Has anyone ran a mk 3 engine with earlier chaincases

Has anyone run a MK3 engine with the pre unit type chaincases ?
Is there any difference in the MK3 engine sprocket offset?
Do you simply drill extra holes to mount the inner case? Etc

Great question. I was struggling with what to do on the Dreer monoshock prototype bike when I mocked it up with the CF primary that Kenny sold me. I ended up just using a complete MkIII engine but converted the transmission to right-foot shift and plugged the crossover holes. 4 ounces instead of several pounds...

I fitted earlier inner and outer primary covers to the 920, which used MK3 crankcases and crank.
There is a bit of info about that here

Probably much easier to drill new holes in the chaincase match the MkIII studs. I would NEVER drill new holes in the crankcase for studs to align a pre-MkIII inner case...

worntorn said:

I fitted earlier inner and outer primary covers to the 920, which used MK3 crankcases and crank.
There is a bit of info about that here

Roadster/Interstate/Thruxton R tank (2020)

Started in working on the primary covers today. Dyno Dave mentioned that he did not understand why people insist on using the wrong part as things are difficult enough already. I seem to be the inclined to use the wrong part. This is an older set of primary covers being fitted to a MK3...

www.accessnorton.com

Click to expand...

Brilliant info
I remember reading that now
It'd be great to have a decent memory
I'm actually an Alton inner case that I'm thinking of mounting
But it's the same as a commando inner case
But I will check to see if there's much difference in the casting
Thanks again