I recently sold a C90 Boulevard and got around 45 mpg on the highway with it. I picked up my new V-Star 1300 Tourer and drove the 168 miles home (to work). I hit reserve at the 167 mile point. The fill took 3.4 gal. I had used mid-grade. Mileage was a nice 49.4 mpg.
Hope this helps,
Dennis