what is wrong with the ****es the vaves i am talken what happens to the ****s do they ceez or get stuck open. Can i change the top ennd tappets and **** off the 02 on to a 03 couse i got a crf 450 02 and it **** so i want a 03 tapp and **** on my 02 couse i wanna race the ****a but carnt couse me ****en bikes let me down so i wanna ****en good bike for once