I hibernated the maxi, too cold, and wanted to find the reason why the chain is slopping causing a racket.
Sure enough it tensions from 1/4 inch to +1 inch in half a wheel cycle (turn).
I measured the chain twice with a 10 lb weight attached and slack on the bench the 1/2" difference I think is acceptable.
Than I measured the sprocked dwell to the rim edge marked at 90 degrees and came up with a 1/8 variation off center.
Losened the sprocked and tapped the sprocket trying to center it, no luck. I than removed the sprocket and eased/beveled the inside circium where it fits to the wheel hub I could now get enough clearance and center the gear perfectly. On the stand and cycling the wheel slow and fast by hand the chain ran smooth with no jumping over the complete range it maintains the proper 3/8 slack.
I had already drained the carburator and cleaned the piston ring grooves not till next year for a road test.