id go for a taller main, and try each needle position, go from the bottom to the top? you running 108 octane or better with 927? ive gone down to -500 feet below sea level and it ran fine all the way up to 4000 feet, up higher it wasnt as pipey but didnt fall off any where..... im running pc's, you guys should be able to ring it out and find a sweet spot, i know its not the porting, proquad and i dont have this problem, is it getting plenty of air?..if anything mabye signing off a little earlyer than an over reved drag port, would be jims motor, but break your arms from 2000 rpm up......its gotta be between the needle position and the air flow, fuckin strange?????....i hope you guys iron this out cause that dead center of the power band is where these passion engines really shine