This engine was locked up solid with dried castor oil residue, and so I overhauled it and painted and polished the various bits.
The piston was okay. I replaced the bearings, the crankshaft key and prop driver, the prop nut, and all bolts with new stainless steel versions. And I hand made the rear cover gasket.
I painted the entire engine, and then after it was cured I scraped the paint off of the fins edges and then polished the edges.
I polished the intake port on the rotary valve. I polished the combustion chamber in the head. I polished the carb body, the carb intake tube, the exhaust header, the muffler, the prop driver, the prop washer, and the belt drive pulley even though it is hidden by the belt cover. I know it's shiny, lol.
This engine did not want to start by hand propping. However, it started instantly when using the electric starter.
Once running, this engine proved to be a sweetheart! She runs great, idles great, has good top end power, and sounds fantastic!