That was fun First time doing surgery on a motorcycle. Took me about 12 hours. As I was pulling off the head I noticed a little pile of loose deposits sitting on the piston. Almost looked like sand . On top of the piston, there had to have been at least a 1/32 inch thick(even at least 1/16 of an inch) in some places) of baked on deposits, covering well over 90% of the piston. Oddly enough, when I finally got the cylinder off I inspected it and it didn't look in too bad of shape. The rings were shot. The cylinder came off the piston way too easy. I'm suprised the bike even ran as good as it did. I pretty much know why there was so much baked carbon on the piston and valves. I let my best friend ride it around a lot. He says that he was not sure where the choke lever was supposed to be and it turns out he was riding it around on FULL choke:bonk: !!!! That explains the black carbon build up but I haven't figured out why there was some sandy, almost DG(decomposed granite) looking stuff mixed in with it, especially that loose pile of junk I saw laying on top of the piston. I've rebuilt quite a few auto motors and have never seen anything like what I saw on my piggy. Really weird stuff. BAD gas maybe....kinda baffled about it. Anybody got any ideas????