I installed a yz450 exhaust cam in my 2001 yz426. I followed the instructions to the letter. I can kick it thru but it is very hard(no tennis shoe's). Tried to bump starting the bike, that didn't work. Went back check the valves again and re-shimmed. It still kicked very hard, tow started it in 3rd. Ran it for about 10 min(not hard). Tried to kick it agian, no luck.I have read everywhere please provide any feedback you guys might have. I am willing to bring the bike to anybody in FL or south GA that has done this mod.