Alright, new news. Still having the issue, but when cruising at about 40mph at 1/4 - 1/2 throttle, it makes an occasional popping noise through the intake and bucks lightly. This is weird since it's got reeds. Also tried various jets (Mikuni 150-180) with no difference. Drilled the gas cap to let in more air (in case of a clogged cap causing lower pressure in the tank) and still nothing. Also running 91 octane.