The vintage Whizzers do well on most hills, whereas the new Edition Whizzer, might need a good run to make it over some hills. Reason is Torque!!
The ratio is much lower than you would guess [many call lower... higher, and higher lower].
When I use the term "lower" I mean the number is lower... example vintage Whizzers final ratio is 9.14861860908223701 X 1 [50.72574 MPH @ 6000 RPMs]. As you can see the motor only needs to turn 6000 RPMs to do 50 MPH, and the motor can be easily made to reach 6000 RPMs. The vintage Whizzers have a lot of low end torque for seveal reason, camshaft design, flat head motor, ignition timing etc. The vintage Whizzer motors pull well from a stop and cruise at a nice RPM [4200 RPMs = 35.5 MPH].
The primary reason the CVT doesn't work well on the Whizzer, also has to do with exessive flywheel action and crankshaft stress. More than once I watched a Whizzer on a DYNO test only to view the CVT, flywheel, and assorted parts traveling down the road like small missles. In all cases the CVT is too wide and makes the motor way too wide. Seems like a sin to make a very thin 4 stroke motor [Whizzer] and then hang massive parts on the drive sde.
Newer motor seems to trade bottom end torque for higher RPMs, as an example the HS motor we supply in our 49 CC kit is shipped with a 15.48 ratio, however the motor redline is 7800 RPMs and doesn't produce massive torque at lower RPMs. The numbers will show the 49 CC 4 stroke motor must turn 7100 RPMs to equal the same approximate speed of 35.5 MPH.
It all in the "gearing". When I raced motorcycles the winner was almost always the one with the correct gearing [I sure knew how to gear my bikes correctly, so guess who won often..LOL].
Have fun,