I have had three scooters and have tuned them all to my needs each time. I respectfully disagree with scooterno, but it is possible to get it wrong.
These CVT transmissions are very simple and self adjusting. If you have ever ridden a 10 speed bicycle just remember how the gearing works on that. You change gear ratios on the front and back de-railers to suite your need for speed or torque.
First the scooter clutch. It is going to engage at a specific CLUTCH rpm every time, BUT this RPM is determined by linear belt speed not front variator RPM. Clutch engagement is all based on centripetal force generated by the clutch pads spinning, and spring tension, and these are fixed constants. Also a constant, is the sheave half's compressed by the clutch main spring. This serves act as your rear gear shift like the rear de-railer of a bicycle, but it is torque selectable, not rider selectable like a bicycle.
Ohh I can't believe I am thinking so hard on a Sunday night.
Now lets move to the variator. The variator is held to its lowest gear by the belt and the main spring tension on the clutch sheave's. At rest you will see the belt on the smallest diameter of the variator, and the largest diameter of the clutch. Once the engine is running the force of the variator weights begins to move the variator sheave halfs together, causing the belt to ride on a larger diameter pulley, and this causes an increase in belt speed, and a corresponding increase in clutch rpm.
Once clutch engagement rpm is achieved the clutch bell begins to lock up and the wheel spins. (You start moving, don't forget the side stand.:smile
So lets say you want to put in heavy rollers, if you do this it will be like staring out on the big sprocket of your bicycle, and lets say your clutch engages at 4000 rpm engine speed. You will wind up with a lower cruise rpm, if you have the torque (legs) to get going. Getting going is hard work on the engine, but once you get going, you can cruise easily.
But lets also say you found a special weight, it is not round, and operates on a principle of leverage. It also is lighter than the stock weight. The special weight lets the engine spin up at a higher RPM, it is lighter. The engine easily makes it to its peak torque RPM, lets say 6000, and the clutch engages, and she moves out briskly and smoothly. Your engine is happy, this is easy work.
of these cases the bike will not move until linear belt speed is great enough to engage the rear clutch at its set engagement RPM. (There is some slippage before full engagement, but for the sake of discussion lets not mention it again). The only difference is the engine didn't have to work as hard to get the bike moving with the special weights. More RPM doesn't equate to more work, just more power available to do work.
Now lets cruise. As the engine rpm rises, everything will reach a point where you are in top gear on the variator, and top gear on the rear main pulley. (no longer calling it a clutch, because it is fully locked and all that is at play now is the pulley and main spring back there).
Any increase in speed will come about as a result of increasing engine RPM.
However: Ahh you never thought we would get here. The special non round weights have an advantage, their shape allows the front variator to move just a little bit further inward making a slightly higher gearing, giving a higher belt speed for the same engine RPM over the stock weights. This is where you have your cake and eat it too. More bottom end power, and lower cruise RPM, plus a brisk down shift to bring the engine back to peak torque if needed for acceleration.
Sliders can increase effective starting torque by raising engine rpm initially, but leverage their unique shape to give a final higher top gear on the variator, and downshift faster than rollers.
Hope this helps someone, I didn't come up with this on my own, Many posters on the board helped me understand CVTs. My cruise RPM dropped by 800, over stock at the same indicated speed.
Time to turn some wrenches ehh.