this happened to one of my buddies. he bouht an rm250 for 800 bucks and the guy said it needed a top end rebuilt. he was planning on making a quick fix and selling it to make some money off it and when he got it home and took it apart he found out the top end needed rebuilt, the bottom end was locked up and he needed to replace a couple of the gears. he ended up putting like over 2 grand into it and lost money when he sold it. i would never buy something that didnt run unless i was positive i knew what was wrong with it