I have been averaging around 57mpg, about 50% highway at 55-65mph and 50% stop and go, about half the time with my pillion aboard. I think my low milage has everything to do with carrying the extra weight and the fact that I am 6'03" tall and sit high with the lycett-type seat. With the medium displacement these bikes have, every bit of weight and windage translates directly to more throttle. I would
NOT say you're fat, but your no race-horse jocky, Scotty.
I'm using fuelly.com to track the milage and it's easy to get a good average becuase it's a rolling tally.
On another note, 10mpg doesn't make as much of a difference on your gas budget if your getting 55mpg to begin with. If your driving 200miles in a pickup truck that gets 15mpg you'll spend ~50 bucks, getting another 10mpg might save you 20 bucks. But do the same 200miles on an Enfield at 55mpg, you only spend $15. Another 10mpg saves less than $3. In other words, a few more mpg makes less of a difference the more your vehicles mpg increases. How's that for long winded?