The sleeve drive sprockets are machined up and the chain fitted. The distance between centres is critical and the chain length dictates that. The distance we’re chasing is 7 inches, which the chain adjuster helps – but the critical distance unfortunately falls between links.

The engine cases will need to be bored for the bearings, so the centres can be moved to provide a small offset. However, changing the centre of the sleeve drive crank will change (raise in this case) the maximum height of the sleeve. This in turn means that the barrel will need to be raised, lowering the compression ratio.

Important to nail this now before machining the cases. I think a maximum of .1" will bring the chain length, tension and adjustment within acceptable limits.