I have an opportunity to buy a 1990 RMX 250 for $500 and I thought this might make a nice spare bike for friends to use. The only think is the owner took the bike apart to paint the frame and now claims he does not have time to put it back together. On top of that he pulled the head and says the piston needs to be replaced. Is this something to stay away from? If not what should I look for and is this a good price? I feel confident I could put the motorcycle back together. Thanks for your input.