Hey all so last weekend after the baja brawl a buddy and I drove all the way down to kentucky for a 05 yz250f. It looked pretty good (the guy had said it needed a new cam chain and new fork sealz) but wouldn't start. I said screw it be cause 1, I drove all the way down there and 2, I have a complete minus the head donor bike so I wasnt too worried. Anyways we got back and it sat for a week untill last thursday when we were trying to get it started.. I had already changed the oil and filter and put fresh gas in and meticulously cleaned the carb. We checked the chain, it waz brand new, valves werw all in spec save for one intake valve and one exhaust valve. They were a teensy bit tight. Anyway, we got it runnin and it ran like crap. But we got it tuned in and it started to run like a champ. And then... it just died.. mid stroke... no sputter just died.. and it kept doing that.. we were confused.. very very confused.. we took it all apart again and everything looked awesome.. the spark plug was loose which I found odd. I had read the cam caps expand when it gets warm and that will stop thw cams but I had them torqued to spec.. thw only thing is my buddy was just pushing the bike through its strokes with the kick and it kept getting stuck, like it was seizing or something, but it would be fine and there was no knocking or valve slap or anything.. I'm very confused.. can anybody help?