Throttle valve components

Throttle valve components

The throttle valve shaft should rotate freely in its guides and this should be checked when the engine is at its normal operating temperature. Any excessive clearance caused by wear or the throttle valve butterfly distorted are liable to cause irregular engine operation which will be more pronounced at idling speed. Should the above conditions be evident then the throttle valve butterfly and the shaft assembly together with its sealing rings must be renewed.

Carburetter cleaning

To thoroughly clean the carburetter proceed as follows:

1. Passages. All fuel passages have a diameter that is specially calibrated to ensure best operating conditions. It is therefore essential that any dirt or scale that has been deposited by petrol must be removed. Thoroughly clean with petrol and blow dry using a compressed air jet directed through all the passages in the castings. It is essential that no drills or other metal objects be passed through the jets or the passages otherwise these could alter the finely calibrated diameters.
2. Calibrated parts. Idling and main jet holders, and the relevant bayonet coupled jets are easily removed by using a suitably sized wrench or screwdriver. To clean the different calibrated parts, thoroughly wash in petrol and blow dry using a compressed air jet. Do not use any fine drills or metallic points as these may alter the fine calibration of the orifices. Should it be necessary to dismantle the carburetter adjustment components for inspection always ensure that after reassembly of the parts that they are seated correctly to avoid possible operating troubles in the future.
3. Filter. To clean the filter unscrew and remove its plug 10 (see FIG 2:9) located on the top of the carburetter cover and then gently ease out the filter. Wash the filter carefully in petrol, also ensure that the filter seat is clean and then blow dry using a compressed air jet.