Drive boss grinding

[wkreps]

So I've heard of shaving a millimeter or two off the end of the drive boss to make sure the drive belt is using all of the variator thus giving you all the top speed that stock will give you. Yeah I know if I alter it ,it's not stock anymore. I wanted to order an extra one in case I eff it up. Then I can put the new one in and say, "enough of that WayneO." For confirmation it is part #22105 that I want to order right? Or should I just leave it alone and look elsewhere to mod?

[de dee]

I shaved 1/2 mm. of off of #22102 where the two halves touch, and do the other side,.  that will narrow the variator by one mm. so the belt will go to the top and give top speed and lower the RPM.  to me that does the same as shaving the drive boss, if your pulley is wider than the belt the boss will do nothing,. the variator is already closed tight,     I did mine last year , 10,000 km ago

[PeTroL42]

So I've heard of shaving a millimeter or two off the end of the drive boss to make sure the drive belt is using all of the variator thus giving you all the top speed that stock will give you. Yeah I know if I alter it ,it's not stock anymore. I wanted to order an extra one in case I eff it up. Then I can put the new one in and say, "enough of that WayneO." For confirmation it is part #22105 that I want to order right? Or should I just leave it alone and look elsewhere to mod?

This post is a little old but I'll give a response.

I suggest leaving the drive boss alone and just get a Dr. Pulley Variator.

It raises the "gear ratio" some what giving you a higher top speed but acceleration will suffer a bit unless you go down in pulley weights.

Installing a Dr. Pulley Variator raised my gear ratio enough for me to put off replacing my final drive gears until I install my bigger bore and piston.

[zombie]

Both very good suggestions.

You HAVE to know what is happening before shimming or milling anything. I have always suggested marking the Var, and rear pulleys w/ a sharpie marker to find out where the belt is riding. Youre marks will be erased by the belt. Then you can see if shimming or milling is needed.

DeeDee is correct in the fact MOST kymco's need a tighter fit between the 1/2's, and PeTrol is right in the Dr. Pulley being a MUCH better var.
Combine all three of our efforts, and make a perfectly tuned CVT. You're up for it big guy. Any machine shop will charge well under 50 bucks to chuck up your parts, and do the work precisely.