I am going to start the top end rebuild of my 2002 Raptor this week and I was hoping to get some advice. First of all; when I take the top end apart, is there anything I should know? Any tips or tricks? My 440ex had an extremely simple top end and I could take it apart and put it back together in under 45 minutes but I'm sure the Raptor is a lot more complicated. Second; I am getting a noise from the top end like somethings hitting and it sounds too heavy to be a valve adjustment problem; more like a cam chain slap. Bad tensioner? Also, it burns a lot of oil and it seems to be low on power so I think getting the cylinder bored and an oversize piston will be on the agenda. How much are the big bore kits and which one should I go with? Any help would be greatly appreciated. Thanks

 

When taking off the head, remove the allen head bolts in a criss cross pattern. A Wiseco piston will run you $130 and a bore/hone another $40. Go here, this will guide you through everything.

 

Don't forget about the two head cover bolts under the intake valve adjust side. A lot of people forget those two and end up buying a new cylinder head with the new head cover.