Stripped Honda Goldwing (no fairing or bags) with a Vetter sidecar
None - in fact with the side car I go from about 50 mpg to about 32 mpg. It's been years since it has been on the road other than to move it to avoid wild fires on the West Coast.
Like what I see for the diesel/bio-d/re-cycled cooking oil type conversions. Having a sidecar does make the engine bog down and having the torque, as well as being able to go green sounds like the way to go. I have been thinking about sticking an extra fuel tank in the side car - a perfect opportunity for a re-cycled oil tank....