i bought a gytr clutch cover from my buddy who has a 2008 250f he had 2 of them and sold me the other one, he said it wil fit my 04 yz450 so i took his word, when i got home i decided to do some research and i got on yamahas websight and it shows that their are 2 different part numbers for the 250f and 450f. I looked at other brands of clutch covers and the part numbers are different for the 250f and 450f my question is what is the difference between the two and is this going to hurt the performance of my bike at all? I havent installed it yet or put it up to my clutch cover to see if thier is any difference, i just dont want to screw anything up. i called him and told him that i dont think its going to fit and he swears it will but he wont give me my money back he said all sales are final. If it dont fit i hope he was joking about refunding my $60. If any body knows the answer that would be awesome. Thanks.