i am looking at buying a 2007 crf250r. the original owner raced it lightly, he is just out of highschool. right now the bike wont start. he has had the valves replaced already, and it needs it now. it might get away with new shims right now, but for th price it might be worth just re-doing them anyhow. i do not race, only trail ride, and not too often. i used to own a 2004 crf250r, so i am familiar with the known valve issues they have when ridden hard, and i never had an issue based on my riding style. overall the bike is really clean. i am skeptical to buy, only because i am not able to start it and test the tranny and clutch, and listen to the engine itself. this is a slight gamble....are there any other known issues that might be going on, other than the valves? thanks for your advice, i appreciate it!