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Honda P50 Shop Manual - Project Moped Manual

1. gt m C i 25 M DES amp E Im 2 PSS t te B ta a 7 x H Bi 18 E 4 ng e P gt TEX 41 2 pee 1 gt t a Ri 26 6 E 1 1 223 lt 4 1 lt 5 4 z cC 25 T Sie m Yay 15 Y TURE H 3 84 TB T LIGHTING SWITCH 1 D 1 t AX a r 4 1 t L I 1 t 4 1 L 1 1 1 8W i R FRONT TURN SIGNAL LIGHT L FRONT TURN SIGNAL LIGHT l 0 4 8 3 e TE EE n 1 E 114 1 ti i i t 11 n na Ut t M i i d 233 44 Hn 99 13 if orn Ii 42 11 I od 14 4 47 1 1 4 L d 8W 1 AC IGNITION COIL E Lu 2 e TAIL STOP LIGHT 6 2 6W REAR TURN L SIGNAL Marii ug FLYWHEEL AC GENERATOR CONTACT BREAKER MOUNTED LIGHT 8w NOTE Indicate optional Part
2. 0 8 2 4 0 8 2 4 0 8 2 ABA 0 8 2 0 9 Pitch 5 0 0 9 Pitch 5 0 0 8 Pitch 5 0 35 35 35 0 8 0 8 0 8 35 3 5 5 0 Fig 3 1 gnition coil 82 ELECTRICAL SYSTEM In order for a gasoline engine to operate fuei mixture must be ignited by one of several methods so that the fuel mixture can be burned to produce useful work The P utilizes C ignition system employing an generator and ignition coil In this system the A C current produced by the A C generator is inter rupted to supply the primary voltage to the primary coil of the externally mounted ignition coil where the high voltage is induced for the ignition This system differs from the conventional ignition system where the D C current is supplied to the ignition coil The chart on the following page lists the electrical system troubles and guides to corrective action Fig 3 2 1 Rotor 2 Stator Stop Light Tail Light AT v4 cot lt ii Primary Coil Light Coil Breaker Fig 3 3 BR BROWN GY GREY W WHITE Y YELLOW G GREEN R RED BK BLACK Electrical Trouble Shooting 83 Trouble Probable cause Corrective action Engine will not start l Spark plug improperly installed l Reinstall No spark at the plug 2 Plug electrode dirty or eroded 2 Clean or replace Weak spark 3 Plug gap too wide 3 Repair or replace 4 Dirty breaker point 4 Repair or replace 5 Improper ig
3. 8 Chee England Leser rS DESEE CHR ES HP MUN 9 For Germany export ass ee Er RS Oe ea 9 DIMENSIONAL DRAWING 10 GENERAL DESCRIPTION ENGINE Operation of Four cycle Engine 2 12 Intake Intake of the fuel air mixture 12 Fa PERSIE a MON ROE Sa MT RCS qs ae 12 TOA dia ni dnb rc eoe e ou a ee 13 FUE COCKS lt t eed ons 13 En RE TOS 13 p 50 Carburetor COT UCHDIELasa eet cos msan eV Inti med 16 Operation of P 50 Carburetor Component Parts 18 Compression Compress the fuel air mixture in the cylinder 19 Pistons coco zeuse o donato dd es QUOQUINI E LUN tU EOD SES SO EG a 19 Offif acci et EAT A GANAS E EISE S VERAT RV REN 20 Piston Shaperices niaren rte et aW A TUS A e ica DAS ea ERR 20 Piston Rings AU TUEVIDEL URS PX ETE VERE Pe CTS SX VUE UIN AR V CEU 20 Cylinder irere racer ete atop UTI obe 21 Combustion Ignition of the compressed air fuel mixture by the spark plug to cause combustion TE EAU E EE ONERE 21 lgt li n SYyslGRmcccecisereneserecteteae tae cevaa a SORGEN
4. be kept completely closed during warm up driving and fully opened after warm up Fig 3 17 Fig 3 17 Operation of P 50 Carburetor Component Parts 1 Main Jet It meters the fuel flow during full throttle con dition top speed to provide a proper fuel mixture Not only does it function at top speed but it also is effective to a certain degree at intermediate speed The larger the main jet size number greater will be the nozzle opening and consequently the fuel flow providing a richer fuel mixture Fig 3 18 Fig 3 18 Main jet 2 Air Jet 1 Genuine parts mark During full throttle opening the fuel mixture at 2 Main jet NO high engine speed will become rich and at slow speed the mixture becomes lean To prevent such a condi tion air is bled into the main jet to maintain a uni form mixture The function of the air jet is to control the amount of the bleed air As the air jet becomes larger the amount of ble ed air is increased resulting in a lean fuel mixture however at a set throttle opening a high engine spe 2 ed will produce a leaner mixture There is only a small variation in fuel consumption between high and low engine speed 3 Needle Jet During full or half throttle opening the fuel which had been metered by the main jet is again metered by the needle jet The adjustment is performed in Fig 3 19 Jet needle conjuction with the jet needle which is explained in 4 Needle clip the followi
5. 94 Fig 4 22 Ratchet pawl K Reassembly Assemble the final driven shaft together with the 50mm thrust washer C to the rear wheel hub 2 Apply grease on the final driven shaft ratchet gro ove and assemble the ratchet pawl 3 Assemble the free wheel sprocket A to the final driven shaft Note After assemblying the free wheel spring A check the spring tension If the spring is weak or the operation is not smooth the ratchet will produce noise and is some case the power will not be transmitted to the rear wheel therefore replace the spring 4 Apply a coating of grease on the inside of the free wheel sprocket hold the racket pawl and assemble on the final driven shaft 5 Coat the free wheel spring B with grease and assemble the pawl on the final driven shaft 6 Set the 50 mm thrust washer B and the 61 circlip on the sprocket 7 Set the 50mm thrust washer A and the 50mm circlip on the final driven shaft Note If grease is not applied the sprocket will turn heavy noisy and the operation will not be smooth ri HONDA MOTOR CO LTD P rx s NN 67 8 2 PRINTEDS JAPAN
6. Excessively worn friction plate disc 2 Replace friction plate 3 Excessively worn ball rolling surface 3 Replace clutch outer 4 Weak clutch spring friction plate and or 5 The clutch weight is not pressing against the ball retainer friction plate due to excessive wear of the 4 Replace weight clutch weight spring hook Engine speed with 1 Loss of clutch spring tension L Replace refer to clutch disengaged is too 2 Excessively worn or burnt clutch weight shoe section 2 3 fast or slow 3 Excessively worn clutch outer friction surface 2 Replace 4 Excessively worn clutch weight hook 3 Replace 4 Replace refer to section 2 3 A Clutch suddenly l Too high an idling speed 1 Adjust to 1500 RPM engages during idling and cause engine to 2 Weak clutch spring 2 Replace stop 3 Clutch defective or cut of adjustment 3 Replace or adjust Cycling lever l Defective free pawl 1 Replace inoperative will not 2 Worn groove in secondary driven sprocket 2 Replace secondary 2 9 2 driven sprocket engage with engine in 3 Free pawl guide disengaged from free pawl ON position 3 Repair 4 Replace refer to section 2 3 A Cycling lever in 1 Excessively worn or defective cycling lever 1 Replace operative will not disengage from engine 2 Free pawl spring bent over 2 Replace in OFF position Engine oil changes to 1 Water mixed in oil Oil even though clean in emulsion 2 Blogged breather pipe appearance may be when u
7. Fit the brake panel on the hub Assemble the front wheel on the fork connect the speedometer cable and brake cable Check the operation of the speedometer and made adjust ment to the brake lever Disassembly of Front Cushion Disassemble the front wheel refer to section 4 1 Remover the 8 mm and 6 mm nuts mounting both the front cushion and fender Disassemble the front cushion assembly and suspen sion arm from the front fork Fig 4 9 Remove the 6mm nut and loosen the front cushion under bolt and the front cushion suspension can be disassembled Fis 4 10 Fig 4 7 1 Valve stem Fig 4 8 1 Ball peen hammer Bearing installer 3 6201 ball bearing Fig 4 9 1 6mm nut 2 8mm nut Fig 4 10 1 Front cushion under bolt 6 mm nut 13 0 512 Distortion mm 0 193in Fig 4 11 I Load kg 2 Spring rate 3 Stroke Fig 4 12 p Handle set bolt 2 Lock nut Fig 4 13 Front fork 5 Front cushion characteristic Fig 4 11 E i wre Reassembly Assemble in the reverse order of removal Note Clean suspension arm and other parts apply grease before assembly Apply grease with the grease gun after as sembly Disasembly of Front Fork Remove front wheel refer to section A Remove head light and disconnect all leads Remove horn and front carrier Loosen handie set bolt and tap lightly to remove the handle Fig 4 12 A tapered plug is fitted on the bottom of the hand
8. throttle grip back and depress the decompression lever Fig 3 67 CAUTION 1 The decompression lever must not be depressed while the engine is running except to stop 2 To stop the engine the motorcycle must be brought to a full stop before depressing the decompression lever Fig 3 66 Drive chain tensioner D Tensioner arm D 6mm washer 2 Tensioner spring 8 Tensioner boot 3 Tensioner pivot 4 Tensioner arm B 5 Tensioner roller 6 Tensioner pivot B Fig 3 67 Engine lever operation 1 Engine lever 2 Decompression cable 3 Decompression arm 4 Cylinder head 5 Rocker arm Inlet side 6 Actuate exhaust rocker to open valve 38 Lubrication System Cylinder Head Oil from the cam chain tensioner roller and the cam chain is carried along the crankcase ribs to drop into the oil guide from where it is fed to the cylinder head through the oil guide Oil enters the camshaft center pin and by centrifugal force is drawn into the spiral groove in the center pin to lubricate the cam surface as well as the rocker arm slipper surface After lubricating the camshaft oil passes through the cam chain chamber and flows back to the crankcase Fig 3 68 Oil lubrication system 1 1 Rib 2 Secondary drive sprocket 3 Cam chain Final drive shaft 5 Rear wheel axle 6 Final driven sprocket 7 Rib 8 Cam chain tensioner roller 9 Oil guide 10 Cam shaft center pin 39 Crankcase Part of oil splashed by the oil splasher on th
9. 0 07 mm 0 0024 0 0028 in diameter enamel or polyester coated copper wire wound around an iron core Essentially it is a transformer to change the 6 12V primary voltage to 10 000 15 000 V secondary voltage The change in the magnetic flux due to the sudden opening and closing of the contact breaker points in utilized to generate high voltage The ignition coil is located in the frame where it is not restricted as in case of being installed in the flyw heel and where it is not directly affected by the heat of the engine Further it is accorded adequate cooling The ignition coil is made durable and of heat re sistant material This greatly assists in prolonging the service life of the breaker points Fig 3 30 Fig 3 30 Ignition coil 1 Primary wire 2 High tension cord 3 Condenser Breaker Points The breaker points interrupt the primary circuit of the ignition coil Points are kept closed by force of the spring and opened by the breaker point cam in corporated in the hub of the flywheel to interrupt the primary circuit At this moment induction occurs at the primay coil Fig 3 31 Contact breaker point 1 Breaker and the high voltage is induced in the secondary coil point 2 Breaker arm 3 Crankshaft in proportion to the number of windiags in the coils Condenser In a household electrical circuit if the circuit breaker is opened sparks will be noticed across the points Similarly when the breaker points are o
10. 0016 in 0 08 0 0032in 7 Connecting rod small end run out Item Standard valve Serviceable limit 0 15 0 35 Run out 0 0059 0 0138 in 1 50 0 0591 in max 8 Clearance at connecting rod large end Item Standard value Serviceable limit 0 00 0 01 Saatana 0 000 0 0004 in 0 03 0 0012 in max H Reassembly 1 Assemble the crankshaft and the free pawl slider Fig 2 49 2 Assemble left crankcase after making sure that the two hollow dowel pins are installed Fig 2 50 Note Check to make sure that the crankcase is clean and free from foreign matters and da mage to gasketing surface Complete the reassembly in the reverse order of disassembly 016 13 034mm 13 0 5134in Fig 2 50 D Right crankcase 2 Left crankcase 3 crankshaft 78 2 4 Carburetor Trouble Probable Cause Corrective Action Engine will not idle 1 Clogged fuel tank cap breather hole l Repair 2 Air leaking in from connecting tube 2 Repair 3 Clogged air cleaner 3 Repair 4 Improper fuel level 4 Adjust 5 Clutch will not disengage 5 Adjust 6 Tappet clearance out of adjustment 6 Adjust Idling out of adjustment 1 Air screw out of adjustment 1 Adjust slow speed 2 Throttle stop screw out of adjustment 2 Adjust eerratic idling 3 Clogged pilot and or slow jet or loose jets 3 Clean repair response to throt tle snap e engi
11. 26 Note Caution not to drop clip into the case 4 Remove piston ring Fig 2 26 1 Piston 2 Clip F Inspection Repair 1 Check cylinder diameter Item Standard value Serviceable limit 42 0 42 01 F Diameter 1 654 1 655 in 42 1 1 658 in max Fig 2 27 Measuring inner diameter 2 Remove carbon deposit from piston head and ring groove exercising care not to damage the piston Note Do not use emery paper 3 Check piston diameter Fig 2 28 Item Standard value Serviceable limit Diameter 41 08 42 0 41 9 1 650 in min 1 646 1 654 in Fig 2 28 1 Micrometer 2 Piston 4 Piston ring side clearance Check the clearance with a new ring Fig 2 29 5 Piston pin bore Item Standard value Serviceable limit 13 002 13 008 13 05 Diameter 5119 0 5121 0 514 in max 6 Piston pin diameter Item Standard value Serviceable limit 12 594 13 000 12 98 T Diameter 651160 5118 in 0 510 in min Fig 2 29 Checking the clearance Fig 2 30 1 Piston ring Z Thickness gauge Fig 2 31 1 Piston 2 Piston ring Fig 2 32 1 Manufacturers mark Fig 2 33 1 Arrow marking 7 Piston ring end gap Fit the ring into the cylinder squarely and measure the end gap with a thickness gauge Fig 2 30 Item Standard value Serviceable limit 01 03 0 004 0 012 in 8 Ring tension 0 6 0 024 in max End gap Item Standard value Serviceable limit Top ring
12. 68 3 155 33kg 72 7 Ibs For Holland 29kg 63 8 105 37kg 81 5 Ibs For Holland 71kg 156 4 165 84kg 185 165 For Holland 40 km h 25 mile h 37 23 mile h 5 10 Gasoline Air cooled 4 stroke cycle Single cylinder tilted up 10 from horizontal OHC and valve 49 3 cc 3 0 cu in 42x 35 6 mm 1 65 x 1 4 in 8 7 1 12 kg cm 171 Ibs in 1 38 PS 5 000 rpm 0 25 kg m 1 81 ft Ibs 2 800 rpm 270gr Ps h 2 900rpm 350gr Ps h 4 000rpm For Holland type 396 x278wx310 hh 15 6x11 0X12 2 in 12 kg 25 4 Ibs 14kg 30 9 105 For Holland type Mounted on rear wheel with torque link Pedal starter Single dawndraft Dry urethene foam 2 5 lit 0 7 US gal 0 6 Imp gal Splash 0 7 lit 1 5 US pint 1 2 Imp pint Description Specifications Ignition system Ignition method Ignition coil Type spark plug Power transmission system Primary reduction method Reduction ratio Clutch type Secondary reduction method Reduction ratio Steering system Steering handle turning radius Steering handle width Caster Trail Tire front Tire rear Brake system Type brake front Type brake rear Method of application front Method of application rear Suspension system Suspension method front Lighting system Headlight rating Taillight rating Stoplight rating Flywheel magneto High voltage C 6HB Sprocket and chain 2 74 1 Centrifugal automatic Sprocket and
13. E EASAN vi 21 Fiywheel AC Generator 22 ignifon 22 Engine CHAIN DRIVEN 4 CYCLE ENGINE is used to provide quiet efficient power 2 POWER TRANSMISSION IS PERFORMED by a specially engineered three stage speed reduction and a reliable centrifugal clutch that automatically disengages at idling speed and engages when throttle is opened eliminating any need for a manual clutch or gear shift 3 ENGINE STARTING AND STOPPING is by opening or closing the decompression lever which relieve the compression from the cylinder 4 THE ENGINE AND THE COMPLETE POWER TRANSMISSION UNIT are contained within the rear wheel hub together with the rear brakes 5 SHIFTING THE CYCLING LEVER located on the engine disengages the engine to permit pedal operation of the P 50 6 CHOKE BUTTON IS CONVENIENTLY LOCATED on the steering head accessible while riding Frame 1 A STEP THROUGH FRAME WITH A LOW CENTER OF GRAVITY makes it easy to mount or dismount and provides for greater stability Frame main structure is a monocoque welded pressed steel sheet for high strength and ridgidity 2 EXPANDING BRAKE SHOES in the front and clamping band brakes in the rear operated independently by the handle levers assure good braking 3 AUTOMATIC ARM CHAIN TENSIONER constantly maintains the pedal drive chain in proper tension
14. The lever is located at the rear of the left crankcase By shifting the lever in the vertical direction the engine is either engaged or disengaged from the rear wheel Engine engaged Position the lever to ON Engine disengaged Position the lever to OFF CAUTION Shifting must be done while the engine is stopped Position the lever to ON Engine engaged With the lever is positioned to ON the free pawl is held in the groove of the secondary driven gear by the force of the pawl spring The power from the engine is transmitted to the final drive shaft which rotates the final driven gear and the final driven shaft coupled to the rear wheel hub Fig 3 61 Postion the Lever OFF Pedal engaged With the lever positioned to OFF the free pawl unlocks from the secondary driven gear groove so that the secondary driven gear rotates freely around the final drive shaft Therefore the power produced by pedaling rotates the freewheel sprocket and the rear wheel hub by means of the drive chain and is trans mitted to the secondary driven gear Thus the cycling can be enjoyed similarly as with the bicycle Fig 3 62 Fig 3 61 Motorcycling D Secondary driven sprocket 2 Final drive shaft 3 Free pawl Lower the lever Fig 3 52 Pedaling 1 Raise the lever 2 Free pawl disengaged Freewheel Sprocket When the freewheel sprocket is rotated by pedal ing the ratchet pawl engages with the freewheel sprocket to brin
15. chain Gear for Holland type 6 25 1 6 95 1 for Holland type Qu 570 mm 22 4 in 66 40 mm 1 58 in 50 mm 1 97 in for Holland type 2 0017 2PR 23 2 00 for Holland 2 25 17 2PR 23 2 25 for Holland Expanding brake shoe External clamping shoe Right handle lever Left handle lever Spring 6V 15W For U S A type 6V 10W For General export England type 6V 6W For France Belgium Holland type 6V 15W For Germany type 6V 5 3W For U S A type 6V 3W For General export England type 6V 1 8W For France Belgium Holland type 6V 1 8W For Germany 6V 17W For U S A type 6V 8W For General export England type 6V 5W For France Belgium type DRIVING PERFORMANCE CURVES 8 x 10 Engine Speed R P M ai Driving Force kg Running Speed km hr ENGINE PERFORMANCE CURVES 1 5 04 02 S 8 16 0 1 s o s 600 o 500 0 5 400 300 Fuel Consumption gr ps hr 200 2 3 4 5 6 7 x10 Engine Speed R P M General England Belgium France and U S A export type Output Transmission P S Engine Speed R P M 1 5 1 0 0 5 DRIVING PERFORMANCE Driving Speed Km Hr ENGINE PERFORMANCE CURVES 3 4 5 6 Engine Speed R P M For Netherlands export type 0 4 0 3 0 2 0 1 700 600 500 400 300 7 x10 Torque kg m Fuel Consumption gr ps hr WIRING DIAGRAM For General export type
16. check can be performed by connecting one of the timing tester leads to the black lead from the engine and the other lead to the engine ground With this hook up rotate the flywheel and adjust the breaker assembly so that the tester lamp will light up when the F mark on the fiywheel is aligned to the timing index mark on the crankcase Fig 1 12 Adjust the breaker points by loosening the breaker plate lock screw and moving the breaker plate with a screwdriver Fig 1 13 2 Normal breaker point gap should be 0 3 0 4 mm 0 012 0 016 in NOTE 1 Inspect the breaker point contact surface Burnt or pitted contact point surfaces will cause poor ignition If necessary dress the surfaces with an oilstone so that the points are making good contact 2 If the point surfaces are stained with oil a The surfaces will darken and result in ex cessive wear b Oil traces if left unremoved for a long time will harden and form insulation coa ting over the point surfaces causing igni tion failure 3 The contact breaker point gap may change slightly when the screw is tightened therefore recheck after making the adjustment to assure that the gap setting has not been disturbed 2 i Alignment mark 2 Flywheel wi 4 Ec Fig 1 13 1 To advance 2 Breaker point 3 Lock screw 4 To retard 5 Screw driver adjusting slot 6 Breaker plate Fig 1 14 1 Normal 2 Worn contact points 3 Side contacting 4 Dirty contact po
17. eliminating any need for adjustment 4 THE EASY STEERING BICYCLE TYPE HANDLEBAR is vertically adjustable A CONVENIENT BASKET IS MOUNTED ON THE FRONT FORK for carrying shopping or other light load SPECIFICA TION FOR P 50 2 SPECIFICATION amp PERFORMANCE Description Specifications Name of motorcycle Model type Type of vehicle Dimensions Overall length Overall width Overall height Wheelbase Min ground clearance Weight Weight empty Empty weight distribution front Empty weight distribution rear Full load weight distribution front Full load weight distribution rear Performance Max speed Climbing ability grade Engine Type fuel used Type engine No of cylinder and arrangement Valve arrangement Total piston displacement Bore x Stroke Compression ratio Compression pressure Max output Max torque Min fuel consumption at max load Dimension mm Total weight Installation and method Starting method Carburetor No and type Air filter type Fuel tank capacity Lubrication method Lubrication system capacity Honda 50 Motorcycle 1 570 mm 65 7 1 730 mm 68 2 in For Holland 620 mm 24 4 in 1 020 mm 40 2 1 050 mm 41 4 in For Holland 1 070 mm 42 4 in 1 090 mm 42 9 in For Holland 4 3 in 130 5 1 For Holland 45 99 1 lbs 46kg 101 3 Ibs For Holland 14 30 8 1605 13kg 28 6 Ibs For Holland 31kg
18. on the rear wheel The engine is fixed on the rear wheel hub through the final driven shaft with five boits The large cast aluminum alloy hub covers the engine crankcase Holes are provided in the huh side wall for the purpose of cooling the engine and internal fins circulates the air within the hub to further promote cooling 4 10 Rim 1 20 17 Spoke 13x 12 40 ea SP JESA EA 1 Brake shoe 2 6201 ball bearing Front wheel axle 4 Speedometer gear 5 Front brake arm Fig 4 9 2 Rear brake shoe spring 2 Rear brake arm 3 Rear brake arm spring 4 Rear brake 5 Rear brake shoe 6 Stop switch spring 7 Final driven shaft Chain tensioner Drive chain 102 Rear wheel hub Fig 4 10 Fig 4 11 Tire construction MD Tread A thick rubber layer Design on the outside is called pattern Rim A steel plate is rolled in and seam welded 3 Carcass Cloth layers 2 PL for two ply 4 Bead Some piano wires are enclosed along the circumference 5 Spoke nipple 6 Spoke nipple 1 Brake shoe 2 Brake arm 3 Brake cam 5 Brake lining 5 Rear brake cable 6 Brake shoe 2 Speedometer gear 8 Brake cam 9 Brake arm 10 Brake lining Fig 4 12 Braking system Tire sizes are standardized by JIS Japan Industrial Standard For instance 2 00 17 2PR means that tire size is 2 00 inches rim diameter 17 inches and two ply carcass Fig 4 11 Brake System The brake system employed i
19. outside of the air screw 9 where it is metered and then enters the bleed hole 4 of the slow jet 10 On the other hand the fuel from the float chamber after being metered by the pilot i2 and metered again at the jet area 12 of the slow jet 14 mixes with the air from the bleed hole 10 within the slow jet and is discharged at the bottom of the throttle valve from the pilot outlet 10 to mix with the main flow of air from the carburetor air inlet and is taken into the engine 3 Float Chamber It is necessary for the carburetor to supply the proper fuel mixture to the engine under all different throt tle opening and engine speed in order to do this the fuel level must be maintained at a constant level It is the function of the float chamber to perform this task The fuel from the tank flows through the passage 49 passes between the valve seat 48 and the float valve and then enters the float chamber 18 As the fuel level in the float chamber rises the float 19 becomes buoyant float arm 2 applies pressure against the float valve forcing it against the valve seat to shut off the flow of the fuel When the fuel in the float chamber is consumed the fuel level drops with the consequent lowering of the float this causes the float valve to unseat and permits the fuel to enter the float chamber This cycle is repeated to maintain a constant fuel level 22 in the float chamber 4 Overflow Pipe When dirt becomes clogged in the float val
20. struction to permit safe and good riding consideration riding comfort will not be realized if the road shocks are transmitted from the wheels P 50 with its bicycle like lightweight frame con struction incorporates a cushion in the front fork for riding comfort Cushions are classified into various types according to their construction P 50 has adopted a bottom link leading link type Fig 4 7 The bottom link type construction ensures smooth Fig 4 7 operation riding comfort and good steerability in dition it allows wheel base to be practically unchanged 1 Pine needle type 2 Telescopic type 3 R s fork type 4j Bottom link type Fig 4 8 1 Front cushion upper metal 2 Front cushion stopper rubber 3 Front cushion spring 4 Front arm pivot bush seal 5 Front arm pivot bushing 6 Front cushion lower metal 7 Front cushion under bush seal 8 6mm hex nut 9 Front cushion under bushing 00 4 5 grease nipple Front suspension arm Front cushion under bolt 13 Front arm pivot collar Front Wheel Tire size 2 00 17 2 PR is used on the front wheel The front axle supports the cast aluminum alloy hub mounted on two 6201 ball bearings The brake panel incorporates the spe edometer gear box Oil seals are incor porated in both the brake panel and the hub to prevent the entry of dust to as sure longer life Fig 4 9 Rim HO 17 Spoke 213 32 Rear Wheel Tire size 2 25 17 2 PR is used
21. 0 Fig 1 21 Fig 1 22 Fig 1 23 2 10 15 mm 3 8 5 8 in 1 To increase 3 Adjusting nut 1 Adjusting nut 3 To decrease 2 To decrease i 10 15 mm 3 8 5 8 in 2 To increase C Frame 1 Brake Adjustment Brakes are the life line of the rider therefore do not neglect to perform the periodic inspection daily inspection and pre riding inspection Front Brake Adjustment The free play of the brake lever that is the dis tance between the normal attitude and the point where the brake starts to take hold should be 10 15 mm 3 8 5 8 in Fig 1 20 Adjustment is made with the adjusting nut Fig 1 21 Rear Brake Adjustment The free play of the brake lever that is the dis tance between the normal attitude and the point where the brake starts to take hold should be 10 15 mm 3 8 5 8 in Fig 1 22 Adjustment is made with the adjusting nut Fig 1 23 2 Security of Component Parts Bolts nuts and other threaded fasteners will be come loose due to vibration fatigue of the fastened parts etc as a result of long use To prevent the at taching fasteners from loosening they should be re tightened periodically Fig 1 24 25 1 Handle set bolts 2 Front arm pivot bolts 3 Front cushion lower bolts 4 Front wheel axle nut 5 Bolts and nuts fixing both ends of rear torque arm 6 Rear axle nut 7 Steering stem nut 8 Crank arm set pin When crank
22. 0 771 43 ws 044 Ibs min EN NR 077 2143 bs 6 44 lbs min Oil rng Qi820510 0 99 lbs min 9 Ring width and thickness Standard value Mu um Thickness All rings E eo ae RA Top ring 0 0470 0 0465in 0 0449 m main 1 SLD m 2 480 2 495 2 44 mm Oil ring 5 5976 0 0982in 0 0960 in G Reassembly 1 Assemble the piston ring to the piston Note a When assemblying new rings roll the rings in their respective piston grooves to check the fit Fig 2 31 b The ring must have the maker 5 mark on the ring toward the top Fig 2 32 2 Install the piston Note Make sure that the arrow on the piston head in pointing downward 3 Install the pin clips at both ends of the piston pin Note a The clip opening should not be aligned to the cut out b Distorted or clips which have lost its tension should be replaced with a new part 4 Before installing the cylinder make sure that the cylinder gasket and the two hollow dowel pins are in place Fig 2 34 5 Space the ring gaps evenly apart for all rings Trim the crankcase gasket with a sharp knife if it extends above the cylinder mating surface Fig 2 34 2 3 Reduction Cam chain tensioner Oil guide Crankshaft 1 Cylinder gasket 2 Hollow dowel pin Trouble Probable Cause Corrective Action Engine will not start 1 Drive plates and friction plates are not making 1 Replace or repair uniform contact refer to section 3 A 2
23. 15 Saddle cushion spring 2 Saddle hinge 48 5 ELECTRICAL EQUIPMENT The electrical equipment used on P 50 not only generates good sparks by the AC generator but also includes many safety components for the safety of the rider In addition turn signal lamps are available as optional parts They are very simple to install Fig 5 1 Head light Horn Ignition coil Spark plug Tail stoplamp Flywhee A C generator Lighting switch Fig 5 1 Installed locations of electrical parts The head light is mounted at the the center of the handle bar and adjustment of the beam angle is made by loosening the head light case fixing nut Two different mounting grooves are provided in the socket for changing the beam adjustment By aligning the mark A or B on the bulb to the corresponding mark on the socket when installing the bulb the best illumination is obtained Fig 5 2 A hole is provided in the head light reflector to utilize the stray light within the head light case to il luminate the speedometer A 6 V 10W bulb is used in the head light When the lighting switch is positioned ON the head light as well as the tail lamp light up and simul taneously the stop lamp and the horn are switched to night circuit in order to obtain the same brightness for the stop lamp and the same sound for the horn as for daytime nnode A 6V SW tail lamp and a 6V 8W stop lamp are inc
24. 2 mark Case index mark 4 Oil guide Cylinder head Chain 7 Chain guide roller 8 Cam sprocket Power Transmission Mechanism The transmission of the rotating power generated at the engine to the rear wheel is made possible by the power transmission mechanism The P50 is not equipped with a transmission however all the speed reducing operations is performed by chains which also drives the rear wheel Fig 3 57 Gears are used on 50 for Holland export type Fig 3 57 Power transmission mechanism D Secondary driven sprocket 2 Riding lever 3 Primary driven sprocket 4 Secondary drive sprocket 5 Final driven sprocket 6 Crankshaft 7 Exhaust valve 8 Final drive shaft 9 Final driven shaft 10 Free wheel 11 Rear wheel hub 32 Clutch Primary drive sprocket 13 R crank arm 14 Decompression 33 Clutch The clutch engages and disengages the power from the crankshaft to the rear wheel When changing speed the power must be disengaged temporarily when starting the power must be transmitted smoothly to the rear wheel P 50 has adopted the centrifugal clutch which performs the operations automatically Fig 3 59 Fig 3 59 Sectional diagram of clutch 1 Clutch outer 2 Clutch weight 3 Drive plate 4 Primary drive sprocket 5 Friction plate 6 Steel ball 7 Ball retainer 34 Automatic Centrifugal Clutch By utilizing centrifugal force the clutch engages and disengages the power automatically in accordance with the engine RPM Th
25. 2 Throttle stop screw Fig 2 52 p Genuine parts mark 2 Main jet No 80 B Float check procedure l Shake the float and listen for fuel inside 2 Submerge in hot water approx 90 C for one minute and check for rise of bubble which indicates leak Clean float chamber before assembly w Fig 2 53 D Needle clip 2 Needle clip plate 3 Cable adjuster Throttle valve 5 Jet needle Needle jet 7 Needle jet holder 8 Main jet C Carburetor Setting Table Setting mark Old type M J main jet A J Air jet A B Air bleed N J Needle Jet J N Jet needle C A Throttle valve A S Air screw S J Slow jet P O Pilot outlet P J Pilot jet V S Valve seat Oil level Setting 50A 50A 1 55 d 58 Pointed mark 55 70 70 ABl 0 41 1 04 1 2 0 4 1 AB2 0 4 x1 0 4 1 AB3 0 4 1 AB4 0 4 1 AB5 0 4 1 AB6 0 4 1 2 6x2 2 6x2 Holland export type 81 New type 50B 58 Outer diameter 3 4 100 AB1 AB2 AB3 AB4 5 6 0 4 1 0 4x1 0 4 1 0 4 1 0 4 x1 0 4 x1 2 6x1 55 131310 3 stages 2 0 width 2 0 011302 3 stages 2 0 width 1 2 11401 3 stages 3 2 0 width 1 2 Depth 0 2 Depth 0 2 Depth 0 2 1 14 16 114 18 1 14 18 35 1 08 2 35 0 8 2 35 1 0 8 2 2 0 8x2 AB2 0 8x2 AB2 08 2 AB3 0 8x2 0 8 2
26. 3 Throttle valve 1 Close 2 Throttle valve spring 3 Throttle valve 4 Cutaway 5 Jet needle 6 Needle jet Fig 3 14 Throttle valve 7 Open 16 P 50 Carburetor Construction 24 F 4 4 Fig 3 15 02 19 20 23 1 Air System The carburetor used is a down draft type which draws the air into the carburetor from the top As shown in the figure 15 the air from the air cleaner enters the inlet opening passes by the throttle valve and is drawn into the engine after passing through the venturi The engine power output is determined by the volume of air flow which is controlled by the move ment of the throttle valve 2 to vary the opening of the venturi 2 Fuel System The air flow passing through the venturi pro duces negative pressure at the restriction under the throttle valve gt where the fuel nozzle is located There are two systems the main and the slow system in the fuel system a Main system The fuel enters the main jet 2 and in the Fig 3 16 main jet it mixes with the air from the air bleed after the air have been metered by the air jet 5 17 The fuel and air mixture passes through the opening between the needle jet and jet needle 8 to be discharged as a spray at the throttle valve The fuel spray mixes with the main incoming air and becomes atomized before being taken into the engine b Slow system The air which enters from the inlet opening passes around the
27. 5 8 in at the end of the lever 5 Are all the main components properly fastened See page 57 6 Do the head tail and stop lights operate 7 Does the horn have the proper loudness 8 Is the rear view mirror positioned correctly 9 Is the front tire air pressure normal 10 Is the rear tire air pressure normal 1 3 kg cm 18 5 Ibs in standard l 7kg cmv 24l bs in standard 2 PERIODIC INSPECTION The schedule of periodic inspection and adjustment for the various components are shown in the following table PERIODIC MAINTENANCE SCHEDULE INTERVALS 2i5 5 E 2 9 a E 9 o gt 255 2 E o 56 too Eno 5 15 ESS East E ITEMS 3 54194 E Fig 1 1 1 Oil level gauge 2 Oil filler opening Engine oil change e 2 Adjust ignition timing e e Adjust tappet clearance e e Servicing air cleaner D Greasing fork pivots front Tighten nuts and bolts e Adjust brakes CAUTION more frequent engine oil change is recommended when operated under dusty condition Tire pressures should be checked weekly A Lubrication Lubricant is required on the rotating or sliding sur faces of the moving parts to prevent wear and possible seizure due to the heat produced by the friction The function of the lubricant is to provide a thin film of oil between the surfaces so that there are no direct sur face to surface contact
28. 6 41 Tap the air cleaner element lightly to remove the dust or wash in water Fig 1 27 wn 1 Element set plate 2 Air cleaner element Fig 1 27 5 Remove the dust from the inside of air cleaner case Fig 1 28 NOTE 1 Caution not to allow oil to get on the air cleaner element After washing reinstall the air cleaner element after it is completely dried 2 After installing the air cleaner case cover check to make sure that the cap is in close fit with the air cleaner element 3 Check to make sure that there is no place for air to leek in Fig 1 29 1 Element set plate 2 Air cleaner element 59 3 Other Inspections and Adjustments l Adiustments of Throttle Grip and Throttle Cable When excessive play exists in the direction parallel to the shaft turn up the grip rubber and check the screw for looseness Fig 1 30 3 When excessive play exists in the rotating kame direction adjust the throttle cable Make the Fig 1 30 1 Grip rubber i Screw adjustment with the adjusting bclt After the adjustment reinstall the cap securely Fig 1 31 ee Pa Fig 1 31 1 Adjusting bolt 2 To decrease 3 To increase 4 Cap 2 Engine Decompression Lever Adjustment The lever play should be 0 1 0 4 cm 0 04 0 16 in Fig 1 32 Fig 1 32 1 Engine lever D 0 1 0 4 cm 0 04 0 16 in The adjustment shall be made by loosening the nut A and turning the nut B Fi
29. GH TENSION CABLE 2 FLYWHEEL 12 47 AC GENERATOR CONTACT BREAKER MOUNTED 4 For Holland export type 1 HORN SWITCH AC HORN LIGHTING SWITCH BR HEAD LIGHT 6V 6W 1 LIGHTING SWITCH SWITCHING ARRANGEMENT HL Ca SL 04 FLYWHEEL AC GENERATOR CONTACT BREAKER MOUNTED For England export type df il HORN sal 1 HORN LIGHTING SWITCH m3 HL E TAIL LIGHT 6V SW AC IGNITION COIL HIGH TENSION CABLE Fi Dal iip 4 SPARK PLUG 7 FLYWEEL A C GENERATOR CONTACT BREAKER MOUNTED For Germany export type gt SPEEDOMETER LAMP Vy 6V 15W LIGHTING SWITCH HEAD LIGHT 6V 15W PN DIN 72601 From T 7 TAIL LIGHT 6V 5W DIN 72601 From L R M LIGHTING SWITCH SWITCHING ARRANGEMENT Ci HL m S ON 3 Lp a gt FLYWHEEL AC GENERATOR SPARK CONTACT BREAKER MOUNTED DIMENSIONAL DRAWING C g M Pe A i ps ut t TE 06 4 9 72 29 1 070 42 4in 1 670 65 7 in uZ 676 uc Or 020 1 S qu e AJ LIE 11 GENERAL DESCRIPTION 3 ENGINE In the gasoline engine the fuel and air is mix in the proper ratio and this mixture is taken into the cyli nder in a vapor condition where it is compresse
30. Remove the speedometer gear from the front brake panel Fig 4 3 6 Remove tire and tube from the rim with tire lever B Inspection 1 Measure rim runout Fig 4 4 Item Standard value Serviceable Fig 43 DS eer EE mit g 1 Speedometer gear ME icd 0 6mm 0 5 mm B 0 024 in 0 020 in 1 0 1 0 mm Vertical runout 0 040 im 0 040 in 2 Measure front axle diameter and bend Item Standard value Serviceable limit Diameter 9 994 9 990 0 3935 0 3933 in Bend 0 2 mm 0 5mm 0 020 in 0 008 in 3 Remove deep grooves and scratches from the drum contact surface and lining C Reassembly 1 Assemble the speedometer gear 2 Set brake shoe on the brake panel 3 Assemble the tire flap over the spoke nipple Fig 4 5 4 Assemble tube and tire Fig 4 5 Tire 2 Rim Note a After assemblying the tire and tube fill tire with approximately O 5kg cm 7 1 Ib in of air and tap all around with a wooden ham mer to prevent tube from being pinched Fig 4 6 Fig 4 6 D Wooden hammer Tire The valve stem should be pointed toward the axle or else air will leak from the base of the stem Fig 4 7 Tire pressure front 1 3 kg cm 18 5 Ib ir Standard rear 1 7 kg cm 24 2 Ib ir Wash off old grease from the wheel hub and bear ing and pack both bearing and hub with new grease Assemble the distance collar 6201 ball bearing and oil seal Fig 4 8
31. SHOP MANUAL HONDA MODEL P30 FOREWORD The P 50 is a gasoline engine powered bicy cle affording all the simplicities of the bicycle with the powered features of a mopet yet so easy to handle that anyone who is abie to ride a bicycle can ride the P 50 without any previous experience It is designed to fulfill the need for a safe economical and easy handling family trans portation This manual has been prepared as a servi cing guide for the P 50 and all personnel who will be servicing the P 50 should read this manual carefully to become familiar with all of its sections The manual is written in tow parts construct ion and maintenance inspection for easy reference Any revisions to this manual will be notified by the Service Bulletin July 20 1967 Service Department Honda Motor Company Ltd CONTENTS FEATURES SPECIFICATION amp PERFORMANCE SPECIFICATION FOR kunt sin Rb nie vis 2 DRIVING PERFORMANCE CURVES 4 ENGINE PERFORMANCE 5 4 WIRING DIAGRAM obe ewe ea RITE RS tec Ca vr ena 6 For General export SAN MGE Cen oisi ips eps 6 For UsSuAnexport hype doceo dett a tette acta s ATL OU E y For France and Belgium export type 8 For Holland axpor type uiis EGER
32. STANDARD TOOLS Oe 10 14 mm double open end wrench Tire tool set Electrician screwdriver Common wood handle screwdriver lt _ External snap ring plier 21 mm T handle socket wrench Internal snap ring closing plier EE Long nose plier e Slip joint plier TEE Half pound ball peen hammer 10 mm T handle socket wrench 9 mm T handle socket wrench 3 cross point T handle screwdriver 2 cross point T handle screwdriver Plastic faced hammer 1 Nut 2 Decompression cable 1 Air cleaner connecting clamp 1 Normal direction of chain 2 1 Engine Removal and Installation A Engine Removal 1 Remove the carburetor cover 2 Remove the high tension terminal 3 Disconnect the decompression cable at the engine Fig 2 1 4 Disconnect the choke cable from the carburetor 5 Loosen the air cleaner connecting lower clamp disconnect the fuel tube and then remove the car buretor Fig 2 2 6 Detach the rear brake cable from the right crank case 7 Disconnect the engine electrical leads Unscrew the rear torque arm attaching cap nut and 8 mm bolt Fig 2 3 9 Separate the exhaust pipe and muffler 10 Loosan the rear axle nut and raise the frame to clear the engine and wheel as a complete unit Note 1 During the engine removal the oil will flow cut if the tappet cap has been removed 2 If the rear wheel and engine is raised the
33. This will prevent wear and friction thus minimizing the possibility of heat genera tion Insufficient lubricating oil or prolonged use of dirty oil will not only reduce the service life of the mechanical components but also adversely affect the performance of the motorcycle 1 Changing and Replenishing Engine Oil 1 Remove the oil level gauge and unscrew the drain plug at the bottom of the crankcase and drain the engine oil completely Engine oil will drain more quickly and thorough ly if the engine is still warm 2 Reinstall the drain plug securely and refill the crankcase with new engine oil Fig 1 1 2 If the engine had been overhauled fill the crankcase with 0 7 of oil 1 5 US 1 2 Imp pt however during oil changes or replenish ments refill according to the oil level gauge The crankcase should be filled with oil up to the upper level mark on the gauge Proper oil checking procedure is not to screw the cap into the crankcase OIL Oil of poor quality may adversely affect the engine performance as well as its life Fig 1 3 4 The grade 10W30 may be used in all seasons regardless of temperature 2 Parts which require lubricating with oil Hanger crank axle Crank pedal Drive chain Chain tensioner Free wheel sprocket Fig 1 5 6 E 97 58 2 Maximum oil Fig 1 3 level 3 Minimum oil level 4 Oil 1 Oil level gauge Outside temp SAE 30 7 D L crank pedal 2 Ha
34. a noise suppressor is installed It incorporates a carbon resistor as shown in figure 34 within a sealed case The carbon resistor functions as an attenuation resistor and the sealed case serves to help prevent high frequency radiation in conjuction with the carbon resistor Fig 3 34 Automatic Spark Advancer To obtain the most effective use of the combus tion pressure the timing of the ignition must be advance as the engine speed increases Considerable time will lapse before the combustible fuel mixture is completely burned after being ignited and the maximum combus tion power is produced The movement of the piston is very rapid and if the ignition should take place when the piston is a top dead center the combution will take place after the piston has started its downward move ment and the maximum utilization of the combustion pressure cannot be realized Therefore the breaker points should open to produce the spark ignition just prior to the piston reaching top dead center and as the engine speed increases the ignition must take place that much earlier Normally centrifugal force is used and the amount of ignition advance is automatically controlled by the engine speed This type advancer is known as the automatic centrifugal spark advancer From the standpoint of safety this automatic spark advancer is employed as a speed governor in the P50 Up to the engine speed of 4500 RPM the ignition will advance to 28 before
35. am center dark Improper bulb installation Lens and reflector 1 Fogged clouded 2 Dust Refer to section 6 for spark plug check Clean Adjust Adjust Replace Replace Repair or replace Repair or replace Repair or replace Repair or replace Repair Repair or replace Repair by raising the ccntact Replace Repair or replace Remagnetize or reolace Replace Adjust focus Clean the lens and reflec tor sur ace after remov ing socket Fig 3 4 1 Spark plug 2 Noise suppressor cap Fig 3 5 1 Attach the cord to frame 2 Test lamp 3 Black lead from the generator Fig 3 6 i Rotor 2 Cam 3 Snap washer 4 Governor weight Governor spring A Inspection of Spark Characteristic The use of the A C ignition system makes it im perative that the inspection of the ignition coil be made by using the generator 1 First check to see that the high voltage is being delivered to the spark plug Ground the spark plug on the engine as shown in Fig 3 4 and perform the starting process If bluish white spark is seen jump ing across the plug points it is an indication that the spark plug ignition coil flywheel A C generator are in good condition If there are no sparks one or more of the components are defective 2 The primary coi
36. and exhaust functions Overhead camshaft OHC Chain type Gear type type Fig 3 50 Overhead camshaft type Fig 3 48 Overhead camshaft type Fig 3 49 Overhead camshaft type Overhead Camshaft When the part shown in the figure is revolved the vertical rod moves up and down Fig 3 51 The camshaft installed the cylinder head is re volved by the timing sprocket installed on the crank shaft through the cam chain The camshaft actuates the rocker arms by providing a rocker movement which operates the valve In order to maintain the cam chain at a specific tension so that the valve timing is not effected a cam chain tensioner is installed within the crankcase to apply pressure against the chain by means of a roller through a spring Fig 3 52 Fig 3 51 Principle of cam Fig 3 52 Over head camshaft mechanism 1 Timing sprocket 2 Crank shaft 3 O mark 4 Camchain tensioner 5 Camchain 6 Piston 7 Valve 8 Camshaft 9 Rocker arm Tappet Clearance The clearance between the valve and rocker arm is referred to as the tappet clearance Proper clea rance is required for the valve to fully close If the clearance is too small it will keeps the valve from completely closing producing a low compression on the other hand if the clearance is too large tappet noise results The tappet clearance will greatly affects the en gine output revolution and noise Standard tappet clearance measured cold is 0 05 mm 0 002 in f
37. ange plug gauge 0 7 lit 3 Point gap requires adjustment cleaning 1 48 U S pt 1 23 4 Ignition timing retarded Imp pt 5 Dragging brakes 2 Gi or replace 6 Lean air fuel mixture 4 Adjust 5 Adjust to 1 5 2 0 depasit donation chamber mm 0 06 0 08 8 Worn piston and rings 6 Adjust carburetor 7 Remove carbon 8 Replace Decompression lever 1 Excessive slack in lever cable l Adjust or replace inoperative A Removal of Cylinder head Camshaft Valve 1 Remove cylinder head cover Fig 2 5 Fig 2 5 1 Cylinder head cover 66 2 Extract the rocker arm shaft and remove the rocker arms Fig 2 6 Fig 2 6 1 Valve rocker arm shaft 2 Valve rocker arm 3 Extract the 3x12 camshaft locking dowel pin and than pull out the camshaft center pin NOTE Camshaft center pin can be easily removed by screwing in a bolt Fig 2 7 4 Disengage the camshaft from the cam chain Qr 2 7 1 3 12 dowel 2 Bolt 3 Camshaft center 5 Unscrew four 6 mm nut a 6mm screw and then separate the cylinder head from the cylinder Fig 2 8 Fig 2 8 1 Cylinder head B Disassembly of the valve 1 The valve can be removed by pressing down on the valve retainer and matching the recess in the retainer to the end of the valve Fig 2 9 Fig 2 9 1 Valve 2 Valve spring retainer 3 Valve spring C Inspection and Repair l If the cylinder head is not prope
38. ankshaft revolutions to complete the intake compression power and exhaust strokes INTAKE Intake of the fuel air mixture Air Cleaner If the air that is used to mix with the fuel is dirty a great amount of dust and grit enters the carburetor to cause troubles and they eventually pass into the cylinder to cause rapid wear to the cylinder The air cleaner serves to clean the air entering the carburetor The air cleaner removes the dust from the air and permits only the clean air to enter the carburetor through the air cleaner connecting tube Fig 3 7 Fig 3 7 Air cleaner construction 1 Air cleaner element 2 Connecting tube 3 Carburetor Fuel Tank Fuel Cock The 2 5 5 3 U S pt 4 4 Imp pt capacity fuel tank also serves as a luggage carrier A cock is inst alled on the fuel tank to control the flow of fuel from the fuel tank to the carburetor Fuel is supplied to the carburetor by gravity feed The fuel filler opening is made into a tubular shape to prevent the fuel from surging out of the cap by vibration Fig 3 8 Carburetor The carburetor performs the function of mixing the fuel with air in the properly proportioned mixture to form a combustable fuel air vapor Shown in figure 3 9 is an atomizer sprayer for home use Air blown through the pipe A increases in velocity as the air leaves the narrow outlet causing a decrease in pressure The decreased pressure draws the water out of the stand pipe B which becom
39. ape of the piston is an elliptical taper This is because the head of the piston compared to the skirt is exposed to much higher temperature and since the expansion is greater it is tapered smaller toward the top The tapering of the piston also tends to les sen the piston slap when the throttle is lightly snapped at light engine loading at low speed Fig 3 23 Piston Rings Usually three piston rings are installed on the piston Starting with the top they are called the top ring second ring and oil ring The top and second rings Serve as a seal for the combustion chamber and also to transmit the high temperature of the piston to the cylinder wall where it is dissipated through the cylinder cooling fins The oil ring Serves to scrape off excessive amount of oil from the cylinder wall and to prevent oil from entering the combustion chamber To prevent flutter the rings are made narrower in width and increased in thickness so that the inertia is decreased while the ring pressure against the cylinder wall is increased Further the top and the second rings are made at a slight taper where it contact the cylinder wall so that the time required for swear in is lessened The groove in the oil ring as well as the bevel of the second ring serves to assist oil scraping and pre vents oil from penetrating into the combustion chamber Thus carbon deposit on the plug piston rings etc is prevented and the oil consumption kept to a min
40. arm set pin becomes loose move both left and right crank arms inward so that no looseness exits in the direction parallel to the shaft In this con dition install the pin into the arm and tighten with the nut 9 Front and rear wheel spokes Riding with loose spokes will place an ununiform loading on the rim as well as on the remaining spokes and will cause the rim to develop runout and the spokes subject to damage The spokes should be inspected frequently and retorqued when they become loose Raise the wheel off the ground and check each spoke for tightness using a spoke wrench Any spoke which is noticeably loose should be torqued to the same value as the remaining spokes so that the spokes are all of uniform torpue Use the spoke nipple tool and torque wrench Fig 1 24 1 Crank arm set pin 2 Front wheel axle nut 3 Crank arm 4 Crank pedal 5 Rear torque arm 6 Carburetor cover 7 Rear axle nut 8 Exhaust pipe Fig 1 25 1 6 14 bolt 2 Spoke 3 Rear axle nut 4 Muffler band 5 6 14 screw 2 ea 6 Spoke 3 Air Cleaner Servicing An air cleaner clogged with dust restricts the free passage of inlet air and results in power loss or drop in acceleration therefore periodic servicing of the air cleaner should be performed 1 Remove the air cleaner cover 2 Remove the air cleaner case cap Fig 1 26 3 Remove the air cleaner element together with the element set plate 1 Air cleaner cover 2 Air cleaner cap Fig 1 2
41. assembled on the crankshaft with the crank pin An oil splasher in shape of a scoop is attached to the large end to splash lubricate the crankshaft cylinder and piston Fig 3 43 M Pa M IRR Fig 3 43 Operation of connecting rod 1 Cylinder 12 Snap ring 3 Piston pin 4 Piston 5 Connecting rod 6 Roller retainer 7 Crank pin 8 Timing sprocket 9 Crankshaft 10 Oil splasher 1 Crankshaft R L EXHAUST Exhausting the burned gases Exhaust Pipe and Muffler If the hot combustion gas and high pressure is ex hausted from the cylinder the gas under pressure will attempt to expand suddenly and produce a loud noise In order to prevent this the temperature and pres sure of the burned gas must be reduced gradually must be routed from the cylinder to the muffler through the exhaust pipe where the gas can gradually by reduced in temperature and pressure before it is exhaust pipe where the gas can gradually be reduced in temperature and pressure before it is exhausted out side Fig 3 44 45 Fig 3 44 Exhaust pipe Fig 3 45 Construction of muffler 1 Outer half inlet pipe 3 Steel wool 4 Guide plate 5 Separator 28 Valve Operating Mechanism The inlet and exhaust valves are installed in the Types of valve operating mechanism cylinder head of the four cycle engine These are Side valve SV type opened and closed to assist in performing the intake Overhead valve OHV type compression combustion
42. at spot groove difference for poor acceleration winter and summer 79 Trouble Probable ause orrective Action slow speed difficult 2 Clogged slow and or pilot jet o high fuel consumption 3 Clogged air vent pipe erratic operation 2 Clean or repair 3 Over flow pipe Servesales as air vent prevent from Poor high speed performande Choke partially closed Clogged air vent pipe Pod Jet needle dropped Loose main jet dropped or clogged blocking 1 Fully open the choke valve 2 Refer to part 4 above 3 Clean main jet and tighten securely 4 Replace jet needle clip Adiustment Procedure 1 Air screw Screw in fully and then back off 1 28 turn 2 Throttle stop screw Loosen the throttle screw fully and then screw in to obtain the proper idle speed of 1500 RPM Determine the proper idle speed by running the engine with the rear wheel off the ground the point of maximum throttle opening with the rear wheel stationary 3 Slow speed adjustment Adjust the engine to smooth operation with the air screw and then adjust to the proper idle speed with the throttle stop screw 4 Medium and high speed adjustment Adjust with the main jet If exhaust gas is dark replace main jet with one of smaller number and visa versa Note Jets are precision parts therefore handle with care to prevent damage Finally check the fuel level Fig 2 51 D Air screw
43. ause the engine to overheat while a rich mixture will cause engine to run sluggish An overflowing of fuel from the carburetor is a possible fire hazard Carburetor 1 Throttle stop screw 2 Air screw should be cleaned and adjust periodically 1 Set the throttle stop screw gradually to the lowest idling speed 2 Next adjust the air screw by turning slowly in both directions to obtain the highest engine speed 3 Reduce the engine speed which has gone up in 2 to the lowest idling speed by regulating the throttle stop screw 4 At this throttle stop screw setting recheck the carburetor adjustment by manipulating the air screw The idling speed should be adjusted to permit the engine to idle smoothly with the rear wheel stationary Fig 1 17 Fig 1 17 NOTE 1 AM adjustment should be made after the engine has attained operating temperature 2 Poor engine performance may occasionally be caused by troubles in the ignition or valve system Therefore when trying to locate an engine trouble attention should be given to not only carburetor adjustment but also to the other systems 3 Lead tetrachloride or other foreign substonce contained in fuel will collect in the float cham ber and if not cleaned periodically will result in restriction to the fuel flow causing poor engine performance It is recommended that the carburetor be cleaned monthly Carburetor Fuel Level Adjustment It is difficult to directly measure
44. ction and Y Y direction as shown in the figure 38 First of all consider the case in which the rotating unit is in perfect balance m O The inertia in the direction of X X produced by the reciprocating motion of M acts intermittently and sets up vibration within the engine This is referred to as 0 balance Fig 3 38 Next 30 of the weight of M is placed on the op posite side of the crank pin the inertia in the X X direction is reduced to 0 7 M However the rotating section becomes unbalanced m 0 3 M and vibra tion is set up in Y Y direction due to the centrifugal force This is called 30 balance To be more specific the amount of vibration reduced in the X X direction will be transferred to the Y Y direction with the total always being equal regardless of the ratis of distribution Fig 3 39 Further if the counter weight is made equal to the M all vibration in the X X direction is transferred to the Y Y direction This is called 100 balance Fig 3 40 Fig 3 37 Crankshaft 1 Connecting rod 2 Timing sprocket 3 6203 ball bearing 4 R crankshaft 5 Crankpin Roller retainer 7 2 8 roller 8 L Crankshaft 9 6202 ball bearing Fig 3 40 100 balance 2 100 of M 26 Combustion Chamber The combustion chamber of P 50 is heart shaped this allows the cylinder head to be made more compact in comparison with the spherical combustion chamber and is possible to obtain a higher compression
45. d and ignited the resulting combustion forces the piston down ward and the combustion pressure is transformed to the rotary motion of the crankshaft by means of the conne cting rod The operation of the engine is quite similar to the pecaling of a bicycle with power produced by ped aling considered as the combustion pressure of an air fuel mixture the foot acting the role of the piston the pedal the connecting rod and the spr ocket simulating the crankshaft ney QV Spark plug Valve 3 Cylinder Piston 5 Connecting rod 6 Crankshaft The gasoline engine produces power at the crankshaft by the following four sequence of events or strokes i Intake 2 Compression 3 Power Exhaust The term cycle is applied to one complete sequence of these four strokes When the entire cycle of events in the cylinder requires four strokes two crankshaft revolution the engine is referred to as a four cycle engine An engine which accomplishes the entire cycle of events in two strokes one crankshaft revolution is referred to as a two cycle engine P 50 is equipped with a four cycie engine Fig 3 3 6 ene Fig 3 1 1 Pedal 2 Sprocket Fig 3 2 Fig 3 3 Intake stroke Fig 3 4 Compression stroke Fig 3 5 Combustion Fig 3 6 Exhaust 1 Inlet valve 2 Exhaust valve stroke stroke 12 Operation of the Four cycle Engine The four cycle engine requires two reciprocating sequence of the piston two cr
46. e center and the extension line of the frame head pipe For 50 the caster is 66 and trail is 40mm 1 57 in Fig 4 3 Steering Handle The steering handle of P 50 is identical to that of a bicycle in shape and method of mounting however in addition it is equipped with a throttle grip front brake lever and a horn button on the right side and a rear brake lever and an engine decompression lever on the left side A head lamp incorporating a speedometer is moun ted at the center and adjustment of the beam can be made by loosening a nut Fig 4 4 Rear brake lever Engine decompression lever Head light switch Speedometer Horn buttonswitch Handle lever pivot screw Rear view mirror Throttle cable outer holder Fig 4 4 Front brake lever Throttle cable hinge Throttle grip Throttle grip set screw B ES Fig 4 5 Adjustment point 1 Handle set bolt A3 The steering handle is designed for easy riding with due consideration to the frame size and the saddle height The handle can be adjusted to any height within the range marked with L M H stamped on the handle Fig 4 5 Front Fork The front fork is mounted the head pipe bet ween steel balls The front cushion incorporated in the front fork dampers and absorbs shocks from the front wheel Fig 4 6 2 Handle set nut Front cushion Fig 4 6 Front Cushion Even though the frame may be light and of con
47. e connecting rod large end reaches the cylinder and lubricates the piston and the piston pin while the rest passes through the cored hole in the right crankcase to the right crankcase cover routed along the crankcase ribs into the rear wheel axle hole and lubricates the secondary drive gear and the final driven gear The final drive shaft is lubricated by splashed oil coming through oil holes in the right crankcase and right crankcase cover Even when the amount of oil decreases and consequently the oil level in the crankcase drops the oil which comes through the cored hole in the right crankcase is picked up by the cam chain tensioner roller and the cam chain and collected in the oil tray so that the oil level in the oil tray is maintained the same to per form the proper lubrication Fig 3 69 Oil lubrication system Il 1 Oil splasher 2 Oil level 33 tray 40 Breather The interior of the crankcase is continually under varying pressure built up by the reciprocating piston in addition the crankcase is filled with gases from the blowby of the piston and the gases produced by the heat of the crankcase For this reason the decom position of the oil is hastened Further it also incre ases the possibility of oil leaks at the case parting surfaces The breather is designed and incorporated in the case to exhaust the crankcase gases to the outside and also to maintain a constant pressure within the crankcase To completely reliev
48. e drive plate and clutch weights are fixed on the crankshaft while the primary drive sprocket rotates freely around the crankshaft At low speed the clutch weights are not actuated so that the crankshaft rotation is not transmitted to the primary drive sprocket As the speed increases centrifugal force causes the weights to move outward overcoming the clutch spring force to make contact with the primary drive sprocket so that the power may be transmitted to the secondary driven gear Fig 3 60 In P 50 the engine is started by pedaling Therefore if the clutch fails to transmit the force produced by pedaling to the crankshaft the engine will not start When the pedal is depressed the primary drive sprocket starts rotating and causes the three steel balls incorporated therein to apply force against the friction plate which in turn makes contact with the drive plate the friction plate is restricted in the direction of rotation by the clutch weights so that the power is trans mitted from the drive plate to the crankshaft Clutch in 1900 2200RPM Fig 3 60 Sectional view of clutch 1 Clutch damper rubber Friction plate 3 Drive plate 4 Steel ball Hook protector Clutch weight Lifter cam 8 Clutch center guide 9 Ball retainer 10 Primary drive sprocket Clutch spring 2 6mm thrust washer 43 6mm cir clip 44 Clutch weight 6mm pin Engine Disengage Lever By shifting the engine disengage lever 50 be pedalled
49. e the pressure from the oil it is dissipated through the labyrinth Fig 3 70 Fig 3 70 Breather 1 R crankcase 2 R crankcase cover 3 Dissipate the internal pressure to the outside A 4 FRAME Frame Construction and Names of Parts The power generated by the engine is transmitted to the rear wheel to produce the driving force An ideal motorcycle should be one which is safe and easy for anyone to ride P 50 is of a lightweight strong low frame type monocoque body construction which has been designed D E with ultimate in safety consideration Fig 4 1 D Handle 2 Tool box 3 Fuel tank 47 Saddle 5 Rear fender Chain case ip Front fork amp Maffler 9 Exhaust pipe 11 Crank arm 1 Front fender Fig 4 1 Tool Box The tool box is mounted on the rear of the fuel tank and contains a spark plug wrench a screw driver and a 10 14 spanner Fig 4 2 1 Tool box 2 10 14 spanner 3 Screw driver 4 Spark plug wrench Fig 4 2 d N 199 40 1 57 Fig 4 3 1 Caster 2 Trail Steerability and Stability The steerability and stability of a motorcycle de pends upon the frame construction the handle and saddle heights and other factors such as caster and trail which are also important Caster is the angle formed by the ground and the extension line of the frame head pipe Trail is the distance measured on the grcund between the vertical line passing the axl
50. ee wheel sprocket 1 Water and dust caused grease to harden 3 2 Weakened free wheel spring T ee 3 Broken ratchet pawl 2 Replace refer 4 Broken internal teeth on free wheel to section 1 sprocket 3 Replace refer 5 Worn free wheel spring B scraping sound to section 1 heard when reverse pedalling 4 4 Bent rear axle 5 4 Repair or replace 87 1 Trouble Probable cause Corrective action Pedal being driven l Solidified grease l Clean apply grease by the rear wheel 2 Broken ratchet pawl 2 Replace refer to 3 Worn final driven shaft groove causing ratchet section J pawl to bind 3 4 Seizure of final driven shaft and free wheel 4 sprocket Unusual noise l Defective free wheel spring B 1 Replace scraping and 2 Lack grease in free wheel 2 Apply grease knocking noise 3 Bent internal teeth of free wheel sprocket 3 Replace free wheel 4 Worn tensioner sprocket 5 Chain tensioner roller not centrally aligned Replace Repair A Disassembly of Front Wheel 1 Disconnect the front brake cable from the brake panel 2 Unscrew the 4x16 screw and disconnect the spe edometer cable Fig 4 1 3 Remove the 10mm nut draw out the front wheel axle and disassemble the front wheel 4 Remove the brake shoe spring and disassemble the front brake shoes Fig 4 2 Fig 4 1 1 416 cross screw 2 Speedometer cable Fig 4 2 1 Front brake shoe spring 2j Front brake shoe 88 5
51. efer to section 2 2 A Remove dynamo cover Separate the left crankcase 1 2 3 4 Remove flywheel magnet 5 6 Remove the free pawl slider 7 Separate the crankshaft from the right crankcase Fig 2 44 G Inspection and Repair 1 Support the crankshaft on v blocks at the bearings and inspect for run out Fig 2 45 Item Standard value Serviceable limit Left crankshaft TIR 0 015 mm 0 05 max at 30 mm 1 2 in 0 0006 in 0 002 in Right crankshaft TIR 0 015 mm 0 05 max at 26 mm 1 0 in 0 0005 in 0 002 in 2 Support the crankshaft on centers and inspect the bearing for wear in both the parallel and normal direction of crankshaft Fig 2 46 Item Standard value Serviceable limit Parallel direction 0 07 0 22 mm 0 1 0 003 0 009 in 0 004 in Nodal 0 007 0 022 mm 0 05 max 0 0003 0 0009 in 0 002 in 3 Crank pin Item Standard value Serviceable limit y 18 60 18 61 18 55 0 7309 in Diameter 0 7328 0 7332 in min Interference 0 06 0 09 fit 0 0024 0 0035 in 4 Timing sprocket root diameter Fig 2 47 Standard value 27 00 27 08 1 063 1 0670 in 5 Connecting rod small end Fig 2 48 Item Standard value Serviceable limit 4 13 016 13 034 mm 13 08 Inner 0 5130 0 5134 in 0 5154 6 Clearance between connecting rod small end to piston pin Item Standard value Serviceable limit 0 02 0 04 Clearance 0 0008 0
52. enturi 5 Throttle valve Float chamber 7 Float 8 Fuel air mixture 9 Intake stroke Fig 3 11 Operation of throttle valve 4 Throttle grip 2 Fuel 3 Carburetor 4 Air 5 Throttle valve 6 Float valve 7 Float chamber 8 Float Fig 3 12 Operation of choke valve Q Choke button Choke cable 3 Carburetor Throttle Valve The throttle valve regulates the amount of air fuel mixture to enter the cylinder The opening or closing of the throttle valve is controlled by the throttle grip through the use of the throttle cable Turning the thro ttle grip inward raises the throttle valve to increase the diameter of air passage in the carburetor as well as the opening of the needle jet so that the amount of fuel to be discharged is regulated maintaining the air fuel mixture ratio constant at all times Fig 3 11 13 and 14 Mixture Ratio The amount of fuel mixed with the air is called mixture ratio a weight ratio The typical ratio is a mixture of 1 pound of fuel to 15 pounds of air This is normal for riding at a constant speed on a level road Actually the mixture ratio will vary with the engine operating conditions such as The leanest combustible mixture ratio 22 1 The leanest operating mixture ratio 18 1 The mixture ratio for complete combustion 15 1 The mixture ratio to obtain maximum power 13 1 o The richest operating mixture ratio 8 1 e The richest combustible mixture ratio 7 5 1 Fig 3 1
53. es atomized as it is formed into a spray The carburetor performs the same function it draws in the air and atomizes the gasoline The fuel which is delivered from the tank first enters the float chamber of the carburetor Fuel in the float chamber is always maintained at a constant level by the action of the float which regulates the valve If there were no means to maintain the fuel level constant the fuel will overflow out of the float chamber or else there will be insufficient flow of fuel into the carburetor During the intake stroke of the engine the inlet valve opens piston moves downward creating negative pressure in the cylinder The air rushes in from the carburetor As air flows through the venturi the velocity of the air increases as it moves through the narrow throat and causes a decrease in pressure causing the gasoline to be drawn out of the nozzle as a spray and mixes with the passing air stream The volume of air fuel mixture that enters the cylinder is regulated by the amount of opening or closing of the throttle valve Fig 3 10 The choke valve is used to permit the carburetor to supply the engine with the rich mixture required for starting during cold weather The choke button is located at the handle mounting Fig 3 12 Fig 3 8 Fuel tank D Fuel filler opening 2 Fuel 3 Tool Kit Fuel cock To carburetor Fig 3 9 Sprayer 1 Water Fig 3 10 Carburetor 1 Air 2 From fuel tank Choke valve 4 V
54. g 1 33 Fig 1 33 1 Nut B 2 To increase 3 To decrease 4 Nut A 3 Handle and Saddle Height Adjustments Adjust the handle and the saddle to the heights most normally used Handle Adjustment Loosen the 6 40 bolt Loosen the handle set bolt and tap lightly Adjust the handle to a suitable height between H and L marked on the stem and fix in place with the handle set bolt and the 6 40 bolt Upper limit M Middle L Lower limit Fig 1 34 Saddle Adjustment Loosen the 8x42 bolt Adjust the saddle to a suitable height with the mark located within the frame and fix the saddle in place with the 8 42 bolt Fig 1 35 Fig 1 34 1 Handle set bolt 2 6x40 bolt 3 Adjusting position Fig 1 35 1 Mark 28 42 bolt 4 Head Light Adjustment Beam Adjustment The head light case mount with exception of those for export to the U S A is of ball and socket type With the nut loosened it can be adjustable in any di rections Fig 1 36 Focus Adjustment There are two types of bulb Type A bulb shall be installed by fitting to the groove A in the socket and type B bulb to the groove B This applies to standard model as well as export models for Netherlands and the United kingdom Fig 1 37 Fig 1 37 Headlight bulb 62 A SPECIAL TOOLS Clutch outer holder Top cone spanner Flywheel holder Flywheel puller 14 mm lock nut wrench Stem nut spanner 63 B
55. g the final driven shaft rear wheel hub to rotate together On the other hand when the freewheel sprocket rotates in the reverse direction or when the final driven shaft rotates the ratchet pawl does not engage with the freewheel sprocket but slides over the teeth In other words the freewheel sprocket is free when it rotates in the reverse direc Fig 3 63 Freewheel sprocket 1 Ratchet tion Fig 3 63 64 65 pole 2 Freewheel spring A Fig 3 64 Operation of freewheel sprocket in pedaling 1 Crankarm Fig 3 65 Operation of freewheel sprocket in motorcycling Drive Chain Tensioner When the drive chain becomes slack adjustment is usually made by the chain adjusters on the rear wheel however in the case of P 50 a drive chain tensioner is installed to provide a constant specified tension for the drive chain making adjustments unne cessory Fig 3 66 Starting and Stopping the Engine Operation of engine lever To start the engine of the P 50 start pedalling this will rotate the crankshaft However because of the engine compression pedalling is difficult this is overcomed by releasing the cylinder compression so that the crankshaft will turn lightly A decompression lever is located on the left handle To be more specific with the decompression iever held down continue pedaling until a certain speed is attained then release the lever to start the engine To stop the engine on the other hand turn the
56. gnition of the compressed air fuel mix ture by the spark plug to cause combus tion When the piston reaches the top dead center at the end of the compression stroke the compressed air fuel mixture must be ignited Ignition System Magneto system a Flywheel magneto rotating permanent magnet b Box magneto P 50 incorporates a flywheel magneto flyweel AC generator Fig 3 28 Flywheel A C generator 1 Ignition coil Condenser 3 Hightension cord 4 Spark plug cap 5 Spark plug 6 Primary coil 7 Lighting coil 8 Ground 9 Contact breaker 0 Head light i Tail stop light 12 Horn Flywheel AC Generator By rotating the flywheel permanent magnet electrical current is generated at the stationery primary coil The primary current of this voltage is interrupted by the contact breaker to produce a high tension vol tage from the ignition coil This high tension voltage is transmitted by the high tension cord to produce a spark at the spark plug which ignites the air fuel mixture The flywheel magneto in addition to the primary ignition coil incorporates the lamp cail for lighting use to operate lamps horn etc Fig 3 29 Flywheel A C generator E 1 Flywheel 2 Groove 3 Contact breaker 4 Primary coil 5 Lighting coil Ignition Coil The ignition coil is composed of a primary coil having approximately 300 turns of 0 44 mm 0 017 in diameter enamel or polyester coated copper wire and a secondary coil having 20 000 turns of 0 06
57. haust valves therefore when ream ing the guides use particular caution to ream the guides to their respective diameters by the use of the proper reamers Fig 2 15 Inlet valve guide reamer tool No 07007 04401 Exhaust valve guide reamer tool No 07007 04411 Valve spring Fig 2 16 ET Item Standard value Serviceable limit NI HET ENG uL MN iio Ae ais di Free 2 length 19 4 0 764 in 18 0 708in min a 5 7 6 3 8 12 45 mm Tension 5 7 6 3 kg 0 489 in Trueness 1 30 2 max Camshaft Fig 2 17 A Item Standard value Serviceable limit iN 21 44 17 8 Cam height 0 844in 0 701 in min Cam height EX a am at base circle ST EN 22222227088 ME Replace cam sprocket if gear teeth are damaged or excessively worn 8 Cam sprocket root diameter Fig 2 18 Standard value 57 45 2 261 in D Reassembly 1 Reassemble tha valve assembly 2 Assemble the cylinder head exercis care not to damage the cam chain and oil guide Note When installing the head do not forget the head gasket and the two hollow dowel pins Fig 2 19 Fig 2 19 1 Hollow dowel 2 Cylinder head gasket 3 Install the four 6mm nuts and a 6mm screw Torque the cylinder head nuts to 90 120 kg cm 6 5 8 7 ft Ibs Note Torque the nuts diagonally and with a uniform force Fig 2 20 4 Align the flywheel top dead center mark T to the
58. ig 2 13 67 Fig 2 11 1 Cylinder head 2 Red lead or bluing Fig 2 12 1 Cylinder head 2 2 400 emery paper 1 Cylinder head 2 Valve seat cutter Fig 2 13 68 Fig 2 14 1 Dial gauge 2 Valve 4 8 4 812mm _ 4 82 4 832mm 189 0 1894in 0 1898 0 0 1902in Fig 2 16 1 Free length 2 Installed length 3 Load Fig 2 17 1 Oil 2 Camshaft 3 Cam total height Check the seating width of the valve by applying a thin even coat of red lead or bluing on the valve face and rotating the valve slowly in the seat while applying slight pressure The valve contact width will be indicated by the transfer of the red lead or bluing Standard Value 0 7 1 mm 0 028 0 039 in The valve seat is reworked by three types of cutter 30 45 and 60 The 45 cutter is used for truing the seat while the 30 and 60 cutter are used to cut the top and bottom of the valve seat to produce the proper seat width and also to position the seat Fig 2 13 Valve Fig 2 14 Item Standard value Serviceable limit Diameter 474 0 1871 min Overall length 49 5 1 945 in Head 0 4 0 6 7 thickness 0 016 0 024 in 02 0 008 in min 48 6 1 913 in min Note Valve marked must be used as inlet valve however valve without any marking be used for either inlet or exhaust The diameters of the valve guides are different for the inlet and ex
59. iming marks to set the piston at top dead center of the compression stroke Check the tappet clearance with a thickness gauge to see if it is of standard clear ance of 0 05 mm 0 002 in If adjustment is necessary loosen the adjusting screw lock nut and make the adjustment with the adjusting screw Both the inlet and exhaust valves should be set to the same clearance Lock the adjust ing screw after the adjustment has been com pleted Fig 1 10 NOTE 1 The adjustment must be made with a cold engine 2 2 When tightening the adjusting screw lock nut Fig 1 10 i Thickness gauge 0 05 0 002 hold the screw to pevent its turning in 2 Nut 3 Screw 4 Tappet ad justing cap 2 Ignition Timing Adjustment An improper ignition timing regardless of the ac curacy of the valve timing or the proper compression pressure will not produce a satisfactory engine per formance lgnition timing out of adjustment will seri ously affect engine power output as well as resulting in engine overheating and causing backfires Check the ignition timing in the following monner 1 Remove the dynamo cover and align the F mark on the flywheel with the timing index mark on the crankcase n this position check to make sure that the contact points are just about to open Fig 1 11 Valve Timing 0 55 0 022 lift Open BTDC 5 IN Close ABDC 10 Open BBDC 10 EX P Close 5 This
60. imum Fig 3 24 Piston Ring Flutter At low speed the piston ring is forced against the upper side of the ring groove only during the intake stroke At high speed however the inertia of the ring overcomes the gas pressure and friction and floats to the top of the groove immediately before the top dead center in the compression stroke At this moment combustion occurs and the ring is forced against the bottom side of the ring groove by the combustion pressure This up and down movement during exhaust intake compression becomes more and more intense coupled with the increasing inertial force As this seq uence is repeated ultimately the ring vibrates viole at high speed at low speed ntly within the ring groove like a pingpong ball between the racket and the table as shown in the figure 25 and thus allow the gas to blow by Fig 3 25 26 Cylinder The piston cannot operate without the cylinder The cylinder wall is exposed to high temperature and pressure together with the wearing action of the reciprocating piston moving at high speed to produce a Ereat wearing effect Therefore adequate attention must be given to the material and construction of the cylinder as well as the piston The cylinder has many Fig 3 27 Cylinder t D Cooling fins cooling fins on the outside so as to increase the heat dissipating area and prevent the cylinder and piston from overheating COMBUSTION I
61. ints 54 3 Spark Plug Inspection The condition of a spark plug is an indicator of engine performance A dirty or damaged spark plug or plug electrode which is eroded will not produce a good strong spark therefore the spark plug should be inspected periodically for cleaning and adjustments Spark plugs with sooty wet electrodes or elec trodes covered with deposits will permit the high tension voltage to bridge over the gap without sparking there fore spark plugs should be cleaned to be free of foreign objects 1 The use of a spark plug cleaner is the recom mended method of cleaning the plugs however a satisfactory cleaning can be performed by us ing a needle or a stiff wire to remove the de Fig 1 15 1 Spark plug posits and then wash in gasoline followed by drying with a rag 2 Adjust the spark gap after cleaning The correct spark gap 0 6 0 7 mm 0 024 0 028 in The standard spark plug C 6HB NOTE 1 Do not remove the deposits by burning 2 When installing the spark plug install finger tight before torquing with a plug wrench 3 The spark plug electrodes will wear as a result of long use causing a wide spark gap and will result in lowering the sparking performance Therefore periodic inspections should be made 4 Carburetor Adjustments A dirty carburetor or carburetor out of adjustment will cause poor engine performance As an example a carburetor set to a lean air fuel mixture will c
62. kets and assemble 3 Loop the chain on the final driven sprocket and assemble Fig 2 41 Note Check to make sure that the final driven sp rocket is fitted to the secondary drive sproc ket flange 4 install the right crankcase cover Note Check for any damage to the right crankcase cover upset of the screw holes breather pipe restriction 5 Assemble the rear brake cam rear brake shoe stop switch spring and the stop switch assembly Check for proper operation after assembly Fig 2 42 6 Reinstall engine refer to section 2 1 B Fig 2 39 Fig 2 40 Fig 2 42 1 210 steel balls 73 ib Sprocket 2 Final driven sprocket flange 2 top switch assembly top switch spring D Oil guide 2 Headed rivet 3 Tensioner arm Fig 2 44 Crankshaft assembly 1 Dial gauge 2 Crankshaft D Dial gauge 2 Crankshaft D Disassembly of cam chain tensioner oil guide 1 Remove cylinder refer to section 2 2 E 2 Remove reduction unit refer to section 2 3 A 3 Tensioner arm may be removed by filing off the headed rivet Fig 2 43 4 Remove the oil guide E Reassembly 1 When assemblying the tensioner arm use a new rivet and peen over thc cnd 2 Check the movement of the tensioner arm after installing the chain tensioner spring 3 Check the tension of the cam chain F Disassembly of the crankshaft Remove cylinder refer to section 2 2 E Remove the reduction unit r
63. l may be checked for condition by the use of a lamp Connect a 6V 3W bulb across the black lead from the generator and the ground and start the engine If the bulb does not light up there is an opening in the black lead or else the coil is defec tive However if the the bulb continues to stay lit the ignition coil or the breaker point is defec tive Fig 3 5 Specification and Performance Type A C ignition system Ignition characteristics Coupled with the Denso A C generator No 0 38000 074 0 Spark length Engine RPM 3 point spark gap tester 1 000 5 mm 0 1968 in 3 000 8 mm 0 3150 min B Inspection of Governor The cam should move smoothly when governor weight is forced in the direction of the arrow Fig 3 6 and should also return smoothly when released If the operation is not smooth remove the snap washer and clean the inside of the cam and check to see that the cam inside surface is not scratched or coated with metallic dust When assemblying apply a coating of grease to the inside of the cam 6 Inspection of Horn The horn trouble are either no sound poor tone or insufficient loudness L If there is no sound check for poor electrical connections horn switch grounding Insufficient loudness adjust the current control screw on back of the horn Fig 3 7 Turn to the right to decrease loudness and to the left to increase loudness Check point and coil disconnect the
64. le pipe stem As the handle setting bolt is tightened the slotted handle pipe expands and locks on the front fork pipe Loosen the stem nut remove the top cone race and pull out the front fork Fig 4 13 Note Watch for the steel balls which will drop out G Inspection Bend in the handle pipe Twist in the front fork Distorted lock nut Pressure failure of the ball race Reassembly Assemble 26 and 21 steel balls into the bottom and top cone race respectively with the use of grease Fig 4 14 Slide the front fork into the stem carefully and make sure that the steel balls are not dropped Tighten the top cone race fully and then back off 1 4 turn Note Front fork should not be loosen nor tighten so that steering is heavy Hold the top cone race and then tighten the stem nut using a special tool spanners Subsequent assembly operation shall be in the re verse order of disassembly procedure Fig 4 15 Rear Wheel Disassembly Remove engine refer to section 2 1 A Remove the 50mm circlip and disassemble the free wheel sprocket 50 mm thrust washer and C Fig 4 16 Remove the 61mm circlip and disassemble the 50 mm thrust washer B free wheel spring B Fig 4 17 Fig 4 15 Fig 4 14 91 T Steering top cone race 2 Front fork HE D Steering stem nut 2 Steering top cone race 3 Special tool spanner Fig 4 16 p Free wheel sprocket 2 50mm thrust washer e
65. leads at the horn terminal and measure the resistance across the terminals It should register about 1 ohm resistance Fig 3 7 41 Screw 2 Nut 85 86 T Trouble Probable cause Corrective action Steering stability is l Improper tire pressure 1 Front tire 1 3 kg cm 18 5 Ib in ery poor Rear tire 1 7 kg cm 24 2 Ib in 2 Loose handle mounting bolt 2 Retorque refer to chart on page 3 Loose front axle 3 Retorque 4 Loose ball race 4 Retorque 5 Rear axle not properly tightened both sides 5 Properly set into the frame groove 6 Loose front suspension pivot bolt 6 Retorque 7 Loose spoke 7 Replace refer to section A 8 Distorted rim 8 Repair or replace 9 Worn front wheel bearing 9 Retorque Noise originating in 1 Lack grease at the pivot and front cushion 1 Apply grease the cushion bottom 2 Loose cushion mountings 2 Retorque Front brake inopera 1 Front brake arm out of adjustment 1 Adjust to1 0 1 5 cm tive 0 40 0 60 in 2 Lining not fully contacting worn e play at end of 3 Oil on drum 2 Repair or replace 3 Clean Excessive vibration 1 Loose rear axle shaft nut 1 Retorque when rear brake 2 Loose rear axle bolt 2 Retorque applied 3 Worn torque arm mounting hole 3 Replace 1 Rear brake dragging 1 Adjust 2 Disconnected or broken drive chain 2 Repair or replace refer to section 1 Pedal inoperative 3 Locked fr
66. left crankcase index timing mark Fig 2 21 Fig 2 21 1 Left crankcase index mark 2 Flywheel magnet 3 timing mark 5 Align the two holes in the cam sprocket so that 5 they are parallel to the gasketing surface top dead center and install the cam chain Fig 2 22 Fig 2 22 1 Cam chain 2 Holes parallel to gasket surface 3 Cam sprocket 6 Align the holes in the oil guide and center pin and tap the center pin in with light stroke Fig 2 23 Note a Insert the center pin so that the O ring on the center pin is below the cylinder head cen ter pin hole While installing the exercise care not to damage the O ring b Check to make sure that the 10mm washer is not missing Fig 2 23 1 Center pin 2 8 11 0 ring 3 Oil guide 7 Align the camshaft lock pin hole with the pin hole in the cylinder head by using a screwdriver for turning and then drive in the 3 12 dowel pin Fig 2 24 Note a After assembly rotate the flywheel several times to check for smooth operation and also check the valve timing b Curing the dowel pin installation exercise care not to damage the gasket bl inder A Fig 2 24 1 3x12 on dowel pin 8 Assemble the cylinder head cover 2 Cam Shaft 77 4 E Disassembly of Cylinder Piston Piston ring Remove cylinder head refer to section 2 2 A 2 Remove cylinder Fig 2 25 Fig 2 25 Cylinder 3 Extract piston pin clip and remove piston pin Fig 2
67. mber will produce a leaner fuel mixture However the range of its effectiveness is mainly at low speed from idling speed to approxi mately 1 4 throttle opening and has no effect above 1 2 throttle opening A throttle stop screw sets the throttle valve in the idle position Screwing in on the stop screw will cause the throttle valve to rise and backing off will lower the throttle valve 6 Slow Jet The slow jet regulates the fuel flow during idling and small throttle opening and permits the air to enter through the air bleed to mix with the fuel for atomization The slow jet is similar to the main jet in that the larger the jet size number the greater will be the fuel flow and consequently a richer fuel air mixture Fig 3 20 7 Air Screw The air screw regulates the amount of air mixing with the fuel in the slow speed system by controlling the amount of pilot air bleeding with the fuel enter ing through the slow jet In this way the proper fuel air mixture is maintained Screwing in the air screw will produce a rich fuel air mixture by restrict ing the air bleed hole and backing off on the screw will result in a lean mixture COMPRESSION Compress the fuel air mixture in the cylinder Piston The piston plays an important role by performing the intake compression power and exhaust functions It is alternately cooled by the intake fuel air mixture or exposed to the hot gases resulting from the com bustion If the pist
68. ne dies during braking Engine stops suddenly 1 No fuel in tank 2 Adjust while running 2 Clogged fuel cock 3 Adjust 3 Dirty spark plug Carboned or wet 4 Clean or repair 4 Spark plug points being shorted Excessive smoking 1 Loose main jet clogged jet 1 Reduce size of main during medium and high 2 Worn jet needle EE o speed 3 Jet needle dropped from holder 2 Um needle one 3 Repair Excessive exhaust 1 Choke not fully opened smoke after fine high 2 Wrong heat range spark plug used or plug 2 Replace or clean fuel consumption carboned 3 Poor quality fuel oil mixed fuel 4 Air screw not properly adjusted 4 Adjust 5 Worn jet needle 5 Adjust or replace Back fires poor 1 Improperly adjusted air screw 1 Adjust acceleration 2 Clogged air bleed system 2 Clean 3 Loose choke valve 3 Slightly over tighten the choke valve Poor starting 1 Excessive use of choke l Start without choking 2 Fuel overflow 2 Refer to section 2 3 Choke relief valve spring defective 3 Replace the choke valve Fuel overflow 1 Dirt caught in float valve 1 Clean poor idling 2 Damaged valve or valve seat 2 Replace poor performance 3 Punctured float 3 Replace at all speed 4 Water mixed in fuel 4 Drain and clean tank gt excessive fuel consumption difficult starting poor acceleration Poor performance 1 Improperly adjusted jet needle l Set clip to the third at medium speed groove on the needle with possible one fl
69. ng section The needle jet opening is made i2 Type mark and genuine parts mark exceptionally accurate for precise control 3 Jet needle 4 Jet Needle The jet needle in conjuction with the needle jet described earlier regulates the fuel mixture at the intermediate throttle opening principally between 1 4 to 3 4 throttle opening The long tapered jet needle is located within the center hole of the throt tle valve with the tapered end inserted into the needle jet The vertical movement of the throttle valve to which the jet needle is attached controls the flow of the fuel in respect to the throttle open ing to afford a correct fuel mixture ratio There are five clip grooves which are counted from the top on the head of the jet needle to regulate the richness of the fuel mixture The fuel mixture becomes richer as the clip is moved progressively from the No 1 groove to the No 5 groove Fig 3 19 5 Throttle Valve The function of the throttle valve is to control the amount of air taken into the engine this deter mines the engine speed the power output and in addition performs the important function of controll ing the fuel air mixture The throttle valve has a cut away on the air inlet side Changing the size of the cut away designated by cut away No the pressure actuating the needle valve can be altered to change the amount of fuel flow and causes a change to the fuel mixture The valve with a larger cut away nu
70. nger crank axle left side 8 Hanger crank axle right side 4 R crank pedal 5 Drive chain e 4 1 Chain tensioner 2 Free wheel sprocket Fig 1 6 3 Greasing Parts which require lubricating with grease Apply grease to grease nipples with grease gun Fig 1 7 8 Parts not requiring periodic oil change or lubrica tion There are some parts which do not require regular lubrication they are only lubricated whenever the parts are disassembled for repair or replacement or when overhauled These parts are Throttle grip Bottom ball race Top ball race Main stand Front and rear wheel bearings B Engine 1 Tappet Clearance Adjustment The tappet clearance will have a great deal of ef fect on the valve timing Further if the clearance is too small it may prevent the valve from fully closing and result in pressure leak at the valve On the other hand an excessive tappet clearance will produce tappet noise causing noisy engine operation The tappet clea rance will also have a varying degree of effect on the engine power output and engine operation 1 Remove the dynamo cover and align the timing mark on the flywheel with the timing index mark on the crankcase Fig 1 9 2 Remove the tappet adjusting cap on the cylinder head and check the clearance between the adjust ing screw and the valve If the valve is actuated by the screw rotate the flywheel one complete revolution and realign the t
71. nition timing 5 Adjust 6 Defective condenser 6 Replace 7 Decrease of magnetic force in the flywheel 7 Replace magneto 8 Defective primary coil 8 Replace 9 Leaky high tension cord 9 Replace 10 Defective ignition coil 10 Replace 11 Insulation failure in ignition coil 11 Repair Engine will not increase l Improper ignition timing l Adjust W speed 2 Defective plug wet 2 Clean or replace 3 Defective governor 3 Repair or replace Excessive engine speed Defective governor Repair or replace Fire emitted from l Too rich a fuel mixture l Adjust carburetor muffler 2 Excessive carbon deposit ae plug or Breaker points readily 1 Points covered with oil E burns 2 Improper point gap 2 3 Improper ignition timing 3 4 Condenser internally shorted 4 5 Improper capacity condenser 5 Horn inoperative 1 Open connection 2 Defective horn switch contact 2 3 Defective light switch contact 3 4 Defective horn 4 Stop lamp defective 1 Broken bulb filament connector unplugged 1 2 Defective stop switch contact 2 3 Defective lighting switch contact 3 Head light bulb 1 Open tail light circuit causing excessive filament burned voltage Head light defective 1 Bulb filament broken connector unplugged 2 also same for tail light 2 Poor socket contact burned contacts 2 3 Defective lighting switch contact 3 4 Loss of magnetism in A C generator 4 5 A C generator lamp coil defective 5 Light be
72. nter of the inlet stroke To take full advantage of the intake fuel enertia to obtain greater power output from the eugine the inlet valve is kept open several degrees beyond bottom dead center In a similar manner the exhaust valve opens several degrees before bottom dead center of the power stroke in order to utilize difference in pressure between the inside and outside of the cylinder for greater scav enging of the exhaust gas trom the cylinder Ihe valve closes several degrees past top dead center beyond the exhaust stroke in order to utilize the exhaust gas inertia to completely rid the cylinder of the exhaust gas During the period of several degrees before and after top dead center of the exhaust stroke both the inlet and exhaust valves are opened this period is called valve overlap and it serves to prevent the resi dual exhaust gases from blocking the entry of the air fuel mixture Fig 3 55 3l Direction of crank shaft rotation Exhaust stroke Combustion stroke Compression stroke Intake stroke Bottom dead center Fig 3 55 Valve timing diagram Correct Valve Timing Procedure Position the O mark on the timing sprocket in line with the upper alignment hole in the cam sprocket when both of the alignment holes are in parallel with the cylinder head parting surfarce as shown in the figure Install the cam chain in this position the valve timing will then be correct Fig 3 56 Valve timing iTiming sprocket
73. oil will flow cut and also seep into the brake housing B Engine Installation Install the engine in the reverse order of removal Note a When installing the drive chain make sure that the opening of the clip is facing in the opposite direction as chain movement Fig 2 4 b Make sure that the tensioner is properly positioned before tightened c Make sure that no oil is leaking from the rear axle collar d Check fcr the installation of the O ring 65 2 2 Cylinder head cylinder piston piston ring Trouble Probable Cause Corrective Action Low compression l No slack in the decompression lever cable l Provide 5 10 mm xe 0 20 0 40 in piay pressure or no pressure 2 Insufficient tappet clearance at the end ot th 3 Gas leak from the cylinder head gasket lever 4 Excessive piston or ring wear 2 Poe mm A in 5 Valve not properly seating or carbon particle 3 Torque all cylinder caught between valve and seat head bolts to the wen proper value refer 6 Valve timing off to torque table 7 Burnt valve or seizure 4 Replace 5 Lap valve seat and remove carbon 6 Retime 7 Replace Excessive smoke 1 Excessive wear or damage to piston cylinder Replace when throttle opened piston ring 2 Excessive wear to valve guide 3 Loose exhaust valve guide Engine overheat 1 Low engine oil level poor quality oil 1 Add oil to the proper level marked on 2 Damaged spark plug wrong heat r
74. on is closely fitted against the cylin der wall without clearance as shown in the fig 3 21 it would not operate smoothly and may result in seizure On the other hand excessive clearance between the piston and cylinder wall will result in insufficient intake of fuel air mixture causing low compression oil pum ping oil enters the combustion chamber etc and consequence poor engine performance Therefore a good seal must be maintained between the piston and cylinder wall For this purpose piston rings are instal led to provide the necessary seal The piston is made of aluminum die casting equiva lent to SAE 8630 This material is light and has good heat conducting property so that the heat from the combustion can be dissipate rapidly Furthermore this material has a small coefficient of expansion thus minimizing the expansion of the piston at elevated temperature and permits a small piston to cylinder clearnace design Fig 3 20 Slow jet 1 O ring 2 Genuine parts mark 3 Slow jet Slow jet NO Fig 3 21 Piston iD Cylinder 2 Piston 3 Piston rings Fig 3 22 Fig 3 24 Piston ring 1 Top ring 2 Second ring Oil ring Fig 3 25 1 Piston 2 Piston ring 3 Blow by Piston Offset As shown in the figure 3 22 the piston pin is offset slightly from the piston centerline This is to reduce the side load against the cylinder wall and by so doing prevent piston slap Fig 3 22 Piston Shape The sh
75. or both the inlet and exhaust valves Fig 3 53 Fig 3 53 Valve tappet clearance i Valve rocker arm 2 Valve tappet clearance 3 Cam shaft Valve Spring Without the proper sealing of the valves maximum engine output and speed performance cannot be realized The valve spring applies force on the valve to keep it closed The spring force should neither be too st rong nor too weak If the spring force is too weak the valve will not close fully resulting in loss of com pression exhaust leak etc on the other hand if the spring force is too strong it requires unnecessary force to operate the valves and also cause rapid wear to the valve seat Fig 3 54 Fig 3 54 Valve amp valve spring Valve 2 Valve spring Valve Timing It may seem to be correct to have the inlet and exhaust valves opening and closing at top dead center and bottom dead center However as can be seen from Fig 3 55 the valves are not timed in this manner If the inlet valve starts to open at top dead center the piston will travel some distance before the valve becomes fully opened to take the air fuel mixture into the cylinder Consequently sufficient air fuel mixture is not ob tained during the inlet stroke Therefore the inlet valve is timed to start opening several degrees before top dead center of the inlet stroke In addition the inertia will keep the air fuel mixture flowing into the cylinder for several degrees beyond the the bottom dead ce
76. orporated in the same unit The head light will not light up when pedaling Brackets for flashlight installation are available as optional parts NOTE Use only lamps of specified rating 49 Fig 5 3 Lighting switch Stoplight bulb Taillight bulb Destination t Headlight bulb d S A 6V 15W France 6V 6w Holland 6V 10W men 6V 5 3W 6V 17W 6V 1 8W 6V 5W 6V 3W 6V 8w B 1 8W 6V 3w un 6v 1 8w 50 MAINTENANCE AND REPAIR 71 INSPECTION AND ADJUSTMENT In order to maintain the vehicle in safe and best operating condition inspections and adjustments should be properly performed There are two types of inspection namely the daily inspection which is performed by the owner before starting the engine and the periodic inspection which is performed by the dealer in accordance with the estab lished schedule 1 DAILY INSPECTION In performing the daily inspection ask yourself the following questions and then check those specific items to assure that the conditions are satisfactory 1 Is the engine oil level correct Check with the dipstick 2 15 there sufficient fuel for the trip Tank capacity 2 5 3 15 the play of the front brake lever normal t should be 10 15 mm 3 8 5 8 in at the end of Specified volume 0 7 the lever 4 Is the play of the rear brake lever normal It should be 10 15 mm 3 8
77. p Fig 4 17 Freewheel s thrust washer a ss 4 f gt B 2 50mm 61 mm circlip Fig 4 18 1 Ratchet pawl Free wheel sprocket 2 Ratchet pawl Fig 4 21 1 Dial gauge 2 Rear wheel axle complete 4 w After removing the free wheel spring A the ratchet pawl can be disassembled Fig 4 18 Remove five 6mm nuts and the 50mm thrust washer A and the final driven shaft can be disas sembled together Fig 4 19 Disassemble tire and tube from the rim using tire lever Inspection Check for wear of the internal teeth on the free wheel sprocket Fig 4 20 Check for wear and damage of ratchet pawl Check free wheel spring for loss of tension Inspect diameter of final driven shaft Item Standard value Serviceable limit d 49 98 50 11 Sprocket 1957 1973 in Lining cam 97 8 98 0 3 850 3 858 in Rear whael axle diameter bend wear Fig 4 21 Item Standard value Serviceable limit Diameter ads ax 2mm 5 mm Bend 0 008 in 0 020 Rim runout Item Standard value Serviceable limit 0 6 1 0 Side runout 0 024 in 0 040 in max Vertical 0 5 mm 1 0 mm runout 0 020 in 0 040 in max Check loss of tension of rear brake shoe spring Check for bend in the rear brake cam 93 Frame trouble diagnosis Trouble Probable cause Corrective action Excessive a
78. pened sparks are produced in most cases This prevents the sudden collapes of the primary circuit and thereby reduces the high voltage required for the secondary coil and further causes sparking across the point which eventually results in burning or pitting of the breaker points The con denser is installed in parallel across the breaker points to prevent this undesirable condition Condenser can be considered as a device to store electrizity lt is made from sheets of mica or paraffin paper and tin foil in alternate layer Fig 3 32 Spork Plug The spark plug plays the role of igniting the com pressed air fuel mixture within the cylinder The spark pug is securely screwed into the cylinder head with a gasket installed It is exposed to high voltage high compression and high temperature hence high strength heat resistance and reliability are essential At the end of the plug are located the center electrode and the grounded side electrode with clear ance of 0 6 0 7 mm 0 024 0 028 in between the electrodes If the spark plug clearance or gap is too wide re sistance to the high voltage to bridge the gap is increased and prevents the spark from being produ ced if the plug gap is too narrow a short is likely to occur due to carbon deposits and in which case a misfire will result Therefore the plug gap should be maintained at the specified clearance and the electrode surfaces always be kept clean The high voltage d
79. ratio In addition its constructed affords better cooling as well as combustion efficiency Fig 3 41 Fig 3 41 Cylinder head 1 Combustion chamber Squish area This is an area provided between the piston and the cylinder head to further compress part of the fuel air mixture at the end of the combustion stroke to creat a turbulence within the main fuel mixture As the swirling fuel mixture is diverted toward the spark plug the flame propagation is accelerated allowing the the leaner than normal fuel air ratio or the slower burning fuel mixture to burn smoothly and decreasing the ten dency for knocking Fig 3 42 Fig 3 42 Squish area 1 Valve 2 Combustion chamber 3 Squish area Connecting Rod The connecting rod plays the important role of converting the reciprocating motion of the piston caused by the combustion of air fuel mixture to the rotary motion of the crankshaft It also transmits the inertia from the crankshaft to the piston so that the intake compession combustion and exhaust strokes can be performed The material of construction must be light and rigid therefore 1 shaped nickel chrome steel is used in most cases The piston end is called the small end and is conn ected by a piston pin and locked with snap rings to prevent the piston pin from moving in the axial direction The crankshaft end is called the large end The large end is fitted with the needle roller bearing to reduce friction and is
80. rly torqued the head will warp or distort due to the high tempe rature and pressure to which it is exposed This will result in improper sealing of the cylinder head and cause troubles due to gas leak air suction and low compression Fig 2 10 2 The warping of the cylinder head does not develop suddenly and therefore it is very difficult to detect Since the head warpage is chiefly dus to improper head torquing adequate attention should be given To check for cylinder head warpage apply a thin coating of red lead or bluing on a surface plate and then work the head mating surface on the coated surface plate The red lead or bluing will be transferred to the head surface indicating high and low spots Fig 2 11 Warped cylinder head may be repaired by sanding the cylinder head on the surface plate using a 200 grade emery paper and then finishing with a 2400 grade emery paper followed by checking as stated above Fig 2 12 Combustion Chamber Item Standard value Serviceable limit Height 5 5 mm 0 22 in Volume 5CC Use a carbon scraper or brush to remove the carbon from the head and exercise care not to damage 3 Inspect the valve seat by assemblying the vaives as shown in Fig 2 13 and pour oil into the com bustion chamber to cover the valves Apply a blast of compressed air into each ports if bubbles are produced it is an indication that the valves are not properly sealing and repair is necessary F
81. s 1 LIGHTING SWITCH SWITCHING ARRANGEMENT GVISWTURN SIGNAL LIGHT REAR RIGHT FLASHER RELAY 1 S TURN SIGNAL LIGHT FRONT RIGHT e lt HIGH BEAM 6V 1 SW INDICATOR LAMP I 1 i i L jd i E i n 1 Ti H iat i i i SELENIUM 617 5 3W HEAD LIGHT hg 6VI5W 15W 4 4 stor LIGHT L BL L 8L 14 Sit GW iE EE lues dj kJ LES nns l i evig Mirum v TURN SIGNAL LIGHT 522224 REAR LEFT Y ACHORM CONDENSER NOTE INDICATE OPTIONAL PARTS 1 STOP LIGHT SWITCH 6v18W NOISE SUPPRESSOR TURN SIGNAL LIGHT i FRONT LEFT BL BLUE 0 ORANGE TOO ee 1 ot LG LIGHT GREEN w WHITE AC IGNITION COIL BR BROWN BK BLACK G GREEN G W GREEN WHITE SPARK PLUG L R RED BR W BROWN WHITE FLYWHEEL A C GENERATOR GY GREY G Y GREEN YELLOW CONTACT BREAKER MOUNTED LBL LIGHT BLUE edA4 y S 203 For France and Belgium export type lt HORN SWITCH STOP LIGHT 6V 5W HEAD LIGHT STOP LIGHT SWITCH r t 99 2 TAL LIGHT VL RC BR MH LIGHTING SWITCH SWITCHING ARRANGEMENT OFF Q EJ ON AC IGNITION COIL HI
82. s an outward expand ing type shoe actuating on the front wheel In ope ration the action of the right brake lever through the brake wire and brake arm forces the cam to rotate and this in turn forces the brake shoe incorporated in the front wheel hub to move outward and come in contact with the inside of the hub On the rear wheel and inward contracting type brake is employed The action of the left brake lever actuates the rear brake cam forcing the brake shoe to move inward and clamps the final driven shaft flange Fig 4 12 In connection with the action of the rear brake cam the stop switch is actuated to light up the stop lamp The stop switch is a self adjusting type which does not require adjustment and lights up the stop lamp by a specified movement of the left brake lever regard less of change in the cam lever position due to wear to the brake lining Fig 4 13 Saddle The saddle can be adjusted to any height with the bolt within the range of the marking shown on the saddle pipe does not appear above the frame A hand grip is provided to the rear and on the underside of the saddle to use for raising the motor cycle on the stand The saddle also serves as a rear cushion to dampen shocks The saddle hinge is sup ported at two points to prevent the saddle from rolling Fig 4 14 15 Fig 4 13 1 Stop switch spring 2 Step switch 3 Rear brake cam Fig 4 14 1 Marking 2 8 42 hex bolt Fig 4
83. sed for a long period thins out and looses lubricating quality Fig 2 35 Fig 2 37 Fig 2 38 1 Rear brake shoe 2 Rear brake shoe spring n 1 Secondary driven sprocket 2 Rear wheel axle 1 14mm lock nut 2 Clutch outer spanner 3 Clutch outer holder 4 Primary drive sprocket 5 Primary driven sprocket A Disassembly of Reduction Gear 1 Remove engine refer to section 2 1 A 2 Remove rear brake shoes Fig 2 35 3 Disconnect rear brake arm and remove rear brake cam 4 Remove right crankcase cover 5 Remove final driven sprocket Fig 2 36 6 Remove secondary driven and drive sprockets to gether with the chain Fig 2 37 7 Unlock the tongued washer and unscrew the 14mm lock rut the primary driven and drive sprockets Fig 2 38 Note The 14 mm lock nut may be removed before the removel of the sprockets Inspection and Repair Check clutch spring tension Inspect for damage and wear of the 10 steel ball Fig 2 39 Inspect drive plate friction surface for wear Inspect secondary drive sprocket for damage Fig 2 40 Inspect sprocket teeth for wear and damage Inspect rear brake shoe for lining warp and thick ness C Reassembly l Loop the chain on the primary drive and driven sprockets and assemble Note Check to make sure that the primary drive sprocket is operating smoothly and lightly 2 Loop the chain on the secondary drive and driven sproc
84. the fuel level therefore the fuel level is determined indirectly by measuring the height H of the float 1 Place the carburetor in inverted position 2 In this position measure H Old type 3 5mm New type 5 0mm with a gauge The tolerance of the float position is O 1mm 0 0040 in If the float height is beyond the specified tolerance make the adjustment by bending the float arm NOTE 1 When making the measurement with the gauge care should be exercised not to deform the float or float arm since the float valve is not spring loaded 2 The float arm is of hook type therefore too large or too small a clearance will effect the valve movement NEW TYPE CARBURETOR The new type carburetor is used on Frame No P50 A148607 and subsequent The valve seat is driven into the float chamber cover therefore the valve will be removed together with the chamber cover This will simplify the valve cleaning operation since the valve does not have to be disassembled The fuel level in the float chamber is measured from the cover flange as shown Fig 1 19 1 2 The main jet can be disassembled by merely re moving the float chamber cover to get access to the valve The oil cover has been deleted as being no long er required In addition the air jet has been made an integral part of the bore 55 Fig 1 18 1 1 Float arm 2 Float 3 Float valve 2 Fig 1 18 2 1 Gauge 2 Float Fig 1 19 2 1Gauge 2Fioat Fig 1 2
85. top dead center however as the speed increases beyond tnis point the governor will start retarding the amount of spark advance until at 5200 RPM the ignition will take place at 10 before top dead center and this will hold the speed of the motorcycle to maximum of 30 km h The P 50 is in this way controlled to operate at the speed of maximum economy and performance which is 4500 RPM 25 km h Fig 3 35 36 Crankshaft The crankshaft in conjunction with the connecting rod converts the reciprocating motion of the piston to the rotary motion The crankshaft consists of three major parts the right crankshaft left crankshaft and crank pin which are assembled into an integral unit by press fitting It is supported at the both ends with 6202 ball bearings The right and left crankshafts are proportionally balanced to reduce vibration and they also serve as a flywheel Fig 3 37 The crankshaft balance affects the riding comfort therefore this balance has been designed to 60 Crankshaft Balance The balance A is computed by the following equation m Gyrating mass unbalance value A x 100 didis M M Reciprocating mass Gyrating mass m is obtained by subtacting the gyrating mass of the crankpin and the connecting rod from the total weight of the counterweight Reciprocating mass M includes the reciprocating mass of the piston piston pin and connecting rod It determines the balance in the X X dire
86. uced by the ignition coil is received by the spark plug and causes a hot spark to jump across from the center electrode to the side electrode and ignites the con bustible mixture within the engine combustion chamber Fig 3 32 Construction of condenser 1 Mica 2 Tin foil 120 6 0 7 0 024 0 028 Fig 3 33 Construction of spark plug I Terminal 2 Insulator 3 Filler powder 4 Wire packing 5 Center electrode 6 Wrenching surface hex 7 Gasket 8 Main body 39 Electrode 10 Spark gap Fig 3 34 Sectional view of noise suppressor D High tension terminal bushing Terminal water proof cap 3 High tension terminal cap 4 Shield case 5 High tension terminal seal 6 Earth band 7 Carbon resistant P50 Rear wheel output power Comparison of governor controlled and uncontrolled power output Using Carburetor MB 8mm MJ52 Tire pressure 1 8 kg cm Governor spec 5 spark advance at 4800 50 RPM min 18 spark advance at 5300 150 RPM Fixed at 28 BTDC Output at rear wheel PS Riding resistance emm 0 Speed 20 Fig 3 36 Governor operation D Governor operating 2 Spring For Holland export Noise Suppressor Oscillating current which includes high frequency wave generated in the high tension ignition circuit ra diates from the high voltage circuit and the frame body and causes interference by causing noise distortion to image to the television set radio etc To prevent this
87. ve fuel overflows from the needle jet and the slow jet overflowing into the cylinder to dilute the lubricating Therefore to prevent a condition where the fuel rises above certain level an overflow pipe is inserted the float chamber to drain any excess fuel The location of the overflow pipe is such that only the fuel rising above the overflow opening is drained out 5 Choke During cold weather starting it may be necessary to initially use a rich fuel mixture For this purpose a choke valve is incorporated When the choke button is pulled the choke valve is closed however there is a relief valve installed on the choke valve and is kept closed by a relief spring When the throttle valve 2 is opened ap proximately 1 4 and the engine pedalled the cylinder suction pressure causes the relief valve to open and permitting the air to enter the carburetor As this air passes the throttle valve a negative pressure is created which draws the fuel out of the pilot outet and the needle jet 7 mixing with the air to form a rich fuel air mixture ideal for starting This mixture is taken into the cylinder for combustion After the engine has started the suction pressure of the intake air increases resulting in a correspond ing wider opening of the relief valve to maintain the same rich fuel air mixture The opening of the relief valve 5 changes ac cording to the opening of throttle valve 2 The choke valve 20
88. xial play in l Grip setting screw loose l Tighten the throttle grip 2 Throttle grip pipe deformed 2 Replace Throttle grip operation 1 Throttle cable binding 1 Repair or replace heavy 2 Lack of grease on the throttle grip pipe 2 Apply grease 3 Throttle grip pipe deformed 3 Replace Excessive looseness at Crank arm improperly installed Adjust the hanger crank axle Noise produced by the Lack of grease on the hanger pipe bushing Apply grease hanger crank axle Torquing Table Torque value Item kg cm ft lbs p SS Engine Right crankcase 80 110 5 8 8 0 Drain plug 320 270 23 1 19 5 Clutch 380 450 27 5 32 Right crankcase cover 80 120 5 8 8 7 8 mm cylinder bolt 70 100 51 7 2 Cord clamp 60 90 4 3 6 5 Dynamo stator 20 40 1 5 2 9 Fly wheel 180 250 13 0 18 1 Dynamo cover 20 40 1 5 2 9 Cylinder head 90 120 4 5 8 7 Cylinder head cover 80 110 5 8 8 0 Spark plug 110 150 8 0 10 8 Tappet adjusting nut 70 100 5 1 7 2 Tappet cap 90 130 6 5 9 4 Stop switch 80 110 5 8 8 0 brake arm 50 70 3 6 5 1 Frame Front cushion pivot bolt 180 230 13 0 16 6 Front cushion bolts 80 110 5 8 8 0 Torque stopper bolt 200 250 14 5 18 1 Torque arm nut 40 70 2 9 541 Crank arm set pin 40 70 2 9 5 1 Handle setting bolt 250 350 18 1 25 3 Steering head stem nut 400 500 28 9 36 2 Seat bolt 200 250 14 5 18 1 Rear axle nut 400 600 28 9 43 4

Honda P50 Shop Manual - Project Moped Manual

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