i was speaking to my dealer today about the cam mod and he said not to do it as he thinks it would make the valves hit the piston and do lots of damage to the top end :wtf although i think he hasn't got a clue what he's on about just thought i'd better check it out, oh and i also heard you should put a yz dirtbike cam in why i thought the crearences were the same but guess what..... the dealer said they aren't :what
find a new dealer. A dealer that is talking that much shit that doesnt have a clue is a bad deal. I put the YZ cam in mine and it works better performance wise. Also, as a rule you should re-jet as soon as you get your YFZ because it is so lean from the dealer. Either www.jdjetting.com or the GYTR jet kit will get you headed in the right direction.
P.S. kick your dealer in the nutz for being so dumb.