this time it wasn’t me 😉
I fully understand why it is required to change the concept as often as needed.
There is something in mind and a POC shows that it might or might not work.
I would try to get any external device driven from the ignition side of the engine. There is a “dry area” with a sealing ring in the clutch cover.
All Z-Kawas I know and that are modified to use a blower/compressor do that from richt hand side.
Ok, an oil pump doesn’t need that massive belt to be driven.
Another thing is the size of the bolt in the alternator / rotor.
In the B1 and B2 engines this bolt is smaller than in all later models.
This smaller screw causes issues already just when the rotor and the starter’s freewheel clutch needs to be fastened.
… and this is a LH (left hand) screw.
You may want to use a B3 or later engine to solve that “screw size” issue.
Using one of the latest Twin engines (1983 and 1984) would give you more space for a large front sprocket and clutch actuation is completely attached to right hand side (no push rod from rear left hand cover).
Just throwing in my 2 cents, but it is worth it to think about using the best foundation that is available.