I think KUBOTA makes a small alternator, if you visit a rewind place, ask about the smallest they know of.
Then you can mount off the crank snout run Alt, inboard or outboard, ahead or behind motor using a toothed belt.
cover your cranksnout, and seal up the oiling, and have gobs of ground clearance.
The starter clutch oil hole should be blocked off, I push on a sleeve with a flange (for install, and removal) If you run a flat block off plate, run a floating seal reatainer outside of that. I used 2.5 OD aluminum by about 5/8 thick, with a 1 inch ID seal (remember, I have a thin sleeve over the oil hole). By using 1/64" over holes in my seal plate, it lines itself up to the cranksnout, and position of the flat blockoff plate, does not need to be precision drilled and dowelled..
I found out the hard way, after I missed a race, I spent about 8 days getting ready for...