I have a 96 yz80 that starts up and idles fine but when you left off the clutch it bogs badly and stay that way until its fully open. I have played with the needle clip with very little effect. I have warmed the bike up and played with the air screw also. Starting at 1 1/2 turns if I tighten down on the screw it starts to bog at a half turn (approx 1 turn from closed). If I open the airscrew it seems to have a no effect. I believe that this may tell me that I need to lean out the pilot but it has a 30 pilot in it and I believe that is already at the smallest pilot I can get. Can some one tell me what I should do next?