I've been waiting for him to come back in and respond to you guys. These ARE from a 79 CX500. I have been working with him via email and phone for a few months now. I rebuilt his carbs for him. He sent them back with black carbon build up inside the venturi. SO he pulled the heads and found a slightly bent valve. So I did a valve job on a set of heads and sent those to him. Still only 70 psi on the right side. After several emails he was convinced to pull the motor down to see what's going on with the right piston. I told him the rings may be stuck and to look for that as a possible issue. So today he sends me an email and says the rings look fine but the piston has marks on each side of it. Also he asked if I had any other ideas of what else it might be. LOL He was sooo focused on what I told him to look for that he didn't see the rod. After we talked and laughed at the missed issue on the phone, I told him we were on a new site and to get registered again and put this post up. I LMAO when I saw how many jumped on this. It just goes to show how many of us are out there willing to help a newbie.
Anyway, he is in need of a block, crank, pistons and rods. His block ended up having rust pits on the R. cylinder anyway. If your close to Mississippi and can help him out cheep I'm sure he would appreciate it. He's worked on this bike for a long time on and off and only has this to show for it. I have parts to build him a short block but it might be cheaper if your closer. He already has the new rings for it.
And due to the large amount of bend in the rod, and there was only a slight bent valve, all I can figure is that the cylinder got flooded with fluid, gas or water, and it hydrolocked that piston when the engine started. That's what happens when the piston can't go up any further but the other piston makes it do it anyway.
Yes I would say these engines are quit resilient. The project I'm working on for myself started out much the same. I started it up before I tore the bike down. Of coarse it ran a bit sluggish, but it ran too!