Just this last weekend in Prescott at the Southwest Fest, I checked mine regularly and was kind of surprised.
First of all, I have a Speedmaster with the stock (16T) front sprocket. (And I like it, don't try to convert me).
While riding mostly twisties I tend to keep the engine turning from 5000rpm to near 7500. And get nearly 50mpg.
On the slab at 5000-5500rpm, it falls to around 40mpg. Must have a lot to do with aerodynamics.
