So I bought this 85 XR250R last weekend. We are talking, he said that he just finished re-building the top end. Replaced the cam chain, adjusted the valves, new gaskets. I was wary but this guy seemed like he knew what he was doing. He even had a honda hat, with a garage full of hondas! Anyways, I start her cold first kick. I'm thinking damn, this is a nice bike. He has got this thing running nice. Cruise around, everything is good. I take it home, and a few days later I take it out with a friend (85 XR350). I make it 4 miles and the head gasket blows! I take it home, take her apart, and sure enough the front head bolts fingertight, totally stripped out. The other head-bolts seem to be randomly torqued. I've got the thing apart, and I'm going to helicoil the hole, I feel like this should fix it. Oh and I can't get a hold of the guy that sold it, at all. Won't return my calls. My question is.. Should I be worried about any other reasons why this thing blew? Say he put it together right, could it be an overheating issue due to some mechanical mystery? Is everything true? I'm thinking that the bolt was overtightened then under heat it pulled the threads. Bolt from stripped head hole.