Honda CG125 Owners Workshop Manual by Pete Shoemark with an additional Chapter on the 1985 on models by Jeremy Churchill Models covered CG125. 124cc. June 1976 to May 1978 CG125K1. 124cc. May 1978 to March 1981 CG125-B. 124cc. March 1981 to March 1982 CG125-C. 124cc. March 1982 to November 1984 CG125-E. 124cc. November 1984 to April 1985 CG125(BR)-E/F. 124cc. April 1985 to April 1988 CG125(BR)-J. 124cc. April 1988 to September 1991 CG125(BR)-K. 124cc.
Acknowledgements Our thanks are due to APS Motorcycles of Wells (formerly Fran Ridewood & Co), Paul Branson Motorcycles of Yeovil, and CSM of Taunton, who supplied the machines featured in this manual. We would also like to thank the Avon Rubber Company, who kindly supplied information and technical assistance on tyre fitting; NGK Spark Plugs (UK) Ltd for information on spark plug maintenance and electrode conditions and Renold Limited for advice on chain care and renewal.
Contents Page Acknowledgements 2 About this manual 2 Introduction to the Honda CG125 5 Model dimensions and weight 5 Ordering spare parts 6 Safety first! 7 Routine maintenance 8 Quick glance maintenance adjustments and capacities 13 Recommended lubricants 13 Working conditions and tools / Chapter 1 Engine, clutch and gearbox 15 Chapter 2 Fuel system and lubrication 52 Chapter 3 Ignition system 60 Chapter 4 Frame and forks 67 Chapter 5 Wheels, brakes and tyres 80 Chapter 6 Elect
The Honda CG125 model The Honda CG125-C model
Introduction to the Honda CG125 The CG125 model first appeared in the UK in June 1976. It can be regarded in many ways as a utility version of the popular CB1 25 with which it shares many features. The basic difference between the two models is the CG125's use of pushrod operated overhead valves in place of the more popular overhead camshaft arrangement. The unit provides surprisingly brisk performance coupled with good fuel economy.
* Ordering spare parts When ordering spare parts for the CG125 models, it is advisable to deal direct with an official Honda agent, who will be able to supply many of the items required ex-stock. It is advisable to get acquainted with the local Honda agent, and to rely on his advice when purchasing spares.
Safety first! Professional motor mechanics are trained in safe working procedures. However enthusiastic you may be about getting on with the job in hand, do take the time to ensure that your safety is not put at risk. A moments lack of attention can result in an accident, as can failure to observe certain elementary precautions.
Routine maintenance Refer to Chapter 7 for information relating to the 1985 on Brazilian models Introduction Periodic routine maintenance is a continuous process that commences immediately the machine is used. It must be carried out at specified mileage recordings, or on a calendar basis if the machine is not used frequently, whichever is the sooner. Maintenance should be regarded as an insurance policy, to help keep the machine in the peak of condition and to ensure long, trouble-free service.
Routine maintenance 4 Check the tyre pressures and tread wear Check the tyre pressures with a gauge that is known to be accurate. It is worthwhile purchasing a pocket gauge for this purpose because the gauges on garage forecourt airlines are notoriously inaccurate. The pressures, which should be checked with the tyres cold, are specified at the end of Routine maintenance and in Chapter 5. At the same time as the tyre pressures are checked, examine the tyres themselves.
' Routine maintenance 10 capacity and place it beneath the engine unit to catch the old oil. Unscrew the drain plug on the underside of the crankcase and allow the oil to drain. Remove the large hexagon-headed plug which is located just below the left-hand engine casing. Remove the plug, followed by the spring and gauze element, and then wash all these components carefully in a suitable solvent. Wipe out any residual oil from the housing with a clean lint-free rag prior to reassembly.
Routine maintenance Checking the condition of the contact breaker points The contact breaker assembly can be viewed through one of the generator rotor slots; turn the rotor until the points open. Use a small screwdriver to push the moving point open against its spring. Examine the point contact faces. If they are burnt or pitted, remove the points for cleaning or renewal, see Chapter 3.4. Light surface deposits can be removed with crocus paper or a piece of stiff card.
Routine maintenance and close the throttle several times, allowing it to snap shut under its own pressure. Ensure that it is able to shut off quickly and fully at all handlebar positions, then check that there is 2 — 6 mm (0.08 - 0.24 in) of cable free play, measured in terms of twistgrip rotation. If adjustment is necessary, use first the adjuster which is set below the twistgrip.
Routine maintenance 2 Clean the centrifugal oil filter Remove the crankcase right-hand cover, as described in Chapter 1.10, then remove its three retaining screws and withdraw the filter cover; note the gasket. Carefully clean out the deposits which will have accumulated around the inner edge of the unit, noting that these may have become quite compacted and may need scraping off. Wash each part out using a lint-free rag soaked in solvent, then dry them off before refitting the cover.
Working conditions and tools When a major overhaul is contemplated, it is important that a clean, well-lit working space is available, equipped with a workbench and vice, and with space for laying out or storing the dismantled assemblies in an orderly manner where they are unlikely to be disturbed.
Chapter 1 Engine, clutch and gearbox Refer to Chapter 7 for information relating to the 1985 on Brazilian models Contents General description 1 Operations with the engine unit in the frame 2 Operations with engine removed 3 Method of engine/gearbox removal 4 Removing the engine/gearbox unit 5 Dismantling the engine and gearbox unit : general ...
Chapter 1 Engine, clutch and gearbox Piston rings : 2 compression, 1 oil scraper Ring to groove clearance Top 2nd Wear limit (both) End gap (Top and 2nd) - installed Wear limit Thickness (Top and 2nd) Wearlimit 0.03-0.05 mm (0.0012-0.0020 in) 0.02-0.05 mm (0.0008-0.0020in) 0.10 mm (0.0039 in) 0.1 5 - 0 . 3 5 mm (0.0059-0.0138 in) 0.60 mm (0.0236 in) 1.50-1.52 mm (0.0591-0.0598 in) 1.45 mm (0.0571 in) Cylinder bore diameter 56.50 - 56.51 mm (2.2244 - 2.2248 in) nominal Wearlimit 56.60 mm (2.
Chapter 1 Engine, clutch and gearbox 17 Gearbox Reduction ratios Primary drive 1st 2nd 3rd 4th 5th Final drive Selector fork claw end thickness ... Wear limit Selector fork bore diameter Wear limit Selector fork shaft diameter Wear limit Kickstart shaft diameter - at pinion Up to engine number 1020010 Engine number 1020011 on ... Wear limit Kickstart pinion bore diameter Up to engine number 1020010 Wear limit Engine number 1020011 on ...
Chapter 1 Engine, clutch and gearbox packing pieces behind it. The exhaust is secured by two nuts to its mounting bracket, which is secured to the frame by a bolt and by the swinging arm pivot bolt retaining nut. These should be removed and the complete system withdrawn. The footrest assembly should be removed after unscrewing the four bolts which hold it to the underside of the crankcase. 7 Remove the gearchange pedal pinch bolt and slide the pedal off its splines.
Chapter 1 Engine, clutch and gearbox 5.6b ... rear mounting nuts to release complete exhaust system 5.7 Release the locking plate to permit sprocket removal 5.8a Disconnect the battery to isolate the electrical system 5.8b ... then separate the generator output lead connector 6 Dismantling the engine and gearbox unit: general 1 Before commencing work on the engine unit, the external surfaces should be cleaned thoroughly.
Chapter 1 Engine, clutch and gearbox spark plug lead, the exhaust pipe and the cylinder head steady bolt, as described in Section 5 of this Chapter. 2 Slacken and remove the three rocker cover mounting bolts, and lift the cover away, taking care not to damage the rubber sealing ring. The rocker arms may be removed as a unit together with their common support bracket. This is retained by a single bolt at each end, and a central bolt.
24 Fig. 1.2 Cylinder head and barrel - component parts / 2 3 4 5 6 7 8 9 10 Inlet valve guide Exhaust valve guide Cylinder barrel Cylinder base gasket Cylinder head complete Cylinder head gasket Cylinder head cover Rubber seal Spacer < Heat shield < 7 7 Gasket - 2 off < 12 Special bolt 13 Sleeve bolt - 4 off 14 Sea/ing washer 15 Sea/ing washer 16 0 ring - 3 off 17 Plug 18 Bolt -2 off 19 Stud-2 off 20 Stud-2 off <\ early models 7.
r 22 Chapter 1 Engine, clutch and gearbox 7.2c Withdraw the pushrods, noting which is inlet and exhaust 7.3 Note the additional, special bolt, which retains head and cam follower shaft \' 7.4a Slide barrel carefully off its studs 7.4b Pack the crankcase mouth with rag if the crankcase is not to be separated 8 Dismantling the engine and gearbox unit: removing the generator assembly 7.
Chapter 1 Engine, clutch and gearbox generator components. The central retaining nut should be temporarily refitted so that it is flush with the shaft end. Do not place undue strain on the assembly using this method. If removal proves difficult, abandon the attempt and obtain the proper service tool. 3 With the flywheel/rotor removed as described above, release the three countersunk screws which secure the generator stator.
9.2a Note thrust washer when removing cam gear shaft 10.3 Home-made peg spanner is crude but proved effective mi 9.2b Lift out the cam gear/cam unit I ^&W 11.1a Pass screwdriver tnrough holes in pump to release mounting screws 10.4 With the nut removed, slide inner housing off its splines 11.
Chapter 1 Engine, clutch and gearbox 25 12 Dismantling the engine/gearbox unit: removing the clutch assembly and crankshaft pinion 13 Dismantling the engine/gearbox unit: removing the gearchange shaft and mechanism 1 Lift out the clutch pushrod together with the cup in which it seats, then remove the four bolts which secure the clutch thrust plate, unscrewing them in a diagonal sequence until the clutch spring pressure is released.
12.1a Remove the pushrod and pushrod seat 0 12.1b Lift away the thrust plate after releasing bolts 12.2a Remove the circlip to allow ... 12.2b ... outer half of clutch centre to be removed, followed by clutch plates . . . 12.2c ... and inner half of clutch centre 1 2.
Chapter 1 Engine, clutch and gearbox 1 2.2e Crankshaft pinion can be slid off splined crankshaft end 14 Dismantling the engine/gearbox unit: removing the endfloat plunger and neutral switch 1 Although the above mentioned components will not prevent crankcase separation, it is advisable to remove them as this will need to be done prior to reassembly. The plunger assembly is retained by a single fixing bolt, and can be with* drawn from the crankcase after this has been released.
1 2 3 4 5 6 7 Fig. 1.6 Crankshaft and piston 8 Crankpin Crankshaft assembly 9 Cam drive gear Piston ring set 10 Woodruff key Piston 11 Main bearing (left-hand) Gudgeon pin 12 Main bearing (right-hand) Connecting rod 13 Small end bearing RH flywheel 14 Circlip-2off LH flywheel Fig. 1.
14.1 End-float plunger is retained by a single bolt 14.2 Neutral indicator switch is easily withdrawn 16.1a Disengage and remove the kickstart mechanism 16.1b Crankshaft assembly lifts easily out of case I 1 16.2a Lift selector fork assembly slightly to allow selector drum to be withdrawn 16.
r 30 Chapter 1 Engine, clutch and gearbox 1 6.3a Lift out mainshaft and layshaft clusters complete 1 6.3b Do not lose these shims which may remain in case • 17.1a Clean cases thoroughly and check bearings etc 17.1b Ensure that oilways are kept clear 18 Crankshaft and gearbox main bearings: removal 1 The crankshaft bearings will remain on their shafts when the crankshaft assembly is withdrawn from the crankcase.
Chapter 1 Engine, clutch and gearbox A certain amount of side play is intentional, and should be between 0-05 - 0-30 mm (0-002 - 0 0 1 2 in) on a new crankshaft. The maximum allowable side play is 0-80 mm (0032 in) and can be checked with a feeler gauge between the flywheel face and the edge of the connecting rod. 2 It is not possible to separate the flywheel assembly in order to replace the bearing because the parallel sided crankpin is pressed into the flywheels.
Chapter 1 Engine, clutch and gearbox 5 Piston ring wear is measured by removing the rings from the piston and inserting them in the cylinder bore using the crown of the piston to locate them approximately 25 mm (1 in) from the top of the bore. Make sure they rest square with the bore. Measure the end gap with a feeler gauge; if it exceeds 0-6 mm (0-024 in) the rings require renewal.
23.1a Compress springs and prise out collet halves, to release ... 23.1b ... the top spring seat . 23.1 c ... and valve springs 23.1d Note lower outer spring seat around valve guide 23.1 e Valve can be withdrawn for cleaning and examination 23.
Chapter 1 Engine, clutch and gearbox 24 Examination and decarbonisation: cylinder head 1 Remove all traces of carbon from the cylinder head and valve ports, using a soft scraper. Extreme care should be taken to ensure the combustion chamber and valve seats are not marked in any way, otherwise hot spots and leakages may occur. Finish by polishing the combustion chamber so that carbon does not adhere so easily in the future. Use metal polish and NOT emery cloth.
Chapter 1 Engine, clutch and gearbox 4 Measure the uncompressed length of the clutch springs which should be 35.5 mm (1-398 in) when new. Should any spring have settled to the specified service limit or shorter, all four springs should be renewed as a set. 5 Check the condition of the thrust bearing assembly and pushrod, which are located in the clutch centre. Excessive play or wear will cause noise and erratic operation.
Chapter 1 Engine, clutch and gearbox 2 Fit the neutral switch contact to the end of the selector drum, and then lower it, contact downwards, into the crankcase half, so that the contact aligns with the neutral switch. It will be necessary to lift the selector fork assembly slightly, so that the selector fork pins can be engaged in their tracks in the selector drum. When the assembly has been installed correctly, lubricate it with engine oil, and check gearbox operation by turning the selector drum.
32.2f Slide 2nd gear pinion (1 7T) into position 32.2g Slide shim and sleeve gear onto other end of shaft 32.2h Place 4th gear pinion (27T) in position on layshaft and fit washer and clip 32.2i Fit 3rd gear pinion (29T) 32.2j Bottom gear pinion (36T) has renewable bush 32.2k ...
32.21 Fit kickstart pinion (also bushed) 32.2m Note: If layshaft has this circlip groove, it must be ignored. Do not fit circlip 32.2n Slide 5th gear pinion (25T) into position - no circlip 32.2o Fit 2nd gear pinion (32T), and thrustwasher ' 32.2p The assembled clusters should look like this: 32.
33.1 Lower fork is retained by spring-loaded ball 33.2a Do not omit the neutral switch contact during reassembly 33.2b Place gearbox components into left-hand casing 33.3 The crankshaft will drop into position 33.4a Fit the kickstart mechanism .. 33.4b ...
Chapter 1 Engine, clutch and gearbox 34 Preparation of crankcase jointing surfaces: joining the crankcase 1 Coat the jointing surfaces of both crankcases with a thin layer of gasket cement, and fit the crankcase gasket to the lefthand casing half. 2 With the left-hand crankcase lying on its left side on the workbench, lower the right-hand crankcase on to it, taking care to locate the right-hand main bearing in its housing and the gearshafts in their respective bearings.
35.2a Detent roller arm is retained by a shouldered bolt 35.2b Note locating pin which engages in camplate 35.2c Fit camplate and tighten bolt 35.2d If the gearchange pedal shaft has been dismantled, reassemble . . . 35.2e ... ensuring that springs are aligned properly 35.
Chapter 1 Engine, clutch and gearbox 36 Replacing the clutch assembly and centrifugal oil filter 1 Place the clutch outer drum in position on the gearbox mainshaft end, followed by the splined thrust washer and inner clutch centre half. Fit the clutch plates, starting with a friction plate, then a plain plate. Build up the layers of plates, finishing with a friction plate, and ensuring that the internal splines of the plain plates are in line.
I 36.2c Fit pressure plate and pushrod and cup 36.2b Position springs over threaded pillars /P. 36.3a Slide on the inner half of centrifugal filter 36.3b Note markings on special washer 36.3c ... which should be fitted thus 36.
Chapter 1 Engine, clutch and gearbox Fit the endfloat plunger in its bore, and depress it against spring pressure while the retaining bolt is tightened. 4 Place the generator stator in position, noting the flat at the top which engages with the head of the cam gear shaft. Ensure that the rubber fillet through which the generator cables pass is located correctly. The generator rotor can now be placed over the mainshaft, and its securing nut tightened to a torque setting of 4.0 - 5.
37.2b ... aligning the timing marks as shown 37.3a Do not omit thrust washer or small spring when refitting cam gear shaft 37.3b Depress end float plunger while single bolt is tightened 37.4a Reconnect lead to neutral switch 37.4b Ensure that generator leads pass behind guide plate 38.
Chapter 1 Engine, clutch and gearbox 39 Refitting the piston, cylinder barrel, cylinder head and rocker arms 1 Raise the connecting rod to its highest point and pad the mouth of the crankcase with clean rag as a precaution against displaced parts falling in. 2 The piston is marked 'IN' denoting the inlet valve cutaway, and must be fitted in the correct relative position ie, towards the rear. 3 Lightly oil and fit the piston onto the connecting rod by inserting the gudgeon pin.
Chapter 1 Engine, clutch and gearbox 47 39.7a Fit new head gasket. Note position of dowels 39.7b Ensure that pushrods engage in cam followers correctly 39.8a Refit pushrod guide and rocker assembly ... 39.8b ... oiling them liberally 40 Refitting the engine/gearbox unit in the frame 39.9 Adjust valve clearances, then refit cylinder head cover 1 It is worth checking at this stage that nothing has been omitted during the rebuilding sequences.
Chapter 1 Engine, clutch and gearbox ensuring that all gaskets and/or O-rings are renewed if necessary, that all components are refitted the correct way round and in the correct order and that the fasteners are securely tightened. Refit the throttle valve assembly which will have been left attached to the throttle cable, and screw down the mixing chamber top. The air hose from the air filter box can now be reconnected to the carburettor.
40.3a Push breather pipe over crankcase stub 40.3b Reconnect clutch cable, and check adjustment 40.3c Refit the carburettor, noting guide for HT cable 40.4a Footrest assembly bolts onto underside of crankcase • 40.4b Fit new sealing ring in the exhaust port ... 40.4c ... then fit exhaust system. Note packing pieces .
Chapter 1 Engine, clutch and gearbox 41 Starting and running the rebuilt engine 1 Make a final check around the engine to ensure that everything has been refitted correctly and tightened down securely. Before starting the engine, unscrew the plug at the top of the cylinder head cover, and watch this carefully during the first few seconds of running to ensure that the oil is circulating properly.
Chapter 1 Engine, clutch and gearbox Symptom Cause Noisy engine Tappet noise: Excessive tappet clearance Weakened or broken valve spring Knocking noise from cylinder: Worn piston and cylinder bore Carbon in combustion chamber Worn gudgeon pin or connecting rod small end Rebore cylinder and fit oversize piston. Decoke engine. Renew. Engine noise Excessive run-out of crankshaft Worn crankshaft bearings Worn connecting rod Worn transmission splines Worn or binding transmission gear teeth Renew.
Chapter 2 Fuel system and lubrication Refer to Chapter 7 for information relating to the 1985 on Brazilian models Contents General description Petrol tank : removal and replacement Petrol feed pipe : examination Petrol tap : removal, repair and replacement Carburettor: removal - pre (T)PFC type Carburettor: overhaul - pre (T)PFC type Carburettor: adjustment - pre (T)PFC type .
Chapter 2 Fuel system and lubrication 53 underside of the top, and disengaging the cable end from its recess in the valve. The needle is held by a spring clip, which is itself positioned by a second clip inside the valve. It is normally advisable to leave this assembly undisturbed unless obviously worn. 3 Slacken and remove the two flange mounting nuts, and pull the carburettor body clear of the mounting studs. Do not remove the heat shield or spacing block unless necessary.
Chapter 2 Fuel system and lubrication 5.3a Remove carburettor body from inlet port carburettor fuel level. If the needle seat is worn or damaged it must be renewed also; on later models note that this means renewing the complete carburettor assembly. 3 The main jet is screwed into the jet holder which is itself screwed into the central column projecting from the carburettor underside.
Chapter 2 Fuel system and lubrication 55 Fig. 2.1 Carburettor 077A type 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Gasket set Needle valve assembly Needle jet Float assembly Mixing chamber top Float bowl assembly Pilot and throttle stop screws Throttle valve assembly Carburettor complete Rubber cap Needle jet holder Drain pipe Clip Main jet Pilot jet 12 6.1 Float bowl is retained by three screws - later type 6.
6.3a Main jet can be unscrewed for cleaning . 6.3b . . . as can the jet holder Fig. 2.2 Carburettor - PD88E type 6.
Chapter 2 Fuel system and lubrication 57 system is kept airtight, particularly at the exhaust port. Air leaks here will cause mysterious backfiring when the machine is on overrun, as air will be drawn in causing residual gases to be ignited in the exhaust pipe. To this end, make sure that the composite sealing ring is renewed each time the system is removed. 12 Oil pump: removal, examination and renovation 1 Pull off the right-hand side panel to gain access to the air cleaner case.
12.2a Note alignment marks on oil pump components 12.2c ... to allow pinion ... 12.3 Check pump components as described 12.2b Casing is secured by two bolts, and can be removed ... 12.2d ... and spindle to be withdrawn 13.
Chapter 2 Fuel system and lubrication 14 Fault diagnosis: fuel system and lubrication Symptom Cause Remedy Excessive fuel consumption Air cleaner choked or restricted Fuel leaking from carburettor. Float sticking Badly worn or distorted carburettor Jet needle setting too high Main jet too large or loose Carburettor flooding Clean or renew. Check all unions and gaskets. Float needle seat needs cleaning. Replace. Adjust to figure given in Specifications. Fit correct jet or tighten if necessary.
Chapter 3 Ignition system Refer to Chapter 7 for information relating to the 1985 on Brazilian models Contents General description Generator : checking the output Contact breaker : adjustment Contact breaker : removal and renewal Checking the ignition timing 1 2 3 4 5 Ignition coil : checking Condenser : location, removal and replacement Spark plug : checking and re-setting the gap Fault diagnosis Specifications Ignition timing Initial - 'F' mark aligned Advance starts at Full advance at Ignition system
Chapter 3 Ignition system IGNITION COIL 61 CONDENSER SPARK PLUG CONTACT BREAKER Fig. 3.2 Ignition system: component location 3 Contact breaker: adjustment 1 To gain access to the contact breaker assembly, the lefthand outer casing should be removed. It is retained by four screws. The contact breaker is mounted on the stator or backplate, and operated by a cam which is fitted to the centre boss inside the flywheel/rotor.
Chapter 3 Ignition system 3.1 Automatic timing unit in flywheel rotor may be lubricated lightly 3.3 Check contact breaker gap using feeler gauge i 4.3 Flywheel rotor centre has thread to accept extractor 5 4.4 A : E clip. B : Fixed contact securing screw C : Terminal Checking the ignition timing 1 The ignition timing can be checked using a battery and bulb arrangement connected as shown in the accompanying diagram.
Chapter 3 Ignition system and battery arrangement connected as shown in the accompanying diagrams. Should any of these checks not produce the expected result, the coil should be removed and taken to a Honda Service Agent or Auto-Electrical specialist for a more thorough check. 7 altered from standard. The use of too cold, or hard, a grade of plug will result in fouling and the use of too hot, or soft, a grade of plug will result in engine damage due to excess heat being generated.
Bulb should not light B Fig. 3.4 Condenser: test sequence A: Using a battery/bulb arrangement B: Using a multimeter 6V10-20W Bulb should not light Bulb should not light. Bulb should light. Fig. 3.
Electrode gap check - use a wire type gauge for best results Electrode gap adjustment - bend the side electrode using the correct tool Normal condition - A brown, tan or grey firing end indicates that the engine is in good condition and that the plug type is correct Ash deposits - Light brown deposits encrusted on the electrodes and insulator, leading to misfire and hesitation.
DO Chapter 3 Ignition system 9 Fault diagnosis : ignition system Symptom Cause Remedy Engine will not start Plug faulty Defective ignition coil Dirty points Poor points contact Check plug and adjust gap or renew. Renew. Clean or renew and check gap. Check for arcing. Renew condenser.
Chapter 4 Frame and forks Refer to Chapter 7 for information relating to the 1985 on Brazilian models Contents General description 1 Front forks : removal - general 2 Front forks : removing the fork assembly from the frame 3 Front forks : removing the fork legs from the yokes ...
2 Chapter 4 Frame and forks Front forks: removal — general 1 It is unlikely that the forks will require removal from the frame unless the fork seals are leaking or accident damage has been sustained. In the event that the latter has occurred, it should be noted that the frame may also have become bent, and whilst this may not be obvious when checked visually, could prove to be potentially dangerous.
Chapter 4 Frame and forks 69 2 Ball bearings are cheap. If the originals are marked or discoloured, they should be renewed. To hold the steel balls in position during reassembly, pack the bearings with grease. 6 Fork yokes: examination 1 To check the top yoke for accident damage, push the fork stanchions through the bottom yoke and fit the top yoke. If it lines up, it can be assumed the yokes are not bent. Both must also be checked for cracks. If they are damaged or cracked, fit new replacements.
' >. Fig. 4.
Chapter 4 Frame and forks 71 diameter measured and compared with the figures given in the Specifications section of this Chapter. Play between the lower bush/piston and the inside of the lower leg, must not exceed 0.2 mm (0.008 in). 5 The lower leg bore and the fork stanchions must also be examined for signs of scoring, which is usually caused by grit particles becoming embedded in the seal lip. The stanchions should be checked for straightness, especially if accident damage is suspected.
k 7.4b ... and lower, plain bush, for wear 7.6a Note the position of spring rings ... 7.6b ... which locate the bushes on the stanchion 7.6c Do not omit restrictor, if removed 7.6d Fit lower leg over bushes 7.
Chapter 4 Frame and forks 7.6f Do not omit the screw in base of lower leg, where necessary 8 Fork legs: dismantling, examination and renovation CG125 K1. B, C and E models 1 The forks fitted to all later models differ in having longer fork springs that are much smaller in diameter so that they fit inside the fork stanchions. The metal shrouds of the early forks are replaced by a small rubber dust seal leaving the surface of the stanchion exposed.
Chapter 4 Frame and forks V Fig. 4.
1 1.4a Slacken and remove pivot shaft nut Fig. 4.4 Front forks - CG125 K1 and later models 1 2 3 4 5 6 7 8 Top bolt O-ring Washer Dust seal Stanchion Circlip Backing ring Oil seal 9 10 11 12 13 14 15 16 Upper bush Circlip - 2 off Lower bush Circlip Spring Lower leg Sealing washer Oil drain bolt 1 1.4b ... and withdraw the pivot shaft 11.4c Remove swinging arm from frame 1 1,4d ...
Chapter 4 Frame and forks 1 1.5 Bushes can be pressed out if worn 1 1.6 Check that torque arm mounting is secure 11 Fig. 4.
Chapter 4 Frame and forks Fig. 4.
Chapter 4 Frame and forks 16 Speedometer head: removal and replacement 19 Steering lock: removal and replacement 1 The speedometer is secured to a bracket that bolts to the top yoke, on which the speedometer head is rubber mounted to prevent internal damage by vibration. 2 To remove the instrument unscrew the drive cable and take off the headlamp unit to allow the indicator and internal lighting lamps to be disconnected. Unscrew the mounting nuts and remove. Replace in reverse order of dismantling.
Chapter 4 Frame and forks /» 21 Fault diagnosis: frame and forks Symptom Cause Remedy Machine veers either to the left or the right with hands off handlebars Bent frame Twisted forks Wheels out of alignment Check, and renew. Check, and renew. Check and realign. Machine rolls at low speed Overtight steering head bearings Slacken until adjustment is correct. Machine judders when front brake is applied Slack steering head bearings Worn fork bushes Tighten, until adjustment is correct.
. Chapter 5 Wheels, brakes and tyres Refer to Chapter 7 for information relating to the 1985 on Brazilian models Contents General description Front wheel : examination and renovation Front wheel: removal Front brake: examination and renovation Adjusting the front brake Front wheel bearings: removal and replacement Front wheel : replacement Rear wheel : examination Rear wheel : removal 1 2 3 4 5 6 7 8 9 Rear brake : examination and renovation Rear wheel bearings : removal and replacement ...
Chapter 5 Wheels, brakes and tyres 3 Front wheel: removal 1 With the machine supported on the centre stand, block the stand and crankcase to raise the wheel clear of the ground. 2 Detach the speedometer drive cable at the wheel, by unscrewing the knurled gland nut which retains it. Remove the front brake cable. 3 Remove the wheel spindle nut and split pin, and withdraw the spindle with the aid of a tommy bar. The wheel can now be lowered clear of the forks and put to one side.
3.2 Detach the speedometer and brake cables 3.3 Withdraw the wheel spindle, and lower the wheel clear 4.1 a Brake plate assembly can be lifted out of drum ... 4.1b ... for examination and renovation 4.2 Examine the brake drum surface for signs of scoring 4.
Chapter 5 Wheels, brakes and tyres 83 adjusted by removing the operating arm from the brake camshaft and rotating it by one or two splines until the angle is correct. Ensure that all components are correctly secured on reassembly. 6 4.7 Align punch marks to ensure operating arm is refitted correctly on brake camshaft 5 Front wheel bearings: removal and replacement 1 There are two bearings in the front wheel.
Chapter 5 Wheels, brakes and tyres 8 Rear wheel: examination 1 Place the machine on the centre stand and before removing the rear wheel, follow the procedure described for checking the front wheel for alignment of the rim, loose or broken spokes or any other defects. 9 Rear wheel: removal 6.3c Tap bearings into place using a socket as a drift 1 Start by removing the two halves of the rear chain enclosure, and place these to one side. There is no need to remove the left-hand engine casing.
Chapter 5 Wheels, brakes and tyres 3 Remove the spring pin which retains the torque arm nut, then remove the nut and disengage the torque arm from the brake plate. Slacken off the two wheel spindle drawbolt adjusters, having made a note of their position against the graduations on the fork ends. Pull out the split pin from the castellated wheel spindle nut, and remove the nut.
Chapter 5 Wheels, brakes and tyres Fig. 5.2 Rear brake - component parts 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Drawbolt Rear wheel spindle Spacer Brake plate Cam Actuating lever Rubber washer Brake shoes - 2 off Return springs - 2 off Shouldered bolt Washer Washer-2 off Bolt Nut-2 off Nut Washer Spring washer Split pin 10 11 Rear wheel bearings: removal and replacement 1 Remove the oil seal and remember it has to be replaced by a new one.
Tyre changing sequence - tubed tyres Deflate tyre. After pushing tyre beads away from rim flanges push tyre bead into well of rim at point opposite valve. Insert tyre lever adjacent to valve and work bead over edge of rim. Use two levers to work bead over edge of rim. Note use of rim protectors Remove inner tube from tyre When first bead is clear, remove tyre as shown When fitting, partially inflate I inner tube and insert in tyre Work first bead over rim and feed valve through hole in rim.
11.2b New bearings must be fitted if worn 11.2c A large socket makes a useful drift 11.2d New seals should be fitted together with bearings 12.1a Sprocket is retained by large diameter circlip 12.1b The pins engage in bonded rubber bushes 12.
Chapter 5 Wheels, brakes and tyres 16 Fig. 5.3. Rear wheel and hub - component parts / 2 3 4 5 6 7 8 Drawbolt Rear wheel sprocket Bonded rubber bush -4 off Dust cover Rear hub Spacer Wheel rim Tyre (3.00x17-6PR) 9 10 11 12 13 14 15 16 Inner tube Rim tape Sprocket mounting pin — 4 off Castellated nut Nut-4off Circlip Seal Nut-2 off 14 Final drive chain: examination, adjustment and lubrication 1 The rear chain on CG125 models derives considerable benefit from its complete enclosure.
14.2a Plug can be removed for lubrication and chain tension check 14.2b Ensure that drain holes remain clear- unblock if necessary 14.4 Marks ensure correct wheel alignment 14.8 Closed end of link should face direction of travel l> 14.9 An equivalent British-made chain is available Fig. 5.
Chapter 5 Wheels, brakes and tyres 15 Rear wheel: replacement 1 Clean and grease the rear wheel spindle, check that the sprocket and dust cover have been refitted to the hub left-hand side, and refit the brake plate assembly to the drum. Fit one of the chain adjusting drawbolts under the spindle head.
1 92 Chapter 5 Wheels, brakes and tyres 17 Fault diagnosis: wheels, brakes and tyres Symptom Cause Remedy Ineffective brakes Worn brake lining or pads Foreign bodies on brake linings surface Incorrect engagement of brake arm serration Worn brake cam Renew. Clean. Buckle orflat in wheel rim, most likely front wheel Check rim alignment by spinning wheel. Correct by retensioning spokes or building on new rim. Check tyre alignment.
Chapter 6 Electrical system Refer to Chapter 7 for information relating to the 1985 on Brazilian models Contents General description 1 Checking the electrical system : general 2 Charging system : checking the output 3 Rectifier : checking for malfunctions 4 Battery : charging procedure and maintenance 5 Headlamp : replacing bulbs and adjusting beam height 6 Tail and stop lamp : replacing bulbs 7 Rear brake stop lamp switch : adjusting 8 Front brake stop lamp switch : location and replacement 9 Instrument il
3 Chapter 6 Electrical system Charging system: checking the output 1 A defect in the charging system will produce poor headlamp performance, and probably, repeatedly discharged batteries. In order to check that the battery is receiving the correct charge, the following procedure should be adopted: 2 Obtain a 0 - 10 volt dc voltmeter, and connect this between the two battery terminals.
Chapter 6 Electrical system Green/red Black Pink Points opened. Fig. 6.2 Checking the generator stator Fig. 6.3 Flywheel generator and left-hand cover ; 2 3 4 5 18 18 3 Symptoms of a damaged rectifier; a persistent flat battery or persistent overcharging. Note that if the battery is connected up incorrectly, a damaged rectifier is very likely to result.
Chapter 6 Electrical system Battery charging instructions Normal charge Rapid charge Charging current rate 0.6 AH 2.0 AH max. • Checking for full charge (1) Specific gravity: 1.260- 1.280 (20°C: 68° F) maintained constant (2)0.2AH -0.6AH (3) 7.5V-8.3V (1) Specific gravity: 1.260 - 1.280 maintained at 20° C (68°F) (2) Voltage: When large volume of gas is emitted from the battery (in about 2-3 hours for fully discharged battery), reduce charging rate to 0.2A.
Chapter 6 Electrical system —loWER LEVEL UASA 6N6-3B VUASA BATTERY CO-. LTD- MADE IN JAPAN 4.1 Rectifier is rubber-mounted to battery carrier 5.4 Maintain electrolyte between two level marks and twist it anticlockwise to release it. On CG125-C and E models twist the holder anticlockwise to release it, and withdraw it, noting how the locating tangs must be engaged with the matching reflector cutouts if the holder is to be refitted correctly. Detach the bulb as described above.
11 Fig. 6.6 Headlamp u n i t - CG125. CG125 K1 and B models 1 Rim 2 W-clip - 4 off 3 Screw 4 Washer 5 Reflector 6 7 8 9 10 Headlamp bulb Bulbholder Pilot lamp bulb* Grommet Shell 11 Bolt -2 off 12 Washer - 2 off 13 Nut - 2 off *not fitted to early CGI25 models Fig. 6.
Chapter 6 Electrical system w r 6.7 Note how W-clips are fitted before disturbing them 8 7.2 Tail lamp lens is retained by two screws Rear brake stop lamp switch: adjusting 1 To adjust the stop lamp switch hold the switch body and with the correct size spanner screw down the adjuster nut thus raising the rear brake light switch and making it operate sooner. Never adjust too tightly; the light should come on just as the first braking pressure is felt.
Chapter 6 Electrical system Fig. 6.8 Speedometer - early models (later models similar) / 2 3 4 5 6 Bulb(6v3w) Bulb(6v1.7w)-2off Speedometer assembly Mounting bracket Rubber ring - 2 off Rubber washer - 2 off 7 Spacer -2 off 8 Speedometer cable complete 9 Inner cable 10 Bolt-2 off 11 Nut 12 Washer-2 off 14 Horn push and horn: adjustment 1 The horn push button is incorporated in the handlebar control and must be replaced if it malfunctions.
Chapter 6 Electrical system 14.2 Horn is located here 15.1 Main fuse holder clips to battery case 15.2 Spare fuses should be kept in holder inside panel 17.2 Wiring is colour-coded to facilitate tracing of faults is to drain off excess power generated when only the side lights are in use and to convert it to heat which is dissipated by the air stream. When the main headlamp is in use, the resistor is switched out of the circuit so that full current is available to meet the increased electrical demand.
Chapter 6 Electrical system 29 22 13 20 22 Fig. 6.
FLASHING I N D I C A T O R CONTROL-HORN SWITCH ARRANGEMENT W R o -o R HO L FREE (N) R.FRONT FLASHING INDICATOR LAMP L o wife coior Gr o LB PUSH 0 IGNITION SWITCH ARRANGEMENT E ooo // BAT HO OFF ON wire color O O R Bk IG a Bk.
FRONT R H A N D IDICATOR LAMP HEADLIGHT SPEEDOME-£
LIGHTING SWITCH REAR R HAND FLASHING INDICATOR LAMP NEUTRAL INDICATOR SPEEDOMETER LIGHT STOP /TAIL SWITCH LAMP CONTINUIT IGNITION SWITCH FLASHING "HORN-DIMMER SWITCH INDICATOR BA' o-oo oo o-o aoo o-o "o-o-o-o oo ». O ON Colour key E u \ O fO •o H, IN) o L .
The CG125 (BR)-E/F model The CG125 (BR)-J model
Chapter 7 The 1985 on models Contents Introduction Routine maintenance: schedule modifications Routine maintenance: changing the engine oil - CG125(BR)-K model Routine maintenance: air filter and fuel tap Routine maintenance: checking brake shoe wear Routine maintenance: checking the side stand Compression test: all models Engine modifications: general Dismantling and reassembling the engine/gearbox unit: separating the crankcase halves Gear selector mechanism: general Petrol tank: removal and refitting (T)
Chapter 7 The 1985 on models Cylinder bore Gasket surface maximum warpage Piston to cylinder clearance Wear limit 0.100 mm (0.0039 in) 0.010 - 0.040 mm (0.0004 - 0.0016 in) 0.100 mm (0.0039 in) Cylinder head Gasket surface maximum warpage 0.100 mm (0.0039 in) Crankshaft Connecting rod small-end bore ID Wear limit Big-end bearing maximum radial play Crankshaft maximum runout 15.010 - 15.028 mm (0.5909 - 0.5917 in) 15.060 mm (0.5929 in) 0.050 mm (0.0020 in) 0.050 mm (0.
Chapter 7 The 1985 on models 109 Torque wrench settings Component Petrol tap filter bowl Engine oil drain plug (where fitted) Oil filter gauze cap: CG125(BR)-E/F and J models CG125(BR)-K model kgf m 0.3 - 0.5 2.0 - 3.0 Ibf ft 2 - 3.5 14.5 - 22 1.0 - 3.5 1.
Chapter 7 The 1985 on models 110 Tyres Sizes: CG125(BR)-E/F and J models CG125(BR)-K model Pressures - tyres cold: Solo Pillion Torque wrench settings Component Front wheel spindle nut: Castellated nut — with split pin Self-locking nut Brake actuating arm pinch bolts Rear wheel spindle nut: Castellated nut — with split pin Self-locking nut Rear brake torque arm mountings Front Rear 2.75 - 18 42P 2.75 - 18 42P 90/90- 18 51P 90/90 - 18 57P 25 psi (1.75 kg/cm2) 25 psi (1.75 kg/cm2) 28 psi (2.
1.7a Chain enclosure is secured by three bolts at the rear on BR-E/F and BR-J models ... 1.7b ... and by two bolts at the rear on BR-K model 1.7c Note later type of flasher unit 1.7d Headlamp bulb removal procedure is similar to earlier models 1.7e ... ensure bulb locating tangs engage with matching slots in holder 1.7f Pilot lamp bulbholder is a press fit in reflector ... 1.7g ... bulb is of bayonet type - always ensure correct wattage bulb is fitted 2.
Chapter 7 The 1985 on models 112 2 Routine maintenance: schedule modifications 1 With reference to the Routine maintenance section at the front of this mapual, note that the service schedule has been altered slightly.The pre-ride (daily) check, the monthly/600 mile check and the three-monthly/1800 mile check remain unchanged. Note, however, that the battery is now retained by a metal strap which is secured by a single bolt.
Chapter 7 The 1985 on models machine so that the brake components can then be dismantled, cleaned, checked for wear, and reassembled. It is important that moving parts such as the brake camshaft are lubricated with a smear of high melting-point grease on reassembly. 6 Routine maintenance: checking the side stand 1 Examine the side stand for cracks or bending, and lubricate the pivot with a multi-purpose or graphited grease.
Chapter 7 The 1985 on models 114 machines and can be easily obtained from a good motorcycle dealer. 2 Note that the piston crown marking mentioned in Chapter 1, Section 39 is now AD. Its purpose is the same; to identify the (larger) inlet valve cutaway which must face to the rear on reassembly. 3 The clutch release mechanism is very slightly modified (see accompanying photographs).
Chapter 7 The 1985 on models 2 Unscrew the three retaining screws to release the pump cover from the base of the float bowl. Withdraw the cover, noting the presence of the coil spring, followed by the diaphragm and rod. Check that the diaphragm is free from cracks or splits, that the rod is straight and that the two are securely fastened. Renew any component that is found to be worn or damaged. 3 Remove the float bowl as described in Chapter 2 and examine the rod gaiter; renew it if it is split or damaged.
13.1a Float bowl can be removed complete with pump assembly 13.1b Do not dismantle accelerator pump linkage unless absolutley necessary 13.2a Pump cover is retained by three screws - note coil spring and valve in centre of cover 13.2b Check pump diaphragm for splits and rod for straightness 13.3 Check that rod gaiter is undamaged - note pump delivery valve in gasket surface 13.4a Carefully clean components of pump one-way valves ... 13.4b ...
Chapter 7 The 1985 on models 14 (T)PFC carburettor: refitting Brazilian models CG125-C. E and 1 Refit the throttle valve assembly ensuring that the groove in the valve engages with the locating pin set in the carburettor body, and that the needle enters correctly into the jet, then tighten the carburettor top securely. Check that the valve opens and closes smoothly.
Chapter 7 The 1985 on models 17 Condenser: general 19 Front fork legs: removal 1 Note that while the condenser is mounted as described in Chapter 3, it is no longer listed as a separate item and can only be purchased (as a genuine Honda replacement part) as part of the ignition HT coil assembly. 2 Owners are therefore advised to find a good Honda Service Agent who will find a suitable separate replacement from his stocks and fit it to the coil.
Chapter 7 The 1985 on models 5 Remove the damper rod Allen bolt. If this has broken free from the lower leg but will not unscrew from the damper rod, obtain a piece of hardwood dowel of the same length and diameter as the fork spring(s) and grind a coarse taper on one end. Compress the stanchion fully into the lower leg and insert the dowel into the stanchion so that its tapered end engages with the head of the damper rod.
Chapter 7 The 1985 on models at the top. Refit the fork leg top bolt; tighten it to its specified torque setting when the stanchion is held either in a vice with padded jaws or in the machine's fork yokes. 21 Front fork legs: reassembly 1 On reassembly, all components should have been checked for wear and renewed as necessary and should be completely clean and dry. 2 Clamp the lower leg vertically in a vice by its spindle lug.
Chapter 7 The 1985 on models 24.3 Press latch on each side to release seat (tail fairing will obscure latches on BR-K model) 24.5a Remove grab rail (four bolts), then two rear bolts (arrows) ... 23 Swinging arm: check, removal and refitting CG125(BR)-K model Check 1 With the machine on its centre stand, grasp both swinging arm ends and attempt to move them from side to side. If a significant amount of side play exists the bearings should be renewed.
IS) Fig. 7.4 Front wheel and brake 1 Wheel spindle 2 Washer - 2 off 3 Spacer 4 Oil seal 5 Bearing - 2 off 6 Nut-4 off 7 Hub flange 8 Stud - 4 off 9 Spacer 10 11 12 13 14 15 16 17 18 Brake shoe - 2 off Return spring - 2 off Seal Speedometer drive gear Washer - 2 off Camshaft Brake plate Screw Castellated nut 19 20 21 22 23 24 25 26 27 Split pin Dust seal Return spring Wear indicator plate Actuating arm Bolt Nut Trunnion Adjusting nut •"X. }. '>..
Chapter 7 The 1985 on models 27 Brakes: overhaul 1 When overhauling the brakes check that the brake operating cam is working smoothly and is not binding in its pivot. The cam can be removed by withdrawing the pinch bolt from the actuating arm and pulling the arm off the shaft. Before removing the arm, if the manufacturer's alignment punch marks cannot be seen, it is advisable to mark its position in relation to the shaft so that it can be relocated correctly with the wear indicator pointer.
FRONT RIGHT-HAND PLASHING INDICATOR LAMF NEUTRAL ( \ N I I — ' REAR RIGHT-HAND FLASHING INDICATOR LAMP I 1 INDICATOR NIGH BEAM INDICATOR METER LIGHT AD LAMP ( P1LOT rG- LAMP REAR LEFT-HAND FLASHING INDICATOR LAMP FRONT LEFT-HAND f 1 I ^LASHING INDICATOR \ ^ J _ J 1 Lb 1 | T W 1 1 1 i 1i i i i 11i I L TL R HO AT Lo Hi Cl LIGHTING. DIMMER .TURN SIGNAL .
Conversion factors li. Length (distance) Inches (in) Feet (ft) Miles X X X 25.4 0.305 1.609 Cubic inches (cu in; in3) Imperial pints (Imp pt) Imperial quarts (Imp qt) Imperial quarts (Imp qt) US quarts (US qt) Imperial gallons (Imp gal) Imperial gallons (Imp gal) US gallons (US gal) X X X X X X X X 16.387 0.568 1.137 1.201 0.946 4.546 1.201 3.785 Mass (weight) Ounces (oz) Pounds (Ib) X X 28.35 0.454 X X X 0.278 4.448 inch X 0.070 inch X inch inch Inches (in) Feet (ft) Miles X X X 0.
Index Acknowledgements 2 Adjustments brakes 12, 83,86, 112 carburettor 54, 117 clutch 12 contact breaker points 10, 61 final drive chain 9, 87 ignition timing 11, 62 spark plug 63 steering head bearings 12 valve clearances 10, 46 Air filter 10, 57 Automatic timing unit 61 B Battery charging and maintenance 95 check 9 specifications 93,110 Bearings engine big-end 30 main 30 small-end 31 gearbox 30 steering head 12, 69 wheel front 83 rear 86 Brakes adjustment 12, 83, 86 check 8, 112 examination and ren
'Decarbonising 34 Dimensions 5, 107 Dualseat78, 121 Electrical system battery 9, 95 charging system 94 check 93 fault diagnosis 102 flashing indicators 99 fuse 100 headlamp 97, 99 horn 100 rectifier 94 regulator/ rectifier 121 resistor 100 specifications 93, 109 ; speedometer 78, 99, 121, 123 I wiring 101 I wiring diagrams 103-105, 124 Engine < bearings 30, 31 .
h 128 Parts - ordering 6 Pedal - rear brake 77 Petrol pipe 52 tank 52, 114 tap 53 Piston examination and renovation 31 modifications 113 refitting 46 removal 19 Primary drive pinion examination and renovation 34 refitting 40.
