Honda CG125 Owners Workshop Manual


Filed Under (Honda) by admin on 25-11-2010

Clean the air filter Pull off the right-hand side panel and remove the two nuts which secure the air filter cover. Withdraw the cover, checking that the sealing gasket is in good condition, pull out the retaining spring and withdraw the element assembly. Peel off the inner and outer foam sleeves. Wash all components in white spirit (Stoddard solvent) or in warm water and detergent and dry them thoroughly. Soak the foam sleeves in the specified oil, then squeeze them gently (do not wring them out or they will be damaged) to expel all surplus oil. Refit the sleeves to the element frame. On reassembly ensure that all components are correctly fitted so that unfiltered air cannot bypass the element. 2 Check the spark plug Remove the spark plug cap, unscrew the plug and check its condition, comparing it with the photographs on page 65. If it is badly worn or fouled it must be renewed. If it is fit for further service check the gap and reset it if necessary, as described in Chapter 3.8. 3 Check the valve clearances It is important that the correct valve clearance is maintained. A small amount of free play is designed into the valve train to allow for expansion of the various components. If the setting deviates greatly from that specified, a marked drop in performance will be evident. In the case of the clearance becoming too great, it will be found that valve operation will be noisy, and performance will drop off as a result of the valves not opening fully. If on the other hand, the clearance is too small the valves may not close completely. This will not only cause loss of compression, but will also cause the valves to burn out very quickly. In extreme cases, a valve head may strike the piston crown, causing extensive damage to the engine. The clearances should be checked and adjusted with a cold engine. Place the machine on its centre stand and remove the rocker cover, taking care not to damage the 0 ring. Remove the gearchange pedal and the left-hand outer cover to expose the generator rotor. Remove plug and allow old oil to drain Remove the spark plug, then slowly rotate the engine anticlockwise by way of the generator rotor, watching the inlet valve. When it has opened and closed again (sunk down and risen up to its original position), rotate the engine further until the T mark on the rotor periphery aligns exactly with the raised index mark which is positioned between 12 and 1 o’clock (from the crankshaft) on the generator stator. The engine will then be in the correct position for checking the valve clearances, namely at Top Dead Centre (TDC) on the compression stroke; check that there is free play at both rockers. Using a 0.08 mm (0.003 in) feeler gauge, check the clearance between the top of each valve stem and its corresponding rocker. The feeler gauge must be a light sliding fit, with the rocker and valve stem just nipping it. If necessary, slacken the locknut, and turn the small square-headed adjuster to obtain the correct setting. Tighten the locknut, holding the adjuster at the same time to prevent it from moving. Finally, recheck the setting and then repeat the procedure on the other rocker. 4 Check the contact breaker points and ignition timing Note: since the generator stator plate is located by its countersunk retaining screws, the ignition timing can only be altered by opening or closing the contact breaker gap; therefore both operations are described as one. The full procedure is given here for ease of reference, but if the points are found to be in good condition and if the gap has not altered or is within the tolerance, then the ignition timing will be sufficiently accurate and there will be no need to carry out the full check. First remove the gearchange pedal, the left-hand outer cover, the spark plug and the left-hand side panel