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BR-250 / BR-250SS / M2-250   
SERVICE MANUAL 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Manufactured by PGO 

of Motive Power Industry Co., Ltd 

 

 

Summary of Contents for Bug Rider BR-250

Page 1: ...BR 250 BR 250SS M2 250 SERVICE MANUAL Manufactured by PGO of Motive Power Industry Co Ltd...

Page 2: ...__________________________________________________________________ INSPECTION ADJUSTMENT __________________________________________________________________________________ SERVICE INFORMATION 1 1 MAIN...

Page 3: ...area or fuel storage area SPECIFICATIONS ENGINE Throttle grip free play 2 6mm Spark plug NGK DPR7EA 9 Spark plug gap 0 9mm Valve clearance IN 0 1mm EX 0 1mm Idle speed 1450 50rpm Engine oil capacity C...

Page 4: ...e 2 3 I R R Spark plug Clean at every 3000km and replace if necessary Brake system I I I I I I Drive belt I Suspension I I Nut bolt fastener I Tire I I Steering head bearing I I I Brake fluid Perform...

Page 5: ...nt Measure the throttle grip free play Free Play 2 6mm Major adjustment of the throttle grip free play is made with the adjusting nut at the carburetor side Adjust by loosening the lock nut and turnin...

Page 6: ...Capacity At disassembly 1 1 liter At change 0 9 liter Recommended Oil SAE 15W40 API SG CD Start the engine and check for oil leaks Stop the engine and recheck the oil level OIL FILTER SCREEN INSPECTIO...

Page 7: ...y fouling deposits with a spark plug cleaner or a wire brush Specified Spark Plug NGK DP7EA9 Measure the spark plug gap Spark Plug Gap 0 9mm Torque 7 8 9 8N m VALVE CLEARANCE Gap Wear Fouling Deposits...

Page 8: ...DLE SPEED Lift up the seat and remove the inspection cover Warm up the engine before this operation Start the engine and connect a tachometer Turn the throttle stop screw to obtain the specified idle...

Page 9: ...utton to test the compression Compression 16 5 2kg cm If the compression is low check for the following Leaky valves Valve clearance to small Leaking cylinder head gasket Worn pistons Worn piston cyli...

Page 10: ...l the final reduction with the recommended oil SAE90 Gear Oil Capacity At disassembly 200cc At change 180cc Reinstall the oil check bolt and check for oil leaks DRIVE BELT Remove the left crankcase co...

Page 11: ...fill the reserve tank with recommended coolant to the F level line Recommended Coolant SIGMA Coolant Standard Concentration 30 COOLANT REPLACEMENT Remove the front cover Remove the radiator cap Remov...

Page 12: ...ront rear brake fluid level is at the upper limit If the brake fluid is insufficient fill to the upper limit Specified Brake Fluid DOT 3 BRAKE DISK BRAKE PAD Check the brake disk surface for scratches...

Page 13: ...heck that the steering handlebar rotates freely If the handlebar moves unevenly binds or has vertical movement adjust the steering head bearing SUSPENSION Check the action of the front rear shock abso...

Page 14: ..._________________________________________________________________ INSPECTION ADJUSTMENT __________________________________________________________________________________ SERVICE INFORMATION 2 1 MAINT...

Page 15: ...SPECIFICATIONS ENGINE Throttle grip free play 2 6mm Spark plug NGK DPR7EA 9 Spark plug gap 0 9mm Valve clearance IN 0 1mm EX 0 1mm Idle speed 1450 50rpm Engine oil capacity Cylinder compression 16 5 2...

Page 16: ...2 3 I R R Spark plug Clean at every 3000km and replace if necessary Brake system I I I I I I Drive belt I Suspension I I Nut bolt fastener I Tire I I Steering head bearing I I I Brake fluid Perform p...

Page 17: ...oth movement Measure the throttle grip free play Free Play 2 6mm Major adjustment of the throttle grip free play is made with the adjusting nut at the carburetor side Adjust by loosening the lock nut...

Page 18: ...apacity At disassembly 1 1 liter At change 0 9 liter Recommended Oil SAE 15W40 API SG CD Start the engine and check for oil leaks Stop the engine and recheck the oil level OIL FILTER SCREEN INSPECTION...

Page 19: ...Clean any fouling deposits with a spark plug cleaner or a wire brush Specified Spark Plug NGK DP7EA 9 Measure the spark plug gap Spark Plug Gap 0 9mm Torque 7 8 9 8N m VALVE CLEARANCE Gap Wear Fouling...

Page 20: ...LE SPEED Lift up the seat and remove the inspection cover Warm up the engine before this operation Start the engine and connect a tachometer Turn the throttle stop screw to obtain the specified idle s...

Page 21: ...tton to test the compression Compression 16 5 2kg cm If the compression is low check for the following Leaky valves Valve clearance to small Leaking cylinder head gasket Worn pistons Worn piston cylin...

Page 22: ...the final reduction with the recommended oil SAE90 Gear Oil Capacity At disassembly 200cc At change 180cc Reinstall the oil check bolt and check for oil leaks DRIVE BELT Remove the left crankcase cov...

Page 23: ...necessary fill the reserve tank with recommended coolant to the F level line Recommended Coolant SIGMA Coolant Standard Concentration 30 COOLANT REPLACEMENT Remove the front cover Remove the radiator...

Page 24: ...ke fluid level is at the upper limit If the brake fluid is insufficient fill to the upper limit Specified Brake Fluid DOT 3 BRAKE DISK BRAKE PAD Check the brake disk surface for scratches unevenness o...

Page 25: ...freely If the handlebar moves unevenly binds or has vertical movement adjust the steering head bearing SUSPENSION Check the action of the front rear shock absorbers by compressing them several times...

Page 26: ...__________________________________________________________________________________ __________________________________________________________________________________ LUBRICATION SYSTEM ______________...

Page 27: ...3 LUBRICATION SYSTEM 1 BR M2 250 ENGINE LUBRICATION SYSTEM Oil Pump Oil Filter Screen Crankshaft Rocker Arm Shaft...

Page 28: ...pump is installed check each part for oil leaks SPECIFICATIONS OIL PUMP Standard mm Service Limit mm Inner rotor to outer rotor clearance 0 15 0 20 Outer rotor to pump body clearance 0 15 0 20 0 25 Ro...

Page 29: ...cap Remove the oil filter screen and spring Check the oil filter screen for clogging or damage and replace if necessary Check the filter screen O ring for damage and replace if necessary Install the o...

Page 30: ...9 3 Remove the A C generator starter driven gear 9 4 Remove the attaching bolt and oil separator cover Pry the circlip off and remove the oil pump driven gear then remove the oil pump drive chain Rem...

Page 31: ...ure the inner rotor to outer rotor clearance Service Limit 0 20mm replace if over Measure the rotor end to pump body clearance Service Limit 0 12mm replace if over OIL PUMP ASSEMBLY Install the outer...

Page 32: ...ut binding OIL PUMP INSTALLATION Install the oil pump and oil separator and tighten the two bolts Make sure that the pump shaft rotates freely The arrow of oil pump is upside Install the pump drive ch...

Page 33: ...____________________________________________ __________________________________________________________________________________ CYLINDER HEAD VALVES ___________________________________________________...

Page 34: ...4 CYLINDER HEAD VALVES 1 BR M2 250 ENGINE SCHEMATIC DRAWING...

Page 35: ...Service Limit mm Item SH50CA SH50CA IN 0 10 EX 0 10 Cylinder head compression pressure 15kg cm Cylinder head warpage 0 05 IN 34 2987 34 14 EX 34 1721 34 02 IN 10 00 10 015 10 10 EX 10 00 10 015 10 10...

Page 36: ...e stem oil seal Compression too low Incorrect valve clearance adjustment Abnormal noise Burned or bend valves Incorrect valve clearance adjustment Incorrect valve timing Sticking valve or broken valve...

Page 37: ...case Hold the round hole on the camshaft gear facing up and the location is the top dead center on the compression stroke Remove the two bolts attaching cam chain tensioner and the tensioner First rem...

Page 38: ...obe height Service Limits IN 34 14mm replace if below EX 34 02mm replace if below Check each camshaft bearing for play or damage Replace the camshaft assembly with a new one if the bearings are noisy...

Page 39: ...thermostat water hose Remove the camshaft 4 4 Remove the carburetor and intake manifold Remove the bolt attaching the thermostat housing and the thermostat housing Remove the cylinder head Remove the...

Page 40: ...rbon deposits from the exhaust port and combustion chamber INSPECTION CYLINDER HEAD Valve Spring Compressor Cylinder Head Be sure to compress the valve springs with a valve spring compressor Mark all...

Page 41: ...elow Outer IN EX 39 5mm replace if below VALVE VALVE GUIDE Inspect each valve for bending burning scratches or abnormal stem wear Check valve movement in the guide Measure each valve stem O D Service...

Page 42: ...fts CAMSHAFT INSTALLATION Turn the A C generator flywheel so that the T mark on the flywheel aligns with the index mark Gasket Cam Chain Guide Valve Rocker Arms Plastic Hammer Cam Chain Cylinder Head...

Page 43: ...he cylinder head Tighten the four cylinder head nuts and the two bolts between the cylinder head and cylinder Torque Cylinder head cap nut 19 6N m Cylinder cylinder head bolt 7 8 11 8N m Turn the cam...

Page 44: ...it Tighten the cam chain tension cap screw CYLINDER HEAD COVER INSTALLATION Adjust the valve clearance 1 6 Install a new cylinder head cover O ring and install the cylinder head cover Install and tig...

Page 45: ...________________________________ __________________________________________________________________________________ __________________________________________________________________________________ C...

Page 46: ...5 CYLINDER PISTON 1 BR M2 250 ENGINE SCHEMATIC DRAWING...

Page 47: ...position 9mm from bottom of skirt 9mmfrom bottomofskirt Piston to cylinder clearance 0 010 0 040 0 01 Piston pin hole I D 17 002 17 008 17 04 Piston pin O D 16 994 17 000 16 96 Piston to piston pin cl...

Page 48: ...emove the cylinder gasket and dowel pins Clean any gasket material from the cylinder surface PISTON REMOVAL Remove the piston pin clip Press the piston pin out of the piston Dowel Pins Gasket Place a...

Page 49: ...ance Service Limits Top 0 09mm replace if over 2nd 0 09mm replace if over Remove the piston rings and insert each piston ring into the cylinder bottom Measure the piston ring end gap Service Limit 0 5...

Page 50: ...rections Service Limit 72 80mm repair or replace if Over Measure the cylinder to piston clearance Service Limit 0 1mm repair or replace if Over The true roundness is the difference between the values...

Page 51: ...all the piston rings onto the piston Apply engine oil to each piston ring PISTON INSTALLATION Second Side Rail Top Be careful not to damage the piston and piston rings during assembly All rings should...

Page 52: ...refully lower the cylinder over the piston by compressing the piston rings Install the cam chain guide Gasket Cylinder Dowel Pin Be careful not to drop foreign matters into the crankcase Position the...

Page 53: ...nstall the cylinder gasket and dowel pins Connect the water hose to the cylinder Install the cylinder head 4 9 Tighten the cylinder base bolt Insert the tab on the cam chain guide into the cylinder gr...

Page 54: ...___________________________________________ __________________________________________________________________________________ _________________________________________________________________________...

Page 55: ...6 DRIVE AND DRIVEN PULLEYS KICK STARTER 1 BR M2 250 ENGINE SCHEMATIC DRAWING...

Page 56: ...3 963 4 037 2 0 Clutch outer I D 153 0 153 2 153 5 Driven face spring free length 131 130 5 Driven face O D 26 960 26 974 26 90 Movable driven face I D 27 060 27 090 27 13 Weight roller O D 18 9 19 0...

Page 57: ...over bolts and left crankcase covers Remove the seal rubber and dowel pins INSTALLATION Install the dowel pins and the seal rubber Install the left crankcase cover Install the cable clamp to the speci...

Page 58: ...lley face Universal Holder Remove the drive belt from the movable drive face INSPECTION Check the drive belt for cracks separation or abnormal or excessive wear Measure the drive belt width Service Li...

Page 59: ...the ramp plate Remove the weight rollers INSPECTION Check each weight roller for wear or damage Measure each weight roller O D Service Limit 18 00mm replace if below Measure the movable drive face bus...

Page 60: ...drive pulley collar for wear or damage Measure the O D of the drive pulley collar sliding surface Service Limit 26 90mm replace if below ASSEMBLY Install the weight rollers into the movable drive fac...

Page 61: ...ace INSTALLATION Install the movable drive face onto the crankshaft Lay the drive belt on the driven pulley Set the drive belt on the drive pulley collar Install the drive pulley face washer and drive...

Page 62: ...ch outer with the universal holder and remove the clutch outer nut Universal Holder Remove the clutch outer INSPECTION Inspect the clutch outer for wear or damage Measure the clutch outer I D Service...

Page 63: ...Set the tool in a vise and remove the clutch drive plate nut Lock Nut Wrench 39mm Loosen the clutch spring compressor and disassemble the clutch driven pulley assembly Remove the seal collar Pull out...

Page 64: ...ven face spring free length Service Limit 130 5mm replace if below Check the driven face assembly for wear or damage Measure the driven face O D Service Limit 39 92mm replace if below Check the movabl...

Page 65: ...e the outer bearing out of the driven face Apply grease to the outer bearing Drive a new outer bearing into the driven face with the sealed end facing up Bearing Driver Seat the snap ring in its groov...

Page 66: ...EN PULLEYS KICK STARTER 12 BR M2 250 ENGINE Bearing Driver CLUTCH DISASSEMBLY Remove the circlips and retainer plate to disassemble the clutch Circlips Keep grease off the clutch linings Retainer Plat...

Page 67: ...shoes and clutch springs onto the drive plate Install the retainer plate and secure with the circlips CLUTCH DRIVENPULLEYASSEMBLY Clean the pulley faces and remove any grease from them Apply grease to...

Page 68: ...the specified torque Torque 49 0 58 8N m Clutch Spring Compressor Outer Driver 39mm INSTALLATION Install the clutch driven pulley onto the drive shaft Install the clutch outer Hold the clutch outer wi...

Page 69: ...6 DRIVE AND DRIVEN PULLEYS KICK STARTER 15 BR M2 250 ENGINE Torque 49 0 58 8kg m Universal Holder Install the drive belt 6 7 Install the left crankcase cover 6 3 Special...

Page 70: ..._______________________________ __________________________________________________________________________________ __________________________________________________________________________________ FI...

Page 71: ...7 FINAL REDUCTION 1 BR M2 250 ENGINE SCHEMATIC DRAWING...

Page 72: ...ATIONS Specified Oil SAE 90 Oil Capacity At disassembly 0 2 liter At change 0 18 liter TORQUE VALUES Transmission case cover bolt 25 5 31 4N m Oil check bolt 9 8 14 7N m SPECIAL TOOLS Bearing remover...

Page 73: ...kcase cover 6 3 Remove the clutch driven pulleys 6 4 Drain the transmission gear oil into a clean container Remove the transmission case cover attaching bolts Remove the transmission case cover Remove...

Page 74: ...drive shaft and gear for wear or damage Check the transmission case covers bearings for excessive play and inspect the final shaft bearing oil seal for wear or damage Drive Shaft Bearing Final Shaft...

Page 75: ...the bearing remover Remove the final shaft oil seal Drive new bearings into the transmission case cover BEARING REPLACEMENT LEFT CRANKCASE COVER Remove the drive shaft Remove the drive shaft oil seal...

Page 76: ...NE Drive new bearings into the left crankcase Install a new drive shaft oil seal FINAL REDUCTION ASSEMBLY Install the drive shaft into the left crankcase Install the final gear and final shaft into th...

Page 77: ...nter shaft Install the dowel pins and a new gasket Install the transmission case cover Install and tighten the transmission case cover bolts Install the clutch driven pulley Install other removed part...

Page 78: ...ghten the oil check bolt Torque 9 8 14 7N m Start the engine and check for oil leaks Check the oil level from the oil check bolt hole and add the specified oil to the proper level if the oil level is...

Page 79: ...___________ _________________________________________________________________________________ _________________________________________________________________________________ CARBURETOR _____________...

Page 80: ...e pressure present on the downstream side of the venturi A Negative pressure is admitted into the diaphragm chamber through an orifice provided in the piston valve rising negative pressure overcomes t...

Page 81: ...mixture is metered by the pilot screw and sprayed into the main bore through the pilot outlet port 8 3 COASTING ENRICHMENT SYSTEM The coasting enrichment system is included in the slow system At the...

Page 82: ...8 CARBURETOR BR M2 250 ENGINE...

Page 83: ...etered fuel enters the needle jet mixes with the air admitted through the main air jet and forms an emulsion The emulsified fuel then passes through the clearance between the needle jet and jet needle...

Page 84: ...rich in fuel content reaches upper part of The fuel pipe and mixes again with the air coming through a passage extending from main bore The two succesive mixings of fuel with air are such that proper...

Page 85: ...ses and the needle valve pushes up against the valve seat When this occurs no fuel enters the float chamber As the fuel level falls the float lowers and the needle valve unseats itself admitting fuel...

Page 86: ...uel air mixture ratio When the rider open the throttle grip quickly the intaken air volume becomes large and air velocity at the bottom of the throttle valve piston valve is slow and sucking volume of...

Page 87: ...hly not just the perceived problem area Clean the circuits in the carburetor body with a spray type cleaner and allow each circuit to soak if necessary to loosen dirt and varnish Blow the body dry usi...

Page 88: ...r the battery has been connected NOTE To inspect the function check for change of temperature from the cold condition CAUTION FLOAT HEIGHT ADJUSTMENT To check the float height turn the carburetor upsi...

Page 89: ...________________________________________________________________________ __________________________________________________________________________________ A C GENERATOR STARTER CLUTCH _______________...

Page 90: ...9 A C GENERATOR STARTER CLUTCH 1 BR M2 250 ENGINE SCHEMATIC DRAWING...

Page 91: ...installed fill with the recommended engine oil and coolant Then bleed air from the water jacket Refer to page 18 4 for A C generator inspection SPECIFICATIONS Engine oil SAE15W 40 API SG CD Oil capac...

Page 92: ...r coil Remove the three A C generator stator bolts and the stator FLYWHEEL REMOVAL Hold the flywheel with a flywheel holder and remove the flywheel nut Remove the flywheel with a flywheel puller START...

Page 93: ...ter driven gear for wear or damage Measure the starter driven gear I D and O D Service Limits I D 22 15mm replace if over O D 41 50mm replace if below Inspect the starter idle gear and shaft for wear...

Page 94: ...flywheel Hold the flywheel with the flywheel holder and tighten the flywheel nut Torque 34 3 39 2N m STATOR INSTALLATION Install the A C generator stator on the right crankcase cover and secure it wi...

Page 95: ...the water pump shaft groove with the oil pump shaft Tighten the nine right crankcase cover bolts Connect the water hoses to the right crankcase cover Add the recommended engine oil 3 3 Fill the coolin...

Page 96: ..._____________________________________ __________________________________________________________________________________ _______________________________________________________________________________...

Page 97: ...10 CRANKCASE CRANKSHAFT 1 BR M2 250 ENGINE SCHEMATIC DRAWING...

Page 98: ...oved before separating the crankcase Cylinder head 4 4 Cylinder piston 5 3 Right crankcase cover drive and driven pulley 6 3 A C generator starter clutch 9 3 Rear wheel rear shock absorber Starter mot...

Page 99: ...left crankcase Place the crankcase with the left crankcase down and remove the right crankcase from the left crankcase Remove the gasket and dowel pins Remove the crankshaft from the left crankcase R...

Page 100: ...TION Measure the connecting rod big end side clearance Service Limit 0 6mm replace if over Measure the connecting rod small end I D Service Limit 17 06mm replace if over Measure the crankshaft runout...

Page 101: ...ASSEMBLY Clean off all gasket material from the crankcase mating surfaces Install a new oil seal into the left crankcase Place the left crankcase down and install the crankshaft into the left crankca...

Page 102: ...rankcase Install and tighten the right and left crankcase attaching bolts Torque 7 8 10 8N m Install the cam chain Install the cam chain tensioner slipper Install and tighten the cam chain tensioner s...

Page 103: ...10 CRANKCASE CRANKSHAFT 7 BR M2 250 ENGINE Torque 7 8 11 8N m Cam Chain Tensioner Slipper Bolt...

Page 104: ...______________________________________ __________________________________________________________________________________ ______________________________________________________________________________...

Page 105: ...11 COOLING SYSTEM 1 BR M2 250 ENGINE SCHEMATIC DRAWING...

Page 106: ...ant with fresh water as soon as possible After servicing the system check for leaks with a cooling system tester SPECIAL TOOL Mechanical seal driver TORQUE VALUES Water pump impeller 9 8 13 7N m Water...

Page 107: ...1 064 1 062 1 059 1 056 1 053 1 050 1 047 45 1 080 1 078 1 076 1 074 1 072 1 069 1 056 1 063 1 062 1 057 1 054 50 1 086 1 084 1 082 1 080 1 077 1 074 1 071 1 068 1 065 1 062 1 059 55 1 095 1 093 1 091...

Page 108: ...OR INSPECTION Remove the front upper cover 2 5 Remove the front lower cover 2 5 Inspect the radiator soldered joints and seams for leaks Blow dirt out from between core fins with compressed air If ins...

Page 109: ...om the radiator filler Remove the overflow tube clamp and disconnect the overflow tube Loosen the hose band and disconnect the upper hose and lower hose from the radiator Disconnect the thermostatic s...

Page 110: ...ts and two nuts on the radiator RADIATOR DISASSEMBLY Remove the four bolts and then remove the fan shroud from the radiator Check fan motor by battery Fan Shroud Radiator Bolts Thermostatic Switch Wir...

Page 111: ...thermostatic switch OFF When coolant temperature over 85 90 the thermostatic switch ON Install the fan shroud on the radiator with the four bolts RADIATOR INSTALLATION Install the radiator on the radi...

Page 112: ...vent tube to the radiator filler After installation check for coolant leaks Install the front upper cover Air Vent Tube Radiator Upper Hose Overflow Tube Lower Hose Bolts Thermostatic Switch Wire Nut...

Page 113: ...seal coolant leakage If the mechanical seal is leaking remove the right crankcase cover and replace the mechanical seal WATER PUMP IMPELLER REMOVAL Remove the coolant inlet hose and outlet hose Remov...

Page 114: ...or wear or damage WATER PUMP SHAFT REMOVAL Disconnect the water hose from the right crankcase cover Remove the eight bolts attaching the right crankcase cover Impeller Left Hand Threads Water Pump Cov...

Page 115: ...emove the water pump shaft and inner bearing Remove the water pump shaft outer bearing MECHANICAL SEAL REPLACEMENT Drive the mechanical seal out of the water pump assembly from the inside Inner Bearin...

Page 116: ...p shaft outer bearing into the water pump assembly from the inside Install the water pump shaft and shaft inner bearing into the waster pump assembly Install the snap ring to secure the inner bearing...

Page 117: ...ALLATION When the mechanical seal is replaced a new seal washer must be installed to the impeller Install the impeller onto the water pump shaft Torque 9 8 13 7N m When installing the water pump assem...

Page 118: ...Install the water pump cover and tighten the 4 bolts Torque 7 8 11 8N m THERMOSENSOR THERMOSENSOR REMOVAL Remove the seat met in box and center cover Drain the coolant Disconnect the thermosensor wir...

Page 119: ...ensor wire Fill the radiator with coolant 3 9 Install the center cover met in box and seat 2 3 THERMOSTAT THERMOSTAT REMOVAL Remove the seat met in box and center cover Drain the coolant Disconnect th...

Page 120: ...ned for about 5 minutes and holds the temperature at 70 Thermometer housing halves Remove the thermostat from the thermostat housing THERMOSTAT INSPECTION Suspend the thermostat in a pan of water over...

Page 121: ...ENGINE THERMOSTAT INSTALLATION The installation sequence is the reverse of removal Fill the cooling system with the specified coolant 3 9 Replace the O ring with a new one and apply grease to it O rin...

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