I was looking at a 99 KX250 on Cragislist today and he had the cylinder off the bike. There was a small scratch on the top side of the piston and on the cylinder as well. The scratch wasn't too bad, what is the best way to fix it? He had a sleeve he was going to give me as well. Also, would the bottom end be OK? He said he pulled it apart and it still ran but compression was low. Is there a way to know if the bottom end is good still?