Last summer i bought a 2006 RMZ 250 that only had about 12 hours on it. The guy that had it before me didn't say anything about performance mods that it may have, so i figured it was stock. My buddy has a CRF250R that has a full exhaust and a air filter and i absolutely smoke him when we race. So one question i have is: Is there any way of being able to have an idea of what's done to the bike without opening it up? The bike likes to overheat if i'm just ideling around the woods, so i think it may be bored out a bit? It wiseco piston stickers on it, and after looking i noticed it had a edelbrock carb, it also has a twin air air filter. Near the end of last summer i was casually riding it when i shifted into second gear and the back tire locked up. I no longer have second gear, it just grinds and sometimes locks up. Does anyone know what could have went wrong?