I go about 150 between fill ups depending on speed and throttle input. With stock gearing I got 45 mpg on long 2 lane trips (3000 plus miles) and with the 45 tooth in the back I now get 43 mpg. I can't find it right now but somewhere there on the Internets is an article that explains that there is a math error in the chip that causes surging around 3,700 and 3,900 rpm. I'm sure others who are more knowledgeable will soon chime in.