I went out to the oregon dunes for this memorial day weekend, and first thing saturday morning I unload my 2004 yz450f, and on the first kick I broke the internal component of the kick starter. I dont know what the part is called but it was the main shaft that the kick starter assembly is centered around. Any way, Somehow that shaft got twisted and broke inside the motor. Has anyone else had this happen to them, and if so, why would it happen. Oh - and by the way I fixed it that day. Florence yamaha didnt have the part, but I was able to get it welded by a local guy (he did an awesome job). And thanks to a bunch of help from the people in the parking lot, I had the motor put back together, and had the bike starting fine by 4:00 that afternoon.