You tear the 420 down. It is a brand new mainshaft. The adapter is a bit over 1" thick.
I don't have my reasonable camera on me right now.
Motor looks like it is okay.
I think what happened is that the gasoline broke up the carbon that was built up on the pistons. After turning on and off a couple of times a chunk of carbon became lodged between the piston and the cylinder wall. Quasi siezing the motor. After that chunk of carbon dissolved (using lots of different lubricants) it turned over perfectly.
Not really sure. All I know is that the dam thing runs again.
Not the first time the cruiser has fixed itself
