^^^ Jcampbell speaking the truth, with a polini pipe hes running a 60 jet so without the pipe we are talking 56 probably. Also, as far as I remember there is a restrictor in the stock airbox, do not use it with the new airbox, you probably didnt but just incase. And get a pipe, your engine is taking huge breaths with the new carb/filter and cant breathe out, that causes serious backpressure...