Hi
Any one knows what if put different cylinders in a same bike, what 'd it be? there's different parts number on Sp.SE and R model, also pistons. any professional can help me out this mechanical problem?

This is what the problem on my NSR250, First start around a hour, runs excellant, after hour run, suddenly stop!! after 30 mins break, runs again, but not even can ride well, only short run, what kinda problem could be ?
_________________
1996 HONDA RS250
1995 MC28 NSR250 SE red/white/green
1994 MC28 NSR250 sp W/ RS250 engine