From the CSC blog:
source:
http://californiascooterco.com/blog/?p=30049
It's quite puzzling; the RX3S looks like more of a road bike, with slightly less ground clearance and what is likely to be a smoother engine at speed, but the speed figure seems rather pessimistic for the power output. Just 87mph from a 36hp bike? That has to be either wrong or geared to climb trees.
The RX4 is impressive. Much is being made of the 450lb weight but honestly it's not bad given the competition.
I'm really hoping Joe Berk in his capacity as quasi-official voice of CSC, or someone else that knows the RX3 well rides both a lot, I"m genuinely curious of the differences.