[gil]

Let me pitch in with my observations from my almost 800 mile round trip, on y 2009 Yamaha Virago 250. From Santa Cruz County, CA to Santa Ana, CA. My bike has 17/38 sprockets with X Ring chain and a small spitfire Windshield. I took the fastest rout there, that was mostly interstate 5. When I rode tucked in and to speed of 85mph for all of the tank, before reserve witch is 80 miles or so, I got 51 mpg. When I got stuck in 50 mph LA traffic on I5 and city riding,40 mph, I got 83 mpg. On the way back I drafted a tractor trailer for 100 miles at 65+ mph, two second fooling distance, and no tucking, I got 77 mpg. On a side note I like the 17/38 sprockets with small windshield, it's perfect.

One down side to these air cooled bikes is the intricate ducting that might be needed depending on the aero design.

Hope this helps. Gil.