after being *@#&*@#&*@#&*@#&ed around by experts for several weeks i finally got a gasket set yesterday COMETIC is supposedly a very good brand (much thicker than the MCAS head gasket which recently blew after 250km's Base gasket - fitted but didn't have holes for the locater lugs on the bottom of the cylinder - apply hole punch - all good. Head Gasket - look good but simply doesnt fit - if you line up the locater bolts then the it is 4mm+ out of place on the piston - if you line up the piston the locator pins are out and there is not sufficient coverage around the inside of the timing chain/outside of piston. Packaging says the gasket kits is for an 05-08 YZ450 From what i have seen yz and piston/cylinder wr parts are largely interchangeble but that doesn't help. Did the yz piston change in 05? The frame changed in 07 but i don't recall any motor changes?