
 
 

 

 

 
 

Center gear shift fork

R/L gear shift fork

Summary of Contents for 2002/24 ATV-300XS

Page 1: ...SERVICE MANUAL ATV 300XS 2002 24 JULY 31 2007 High Power Engine HER CHEE INDUSTRIAL CO LTD ...

Page 2: ...fied mechanics this manual supplies service data necessary for repairs and maintenance It is highly recommended that a qualified mechanic regardless of technical level should study the service manual in full before attempting service on ATV 300XS All the data and diagrams provided in this service manual are valid at the time of publication Information may be updated without notice due to improveme...

Page 3: ...ssion Gear I 17 Lubrication I 23 Chapter 2 Fuel System Carburetion Carburetor II 3 Fuel Tank II 8 Air Cleaner II 11 Exhaust System II 13 Chapter 3 Clutch and Starting System Clutch III 2 Starting System III 4 Chapter 4 Frame Cover Frame Cover IV 2 Chapter 5 Wheels Tyres Brakes Handlebar Steering V 2 Front Rear Wheel V 6 Suspension System V 9 Hydraulic Brake System V 14 Chapter 6 Electrical Equipme...

Page 4: ...e VIN Vehicle Identification Number is attached to the lower front right side of frame behind the frame number The engine serial number is stamped on the upper rear right crankcase The carburetor identification number is stamped on the right side of the carburetor VIN No Frame No Engine No Carburetor Identification No ...

Page 5: ...hall be performed in the order of first the large screws and then the small ones and from inside to outside in opposite angles by tightening the torque locks z All items must use original parts pure oil and greases z All service shall use special tools and general tools to repair z All dismounted items requiring for checks shall be duly cleaned and for assembly all items shall be duly lubricated ...

Page 6: ...peration is performed by over 2 people the assignment shall be conducted in coordination and safety shall be the first priority z Definition of signs The sign given in the Service Manual shall refer to the operation methods and observation OIL Lubrication by designated lubricant GREASE Lubrication by grease Special Tool Parts on which special tools shall be used General Tool General tools shall be...

Page 7: ...ear 0 242 Fifth gear 0 299 Reverse gear 0 065 CLUTCH TYPE Wet Multi disc ENGINE OIL CHANGE 10W 40 Standard 2 0 Lit ENGINE IDLE SPEED 1400 100 rpm VALVE CLEARANCE 0 08 0 12 mm STARTING Electric starter and pull start SPARK PLUG NGK DR8EA SPARK PLUS GAP 0 6 0 7 mm IGNITION C D I SUSPENSION Front Double A Arm with preload adjustable shock Rear Swing arm with preload adjustable shock BRAKE Front Doubl...

Page 8: ...flange bolt 6 8 4 0 Rear swing arm fixed nut 1 14 9 Nylon insert type Rear brake panel flange bolt 4 12 7 Front suspension fixed nut 4 10 4 0 Nylon insert type Rear suspension flange bolt 2 10 4 0 Front rim nut 2 18 15 Rear rim nut 2 18 15 ENGINE Locking Place Qty Dia mm Torque kg m Remark Breather separator Allen bolt 1 6 1 2 Hex socket flange bolt Cam chain tensioner mounting bolt 2 6 1 2 Hex fl...

Page 9: ...Information for Preparation The following drawing that shows the disassembling situation of the cover parts for ATV 300XS ...

Page 10: ... spark plug and test Diagnose Check and Adjust Reason of Trouble fuel tank without gasoline tubing to carburetor blocking float chamber tubing blocking fuel filter blocking fuel cup blocking air in fuel tank blocking spark plug grimy or damage C D I damage main switch damage ACG fulser coil damage high tension coil damage ACG lighting coil damage valve set damage cylinder piston piston ring damage...

Page 11: ...ine over heat increase engine speed or continue turning at high speed Check and Adjust air cleaner blocking fuel supply isn t smooth air hole of air tank blocking exhaust pipe blocking manual choke stay on fuel cup damage C D I damage pulser coil damage valve gap adjusting isn t correct valve seat over abrade valve seat damage cylinder piston abrade cylinder gasket leakage valve timing isn t corre...

Page 12: ... fuel adjuste screw carburetor sucking air loosen spark plug connecct with spark cap and contract with frame check the spark plug sparking check A C G end Reason of Trouble C D I damage pulser coil damage fuel mixture too lean locking screw fuel mixture too rich loosing screw spark damage or stain C D I damage A C G damage coil damage spark plug cable damage main switch damage A C G damage air blo...

Page 13: ... adjusting valve gap check fuel cup supply normal carburetor blocking check and adjust valve timing Reason of Trouble C D I damage ACG pulse coil damage fule filter blocking air hole of fuel tank blocking fuel cup damage fuel in tank is not sufficient camshaft gear mark position is not correct normal spring broken or elastic deformation end check the spring of valve adjusting isn t correct valve s...

Page 14: ...n battery measure the resistance of ACG coil check the regulator check socket of regulator loosen Reason of Trouble battery damage coil damage terminal damage YL wire damage Red wire damage regulator damage socket damage ACG damage over charge main switch at ON the battery have voltage main switch at ON the battery have no voltage normal socket loosen GR wire broken regulator damage socket damage ...

Page 15: ... loosen check C D I unit socket loosen check the terminal of C D I unit unimpeded measure resistance check relate spare parts Reason of Trouble the previous spark plug damage spark plug cap loosen main switch damage pulser coil damage coil damage lighten coil damage the previous C D I unit damage socket damage normal abnormal main switch damage socket joint connect abnormal change CDI unit abnorma...

Page 16: ... 08mm intake valve Valve Gap 0 12mm exhaust valve Idle Speed 1400 100 rpm Engine oil type SAE 10W 40 Synthetic 1 6 L At oil change Engine Oil Capability 2 0 L After engine overhaul Compression Pressure 13 kg cm2 1400 rpm Ignite Timing 17 BTDC 1400 100 rpm CHASSIS ITEM SPECIFICATION REMARK Parking brake lever free play 10 20 mm Left lever free play 5 10 mm Throttle free play 2 6 mm Front Tire Press...

Page 17: ... I D Suspension I I Re tighten up bolts and nuts I I Tire and Wheel I I I Steering system and shaft bearing I Service Interval 1 Initial Service 20 hours or 150km either earlier time for new vehicle 2 Regular Check Every 100 hours or 1000km earlier time 3 Regular Check Every 200 hours or 2000km earlier time Note 1 Used in dusty sandy snow area need to be inspected Note 2 Used in rainy muddy condit...

Page 18: ...l lock the brake The main adjusting nut for throttle play is located under the handle bar Loose the fixed nut and adjust the play nut to proper position The throttle lever control bolt is located the throttle base Loose the fixed nut and adjust the screw to The throttle lever free play 2 6 mm get proper position ...

Page 19: ... mm AIR CLEANER Remove the seat Pull to open 4 clips on air cleaner cover and remove the cover Take out the air filter Check the filter whether is dirty or damaged If it s dirty or damaged then clean it or change a new one Attention Clean the element and frame in a high flash point solvent squeeze the solvent out of the foam and let the guide and element dry completely Check period If the ATV ofte...

Page 20: ... hole Measure valve clearance with a feeler gauge of the specified thickness To adjust the valve clearance loosen the locknut and turn the adjuster Attention When you adjusting the valve don t invert the crankshaft otherwise cannot adjust the exhaust valve Valve gap check and adjust Valve gap IN 0 08 mm EX 0 12 mm Loose the fixed nut and rotating the adjusting nut reach to the proper gap Tie up th...

Page 21: ...correct this problem before proceeding Adjust the idle speed adjust screw reach to the normal idle speed The idle speed is about 1400 100 rpm IGNITION TIMING The ignition system of this ATV is controlled by C D I unit thus don t need to adjust anything If the ignition timing isn t correct then checking the ignition system whether normally Remove the 14 mm A C G cap Using the timing light to check ...

Page 22: ...cap and spark plug Install the pressure gauge Rotate the throttle and press the electric start button The normal cylinder pressure is 12 14 kg cm2 If the cylinder pressure is too low then check the following items Valve leakage Valve gap is too tie Cylinder head gasket is damage Piston ring wear out Piston cylinder wear out If the cylinder pressure is too high then check the combustion chamber and...

Page 23: ...within bottom mark of the gauge then the oil quantity is enough Refill the engine oil if it s too less The standard oil type is SAE 10W 40 Re install the oil level gauge Change the engine oil Take out the oil level gauge Remove the oil release bolt underneath the engine and release the oil Install the oil release bolt Fill the engine oil Confirm the washer of the bolt whether damaged Engine oil qu...

Page 24: ...procket When install the chain clip beware the clip direction BRAKE SYSTEM Parking brake and rear brake Check all the brake shoes If the brake shoes have any dint or wearing very serious then change it Check the play of brake lever normal play 10 20 mm If the brake lever play is too much adjust the fix bolts on right brake lever If the play of the rear brake over the normal value then adjust the a...

Page 25: ...F NUTS AND BOLTS Check the fixing nuts bolts on all parts to see if the nuts bolts loosen then tie up with certain locking torque SUSPENSION Front Hold the brake lever and push the handlebar Check the fork movement and other parts if is loose or oil leaking Rear Check the damping of rear suspension Check the suspension bush function normally Inspect all suspension fasteners before riding ...

Page 26: ... used in ATV tires The tire pressure can be very depends on different operation condition Please check the mark on tire for operation pressure tolerance CHECK AND ADJUST Check the shaft and nut of front wheel whether loosen Check the nut of rear wheel whether loosen Locking Torque Front wheel 18mm nut 14 kg m Rear wheel 18mm nut 14 kg m ...

Page 27: ...n connector Reverse and neutral switches Starter cable Disconnect the reverse cable Disconnect the clutch cable from the lifter arm and detach the cable from the bracket Remove the drive sprocket cover remove the drive sprocket and pull the drive chain back so that it doesn t interfere with engine removal Remove the engine mounting bolts nuts and brackets at the lower front and lower rear Have an ...

Page 28: ...the mounting bolt holes then install the brackets bolts and nuts The remainder of installation is the reverse of the removal steps with the following additions a Use new gaskets at all exhaust pipe connections b Adjust the clutch cable and the throttle cable c Fill the engine with oil Run the engine and check for leaks Finish mounting the engine be sure to check the throttle cable tolerance Use re...

Page 29: ...al Leaking of cylinder head gasket Bottom of cylinder head damaged Wrong installation of spark plug Valve gap adjustment 0 08 mm Compression Pressure too high Too much carbon residue inside combustion chamber Emission with White Smoke Valves or valve guide attrition Oil seal on valve attrition Piston ring attrition Noise Bad adjustment of valve gap Valve burn or spring damaged Camshaft or rock arm...

Page 30: ...head z Cleaning before check parts and smear motor oil appointed in sliding face before installing Remove Cylinder Head 5 4 3 2 1 SEQ Operation Parts Name Q ty Remarks 1 2 3 4 5 Disassembly Cap nut of exhaust pipe 8mm Exhaust pipe of front section Exhaust pipe gasket Hex flange bolt Intake manifold assembly 2 1 1 2 1 Unscrew the bolts cross wise for 2 3 times WARNING Don t knock cooling fin Assemb...

Page 31: ... bolt Hex flange bolt Hex flange bolt Hex flange bolt Plain washer Cylinder head cover assembly Hex acorn washer face nut Plain washer Hex socket bolt Dowel pin Cylinder head Cylinder head gasket 1 3 3 1 2 1 1 5 1 4 6 2 2 1 1 6 28 6 52 6 35 6 80 6 115 6 136 6 5 14 1 6 M10 P1 5 10 20 2 10 105 P1 25 8 12 Check the gasket if wear out or damaged Assembly 15 1 Operation with sequence in reverse of disa...

Page 32: ...rm shaft comp Valve arm rocket assembly Valve cotter Valve spring assembly Inlet Exhaust valve Valve stem seal Hex flange bolt Camshaft sprocket Camshaft comp 2 2 2 8 4 4 4 2 1 1 The dowel pins are located underneath the cylinder head cover Using 8mm bolt to pull out the shaft from R side 38T Assembly 10 1 Operation with sequence in reverse of disassembly ...

Page 33: ... Limit Replace if over 12 04mm Check the rock arm shaft outside diameter Working Limit Replace if under 11 92mm Note If the sliding face of rock arm wear out then check the cam surface of the cam shaft Check the gap between rock arm and shaft Working Limit Replace if over 0 07 mm Remove valves Use valve spring holder tool to remove the spring holder cotter spring valve and seal Note Valve spring m...

Page 34: ...iameter working limit Replace under 5 45 mm Valve guide inside cylinder head working limit Replace if over 5 53 mm Cylinder head assembly Install valve seal spring seat Install valve into cylinder head with some lubrication oil on seal and spring seat Install springs spring holder cotter and use special tool to assembly Valve spring holder tool TLH3 03 Use rubber hammer hit the valve top for 2 3 t...

Page 35: ...LINDER HEAD VALVE Camshaft adjustment After install the cylinder head it s necessary to setup the camshaft timing Before put the timing chain on cam sprocket turn the T mark on ACG flywheel aim at the crankcase sign MEMO ...

Page 36: ...on wear out Disassembly of Cylinder Piston SEQ Operation Parts Name Q ty Remarks 1 2 3 4 5 Disassembly Cylinder Cylinder and gasket Hex flange bolt Cylinder Oil ring Cylinder gasket Dowel pin 2 1 1 1 2 WARNING Don t knock the cooling fin Clean the gasket stick on crank case Replace if necessary Replace if deformed 6 7 8 9 Disassembly Piston Piston pin clip Piston pin Piston ring set Piston 2 1 1 1...

Page 37: ...ock Clean all old gasket material from the tensioner body and from its mating surface on the cylinder block Installation Lubricate the friction surfaces of the components with moly based grease Install a new tensioner gasket on the cylinder Cut the cable tie and remove the coat hanger wire Install the tensioner sealing bolt and a new sealing washer and tighten the sealing bolt to toque Disassembly...

Page 38: ...ve with a pointed tool Push the piston pin part way out then pull it the rest of the way Inspection of Piston Remove the top and second piston rings Remove the upper oil ring side rail and expander then remove the lower side rail Warning Be ware not to scratch the piston during ring removal ...

Page 39: ...nd put into the bottom of cylinder Note Use piston to press the ring into cylinder Measure the opening gap of the piston ring when pressed into cylinder Working limit Top ring replace above 0 5mm 2nd ring replace above 0 5mm Measure the hole of the piston pin Working limit Replace if inside diameter is over 17 04 mm Measure outside diameter of piston pin Working limit Replace if under 16 96 mm ...

Page 40: ... be greased with oil Warning Do not scratch piston and do not band piston rings The mark on piston ring must face up Be sure the rings rotate freely after install into piston Piston installation Clean the gasket stick on top of crankcase Install piston piston pin and clips Warning The IN mark on top of cylinder must aim at the intake valve direction Piston pin clip must not drop into crankcase Use...

Page 41: ...urface piston and piston rings must be greased with oil Beware of the pressure from piston ring when install into cylinder Warning Be careful not to damage or band the piston ring The opening section of piston rings should not be the same with piston pin and set into 120 to each other Fit the cylinder into correct position ...

Page 42: ...reather plate gasket Left crankcase Crankcase gasket Right crankcase Dowel pin Hex flange bolt Plain washer Stud bolt Stud bolt 14 1 1 1 1 1 1 1 1 1 2 1 1 2 2 M6 35 M6 45 M6 65 M6 12 Use rubber hammer slightly hit the gear to remove the crankcase Scratch off the gasket which between crankcases and use new gasket after disassembly Do not damage the crankcase surrounding edge Check the oil seal is a...

Page 43: ...ft Thrust washer Reverse idle gear Reverse idle gear bush Thrust washer 1 1 1 2 1 2 1 1 1 The gear assembly should pull out at the same time with drum shaft assembly Beware keep the washer and cir clip in original order The ball and needle bearings are located on crankcase Check the bearing is functioning well or not Be ware of the gear set sequence and assembly direction Assembly 9 1 Operation wi...

Page 44: ... Hex socket bolt Hex washer face bolt Neutral switch rotor comp Reverse stopper cam comp Hex flange bolt Reverse shift stopper comp Gear shift fork assembly Gear shift spindle comp Hex socket bolt Gear shift drum assembly 1 1 1 1 1 1 2 1 1 1 1 2 1 1 1 2 1 2 1 1 1 Parts from sequence 1 to 11 are removed during previous L crankcase disassembly Parts from sequence 12 to 17 are removed during previous...

Page 45: ...iameter limit Replace if under 5 7mm Check the inside diameter of the forks Working diameter limit Replace if over 13 04mm Check the outside diameter of the forks Working diameter limit Replace if over 12 96mm Check the fork ear thickness applied to gear shaft area Working diameter limit Replace if under 4 50mm Check the shift drum grooves for wear especially at the points Center gear shift fork R...

Page 46: ...ring Semi cycle key Radial ball bearing Radial ball bearing 1 1 1 1 1 1 The crankshaft assembly normally is not for disassembly It will generate more problems if the L R cranks are disassembled The semi cycle key normally was took out when disassembly the flywheel Beware keep it in certain place to avoid lost Assembly 6 1 Operation with sequence in reverse of disassembly ...

Page 47: ...e with a feeler gauge The connecting rod side clearance limit is 0 80mm Check the connecting rod radial clearance with a dial indicator The connecting rod big end radial clearance limit is 0 05mm Place a V block on each side of the crankshaft A and measure run out at the ends B ...

Page 48: ...FT Check the connecting rod Working diameter limit Replace if over 17 10mm Check the balancer gear and bearing journals for wear or damage Use a special tool TLH3 01 to pull the crankshaft and push the left crankcase onto the crankshaft ...

Page 49: ...in check the oil quantity Remove the oil level gauge and check if the oil level under the lower limit then adds the standard oil to upper limit of gauge Oil Exchange The motor oil will flow more easily if the engine is warm The oil release bolt is under crankcase Locking torque 1 5 kg m Remove the right crankcase cover to check and clean the oil filter Replace new filter if it s damaged Adding the...

Page 50: ...Pan Philips bolts on the rear foot fender Remove foot peg and fender together Take off 12 bolts on R crankcase cover and remove the cover Remove the gasket and 2 dowel pins Release the clutch cable fix nut from the left side of the engine Pull out the cable from the clutch lever on top of right crankcase cover R crankcase Gasket dowel pin ...

Page 51: ...er down the brake pedal for easier disassembly Release brake pedal reset spring Lift the vehicle from right side and flip over to left side Then remove the oil tube fix bolt on top of right crankcase cover Beware not to lost the copper washers Remove the nylon insert bolt on reverse stopper lever ...

Page 52: ...ontact switch connectors Remove 10 M6 32mm 1 M6 40mm and 1 M6 50mm hex flange bolts Put away all wires cables Slightly hit the right crankcase cover from side way and pull out to remove the cover Attention Beware the light green wire is for the neutral signal the gray wire is for the reverse signal ...

Page 53: ...eware not to lost the dowel pins Remove 4 M6 28mm hex bolts and 4 springs under the clutch lifter plate Hold the lifter plate together with the needle roller bearing Before remove the locknut punch out the lock section on the nut Remove the locknut and clutch center ...

Page 54: ...l pipe from the crankcase remove these 2 bolts Carefully pull the oil pipe off the crankcase Remove this dowel pin and O ring from the oil pipe Remove the oil pump mounting bolts Use reversed procedure to setup the parts that has been removed Oil pipe Attention Beware all dowel pins are located into the crankcase Replace new gasket of the right crankcase cover after disassembly ...

Page 55: ...il Pump Disassembling Remove the snap ring and washer Remove the pump driven gear and shaft Remove the pump cover bolts and separate the cover from the pump body z Remove the rotors wash all the components in solvent rotor ...

Page 56: ...gap between the pump body and outer rotor The gap limit is 0 25 mm Check the gap between inner and outer rotor The gap limit is 0 2 mm Check the gap between the rotors and a straightedge laid across the pump body The gap limit is 0 1 mm ...

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