I have a 49cc Yamaha scooter. It had a CVT and a carburetor, and top on it 43 on GPS. It will go to about 46 with a slight down hill, but its screaming at that point so i don't do it.lol. sounds like my rig on a good day. snap crackle and pop...pop....pop.
I'm "only" getting 85 mpg too. inefficient engine coupled to a single speed tranny is probably why.
I think otherwise a 49cc (like a fancy-smancy Honda Metropolitan) setup has several speeds/CVT, high compression engine, and fuel injection.
which = what? 130 mpg?
It gets 90 mpg when run hard, but if I keep it around 25 mph, it gets just over 100 mpg.