Woohoo! Progress, sort of. Took some of the engine covers to work and blasted them just to get myself motivated again and back on this project. Valve cover turned.out nice, although whatever Yamaha used for clearcoat in 74 was some tough shit. Took 30 minutes just to get the thing cleaned up. Original right side cover was another story. Hundreds.of tiny holes and pits in the aluminum. None all the way though, but just horribly pock marked. I have the other side cover from my spare engine that is in much better shape and I'll be blasting that next week.
Side note. While looking at the upper and lower main cases and trying to figure out what to tape or mask off, I think I've come to the conclusion that these will be sent out for soda blasting as it's much easier on the aluminum and doesn't leave tiny bits of sand stuck in little crevices that are a bitch to get out. I hate paying someone to do something I could do myself, but I just don't have the resources to do soda blasting and don't wanna screw up the main case internals.