cylinders

Hey, new to the xs world and new to the forum. I just picked a 1978 xs400. It's been sitting for a long time and the motor was locked up so I started pulling it apart to see what I could find. I put some marvel in the cylinders and let it sit. Pulled the side cover and put a wrench on the crank...

Hey Ive bought a 1978 XS 250 cheap and i found a XS400 cylinder bloke and pistons and i was wondering if anyone has ever done that conversion before and is it possible and how much work is it?

how can i see if my rings are bad? do i need to check the gap? really want to figure out if theyre bad before trying to track down a set...