I have never actually calculated my mileage; just estimated quick in my head to get ball-park mileage. Its always been about 33mpg. Thats just me on the bike with the summer windscreen, or me and my girl friend w/ screen, or me, the girl, the trailer loaded up and the screen. City or highway.
Only once did I get better than roughly 33mpg, and that was the first day I had the bike. It turned in about 40mpg that day.
It will be interesting to see what my triple K&N's, Power Commander V, and Auto Tune net me for mileage after a few weeks of riding to let the Auto Tune do its thing. Hopefully I don't loose to much.
Sometimes I miss my 03 Sprint ST and its 50mpg......