Just how far did you ride the bike? The cam and rockers look fine. No issue there. The piston and cylinder on the other hand do not look good for a fresh start up. I know you had the lower end apart as you replaced some transmission parts. It looks like there was some contamination that marked up the piston and cylinder. Have the piston and cylinder measured again. What size piston did you install? I'll call my machinist and ask how much clearance he would have set the cylinder to. Usually it's 3 to 4 thou. Did you oil the rings and piston or install it dry?