My bike did 47/48 MPG originally. I'm not sure exactly how much I lost by rejetting, cuz I added a windshield and large lowers at around the same time. When I did that, my mileage dropped to 37/38. I recently changed out the lowers for a pair about the size of those sold by Memphis Shades, and I'm now seeing 43/44 MPG. Based on all this, I don't think the jets/pipes really made much difference.
