Honda MBX50 Workshop Manual Download Page 65

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�HONDA

� MBX50· MBX80

Place the cylinder gasket on the crankcase.

Lubricate the piston with engine oil and install the

cylinder over the piston while compressing the

piston rings.

NOTE

/ Do not damage the piston.

Install the cylinder head and new cylinder head

gasket (Page 6-4).

Install thereed valve and intake pipe.

Install the e)(haust muffler.

Install thecarburetor (Page 4-9).

Install the radiator (Page 10-5).

Fill the cooling system with the recommended

coolant (Page 10-3).

Perform the following inspections and operation:

Cylinder compression (Page 3-7); compression leaks.

Engine noise.

Secondary air leaks.

Air bleeding from oil pass tube (Page 2-7).

REMOVAL

Remove the craburetor (Page 4-9).

Remove the intake pipe (Page 6-5).

NOTE

Do not remove the oil pass tube or locate the

end of the tube lower than the oil pump.

Bleed air from the oil pass tube when it has

been disconnected or the end has been located

lower than the oil pump.

CYLINDER HEAD/CYLINDER/PISTON

(1) CYLINDER GASKET

(1) INTAKE PIPE

(2) OIL PASS TUBE

Summary of Contents for MBX50

Page 1: ...o to section 18 TROUBLESHOOTING ALL INFORMATION ILLUSTRATIONS DIREC TIONS AND SPECIFICATIONS INCLUDED IN THIS PUBLICATION ARE BASED ON THE LATEST PRODUCT INFORMATION AVAILABLE AT THE TIME OF APPROVAL FOR PRINTING HONDA MOTOR CO LTD RESERVES THE RIGHT TO MAKE CHANGES AT ANY TIME WITHOUT NOTICE AND WITHOUT INCURRING ANY OBLIGATION WHATEVER NO PART OF THIS PUBLICATION MAY BE REPRODUCED WITHOUT WRITTE...

Page 2: ...F No AC03 5000001 HONDA MBX50 MBX80 2 The frame serial number is stamped on the steering head right side 3 The engine serial number is stamped on the left crankcase 4 The carburetor identification number is on the carburetor body left side ...

Page 3: ...ome work make sure the area is well ventilated Never run the engine in a closed area The exhaust contains poisonous carbon monoxide gas VI W A RNIN6 1 Y Gasoline is extremely flammable and is explosive under certain conditions Do not smoke or allow flames or sparks in your working area SERVICE RULES W R NINX I J I The battery electrolyte contains sulfuricacid Protect your eyes skin and clothing In...

Page 4: ... in 170 mm 6 7 in 89 kg 196 lb 98 kg 216 lb 248 kg 547 lb 268 kg 591 lb Semi double cradle Telescopic 115 mm 4 53 in Swingarm shock absorber 85 mm 85 mm 3 35 in 2 50 18 4PR 2 75 18 6PR 175 kPa 1 75 kg cm2 25 psi 175 kPa 1 75 kg cm2 25 psi 175 kPa 1 75 kg cm2 25 psi 280 kPa 2 80 kg cm2 40 psi Single disc brake Internal expanding shoe 1 2 liters 3 2 US gal 2 6 Imp gal 1 2 liters 0 3 US gal 0 3 Imp g...

Page 5: ... Type 5 8 kw 7 000 min 1 7 0 kw 5 750 min 1 7 9 ps 7 000 rpm 9 6 ps 5 750 rpm 8 3 N m 0 85 kg m 6 1 ft lb 11 7 N m 1 2 kg m 8 7 ft lb 6 500 min 1 rpm 5 500 min 1 rpm 0 9 liters 1 0 US qt 0 8 Imp qt 1 2 liters 1 3 US qt 1 1 Imp qt 670 cm3 40 9 cu in Forced and wet sump Oiled polyurethane foam 1 275 kPa 13 0 kg cm2 185 psi 1 400 min 1 rpm PF16 18 mm 0 71 in venturi PF16 16 mm 0 63 in venturi bore bo...

Page 6: ...0 24 Self looking nut Rear shock linkage 3 10 40 50 4 0 5 0 29 36 Swingarm pivot nut 1 14 70 85 7 0 8 5 51 62 Self locking nut Front brake disc 3 8 27 33 2 7 3 3 20 24 Front brake master cylinder 2 6 10 14 1 0 1 4 7 10 Brake bleeder valve 1 4 7 0 4 0 7 2 9 5 1 Brake hose bolt 2 10 25 35 2 5 3 5 18 25 Brake caliper bracket 2 8 24 30 2 4 3 0 17 22 Brake caliper bracket pin nut 2 8 20 25 2 0 2 5 15 1...

Page 7: ...llation 07945 1660000 1 Balancer installation 07936 1660000 1 Removal of small balancer bearing water pump bearing and mainshaft bearing 07936 1660100 1 07936 3710200 1 07631 0010000 1 Main bearing removal 07964 1870100 1 Small balancer bearing and mainshaft bearing installation 07917 3230000 1 07944 1150001 1 07914 3230001 1 07747 0010700 1 07967 GE20000 1 07945 4150400 1 Water pump mechanical se...

Page 8: ...MEMO HONDA MIX50 MBXIO ...

Page 9: ...HONDA MBX50 MBX80 CABLE HARNESS ROUTING GENERAL INFORMATION 1 RADIATOR OVERFLOW TUBE 2 HIGH TENSION CORD 4 TACHOMETER CABLE f J I J l 1 Ci c 3 CLUTCH CABLE 6 WIRE HARNESS 7 SPEEDOMETER CABLE ...

Page 10: ...GENERAL INFORMATION 1 8 HONDA MBX50 MBX80 5 AlTERNATOR NEUTRAL SWITCH WIRES 4 WIRE HARNESS ...

Page 11: ...CABLE 5 BRAKE HOSE 6 OIL LEVEL 7 SENSOR 15 FUSE HOLDER 14 REAR BRAKE LIGHT SWITCH GENERAL INFORMATION 1 CLUTCH CABLE 2 TURN SIGNAL SWITCH COUPLER 8 IGNITION COIL 9 CDI UNIT 10 HIGH TENSION CORD 12 TACHOMETER CABLE 1 CLUTCH CABLE 1 9 ...

Page 12: ...N IZATION CYLINDER EX PORT DECARBONIZATION MUFFLER DECARBONIZATION I ODOMETER READING NOTE2 0 0 0 f c 4 C er Refer to c s oc s c s Oj o R R Page2 3 A R R R Page3 4 C C C Page3 3 I I Page3 5 4 7 I Page3 8 I Page3 8 I I Page3 8 I I I I Page3 2 I I I I Page3 5 I Page3 2 C C C C Page3 2 I I Page3 7 l L l L l L 1 L Page3 11 I I Page3 9 3 10 I I Page3 13 I I I I I I Page3 13 I I I I I I I Page3 9 I I I ...

Page 13: ...OW 9 r Apply locking agent to the threads of the oil pump mounting bolt and screw LUBRICATIO 7 OIL PUMP 4 OIL PUMP OIL TANK CAPACITY 1 2 lit 1 3 US qt 1 1 Imp qt Do not attempt to disassemble the oil pump 8 OIL PUMP BLEEDER BOLT 2 I 2 0 ...

Page 14: ...ORMATION TROUBLESHOOTING TRANSMISSION 01L 01L STRAINER CLEANING OIL PUMP REMOVAL OIL PUMP INSPECTION OIL PUMP INSTALLATION 01L PUMP BLEEDING OIL TANK CHASSIS LUBRICATION POINTS HONDA MBXSO MBXSO 2 0 2 2 2 2 2 3 2 4 2 5 2 6 2 6 2 7 2 8 2 9 ...

Page 15: ...its equivalent 0 9 lit 1 0US qt 0 8 Imp qt at disassembly 0 8 lit 0 8 US qt 0 7 Imp qt at change Use HONDA 4 STROKE OIL or OIL VISCOSITIES equivalent API SERVICE CLASIFICATION SE or SF VISCOSITY SAE 10W 40 JO 10 10 10 20 JO 40 c TORQUE VALUES Oil pump mounting bolt Oil pump mounting screw 8 12 N m 0 8 1 2kg m 6 9 ft lb 8 12 N m 0 8 1 2 kg m 6 9 ft lb TROUBLESHOOTING Excessive smoke excessive carbo...

Page 16: ...rmal operating temperature Remove the oil filler cap Remove the oil drain plug and drain the oil Reinstall the drain plug TORQUE 20 25 N m 2 0 2 5 kg m 14 18 ft lb CAUTION Make sure that the sealing washer on the drain plug is in good condition Refill the engine up to the proper level Oil CAPACffV 0 8 lit 0 8 US qt 0 7 Imp qt SPECIFIED Oil 10W 40 or equivalent Start the engine and check for leaks ...

Page 17: ...ner screen Clean the oil strainer screen with compressed air Installation of the oil strainer is the reverse order of removal Fill the oil tank with the recommended oil up to the proper level Bleed air from the oil pump and oil pipe Page 2 7 CAUTION a Connect the oil pipe securely e Check for leaks 1 OIL PUMP 2 OIL TUBE 1 OIL STRAINER ml SCREEN 2 01L TUBE 111 t fe CLIP 3 OIL STRAINER JOINT 4 OIL T...

Page 18: ...rew attaching the oil pump Disconnect the oil tube from the oil pump and pinch the end of the oil tube to prevent oil from flowing out Disconnect the oil pass tube from the inlet pipe NOTE Use care not to allow oil to flow out of the oil pass tube Remove the oil pump from the crankcase 2 5 1 OIL PUMP MOUNTING BOLT 2 SCREW 3 OIL PASS TUBE 4 OIL TUBE 1 OIL TUBE 2 TUBE CLIP 1 OIL PUMP 2 INLET PIPE 3 ...

Page 19: ...fore installation Make sure that the oil pump is inserted into the crankcase properlv 1 MATING FACE 1 01 L PUMP SET PLATE Secure the oil pump using the oil pump set plate I bolt and screw I NOTE Apply locking agent to the bolt and screw I threads __J Reconnect the oil pump control cable Reinstall the oil tube and oil pass tube Install the carburetor Page 4 9 NOTE Perform the following inspections ...

Page 20: ...eder bolt at the top of the oil pump Tighten the bleeder bolt when the oil is free of air bubbles 01L PASS TUBE NOTE Bleed air from the oil pass tube when the tube is disconnected or there is air in the oil tube and oil pump Made sure that there is fuel in the fuel tank 25 50 parts fuel to 1 part lubricant Start the engine and run it for about 10 minutes with the oil pump control lever in the full...

Page 21: ...age 4 10 Remove the rear suspension linkage mudguard Page 13 13 Disconnecto the oil tube at the oil pump and drain the oil Disconnect the oil level warning unit coupler Remove the oil tank attaching bolt and tank Install the oil tank in the reverse order of removal LUBRICATION 1 OIL TANK MOUNTING BOLT 2 OIL LEVEL WARNING UNIT COUPLER ...

Page 22: ...UTCH AND BRAKE 5 FRONT FORK LEVER PIVOTS A T F 2 3 THROTTLE GRIP I 11 FOOT PEG PIVOT 6 or CABLE LUBRICANT SPEEDOMETER AND I I I TACHOMETER CABLES STEERING HEAD BEARINGS 1 8 SPEEDOMETER DRIVE GEAR 9 WHEEL BEARINGS 12 BRAKE PEDAL PIVOT 10 MULTIPURPOSE GREASE MLG1 No 2 MoS2 Additive REAR SUSPENSION LINKAGE 2 9 ...

Page 23: ...R U NGI BR7ES ND W22ESR U Plug gap NGI BR9ES ND W2J ESR U NGI BR7ES ND W22ESR U NGK BABES ND W24ESR U Ignition timing F mark Retard start Full ratard Idle speed Air screw opening Cylinder compresssion Throttle grip free play Coolant capacity CHASSIS Rear brake pedal free play Clutch lever free paly Drive chain slack Tire Tire size Front Rear Cold tire pressure Front Rear Minimum tread depth Front ...

Page 24: ... the strainer cup After installing turn the fuel valve ON and check that there are no oil leaks THROTTLE OPERATION Check for smooth throttle grip full opening and automatic full closing in all steering positions Check the thrattle cables and replace if deteriorated kinked or damaged Lubricate the throttle cable Page 2 9 if throttle operation is not smooth Measure throttle grip free P lay at the th...

Page 25: ...he adjuster Tighten the lock nut Recheck throttle operation AIR CLEANER Remove the left side cover Remove the three screws attaching the air cleaner cover and cover Remove the element INSPECTION AND ADJUSTMENT 1 ADJUSTER 2 LOCK NUT 1 AIR CLEANER COVER 1 ELEMENT 3 3 ...

Page 26: ...S BR7 ES ND W27 ESR U W24 ESR U NGK BR9 ES BABES Disconnect the spark plug cap Clean any dirt from around the spark plug base Remove and discard the spark plug Measure the new spark plug gap using a wire type feeler gauge SPARK PLUG GAP 0 7 0 8 mm 0 028 0 031 in Adjust by bending the side electrode carefully With the plug washer attached thread the spark plug in by hand to prevent crossthreading T...

Page 27: ... pump control cable should be adjusted after the throttle grip free play has been adjusted Loosen the lock nut With the throttle fully open align the index mark on the pump body with the reference mark on the control lever by turning the adjusting nut Tighten the lock nut CAUTION The idex mark on the control lever must be in line with the reference mark on the pump body Failure to do so reduces th...

Page 28: ...y faulty parts On the Deluxe model remove the under cowl Page 14 3 Remove the left crankcase cover Connect a stroboscopic timing light to the high tension wire Start the engine and bring engine speed to 3 000 min 1 rpm Aim the time light at the timing mark The F mark should align with the index mark Bring engine speed to 9 000 min 1 rpm and check that the index mark is between the fulIretard marks...

Page 29: ...by Blown cylinder head gasket Worn piston rings Worn cylinder High compression can be caused by e Carbon deposits in combustion chamber or on piston head CLUTCH Inspect the clutch lever free play at the end of the lever FREE PLAY 10 20 mm 3 8 3 4 in Adjust free play by loosening the lock nut and turn ing the adjusting nut until the free play is 10 20 mm 3 8 3 4 in l 10 20 mm 3 8 3 4 in T INSPECTIO...

Page 30: ...ving the radiator cap or severe scalding may result COOLING SYSTEM HOSES Inspect the hoses for cracks or deterioration and replace if necessary Check the hose clamps and tighten if necessary RADIATOR CORE Check the air passages for clogging or damage Straighten bent fins Remove insects mud or any obstruction with compressed air or low water pressure Replace the radiator if the air flow is restrict...

Page 31: ...E FLUID LEVEL Check front brak fluid reservoir level If the level nears the lower level mark fill the reservoir with SAE J1703 or DOT 3 BRAKE FLUID to the upper level mark Check the entire system for leaks if the level is low CATUION Do not remove the cover until the hand leber has been turned so that the reservoir is level Avoid operating the brake lever with the cap removed Brake fluid will squi...

Page 32: ... aligns with the reference marl on full application of the rear brake Page 13 6 Adjust the brake Iight switch so that the brake Iight will light when the brake pedal is depressed and the brake begins engagement NOTE Do not turn the switch body The fron brake light switch does not require adjustment Adjust by turning the switch adjusting nut as shown 3 10 1 ADJUSTING NUT HONDA MBXSO MBX80 1 ARROW M...

Page 33: ...en the rear axle nut Tighten both adjusting nuts Be sure that the index mark aligns with the same graduation on the scale on both sides Tighten the rear axle nut TORQUE 55 70 N m 5 5 7 0 kg m 40 51 ft lb Retighten both adjusting nuts Check the rear brake pedal after the drive chain tension has been adjusted INSPECTION AND ADJUSTMENT 1 ADJUSTING NUT 2 GRADUATED SCALE 3 INDEX MARK 4 CHAIN ADJUSTER 5...

Page 34: ...sary CAUTION Never install a new drive chain on worn sprockets or i t worn chain on new sprockets Both chain and sprockets must be in good condition or the new replacement chain or sprockets willwear rapidly NOTE Commercial aerosol type drive chain lubri cants are recommended Lubricate the drive chain saturating each chain link joint Install the drive chain and master link Install the master link ...

Page 35: ... tread depth at the center of the tires Replace the tires if the tread depth reaches the folowing limit Minimum tread depth Front 0 8 mm 1 32 in Rear 0 8 mm 1 32 in Check that all chassis nuts and bolts are tightened to correct torque values Check all cotter pins and safety clips Remove the muffler Page 5 3 Remove the diffuser pipe attaching screw Remove the diffuser pipe from the muffler Clean th...

Page 36: ...4 0 HONDA MBXSO MBXSO 1 Align with frame pipe ...

Page 37: ...R REMOVAL THROTTLE VALVE DISASSEMBLY FLOAT FLOAT VALVE JET DISASSEMBLY JETS FLOAT VALVE FLOAT ASSEMBLY 4 2 4 2 4 3 4 4 4 5 4 6 FUEL SYSTEM FLOAT LEVEL ADJUSTMENT 4 7 THROTTLE VALVE CABLE 4 8 INSTALLATION CARBURETOR INSTALLATION 4 9 FUEL TANK 4 9 AIR CLEANER 4 10 4 1 ...

Page 38: ...ion 5 Air cleaner clogged Engine Idles roughly staiis or runs poorly 1 Idle speed incorrect 2 lgniton malfunction 3 Low compression 4 Rich mi ture 5 lean mixture 6 Air cleaner clogged 7 Air leaking into inlet pipe 8 Fuel contaminated 07401 0010000 MBX50 I MBX80 I SW B SA Free SW B Limited E G 16mm 0 63in 13mm 0 51in 18mm O 71in PF16A PF16E PF06D PF26D 125 60 130 210 210 210 37V 2nd groove 37F 2nd ...

Page 39: ...ube Disconnect the fuel line Disconnect the drain tube Loosen the tube band Remove the nuts attaching the carburetor to the engine inlet pipe Disconnect the air vent tube Remove the carburetor from the engine NOTE Keep dust and dirt from entering the carbu retor and cylinder 1 FUEL VALVE 2 FUEL TUBE 1 TUBE BAND FUEL SYSTEM 2 DRAIN TUBE 1 AIR VENT TUBE ...

Page 40: ...uretor top and pull out the throttle valve Disconnect the throttle cable from the throttle valve Remove the return spring carburetor top and sealing cap 4 4 HONDA MBX50 MBX80 1 CARBURETOR TOP 1 THROTTLE VALVE 1 SEALING CAP 2 CARBURETOR TOP 3 RETURN SPRING ...

Page 41: ...l the float pin off the chamber CAUTION Remove the floatpin in the arrow direction Remove the carburetor float and float valve FLOAT FLOAT VALVE INSPECTION Check the valve seat for wear or damage Check the float for deformation or presence of fuel 3 JET NEEDLE 4 THROTTLE VALVE 1 FLOAT FUEL SYSTEM 1 CABLECLIP NEEDLE CLIP Standard position 2nd groove 1 FLOAT PIN 2 VALVE SEAT CONTACTING FACE 4 5 ...

Page 42: ...choke starter valve Blow open all jets and body openings with corn pressed air CAUTiON Never use compressed air to clean the body when the float assembly is installed This could damage the floats Check each part for wear or damage Inspect the choke starter valve The knob should be held securely when pulled out fully HONDA MBXSO M SX80 1 STOPSCREW 2 MAIN JET I l 3 NEEDLE JET HOLDER 4 NEEDLE JET 0 r...

Page 43: ...and float pin CAUTION I Insert the float pin in the arrow direction Check the float for operation Install the float chamber FLOAT lEVEl ADJUSTMENT Measure the float level with the float tip just con tacting the float valve FLOAT LEVEL 13 5 mm 0 53 in 1 0 mm Replace the float assembly if not within specifica tion FUEL SYSTEM 1 SLOW JET 2 MAIN JET 3 STOP SCREW 4 AIR SCREW 1 FLOAT PIN 2 FLOAT VALVE 3...

Page 44: ... the carburetor body NOTE Align the groove in the valve with guide pin on the carburetor body Tighten the carburetor top CAUTION Hand tighten the carburetor top Do not use tools to forcefully tighten the top This could cause distortion and malfunction 4 8 1 CABLE CLIP 2 JET NEEDLE 3 THROTTLE VALVE 4 NEEDL CLIP Standard position 2nd groove HONDA MBXSO MBXSO 5 SEALING CAP 6 RETURN SPRING 1 THROTTLE ...

Page 45: ...ers Remove the fuel tank mounting bolt Turn the fuel cock to OFF and disconnect the fuel line Remove the fuel tank INSPECTI ON Check the vent hole of the filler cap for blockage FUEL STRAINER Keep gasoline away from flames or sparks Wipe up spilledgasoline at once Check that fuel is flowing out of the fuel valve freely If fuel flow is restricted clean the fuel strainer NOTE Do not overtighten the ...

Page 46: ...he air inlet tube from the case AIR CLEANER CASE INSTALLATION Clean the air cleaner element Page 3 3 Install the air cleaner case in the reverse order of removal NOTE Apply adhessive Cemedain No 540 or its equivalent to the air cleaner tubes if they are disconnected Align the air inlet tube with the frame tube when installing the air cleaner case 1 5 Apply adhessive 6 AlR CLEANER TUBE 4 10 HONDA M...

Page 47: ... g t o ENGINE REMOVAL INSTALLATION 5 1 DRIVE CHAIN MASTER LINI 2 RETAII IING CLIP Note the installation ...

Page 48: ...ENGINE REMOVAL INSTALLATION 5 1 SERVICE INFORMATION ENGINE REMOVAL ENGINE INSTALLATION 5 2 5 3 5 7 it HONDA MBX50 MBX80 ...

Page 49: ...ced with the engine installed in the frame Clutch Alternator Gearshift linkage Carburetor Kickstarter Coo ing system SPECIFICATIONS Engine dry weight Transmission oil capacity MBX50 Approximately 17 5 kg 38 6 lb MBX80 Approximately 18 9 kg 41 7 lb 0 9 lit 1 0 US qt 0 8 Imp qt at engine assembly 0 8 lit 0 8 US qt 0 7 Imp qt at change 5 2 ...

Page 50: ... Remove the two exhaus pipe flange nuts Remove the muffler mounting nut and remove the muffler Remove the seat and both side covers Turn the fuel valve OFF and disconnect the fuel tube at the fuel valve Remove the fuel tank mounting bolt and tank 5 3 1 MUFFLER HONDA MBXSO MBXSO 1 EXHAUST PIPE FLANGE NUTS 1 FUEL TANK MOUNTING BOLT ...

Page 51: ... coolant Disconnect the radiator hose at the cylinder head Remove the radiator Page 10 4 Remove the spark plug cap Disconnect the temperature sensor wire connector Disconnect the oil pump control cable Disconnect the oil tube at the oil pump Page 2 4 ENGINE REMOVAL INSTALLATION 2 DRAIN BOLT 1 SPARK PLUG CAP 2 RADIATOR HOSE 3 TEMPERATURES SENSOR CONNECTOR 1 OIL PUMP CONTROL CABLE ...

Page 52: ...n the air cleaner tube band Remove the two carburetor mounting nuts carbure tor and insulator Remove the four bolts attaching the left crankcase cover and cover 5 5 HONDA MBXSO MBX80 1 ALTERNATOR NEUTRAL SWITCH WIRE CONNECTORS 1 AIR CLEANER TUBE BAND 2 CARBURETOR INSULATOR 1 LEFT CRANKCASE COVER ...

Page 53: ...d carefully remove the drive chain master link retaining clip and remove the drive chain Remove the gearshift pedal pinch bolt and gearshift pedal Disconnect the clutch and techometer cables ENGINE REMOVAL INSTALLATION 1 MASTER LINK 2 RETAINING CLIP 1 GEARSHIFT PEDAL 1 CLUTCH CABLE 2 TACHOMETER CABLE 5 5 ...

Page 54: ...ill the cooling system with the recom mended coolant Page 10 3 0 Check the locations of the cables and pipes Page 1 7 e Bleed air from the oil pump Page 2 7 Adjust the oil pump control cable Page 3 5 Adjust the clutch lever free play Page 3 7 o Install the drive chain master link properly Page 3 12 Adjust the drive chain tension Page 3 11 REAR AXLE NUT TORQUE 55 65 N m 5 5 6 5 kg m 40 48 ft lb 5 7...

Page 55: ... HONDA MBX50 MBX80 CYLINDER HEAD CYLINDER PISTON 8 12 N m 0 8 1 2 kg m 6 9 ft lb I 6 6 0 ...

Page 56: ...CYLINDER HEAD CYLINDER PISTON SERVICE INFORMATION TROUBLESHOOTING CYLINDER HEAD CYLINDEA PISTON REED VALVE 6 1 HONDA MBX50 MBXSO 6 2 6 2 6 3 6 5 6 10 ...

Page 57: ...ion too low hard starting or poor performance at low speed 1 Blown cylinder head gasket 2 Loose spark plug 3 Worn stuck or broken piston rings 4 Worn or dmaged cylinder and piston 5 Faulty reed valve Compression too high overheating or knocking 1 Excessive carbon buildup in cylinder head or on piston top 18 22 N m 1 8 2 2 kg m 13 16ft lb 8 12 N m 0 8 1 2 kg m 6 9 ft lb STANDARD mm in 38 998 39 013...

Page 58: ...or cap or severe scalding may result Remove the coolant drain bolt and drain the coolant Disconnect the radiator hose from the cylinder head Remove the spark plug cap Disconnect the temperature sensor wire connector Remove the four flange nuts attaching the cylinder head to the cylinder 6 3 1 RADIATOR CAP HONDA Ml lXSO MBXSO 2 DRAIN BOLT 1 HIGH TENSION CORD 2 RADIATOR HOSE 3 TEMPERATURE SENSOR WIR...

Page 59: ... combustion chamber Clean the head gasket surface of any gasket mate rial NOTE Avoid damaging the gasket surfaces INSTALLATION Install the cylinder head using a new cylinder head gasket Install the four flange nuts and tighten to the specified torque in the sequence shown TORQUE 18 22 N m 1 8 2 2 kg m 13 16 ft lb Fill the cooling system with the recommended coolant Page 10 3 CYLINDER HEAD CYLINDER...

Page 60: ...s tube or locate the end of the tube lower than the oil pump Bleed air from the oil pass tube when it has been disconnected or the end has been located lower than the oil pump Remove the radiator Page 10 4 Disconnect the radiator hose from the cylinder Remove the cylinder CAUTION Do not pry strike the cylinder or cooling fins Place a clean shop towel into the crankcase to keep debris from falling ...

Page 61: ...clip fall into the crankcase Do not re use the piston pin clips PISTON RING EXPANDER REMOVAL Spread each piston ring and remove by lifting it up at a point just opposite the gap Remove the expander CYLINDER PISTON INSPECTION Check the cylinder and piston for wear or damage Clean carbon deposits from the exhaust port area CAUTION Do not damage the cylinder CYLINDER HEAD CYLINDER PISTON 1 PISTON 2 P...

Page 62: ...ton at a point 10 mm 3 8 in from the end of the skirt SERVICE LIMIT MBX50 38 920 mm 1 5323 in MBX80 49 420 mm 1 9457 in Calculated the piston to cylinder clearance SERVICE LIMIT 0 090 mm 0 0035 in Measure the 1 0 of the piston pin bore SERVICE LIMIT 12 030 mm 0 4736 in Measure the 0 0 of the piston pin SERVICE LIMIT 11 980 mm 0 4717 in Calculate the piston pin to piston clearance SERVICE UMIT 0 04...

Page 63: ...E Press each piston ring into place at several points to make sure that it is flush with the piston surface If not clean carbon deposits from the ring groove They should be free engough to be rotated in the ring lands CONNECTING ROD INSPECTION Install the bearing and piston pin in the connecting rod small end and check for excessive play Measure the connecting rod small end I D SERVICE LIMIT 17 03...

Page 64: ...o not replace one without replac ing another Install the connecting rod small end bearing piston and piston pin NOTE Install the piston with the IN marking facing the inlet side e Dip the small end bearing and piston pin in clean oil before installation Install new piston pin clips NOTE Do not let the clip fall into the crankcase Align each ring end gap with the dowel pin in the ring land 6 9 4 PI...

Page 65: ... 10 5 Fill the cooling system with the recommended coolant Page 10 3 Perform the following inspections and operation Cylinder compression Page 3 7 compression leaks Engine noise Secondary air leaks Air bleeding from oil pass tube Page 2 7 REMOVAL Remove the craburetor Page 4 9 Remove the intake pipe Page 6 5 NOTE Do not remove the oil pass tube or locate the end of the tube lower than the oil pump...

Page 66: ...ssemble or bend the reed stopper as this may cause improper engine perfor mance The reed valve must not be disas sembled If the tapper reed or seat is defec tive replace all as a unit INSTALLATION Installation of the reed valve is essentially the reverse order of removal CAUTION I Bleed air from the oil pass tube Page 2 7 After installation check for secondary air leaks 6 11 HONDA MBX50 MBX80 1 RE...

Page 67: ...LINKAGE 2 Thickness 0 5 mm 0 02 in 1 Thickness 1 0 mm 0 04 in Three plates and four discs 5 Apply locking agent 5 Apply locking agent 3 Align the balancer timing when installing the clutch outer 4 WATER PUMP SHAFT 45 55 N m 4 5 5 5 kg m 33 40 ft lb 7 0 ...

Page 68: ...ARTER GEARSHIFT LINKAGE SERVICE INFORMATION TROUBLJ SHOOTING RIGHT CRANKCASE COVER CLUTCH IDLER GEAR 7 1 7 2 7 2 7 3 7 5 HONDA MBX50 MBX80 CLUTCH INSTALLATION BALANCER TIMING 7 10 7 11 7 14 KICKSTARTER SHIFT LINKAGE ...

Page 69: ... STANDARD mm in SERVICE UMIT mm in Clutch spring free length preload Clutch disc thickness Clutch plate warpage Clutch outer I D Kickstarter spindle 0 0 Kickstarter pinion 1 0 Kickstarter idle gear Contershaft 0 0 Gear I D Balancer idle gear shaft O D TROUBLESHOOTING Clutch slips when accelerating 1 No free play 2 Discs worn 3 Springs weak Clutch operation feels rough 1 Outer drum slots rough Abno...

Page 70: ...h arm Disconnect the tachometer cable Disconnect the repiator hoses at the right crankcase cover Remove the bolts attaching the right crankcase cover and remove the right crankcase cover DISASSEMBLY Remove the clutch lifter rod then remove the clutch arm Check the 0 ring for damage fatigue or other faults Check the clutch arm for bending 7 3 1 CLUTCH CABLE 2 TACHOMETER CABLE KICKSTARTER PEDAL 4 HO...

Page 71: ...LLATION Install the clutch arm and clutch lifter rod InstalI the tachometer gear on the right crankcase cover Install the dowel pins and gasket on the cr ankcase CLUTCH KICKSTARTER Gl 8RSHIFT LINKAGE 3 TACHOMETER GEAR 1 CLUTCH ARM 1 OIL SEAL 2 WASHERS 2 TACHOMETER GEAR 1 GASKET 2 DOWEL PINS 7 4 ...

Page 72: ...r and clutch cables Connect the radiator hoses to the water pump Fill the transmission with recommended oil Page 2 3 Fill the cooling system with recommended cciolant Page 10 3 Adjust the clutch lever free play Page 3 7 CLUTCH IDLER GEAR CLUTCH REMOVAL Remove the right crankcase cover Page 7 3 Remove the clutch lifter plate and clutch springs by removing the bolts 7 5 1 KICKSTARTER PEDAL 2 RIGHT C...

Page 73: ...ION Measure each clutch spring free length SERVICE LIMIT 28 5 m_m 1 12 in CLUTCH DISC INSPECTION Replace the clutch discs if they show signs of scor ing or discoloration Measure each clutch disc thickness SERVICE LIMIT 2 50 mm 0 098 in CLUTCH KICKSTARTER GEARSHIFT LINKAGE 1 CLUTCH DISCS MBX80 4 discs 2 PRESSURE PLATE 3 CLUTCH OUTER CENTER 6 CLUTCH PLATES MBX80 3 plates 7 SPLINE WASHER 7 6 ...

Page 74: ...20 mm 0 008 in CLUTCH OUTER INSPECTION Check the slots in the outer drum for nicks cuts or indentations made by the friction discs Measure the clutch outer 1 0 SERVICE LIMIT 17 060 mm 0 6717 in BALANCER IDLER GEAR OIL PUMP DRIVEN GEAR REMOVAL Remove the clutch then remove the balncer idler gear and oil pump driven gear 7 7 HONDA MBXSO MBX80 ...

Page 75: ...ER GEAR INSPECTION Check the balancer idler gear for wear or damage Check the idler gear shaft for bending wear or damage Measure the balancer idler gear shaft O D at two places as shown SERVICE LIMIT 9 930 mm 0 3909 in Check the oil pump driven gear for wear or damage Check the oil pump driven gear shaft for cracks or other defects Replace the shaft and gear with new ones if cracked CLUTCH KICKST...

Page 76: ...engages the bal ancer gear PRIMARY DRIVE GEAR INSTALLATION Install the collar on the crankshaft then install the primary drive gear NOTE Align the punch mark on the end of the crankshaft with the punch mark on the gear InstalI the washer and 12 mm nut on the end of the crankshaft Hord the flywheel with the UNIVER SAL HOLDER and tighten the 12 mm nut to the specified otrque TORQUE 45 55 N m 4 5 5 5...

Page 77: ...gear is in line with the mating line on the shaft nstall the clutch outer without disturbing the setups in steps 1 and 2 Rotate the clutch outer right or left until the gear engages the sub gear then push it in the crankcase Make sure that the sub gear engages the clutch outer gear properly 1 CLUTCH KICKSTARTER GEARSHIFT LINKAGE 2 INDEX MARK 6 PRIMARY DRIVE GEAR 1 CLUTCH OUTER BALANCER IDLER GEAR ...

Page 78: ...mmended transmission oil Page 2 3 1 6 mm BOLT 3 CLUTCH SPRING 2 LIFTER PLATE 5 CLUTCH OUTER KICKSTARTER SPINDLE REMOVAL Remove the right crankcase cover Page 7 3 Remove the clutch assembly Page 7 5 NOTE It is not necessary to remove the clutch to remove the kickstarter spindle Remove the kick return spring from the ratchet guide plate then remove the kickstarter spindle 7 11 6 CLUTCH DISCS MBX80 4...

Page 79: ...ust washer INSPECTION Measure the kickstarter spindle O D SERVICE LIMIT 11 950 mm 0 4704 in Measure the kick pinion gear I D SERVICE LIMIT 12 070 mm 0 4752 in CLUTCH KICKSTARTER GEARSHIFT LINKAGE 1 15 mm THRUST WASHER 2 3 RETURN SPRING 4 COLLAR 5 SPRING 6 RATCHET 7 PINION GEAR 1 KICK STARTER IDLER GEAR 2 RATCHET GUIDE PLATE 1 KICK STARTER PINION GEAR 2 KICKSTARTER SPINDLE 7 12 ...

Page 80: ...h the two bolts Tighten to the specified torque TORQUE 8 12 N m 0 8 1 2 kg m 6 9 ft lb CAUTION Do not mix the 15 mm thrust washer 0 5 mm thick and kick spindle 15 mm thrust washer 1 0 mm thick Install the kickstarter in the reverse order of dis assembly CAUTION Slide the ratchet over the kickstarter spindle with the punch mark on the ratchet aligned with the spring hole in the spindle Do not confu...

Page 81: ...nstall the right crankcase cover Page 7 4 Check the operation of the kickstarter SHIFT LINKAGE REMOVAL Remove the clutch Page 7 5 Remove the kickstarter idler gear Page 7 11 Remove the bolt attaching the clutch stopper arfn and remove the stopper arm and spring CLUTCH KICKSTARTER GEARSHIFT LINKAGE 1 RATCHET GUIDE PLATE 2 DRIVE RATCHET 1 RATCHET GUIDE PLATE 2 KICKSTARTER RETURN SPRING 1 STOPPER ARM...

Page 82: ...withdraw the shift spindle INSPECTION Perform the following operations e Check the shift arm spring for weakness e Check the shift return spring for weakness e Check the stopper spring for weakness e Check the shift spindle for wear or bending 7 15 1 SHIFT ARM SPRING DRUM CAIVl PLATE 2 BOLT 3 SHIFT RETURN SPRING 2 SHIFT SPINDLE 4 STOPPER SPRING 0 ...

Page 83: ...he bolt threads and under sides of the bolt and install the plate with the bolt Tighten the bolt to the specified torque TORQUE 8 10 N m 0 8 1 2 kg m 6 9 ft lb Install the stopper arm and stopper spring in the crankcase a_11d_Aighten the attaching bolt to the specified torn_ue TORQUE 8 12 N m 0 8 1 2 kg m 6 9 ft lb Check the operation of the shift linkage With the balancer properly timed install t...

Page 84: ... 3 WOODRUFF KEY 8 0 HONDA MBXSO MBX80 1 Align the scribed 1 ineon the stator Vl ith the index mark on the crankcase 2 NEUTRAL SWITCH oj 50 60 N m 5 0 6 0 kg m 36 43 ft lb ...

Page 85: ... HONDA MBX50 MBX80 SERVICE INFORMATION ALTERNATOR REMOVAL ALTERNATOR INSTALLATION ALTERNATOR 8 1 8 2 8 4 8 1 ...

Page 86: ...erviced without removing it from the motorcycle Do not remove the pulse generator from the stator base For alternator inspection refer to Section 15 TOOLS Common Universal Holder Flywheel Puller TORQUE VALUE Alternator rotor nut 8 2 07725 0030000 07733 0010000 50 60 n m 5 0 6 0 kg m 36 43 ft lb ...

Page 87: ...e flange bolts and remove the left crank case cover Remove the 12 mm nut attaching the flywheel Remove the flywheel NOTE Keep the woodruff key in a parts rack so it is not Jost ALTERNATOR I LEFT CRANKCASE COVER 1 UNIVERSAL HOLDER 1 ROTOR PULLER 2 ALTERNATIOR ROTOR FLYWHEEL 8 3 ...

Page 88: ...e the netural switch Oil will flow out when the switch is removed Remove the alternator CATUION Do not separate the pulse generator from the stator base Keep the coils in a parts rack to prevent damaging the coil For alternator inspection refer to page 15 6 and 16 4 8 4 2 STATOR HONDA MBXSO MBX80 1 CONNECTORS 1 NEUTRAL SWITCH WIRE 3 NEUTRAL SWITCH ...

Page 89: ...al switch terminal to install the wire Install the woodruff key in the crankshaft l eyway then install the flywheel on the crankshaft NOTE e Check that there are no foreign materials inside the flywheel before installation e Clean the taper hole in the flywheel of burrs and other damage and repair if neces sary TORQUE 50 60 N m 5 0 6 0 kg m 36 43 ft lb ALTERNATOR 1 INDEX MARK 2 STATOR 3 ALIGNMENT ...

Page 90: ...he ignition timing Page 3 6 Install the left crankcase cover NOTE 1 Make sure that the alternator and neutral switch wires are not interfering with the flywheel 1 Do not pinch the wires between the left crankcase cover and case 8 6 HONDA MBXSO MBX 80 1 LEFT CRANKCASE COVER ...

Page 91: ... HONDA MBX50 MBX80 CRANKSHAFT TRANSMISSION M4 t M3 r2 9 9 0 ...

Page 92: ...SERVICE INFORMATION TROUBLESHOOTING CRANKCASE SEPARATION TRANSMISSION DISASSEMBLY CRANKSHAFT REMOVAL CRANKSHAFT INSTALLATION GRANSMISSION ASSEMBLY CRANKCASE ASSEMBLY 9 1 W HON DA MBX50 MBX80 9 2 9 3 9 4 9 4 9 8 9 11 9 12 9 13 ...

Page 93: ...end side clearance Connecting rod big end radial play Crankshaft runout at journals See section 2 See section 6 See section 7 See section 8 07965 1660100 07945 1660000 07936 1660000 07631 0010000 Commercially available 07746 1870100 07794 0010000 07746 0010100 07746 0010300 07746 0010400 07746 0040200 07746 0040400 07746 0040600 07746 0030100 07746 0030200 STANDARD mm in 10 00 10 018 0 3937 03944 ...

Page 94: ...worn 3 Transmission bearing worn Jumps out of gear 1 Gear dogs worn 2 Shih fork bent 3 Shih shaft bent 4 Shift drum stopper damaged 9 3 Hard shifting 1 Incorrect clutch adjustment 2 Shift forks bent 3 Shift shaft bent 4 Shift spindle pawl bent or damged 5 Shift drum cam slot damaged HONDA MBX50 MBX80 ...

Page 95: ...ight crankcase CAUTION I Do notpry between the right and left cases TRANSMISSION DISASSEMBLY GEARSHIFT FORK SHIFT DRUM Remove the shift fork shaft from the right crank case Remove the shift drum and shift forks CRANKSHAFT TRANSMISSION 1 DRIVE SPROCKET 1 LEFT CRANKCASE 2 SHIFT DRUM 2 RIGHT CRANKCASE 1 SHIFT FORK SHAFT 3 SHIFT FORKS 9 4 ...

Page 96: ...ss SERVICE LIMITS Claw thickness 4 50 mm 0 177 in I D 10 50 mm 0 396 in Check the shift fork shaft for wear damage or bending Measure the O D SERVICE LIMIT 9 95 mm 0 392 in Inspect the shift drum grooves and replace the drum if they are damged or show excessive wear Measure the shift drum 0 0 SERIVCE LIMITS 9 5 A 12 85 mm 0 506 in B 35 90 mm 1 413 in B W HONDA MBXSO MBX80 ...

Page 97: ...nt lubri cation Measure the I D of each gear and I D and O D of the C2 bushing SERVICE LIMITS M5 M6 gears 17 10 mm 0 673 in C1 gear 16 60 mm 0 654 in C2 gear 20 10 mm 0 791 in C3 gear 19 10 mm 0 752 in C4 gear 19 10 mm 0 752 in C2 bushingO D 19 90 mm 0 783 in I D 17 10 mm 0 673 in CRANKSHAFT TRANSMISSION 1 MAINSHAFT 2 COUNTERSHAFT 2 MAINSHAFT 1 COUNTERSHAFT C3 M5 M4 M3 rr M6 M2 3 C2 BUSHING 9 6 ...

Page 98: ...ht out from the right crank case BEARING REPLACEMENT Remove the balancer weight left bearing and main shaft left bearing from the left crankcase with the special tools as shown Remove the countershaft left bearing from the left crankcase Remove the mainshaft right bearing from the right crankcase 9 7 HONDA MBX50 MBX80 1 COUNTERSHAFT 2 MAINSHAFT 1 BALANCER WEIGHT 1 BALANCER WEIGHT BEARING 2 BEARING...

Page 99: ...x 47 mm Pilot 17 mm Mainshaftleft bearing Driver A Attachment 28 x 30 mm 07746 1870100 CRANKSHAFT REMOVAL Remove the crankshaft from the right crankcase Drive the crankshaft out of the right crankcase if it is difficult to remove by hands NOTE Use a plastic or brass hammer Screw a nut onto the crankshaft end to prevent damage Protect the crankcase mating surface by resting it on a wooden block CRA...

Page 100: ... feeler gauge SERVICE LIMIT 0 85 mm 0 033 in Measure the connecting rod big end radial clearance at two points in the X and Y directions SERVICE LIMIT 0 05 mm 0 002 in Set the crankshaft on a stand or V blocks and read runout using a dial gauge SERVICE LIMIT 0 10 mm 0 004 in 9 9 HONDA MBX50 MBX80 8 X 8 ...

Page 101: ...as excessive play CRANKSHAFT BEARING REPLACEMENT Remove the left crankshaft bearing with the UNI VERSAL BEARING PULLER Remove the oil seal from the right crankcase Remove the right crankshaft bearing AXIAL CRANKSHAFT TRANSMISSION rPLAY l RADIAL 1 UNIVERSAL BEARING PULLER 07631 0010000 2 LEFT CRANKSHAFT BEARING 1 OIL SEAL 2 RIGHT CRANKSHAFT BEARING 9 10 ...

Page 102: ...ION Hold the left crank weight when driving the bearing CRANKSHAFT INSTALLATION Clean the crankcase mating surfaces before assembl ing and check for wear or damage NOTE If there is minor roughness or irregularities on the crankcase mating surfaces dress them with an oil stone After cleaning lubricate the crankshaft bearings and other contacting surfaces with clean 2 _troke oil 9 11 1 DRIVER A HOND...

Page 103: ...journal and crankpin bearings o Coat the sealing Iips of each oil seal with grease TRANSMISSION ASSEMBLY Drive the balancer weight in the right crankcase while rotating the driver tool to prevent tilting the balancer bearing Apply oil to the gears before installing the mainshaft and countershaft Make sure the gears rotate freely CRANl SHAFT TRANSMISSION 2 BALANCER WEIGHT 1 CRANKSHAFT 1 BALANCER WE...

Page 104: ...ift froks and shift fork shaft Position the shift drum in neutral as shown Make sure that the mainshaft and countershaft rotate freely CRANKCASE ASSEMBLY Install a new gasket and two dowel pins 9 13 1 MAINSHAFT r f HONDA MBX50 MBX80 2 COUNTERSHAFT 1 SHIFT FORK SHAFT 2 SHIFT DRUM 2 GASKET 3 SHIFT FORKS DOWEL PINS ...

Page 105: ...BX80 Place the left crankcase onto the right crankcase Tighten the crankcase bolts in a crisscross pattern Install the drive sprocket CRAN KSHAFT TRANSMISSION 1 LEFT CRANKCASE 2 RIGHT CRANKCASE 3 DRIVE SPROCKET 9 14 ...

Page 106: ...10 0 8 12 N m 6_9 ft lb 0 8 1 2 kg m HONDA MBXSO MBX80 UMP SHAFT BUSHING 1 WATER P ...

Page 107: ... HONDA MBX50 MBX80 SERVICE INFORMATION TROUBLESHOOTING RADIATOR COOLANT RADIATOR WATER PUMP THERMOSTAT TEMPERATURE SENSOR COOLING SYSTEM 10 2 10 2 10 3 10 4 10 6 10 9 10 1 ...

Page 108: ...ES Right crankcase cover bolt TROUBLESHOOTING Engine Temperature Too High 1 Thermostat stuck closed 2 Faulty radiator cap 3 Insufficient coolant 07936 1660000 07954 4150400 07946 1870100 07749 0010000 07746 0040200 STANDARD mm in I 75 105 kPa 0 75 1 05 kg cm2 10 7 14 9 psi SERVICE LIMIT mm in Use only a high quality ethylene glycol based anti freeze containing corro sion protection inhibitors spec...

Page 109: ...en install the drain bolt and reserve tank Fill the system with the recommended coolant up Page 9 2 to the radiator filler neck Install the radiator cap Fill the reserve tank with the coolnantup to the F mark CAPACITY RADIATOR AND ENGINE 520 cm3 31 7 cu in RESERVE TANK 150 cm3 9 2 cu in Bleed air from the radiator Start the engine and n m until there are no air bubbles in the coolant and the level...

Page 110: ...oolant drain bolt and rain the coolant Disconnect the radiator hoses and overflow tube at the radiator Remove the screw attaching the radiator cowl and cowl Remove the radiator mounting bolts and radiator NOTE Take care not to damage the radiator fins 10 4 1 FUEL TANK HONDA MBXSO MBX80 1 COOLANT DRAIN BOLT 1 OVERFLOW TUBE RADIATOR 3 RADIATOR COWL 4 RADIATOR FINS ...

Page 111: ...t does not hold pressure or if relief pressure is too high or too low It must hold specified pressure for at least six seconds NOTE Before installing the cap on the tester water to sealing surfaces RADIATOR CAP REUFT PRESSURE 0 9 0 15 kg cm2 12 8 2 1 psi INSTALLATION Install the radiator in the reverse order of re movl Fill the cooling system with the recommended coolant Page 10 3 After installati...

Page 112: ...e the cap nut copper washer impeller and plain washer from the water pump shaft Disconnect the r adiator hoses from the water pump Remove the right crankcase cover Page 7 3 Remove the water pump shaft from the right crankcase cover 10 6 1 1 WATER PUMP COVER 1 IMPELLER HONDA MBX50 MBX80 2 RADIATOR HOSES 1 WATER PUMP SHAFT ...

Page 113: ...ter pump shaft for bent or other damage Measure the shaft O D SERVICE LIMIT 6 90 mm 0 272 in BEARING MECHANICAL SEAL REPLACEMENT Remove the water pump shaft bearing with the special tool Remove the oil seal and mechanical seal from the right crankcase cover COOLING SYSTEM 1 IMPELLER 2 SEALING PLATE 3 MECHANICAL SEAL 1 BEARING REMOVER SET 12 mm 07936 1660000 2 WATER PUMP SHAFT BEARING 10 7 ...

Page 114: ...eplace the imeller seal plate with a new one INSTALLATION Install the water pump shaft in the right crankcase cover Install the right crankcase cover Page 7 4 Install the plain washer and imeller over the pump shaft Install the copper washer and cap nut and tighten the cap nut Connect the radiator hoses to the water pump Install the two dowel pins and new gasket 10 8 1 DRIVER A HONDA MBX50 MBX80 3...

Page 115: ... thermostat Remove the temperature sensor from the cylinder head TEMPRETURE SENSOR INSPECTION Suspend the temperature sensor in heated water to check its resistance Do not let the temperature sensor touch the pan or false readings will result Replace the temperature sensor if its resistance does not meet the specifications TEMPERATURE SENSOR RESISTANCE Temperature C F 50 122 80 176 100 212 120 250...

Page 116: ... it responds at temperatures other than those specified TECHNICAL DATA Start to open 60 64 C 140 147 F Valve lift 3 mm 0 12 in mimimum when heated to 70 C 158 F for five minutes INSTALLATION Install the temperature sensor and thermostat in the reverse order of removal NOTE Apply liquid sealant to the threads of the temperature sensor before installation Fill the cooling system with the recommended...

Page 117: ...HONDA MIX50 MBX80 24 30 N m 2 4 3 0 kg m 17 22 ft lb FRONT WHEEL SUSPENSION 11 24 30 N m 2 4 3 0 kg m 17 22 ft lb 11 0 ...

Page 118: ...FRONT WHEEL SUSPENSION 11 1 SERVICE INFORMATION GROUBLESHOOTING HEADLIGHT INSTRUMENTS HEADLEBAR FRONT WHEEL FRONT FORK STEERING STEM r i f HONDA MBX50 MBX80 11 2 11 3 11 4 11 5 11 7 11 9 11 13 11 19 ...

Page 119: ...ont axle nut Front brake caliper bracket SPECIFICATIONS Front fork oiI capacity ITEM Front axle shaft ben Front wheel rim runout Rdial Axial Front shock absorber spring free length Front fork pipe bend 07917 3230000 07944 1150001 07747 0010700 07914 3230001 07749 0010000 07746 0010100 07746 0040200 07747 0010100 07702 0010000 8 12 N m 0 8 1 2 kg m 6 9 ft lb 60 90 N m 6 0 9 0 kg m 43 65 ft lb 40 50...

Page 120: ...ht and left shock absorbers 2 Bent fron forks 3 Bent front axle wheel installed incorrectly Front wheel wobbling 1 Axle not tightened properly 2 Distorted rim 3 Worn front wheel bearing 4 Distorted spoke 5 Faulty tire Soft suspension 1 Weak fork spring 2 Insufficient fluid in front forks 11 3 Hard suspension HONDA MBX50 MBX80 1 Incorrect fluid weight in front forks Front suspension noise 1 Slider ...

Page 121: ...4 2 On the Standard model remove the four headlight case mounting bolts and headlight case Remove the headlight mounting bolts and headlight Disconnect the headlight coupler and position Iight connectors FRONT WHEEL SUSPENSION 1 HEADLIGHT BULB SOCKET 2 POSITION LIGHT BULB SOCKET 11 4 ...

Page 122: ...D METER BULB RE PLACEMENT Remove the headlight REMOVAL INSTALLATION Remove the headlight Page 11 4 Disconnect the instrument wire coupler Remove the instrument mounting nuts and remove the instruments Install the instruments in the reverse order of removal 11 5 1 Align HONDA MBX50 MBX80 1 BULB HOLDERS 1 TACHOMETER CABLE 2 SPEEDOMETER CABLE ...

Page 123: ...r screws Remove the four instrument lower cover scrws and separate the instruments Remove the screws attaching each instrument and remove the tachometer speedometer and tempera ture gauge FRONT WHEEL SUSPENSION 3 TEMPERATURE 1 TACHOMETER 2 SPEEDOMETER GAUGE 11 6 ...

Page 124: ...e headlight Page 11 4 Disconnect the handlebar switch wires Remove the left handlebar switch Disconnect the clutch cable Remove the brake master cylinder Remove the throttle grip Remove the handlebar upper holders and hand lebar 11 7 HONDA MBX50 MBXSO ...

Page 125: ...hten the upper bolt first then the lower TORQUE 10 14 N m 1 0 1 4 kg m 7 9 ft lb Apply grease to the throttle grip sliding surface Align the locating pin on the throttle grip housing with the hole in the handlebar and install the throttle grip Connect the clutch cable Align the locating pin on the left handlebar switch with the hole in the handlebar and install the switch Tighten the upper nut fir...

Page 126: ... the axle shaft and front wheel NOTE Do not operate the front brake lever after removing the front wheel To do so will cause difficulty in fitting the brake disc between the brake pads AXLE INSPECTION Set the axle in V blocks rotate and measure the runout Actual runout is 1 2 of the total indicator reading SERVICE LIMIT 0 20 mm 0 008 in 11 9 HONDA MBXSO MBXSO 1 AXLE NUT 1 SPEEDOMETER CABLE ...

Page 127: ...in a truing stand Spin the wheel by hand and read the rim runout using a dial indicator gauge SERVICE LIMIT Radial 2 0 mm 0 08 in Axial 2 0 mm 0 08 in NOTE The COMSTAR TM WHEEL cannot be repaired and must be replaced with a new one if the service limits are exceeded DISASSSMBLY Remove the dust steal bearing and distance collar NOTE Do not forget to install the rim band when replacing the tire or t...

Page 128: ...and distance collar in the right side of the wheel hub Wipe off the excess grease Grease on the disc will cause reduced braking efficiency and may lead to an accident Install the speedometer gearbox retainer aligning the tabs with the grooves in the hub Apply grease to the inside of the dust seal and install Apply grease to the speedometer gearoox and hub retainer Install the speedometer gearbox a...

Page 129: ...er gearbox as shown Connect the speedometer cable to the speedo meter gearbox Install the axle nut and tighten to the specified torque TORQUE 55 70 N m 5 5 7 0 kg m 40 51 ft lb NOTE P ump the brake lever after the front wheel is installed to ensure full braking efficiency 1 SPEEDOMETER GEARBOX FRONT WHEEL SUSPENSION 1 AXLE NUT 2 SPEEDOMETER CABLE 11 12 ...

Page 130: ...hose unless it is absolutely necessary If the hose is loosened or disconnected the brake system must be bled Loosen the handlebar upper holder bolts Loosen the fork bolts and remove them by shift ing the handlebar right and left Loosen the fork pinch bolts Remove the front forks 11 13 HONDA MBXSO MBXSO 1 BRAKE CALIPER 1 UPPER HOLDER BOLTS 2 FORI BOLTS ...

Page 131: ...t is under spring pressure Cover the inner bolt and wrench during removal to prevent injury caused by the bolt wrench or springflying upwards Drain the ATF Automatic Transmission Fluid from the fork by pumping it up and down slowly FORK SPRING INSPECTION Measure the fork spring free length SERVICE LIMITS 482 5 mm 19 00 in FRONT WHEEL SUSPENSION 1 FORK INNER BOLT 11 14 ...

Page 132: ...1 2 of the total indicator reading to determine the actual wear SERVICE LIMIT 0 20 mm 0 008 in Remove the dust seal Remove the set ring with the snap ring pliers Remove the oil seal using the dull end of a screw driver as shown NOTE Avoid damaging the inner and outer surfaces of the fork slider when removing the set ring and oil seal 11 15 1 6 mm HEX WRENCH 07917 3230000 2 SNAP RING PLIERS HONDA M...

Page 133: ...Y NOTE Wash all removed parts in solvent and wipe them off thoroughly before assembly 1 FORK BOLT a 2 tj FORK 3 1NNER BOLT a 4 PISTON RING I 4 5 PISTON f ifi 6 JI REBOUND SPRING rJ ___ 8 OIL LOCK PIECE 1 FRONT WHEEL SUSPENSION r 2 PISTON I 9 DUST 10 SEAL SET RING _ 11 12 OIL SEAL BACK UP _ RING I FORK TUBE 11 16 ...

Page 134: ... Install the oil seal into the top of the fork slider NOTE Apply ATF to the oil seal and drive it in with the fork seal driver The oil seal is seated when the groove in the slider is seen at top of the seal Install the set ring and dust seal Fill the forks with the specified amount of ATF SPECIFIED FLUID ATF CAPACITIES 149 5 154 5 cm2 5 3 5 5 oz Install the fork spring NOTE InstalI the spring with...

Page 135: ...ng surface INSTALLATION Install the front forks Install and torque the fork bolts TORQUE 40 50 N m 4 0 5 0 kg m 29 36 ft lb Tighten the fork pinch bolts TORQUE 24 30 N m 2 4 3 0 kg m 17 22 ft lb Install the handlebar upper holders Page 11 8 lnstall the fronwheel Page 11 12 Install the brake caliper Page 12 9 FRONT WHEEL SUSPENSION 1 FORK INNER BOLT 11 18 ...

Page 136: ...ont forks Page 11 13 Remove the fork bridge Remove the bearing adjustment nut Remove the steering stem top cone race steel balls and bottom cone race Remove the ball races with the special tool NOTE I If the motorcycle has been involved in an accident examine the area around the steer ing head for cracks 11 19 2 STEM NUT 1 BEARING ADJUSTMENT NUT 2 PIN SPANNER HONDA MBX50 MBXSO 1 HEADLIGHT BRACKET ...

Page 137: ...e ball race steel balls and cone race Install the steering stem Install the bearing adjustment nut in the frame neck and tighten it until snug against the top cone race then back it out 1 8 turn Check that the stem rotates freely FRONT WHEEL SUSPENSION 6 7 8 9 BEARING ADJUSTMENT NUT TOP CONE RACE STEEL BALLS 21 TOP BALL RACE 10 BOTTOM BALL RACE 1 BALL RACE REMOVER 07944 1150001 1 BEARING ADJUSTMEN...

Page 138: ...ENSION Install the top bridge Installthe fron forks Page 11 18 Tighten the stem nut TORQUE 60 90 N m 6 0 9 0 kg m 43 65 ft lb Install the removed parts in the reverse order of removal 11 21 HONDA MBXSO MBX80 1 STEM NUT ...

Page 139: ... HONDA MBX50 MBX80 HYDRAULIC BRAKE 12 10 14 N m 1 0 1 4 kg m 7 10 ft lb 15 20 N m 1 5 2 0 kg m 11 14 ft lb 25 35 N m 2 5 3 5kg m 18 25 ft lb 24 30 N m 2 4 3 0 kg m 17 22 ft lb 12 0 ...

Page 140: ...HYDRAU UC BRAKE SERVICE INFORMATION GROUBLESHOOTING BRAKE FLUID AIR BLEEDING BRAKE PAD DISC BRAKE CALIPER BRAKE MASTER CYLINDER 12 1 HONDA MBXSO MBX80 12 2 12 2 12 3 12 4 12 6 12 9 ...

Page 141: ... D Master piston 0 D Caliper cylinder I D Caliper piston O D TROUBLESHOOTING Brake lever soft or spongy 1 Air bubbles in hydraulic system 2 Low fluid level 3 Hydraulic system leaking Brake lever too hard 1 Sticking piston s 2 Clogged liydraulic system 3 Pads glazed or worn excessively 07914 3230001 10 14 N m 1 0 1 4 kg m 7 10 ft lb 25 35 N m 2 5 3 5 kg m 18 25 ft lb 4 7 N m 0 4 0 7 kg m 2 9 5 1 ft...

Page 142: ...ed all the way back to the handlebar grip turn the bleeder valve about 1 2 rotation out then retighten NOTE Do not release the brake lever until the bleeder valve has been closed Release the brake lever gradually and wait several seconds after it reaches the end ot its travel Repeat the above steps until there are no air bubbles in the fluid flowing out of the bleeder valve NOTE Keep the reservoir...

Page 143: ...EPLACEMENT NOTE Do not disconnect the brake hose when re placing the brake pads Remove the pin bolt caps and loosen the pin bolts Remove the caliper bracket bolts and remove the caliper from the fork leg Push the pistons all the way in to allow installation of new brake pads Remove the two pin bolts then the brake pads HYDRAULIC BRAKE 1 GROOVE 2 GROOVE 3 BRAKE PADS 1 PIN BOLTS 12 4 ...

Page 144: ...rake pads Assemble the caliper bracket and caliper and install the caliper on the fork leg TORQUE 24 30 N m 2 4 3 0 kg m 17 22 ft lb Tighten the pin bolts to the specified torque and bend the tabs of the lock washer against the side of each bolt TORQUE 15 20 N m 1 5 2 0 kg m 11 14 ft lb Install the pin bolt caps BRAKE DISC INSPECTION Measure the brake disc thickness SERVICE LIMIT 3 0 mm 0 12 in Me...

Page 145: ...an oil pan under the caliper to receive brake fluid drained Avoid spilling brake fluid on painted surfaces plastic lenses or rubber parts Disconnect the brake hose from the caliper If the piston is seized in the caliper observe the following steps Place a shop towel or rag over the pistons to prevent the pistons and brake fluid from coming out and apply a small amount of air pressure to the fluid ...

Page 146: ...he piston and dust seals with new ones INSPECTION Check the caliper cylinders for scoring scratches or other damage Measure the caliper cylinder I D SERVICE LIMIT 25 450 mm 1 0020 in Check the pistons for scoring scratches or other defects Measure the caliper piston 0 D SERVICE LIMIT 25 300 mm 0 9961 12 7 1 PISTON SEALS 2 3 DUST SEALS HONDA MBX50 MBX80 4 PIN BOOT ...

Page 147: ... with the end 3 5 mm 1 8 1 5 in projecting above the caliper Wipe excess brake fluid off the caliper with a clean cloth Lubricate the inside of the pin boots with silicone grease and install them in the caliper Install the pad spring and pads with the pin bolts NOTE If the brake pad is dirty clean with sand paper Loosely tighten the pin bolts Make sure that the pin bolts are inserted through the h...

Page 148: ...0 kg m 11 14 ft lb After the front brake has been installed bleed air from the system Page 12 3 BRAKE MASTER CYLINDER REMOVAL Drain brake fluid from the bleeder valve by operat ing the brake lever Remove the brake lever front stoplight switch rear view mirror and brake hose Remove the master cylinder from the handlebar DISASSEMBLY Remove the reservoir cap and diaphragm Remove the boot Remove the s...

Page 149: ...Check the master cylinder for score marks scratches or other defects Measure the master cylinder I D SERVICE LIMIT 12 755 mm 0 5022 in Check the master piston for score marks scratches or other damage Measure the master piston O D SERVICE LIMIT 12 640 mm 0 4976 in 1 SPRING 3 SNAP RING 4 MASTER PISTON HYDRAU LIC BR_AKE 2 DIAPHRAGM 12 10 ...

Page 150: ...t the snap ring is seated in the groove properly Install the front stoplight switch INSTALLATION Install the master cylinder on the handlebar Page 11 8 TORQUE 10 14 N m 1 0 1 4 kg m 7 10 ft lb Install the brake hose and seal washer TORQUE 25 35 N m 2 5 3 5 kg m 18 25 ft lb After the front brake has been installed bleed air from the brake hydraulic system Page 12 3 12 11 1 SILICONE 2 HONDA MBXSO MB...

Page 151: ...80 18 25 N m 1 8 2 5 kg m 13 18 ft lb REAR WHEEL BRAKE SUSPENSION 13 27 33 N m 2 7 3 3 kg m 20 24 ft lb 27 33 N m 2 7 3 3 kg m 20 24 ft lb I 70 85 N m 7 0 8 5 kg m 51 62 ft lb 40 50 N m 4 0 5 0 kg m 9 36 ft lb 13 0 IJ ...

Page 152: ...DA MBX50 MBX80 SERVICE INFORMATION 13 2 TROUBLESHOOTING 13 2 REAR WHEEL 13 3 REAR BRAKE 13 6 REAR SHOCK ABSORBER 13 9 REAR SHOCK ABSORBER LINKAGE 13 11 L _ _ _ sw__ 1 N _ G _ A _ R _M _______________ _ ____ 1 _ 3 __ 1 _ 3 ____J 13 1 ...

Page 153: ... Loose wheel bearing 3 Distorted spoke 4 Faulty tire 5 Loose axle 6 Worn swingarm bushing 7 Loose swingarm pivot bolt Soft suspension 1 Weak spring 2 Shock absorbers fluid leaks Hard suspension 1 Bent shock absorber 07967 GE20000 07959 3290001 07746 0010200 07749 0010000 07746 0040200 40 50 N m 4 0 5 0 kg m 29 36 ft lb 18 25 N m 1 8 2 5 kg m 13 18 ft lb 55 70 N m 5 5 7 0 kg m 40 51 ft lb 8 12 N m ...

Page 154: ...Set the axle in V blocks and read the axle bend The actual axle bend is 1 2 of the total indicator reading SERVICE LIMITE 0 20 mm 0 008 in REAR WHEEL BEARING PLAY INSPEC TION Check the wheel bearing play by rotating the wheel by hand Replace the bearings with new ones if they are noisy or have excessive play SERVICE LIMIT 0 027 mm 0 0010 in 13 3 1 CHAIN ADJUSTING NUT HONDA MBX50 MBXSO 2 AXLE NUT 3...

Page 155: ...08 in NOTE I Do not attempt to repair the spokes FINAL DRIVEN SPROCKET INSPECTION Check the final driven sprocket for worn or dam aged gear teeth NOTE The drive chain and drive sprocket must also be inspected if the driven sprocket is worn REAR WHEEL DISASSEMBLY Remove the dust seal bearings and distance collar NOTE Do not forget to install the rim band when the tire and tube are replaced REAR WHE...

Page 156: ...the bearings with the sealed end facing outside FINAL DRIVEN SPROCKET INSTALLA TION Install the final driven sprocket with the protector ring end outside TORQUE 40 50 N m 4 0 5 0 kg m 29 36 ft lb REAR WHEEL INSTALLATION Install the rear wheel and axle shaft Install the driven chain CAUTION Note the direction of the drive chain master link retaining clip 13 5 HONDA MBX50 MBX80 1 DRIVER A 2 ATTACHME...

Page 157: ...ligned with the same scale number on both sides Torque the axle nut TORQUE 55 70 N m 5 5 7 0 kg m 40 51 ft lb Lubricate the drive chain Page 3 12 REAR BRAKE REAR BRAKE LINING THICKNESS Measure the brake lining thickness SERVICE LIMIT 2 0 mm 0 08 in REAR BRAKE DRUM INSPECTION Measure the rear brake drum I D SERVICE LIMIT 111 0 mm 4 37 in 1 CHAIN ADJUSTER REAR WHEEL BRAKE SUSPENSION 2 GRADUATED SCAL...

Page 158: ...L ASSEMBLY Install the felt ring and wear indicator plate NOTE Align the flat on the cam with the flat on the wear indicator plate InstalI the brake arm NOTE I Align the punch mark on the brake cam with the punch mark on the brake arm Tighten the brake arm bolt to the specified torque TORQUE 8 12 N m 0 8 1 2 kg m 6 9 ft lb Install the brake panel on the rear wheel 13 7 1 I I 1 2HONDA MBXSO MBX80 4...

Page 159: ...ove the cotter pin plain washer then remove the brake pedal Assembly of the brake pedal is essentially the reverse order of removal CAUTION Before installing the brakepedal apply grease to the slidingsurface Adjust the brake pedal free play Page 3 10 REAR WHEEL BRAKE SUSPENSION 1 BRAKE ARM 3 ADJU STING NUT 1 RETURN SPRING 2 BRAKE ROD 13 8 ...

Page 160: ...e DISASSEMBLY Install the special tool over the shock absorber spring as shown and tighten the nuts securely Place the shcok absorber in a press and compress the shock absorber spring Pull the damper rod up and remove the upper spring seat Release the press and remove the special tool and spring from the shock absorber 13 9 1 UPPER MOUNTING BOLT HONDA MBXSO MBXSO 2 LOWER MOUNTING BOLT 1 SHOCK ABSq...

Page 161: ...spring and tighten the tool nuts securely Compress the spring with the press pull the damper rod up and place the upper spring seat on the spring Release the press while aligning the spring seat and upper joint Remove the special tool from the shock absorber REAR WHEEL BRAKE SUSPENSION 1 REAR DAMPER ___ 1 FREE LENGTH i 1 SPRING SEAT 2 UPPER JOINT 3 REAR SHOCK ABSORBER COMPRESSOR ATTACHMENT 07967 G...

Page 162: ...r mount with the frame while moving the rear wheel up and down and install the upper monting bolt TORQUE 27 33 N m 2 7 3 3 kg m 20 24 ft lb REAR SHOCK ABSORBER UNKAGE REMOVAL Remove the air cleaner case Page 4 10 Remove the drive chain cover 13 11 HONDA MBXSO MBXSO 1 UPPER MOUNTING BOLT 2 LOWER MOUNTING BOLT 1 AIR CLEANER CASE 1 CHAIN COVER ...

Page 163: ...ear shock absorber lingage pivot bolts and nuts and remove the linkage Check the linkage bushings and collar for wear or damge INSTALLATION Apply paste grease containing more than 45 of molyodenum to each bushings and install the linkage I REAR WHEEL BRAKE SUSPENSION 27 33 N m 2 7 3 3 kg m 20 24 ft lb 13 12 ...

Page 164: ...for cracks or damage Check the bushings for damage or other defects Check the chain slider for wear or damage INSTALLATION Install the torque link and chain slider on the swingarm Install the swingarm TORQUE 70 85 N m 7 0 8 5 kg m 51 62 ft lb Install and torque the swingarm to shock linkage bolt TORQUE 40 50 N m 4 0 5 0 kg m 29 36 ft lb Install the shock link mud guard Install the rear wheel Page ...

Page 165: ...14 0 ...

Page 166: ...FAIRING UNDER COWL 14 1 FAIRING UNDER COWL HONDA MBX50 MBX80 14 2 14 3 ...

Page 167: ...move the three fairing mounting screws and the fairing Remove the four bolts attaching the fairing bracket and bracket Install the fairing in the reverse order of removal FAIRING UNDER COWL 1 FAIRING 2 SCREWS 1 FAIRING BRACKET 14 2 ...

Page 168: ... four screws mounting the under cowl and the under cowl Remove the bolts attaching the under cowl brackets and brackets Install the under cowl in the reverse order of re moval 14 3 1 SCREWS HONDA MBXSO MBX80 2 UNDER COWL 1 UNDER COWL BRACKETS ...

Page 169: ... g M O BATTERY CHARGINGSYSTEM 15 3 BATTERY 1 RESISTOR I 4 ALTERNATOR 15 0 ...

Page 170: ...BATTERY CHARGING SYSTEM 15 1 SERVICE INFORMATION TROUBLESHOOTING BATTERY CHARGING SYSTEM HONDA MBX50 MBXSO 15 2 15 2 15 3 15 5 ...

Page 171: ... speed Capacity Lighting switch OFF Lighting switch ON Regulator TROUBLESHOOTING No power key turned on 1 Dead battery Low fluid level Low specific gravity 2 Disconnected battery cable 3 Fuse burned out 4 Faulty ignition switch Low power key turned on 1 Weak battery Low fluid level Low specific gravity Charging system failure 2 Loose battery connection 12V 3AH 1 280 20 C 68 F 0 3 amperes maximum 2...

Page 172: ...th the tem perature as shown in the accompanying table Replace the battery if sulfation is evident or if the space below the cell plates is filled with sediment WARNING The battery contains sulfun c acid Avoid contact with skin eyes or clothing Antidote Flush with water and get prompt medical attention 15 3 HONDA MBXSO MBXSO 1 NEGATIVE WIRE 1 HYDROMETER 2 POSTIVE WIRE 3 BATTERY HOLDER 2 ELECTROLYT...

Page 173: ...nd sparks away from a charg ing battery Turn power ON OFF at the charger not at the battery terminals Discontinue charging if the electrolyte temperature exceeds 45 C 113 F CAUTION Quick charging should only be done in an emergency slow charging is preferred CAUTION Route the hreatlzer tuhc as shown m1 the hatter_ caution label 0 0 1 a N BATTERY CHARGING SYSTEM 1 CHARGING TIME vs SPECIFIC GRAVITY ...

Page 174: ...good condition and fully charged before performing this test 1 VOLTMETER 2 AMMETER Warm up the engine Remove the frame right side cover Disconnect the black wire at the regulator rectifier coupler Connect an ammeter and voltmeter as shown Start the engine MODEL LIGHTING CHARGEING RPM SWITCH MBX5u OFF 2 000 min 1 rpm max 14 2V ON 2 000 min 1 rpm max 14 2V MBX80 OFF 2 000 min 1 rpm max 14 2V 4 00 mi...

Page 175: ...terminals Replace the regulator rectifier with a new one if the readings do not fall within the limits shown in the table NOTE The regulator rectifier is fully transistoriz ed For accurate testing it is necessary to use a specified electric tester Use of an im proper tester or measurement in improper range may give a false reading Use SANWA ELECTRIC TESTER P N 07308 0020000 or KOWA ELECTRIC TESTER...

Page 176: ...RGING SYSTEM RESISTOR INSPECTION Remove the fuel tank Disconnect the resistor connectors Measure the resistance between the connectors Pink Green 4 ohms Green White Green 6 7 ohms 15 7 1 RESISTOR HONDA MBX50 MBX80 ...

Page 177: ...ON COIL 3 CDI UNIT 4 ALTERNATOR 7 IGNITION SWITCH ON OFF 1 4 ALTERNATOR 1 2 IGNITION COIL 8 DIODE _ Bk R IM t 1 iBk Y 5 f D 10 IGNITION 1 EXCITER COIL 8 Y CONDENSER 6 SCR I PULSE 9 GATE GENERATOR CURCUIT I ___ G _J 3 CDI UNIT 16 1 SPARK PLUG 16 0 ...

Page 178: ...IGNITION SYSTEM 16 1 SERVICE INFORMATION TROUBLESHOOTING IGNITION COiL CID UNIT ALTERNATOR EXCITOR COIL PULSE GENERATOR HONDA MBX50 MBX80 16 2 16 2 16 3 16 4 16 4 ...

Page 179: ...ween CDI unit and ignition switch Between CDI unit and spark plug 3 Faulty ignition switch 4 Faulty ignition coil 5 Faulty CDI unit 6 Faulty alternator ND NGK W24ESR U W27ESR U BRSES BR9ES W22ESR U W22ESR U BR7ES BR7ES W27ESR U W24ESR U BR9ES BRSES 0 7 0 8 mm 0 028 0 030 in 19 3 BTDC at 3 00 min 1 rpm 4 400 5 600 min 1 rpm 3 200 4 900 min 1 rpm 10 3 5 BTDC at 9 000 min 1 rpm 3 3 5 BTDC at 9 000 mi...

Page 180: ...ove the coil by removing the attaching bolts Remove the spark plug cap by rotating it by hand CONTINUITY TE ST Measure the resistances of the primary and secon dary coils Resistances Primary coil 0 2 0 3 Ohms Secondary coil 3 4 4 2 Ohms 16 3 1 PRIMARY 1 SECONDARY HONDA MBX 50 MBX 80 2 IGNITON COIL ...

Page 181: ...at tht re is a charging currentin the condenser for the first time The needle will then remain fixed unless the condenser is discharged Measuring ranges SANWA x K Q KOWA x 100 Q ALTERNATOR EXCITOR COIL PULSE GENERATOR INSPECTION Warm up the engine Stop the engine Disconnect the alternator connectors Measure the exciter coil and pulse generator resist ances Black Red Green Exciter coil 50 300 Ohms ...

Page 182: ...DJ 17 SWITCHES 17 1 SERVICE INFORMATION IGNITION SWITCH HANDLEBAR SWITCHES BRAKE LIGHT SWITCHES NEUTRAL SWITCH 01 L LEVEL SENSOR HONDA MBXSO MBX80 17 2 17 3 17 3 17 4 17 4 17 5 ...

Page 183: ...ue Lg Light Green 0 Orange P Pink R Red W White Y Yellow To isolate an electrical failure check the continuity of the electrical path through the part A continuity check can usually be made without removing the part from the motorcycle Simply disconnect the wires and connect a continuity tester or volt ohmmeter to the terminals or connections A continuity tester is useful when checking to find out...

Page 184: ...nuity tests for the components of the hand lebar cluster switches follow Remove the headlight Continuity snould exist between the color coded wires on each chart LIGHTING SWITCH Terminal Position N p N H Colar colde DIMMER SWITCH I Terminal Position Hi N Lo Colar code HL Hi HL 0 0 0 B TRUN SIGNAL SWITCH Terminal R w Position R 0 0 N L 0 Colar code Lb Gr HORN BUTTON I Terminal HO B Po sition Free P...

Page 185: ...rakelight switch wire leads at the connectors Check the switch for continuity with the rear brake applied Replace the switch if necessary NEUTRAL SWITCH Disconnect the nuetral switch wire Light Green Red and ground wire Green at the connector Check the switch for continuity between the wires with the transmission in neutral and with the transmission in any gear Replace the neutral switch if necess...

Page 186: ...and the black wire terminals with full float position RESISTANCE G R to Bk Approximately 340 ohm Turn the ignition switch ON Connect the oil level sensor coupler to the wire harness Move the float from full to empty and check that the oil warning light comes on If the light does not go on check for blown fuse or bulb loose connection or open circuit in the wire harness Replace the sensor if all of...

Page 187: ...NDA MBXSO MBX80 TROUBLESHOOTI ENGINE DOES NOT START OR IS HARD TO START ENGINE LACKS POWER POOR PERFORMANCE AT LOW AND IDLE SPEEDS POOR PERFORMANCE AT HIGH SPEED POOR HANDLING 14 1 14 2 14 3 14 4 14 4 18 18 1 ...

Page 188: ...oat valve in carbu retor 4 Breather hole in fuel tank cap clogged SPARKS ARE WEAK OR D0 1 1 Faulty spark plug NOT JUMP AT ALL 2 Fouled spark plug 3 Faulty COi unit 4 Broken or shorted high tension cord 5 Broken or shorted ignition coil 6 Faulty ignition switch LOSS OF COMPRESSION 1 Piston rings stuck in ring lands 2 Flaw in casting 3 Compression leak past crankcase 4 Faulty or clogged reed valve 5...

Page 189: ...ke dragging FREELY 2 Worn or damaged wheel bearing 3 Wheel bearing not lubricated properly 4 Drive chain too tight TIRE PRESSURE IS T00 1 Punctured tire LOW 2 Faulty tire valve ENGINE SPEED NOT CHANGED 1 Clutch slipping WHEN CLUTCH IS RELEASED 2 Worn clutch disc 3 Clutch disc warped ENGINE SPEED DOES NOT 1 Carburetor choke closed INCREASE SUFFICIENTLY 2 Restricted fuel flow 3 Air cleaner clogged 4...

Page 190: ...lipping ENGINE KNOCKS 1 Worn piston rings and cylinder 2 Fuel air mixture too lean 3 Excessive carbon build up in combustion chamber 4 Ignition timing too early advanced POOR PERFORMANCE AT LOW AND IDLE SPEEDS CHECK PROBABLE CAUSE 1 Check ignition timing INCORRECT 1 Faulty COi unit 2 Faulty alternator NORMAL 2 Ch ck carburetor air screw INCORRECT 1 Fuel air mixture too lean adjustment To correct s...

Page 191: ...Clogged fuel valve CLOGGED 1 1 Damaged fuel strainer POOR HANDLING Check tire pressure PROBABLE CAUSE 1 Steering heavy 1 Steering cone races excessively tightened 2 Damaged steering steel balls 2 Frant or rear wheel is excessively wobbling 1 Excessive play in wheel bearing 2 Distorted rim 3 Improperly installed wheel hub 4 Rear fork pivot bushing exces sively worn 5 Distorted frame 6 Improper driv...

Page 192: ...MEMO HONDA MBX50 MBX80 ...

Page 193: ... 12V4W CQ B G r W f C C J 1 f Br W Feu de position 12V4W STANDLICHT 11V4W I G tube G tube i J P tube GESCHWINDIGKEITSMESSER BELEUCHTUNG L FRONT TURN SIGNAL 12VIOW O tube SPEEDOMETER LIGHT 12V3 4W CD G Br 0 1 11miI Eclairage du compteur de ilesse 12V3 4W I ill BJ BI BI 12V3 4W c B B l l B1 Feu signal de rirage a ant gauche 12VIOW Br W l Bu V l Br G l r lg f HORN LINKER VOROERER BLINKLICHT 12v1ow W ...

Page 194: ...G w c J J w G I Br W 7 G tube Lb G y 01 1 11 1 1 Lb tl Br 1 1 t t t 1 G Y 1 1 1 1 1 1 1 1 0 1 1 t t 1 1 t 1 1 11 1 0 1 11 1 WR 1 t 1 1 i 1 G R Gr G Bu 1 G 1 P G G W P tube Lt G G Bu FUSE 7A LICENS LIGHT 12V5W lair plaqre 12VSW NUMMERNSCHILDBELEUCHTUNG IIVSW ___________ OJ G Y c CJ G Y f i Bl c J B L REAR TURN SIGNAL 12YIOW Feu signal de virage arritre gauche 12VIOW LINKES HINTERES BLINKLICHT 11VIO...

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