Originally Posted by bxr140
Are you sure its not just the fact that you changed the gearing, so its throwing off the speedo/odo? That's what typically happens in bikes that don't have front wheel speed sensors. I suggest you check your gauges against a GPS.
The speedo is driven by the wheel sensor and as such is unaffected by any gear change. Does not matter what the gearing is, the wheel will be doing the same number of turns at a given speed. Only changing the wheel size would throw the speedo off. Thus the change in fuel economy would have to be due to the engine load changing.