If I set the cruise at 80, I can drop it all the way down to 35 MPG. If I keep it down to 65 MPH or less, I get a solid 50 MPG. The only performance mods are the Screaming Beagle air cleaner, the “off road” mufflers and a remapping of the ECU by the local dealer. I especially love the “Parade Mode”; it really helps keep the heat down so you don’t cook your inner thigh.
Gotta love that Delphi fuel injection!
I’ve got a 95CI kit with a PCIII, S&S gear driven TW25 cams, SE airbox and touring mufflers. At 60MPH I average about 42 MPG. That’s about the best I ever do. Hauling the trailer at 80 I get about 27 MPG.
My Yamaha Zuma scooter, however, gets as much as 90 MPG unless I really flog it (which I always do).
The V-Strom averages 45 MPG. It seems to like about 4,500 RPM steadily for max mileage.
The 1948 HD Panhead maxes out at about 40MPH and my ‘72 Triumph is good for 45-57.
My next bike will be some sort of 250 4-stroke model like a Rebel. That should get max mileage and go fast enough to commute the 15 miles to work without using much gas.