I just bought an 07 yz450f that has a two brothers racing full exhaust system on it. :ride:The problem i have is that it bogs a little off the bottom and when you let off on deceleration, it has a terrible sputter/popping. It has an adjustable air/fuel screw, and it seems to run best when the screw is on 4, and it goes from 1-4. I'm not very familiar with carbs, and i need to know if i need a bigger main jet or a bigger leak jet or what. I think i need a bigger jet, but i'm not sure. Thanks.