we have a b5 and b6 . the b5 is perfect . but the b6 with only 2 races we can not get it to idle right sometimes it is good for a minute and then leans real bad . and on the track it stays at high rpm in the air then when we fill in the pits it bogs and stalls . we bought a new fuel tank , siliconed the carb still with no luck . we also have tried both pipes 2057 and 2013 . we would appreciate any help possible .