Will a 2003 yz450f motor bolt into a 2002 Yz250f frame? I am pretty sure it will and I blown up my 250f motor and have a chance to get an 03 450 motor cheap. What all will I need to change if it will? I am pretty sure I might have to change the head pipe, maybe a carb and ignition. I am thinking of this because the guy that does all of my motor work broke his collar bone and is unable to work on it until, it heals. (he broke this collar bone multiple times and had a plate put in then re broke it and last time it took him a long time to recover.) So any help is appreciated to get me back up and running asap.