jetting ?s 04 yz 125

ive got an 04 yz 125 and im fouling plugs like crazy. part of the problem is i ride in the woods, but it seems like i cant go down a hill without fouling a plug. if i move the jet needle clip up one position to the middle(it was on the 2nd from the bottom) and change the pilot jet from a 40 to a 30 do u think that would solve my problems. a buddy of mine has an 02 yz 125 and he never has this problem.
thank, kyle :bang:

please help any input would be greatly apreciated