On all my other bikes, and cars, commuting around 55 mph yields me the higher gas mileages. More agressive riding reduces the fuel mileage return. I've ridden this CBR for about thirteen fill-ups, and done a fuel mileage calculation each time. The MPG versus riding style is flip-flopped. If I commute the whole tank of gas at 55-60 MPH, straight and level freeway, mostly steady throttle, I get about 65 MPG. But when I go through most of a tank of gas on a day ride up in the mountain twisties, completely flogging the engine, pinning the throttle regularly, full throttle from stop light to stop light, etc. I am rewarded with 74-75 MPG! Any ideas why I am seeing these returns which seem to defy logic?