My opinion: Almost every CVT - scooter are terrible bad, when it comes to hypermiling. Why? Because the rpm are always to high (caused be the centrifugal weight controlled CVT), what keeps the pengine load always low, plus the very bad efficiency of those belt transmissions. Plus: Even if you install heavier variator weighs, the spread of those transmissions is just too tight, like also the transmissions in mostly bicycles are for some reason.
I have now a Daelim S300. It have a pretty modern, balance - shafted engine (247 cm³, DOHC, 25 hp, 15,5 lbf ft), of course one cylinder, injection, catalyst with lambda sond, liquid cooled, not very heavy (about 400 lbs). Minimal consumption at 50 mph on even country roads in summertime: 94 mpg at about 5000 rpm. Considered in insolation not bad, but in comparison to a very good car like "funkhoss"´s Metro....
The engine could easily do half of its rpm at this speed, I can feel it clearly. Note a Honda NC750: More than double of the engine power, three times its size, but pretty much the same consumption at this speed.