Ok, my turn! (all photos are of the actual bike I road)
My first motorcycle, a 1967 Honda CL160, paid $100 for it with a seized engine, few weeks later had it on the road, used it for about 4 years, I always got above 70mpg, often 72-74mpg, never up to 80, altho I didn't try, had plenty of power for in town, and to take passengers, but it wouldn't go much over 65mph (Wisconsin's highest speed limit)
Next!
1975 Yamaha RD350, poor gas mileage! 42-54mpg, had to fill it up every 120-150 miles or risk hitting reserve, the shop manual claimed that at 35mph it would get 75mpg with a 140lb rider, but the engine wanted to go faster all the time.
After burning up the engine on my RD350... twice, I borrowed a 1980 Honda CM400 (night hawk?) it was sluggish, and heavy, but ran really smooth, never managed to get up to 50mpg with it before returning it, was expecting more for a 4 stroke.
I then got a 1972 Honda CB100... or part of one, no title, no gas tank, bent valve, didn't shift correctly, by the time I sold it a few years later it was fully leagel, and ran perfectly, getting no less then 65mpg, and in to the low 70's, partly because I road it with the throttle wide open (60mph top speed), I sold it, when I got my CB125 and also kept a '71 CL100 (scrambler) that is restored aside from needing carb work.
Current ride is a CB125, still ride it with wide open throttle alot, always gets about 65mpg as well, and comes close to 70mpg at times, top speed closer to 65mph if I tuck in.