UPDATE:
ENgine runs surprisingly strong after carb tuning. CUrrently it'll push 8,500 RPM without load just fine, after burnishing and adjusting the points.
I'm a little leery of some extra noise in the case, however, and the clutch is just "there" enough to move. Will probably be swapping the jug, the charging and ignition system, and a new cylinder head onto another motor case soon. Not going to lie, I've been afraid to look inside this one to see what kind of timebomb I've been riding. XD