I've heard a motorcycle has about the same aero drag as a small car. Sanity check: The gas mileage for a small car and motorcycle with the same size of engine isn't very different.
http://www.evconvert.com/tools/evcalc/
Simply amazing. However, there is no preset for a 400 lb motorcycle, so I have been tinkering with the numbers under "1988 Honda Civic DX Hatchback" - basically wildly guessing. My bike is a '78 Honda CB400T. No fairings or windshield. Does anyone know what numbers I should enter for Drag Coef and Frontal Area for my bike? How does a bike compare to an '88 Civic (with drag coef of 0.3 and frontal area of 18)? I have a feeling that non-faired/windshielded bikes are less aerodynamic than I think....