Here’s the final sleeve drive assembly, complete with chain tensioner in situ. The distance between centres is as drawn, with the adjuster fully in to give the full travel as the chain wears. Shown in the orientation it will take in the engine on final assembly.
It looks right and with the 9 holes (3 sets of vernier adjustment) we can get to within a single degree of timing. Spot on!
The valve timing needs some thought still as the Hercules was supercharged, so the inlet opens late. Static timing can be set with the drive sprockets, however, the relative timing between inlet and exhaust can only be changed by re-shaping the holes in the sleeve. I only have one sleeve so that’s a one way operation.
How much is too much? You will only find that out after you’ve done it and there’s no going back. Hmmm..