On all engines after KSS 8373 a suction filter is fitted to the crankcase and periodically this should be removed for cleaning. The filter plug is situated at the rear of the timing side crankcase (just above the frame tube and almost below the magneto chain cover).

Clean the crankcase around the filter plug before removal to avoid any dirt getting in when the plug is taken out. Unscrew the plug (anti-clockwise) and gently prise out the filter, using a small screw-driver at either side of the threaded hole. Do not lose the small lead seating washer which is fitted between the plug and the top of the filter.

Wash the filter in petrol or benzol. DO NOT USE PARAFFIN for cleaning filters. When re-fitting the filter plug do not force it down, as the lead washer is soft enough to give an air and oil tight joint without undue pressure.

Should the suction filter become choked the crankcase will be flooded with oil and excessive smoking at the exhaust will be noticeable.