CVT transmission - Operation Principle for Scooters

Vid here showing how the roller weights push against the plate. Cross section view.

CONTINUOUS VARIABLE TRANMISSION (CVT)

Where your roller weights and plates are located, as u rev up & the RPM increases the force pushes the roller weights outward against the plates & this causes the rear pulley to push against the front pulley, and forces out the belt into a higher gear ratio. As u pick up speed, the belt is forced outwards further.

A lot of scooter enthusiasts think that by changing the rollers to lighter ones it will enhance the power of your scoot. But changing the weights of your rollers would still be restricted by the set parameters of your stock variator and only as far as your belt will travel outwards. In short your engine performance is pretty limited to your factory settings.

Some after market performance enhancements like Malossi, Dr Pulley, can only vary the angle in which the rollers travel and how it pushes against the plate resulting in smoother acceleration. There is actually no power gain. By changing to heavier or lighter weights would only vary the force applied to the plates to force the rear pulley forward faster.

Imagine this if if u're riding a bicycle, if u're in 10th gear at the start, it would be impossible to move forward. So the same principle works here, u'd want the weights to keep u in 1st gear to propel you forward & as the RPM climbs, the weights will push out the pulley into its optimum. So the trick is to find the powerband of your bike where u experience the highest torque & to find the correct roller weights to optimse its operation in the peak horsepower for the engine.

If your rollers are too light, it may give u good acceleration, as it takes less force to push the plates out, but your top end speed would suffer as u'd end up remaining in low gear too long. And just when your engine gets you moving, u'd find yourself running breathless as u'd have peaked out & missed the powerband.

Here's a vid of the cvt in operation to illustrate the point:


Notice the tension of the belt against the pulleys as the engine is revved.