Take off the Dynamo Belt cover, the front part of the rear chain cover, the rear chain sprocket and chain, and the outer half of the primary chain cover. Draw out the split pin from the crankshaft nut. Remove the nut (which is a right hand thread) by means of the special spanner which is provided to fit the external serrations on the nut. It may be necessary to use a mallet to loosen it. Screw the nut right off. This will allow the dynamo driving pulley and the spring to come away. Do not lose the plain washer which is fitted between the nut and the splines on the mainshaft.

It is not possible to remove the clutch or the engine sprocket separately because the front chain is an endless one and cannot be parted. The clutch must be removed as described on page 19 and will then draw off the splines with the engine sprocket and chain. To re-assemble, grease the sprocket internally and place it in position with chain and clutch, grease the splines of the shock absorber clutch and the cams and slide it back into place.

Refit the spring and the pulley, put back the plain washer on to the end of the shaft and screw on the nut making sure that the small tab on the pulley is engaged with one of the serrations in the nut. The nut must be tightened up dead tight so that it clamps the plain washer firmly against the splines on the shaft. Under no circum­stances must the nut be slacked back or loosened in order to get the split pin into place. There are eight splines provided for the pin so that it can always be fitted by driving the nut round until the next slot is opposite the hole in the shaft.