Engine shock absorber

For primary chains click here; for alternators and fittings click here.
The pre-unit plunger and rigid A group uses a duplex chain sprocket, the first year of the swinging arm models used a 4 lobe shock absorber changing in 1955 to a 2 lobe one. The pre-unit singles all used the 4 lobe one up to 1954 and then a 2 lobe one, except the C group which dropped the shock absorber entirely in 1953 when an alternator was fitted. The B and M group did likewise when they gained alternators.
Any sprocket from the relevant section can be fitted; the listings are to show the original application. Overall gearing was usually altered by changing the engine sprocket.

124. Removing pulleys “Pulley is usually driven on to a taper shaft, held by a feather, and secured by a locknut. To remove locknut, fit big spanner on it, and tap butt of spanner with a hammer. Locknut being removed, run engine on stand, when pulley will usually swirl off and hit any fool in its line of travel.”