My unconventional homelite weedwacker friction drive runs 22.5 on the flat, 15-20 uphill, and 33.5 downhill sitting upright (handheld gps). I've now gone thru 2 bottom end cranks since changing the top to a 30cc. new numbers have been 27 flat, solid 20 uphill, and 35 downhill - fuel burn 168 mpg....
I can't believe I just found out about motorized biking! Oh yeah, I've only got $25 invested and that was for 4 parts weedeaters to go with the one I started with. Last count, Frankenstein had 8 donors.