First off since I'm new here I want to say hi to everyone on the forum. This a great place to come and learn. Anyway so it's Saturday and I'm at the Adelanto Gran Prix and I'm fixin to race on Sunday. So I go out for a ride on my WR250 and cruise around the desert semi agressivly, and then all of a sudden the engine dies, and I coast to a stop. I get off to check out what happend and I find the chain popped off. Not a big deal, I thought Id just put it pack on limp back to camp and figure it out there. Upon further inspection I foind that when it came off it slamed into the left side engine case cracking it where the clutch lever gose into the motor, and now the chain all bunched up stuck between the sprocket and my newly busted case. What had happened was the night before, getting the bike ready to race I took apart and regreased the whole rear end. Well it turns out I was too stupid to recheck the tourque on my chain guide which fell off somewhere in the desert, causing the chain incedent. About a $400 and two-three weeks worth of down time mistake. Oh, and I now I dont get to race :( Oh well, I hope you guys can learn form my mistake. Sorry for the long post. I just needed to vent.