my 07 yz450 has and always had a poor throttle responce at o to 1/4 turn. when i snap the throttle it bogs. runs great after 1/4 turn. I have just lived with it, but now that my skills have improved , I need that snap to clear jumps coming out of tight corners. the bike has stock pipe and motor. the fuel screw adjustment makes no difference. Any help would be great. more accurately it may be the first 1/8 turn of the throttle.