Thread: Quad bikes

Cvt quads don't really use a gear box as such, they use a primary and a secondary clutch consisting of 2 sheeves per clutch. Both clutches work together depending on engine rpm and wheel speed. From a dig the primary is wide open allowing the belt to ride low in the sheeves while the secondary is pulled closed so the belt rides high. As engine rpm and wheel speed increase counter weights in the primary under centrifugal force force it closed pushing the belt up to ride high and its the opposite for the secondary. It like the gears on ya mountain bike but it's constant velocity. You can't really gear them up as the clutches would have to be a bigger diameter. Taller tyres may make a difference but at the sacrifice of low down torque. The cvt is pretty cool to tinker with heaps can be done, from machining the sheeves, lightening the counter weights in the primary, uprated secondary clutch spring. Doing all that to 750cc big boy quad makes it another machine. Mine will wheel stand from a get go for along as you can keep in balanced or run out of road lol.

If the vid below works it illustrates how the clutchs work

https://youtu.be/JRHIfoZMD74