How does the CVT transmission work?

belt clutch clutch spring cvt transmission rollers variator

CVT (continuous variable transmission): Also known as twist and go.

PARTS:
*clutch shoe
*drive belt
*variator/pulley
*variator Boss
* rollers Weights
*ramp plate/back plate
*clutch outer/clutch bell
*clutch spring
*drive face


SERVICE AND CHECK-UP OF THE CVT:

Note:
You will need special tools if you are removing the belt and additional parts.
Tools needed:
Universal clutch holder tool
Spring compressor
basic metric tool set


1. Remove all the bolts around the crankcase

2. Remove the kickstart cover (use a rubber mallet when it wont come off after all the bolts have been removed). Shake it a little using the mallet around the case.
Sometimes youll need to remove the kick gear pedal of the crankcase commonly on GY6 engines before removing the crankcase.


3. Remove the nut on variator using the universal holder and the socket wrench 

4. Pull out the driveface on the variator.

5. Remove the rearpulley assembly along with the drivebelt. Makes sure to press on the other half of the rear pulley sheeves and turn it clockwise to loosen the belt for easier removal.

6. Removing the belt from the clutch.

7. Pull-out the variator, make sure to pull it at the backplate so the rollers wont fall out.

- Check the drive belt for cracks and wear and tear, a drive belt has a lifespan of 1500-5000 miles (Check every 1000 miles replace if necessary).

- Check the weight rollers for flatside it should be in a round proportion. Replace if necessary

- Be sure to replace parts with good quality parts.

HINT
You can replace rollers weight according to factory standard or use a DIY tuning kit for rollers

Lighter rollers: good for aggressive acceleration up to middle range but slows down on top speed.
Heavier rollers: slow on starting point but good on mid range to topspeed.

Variator: check for scratches and uneven wear where the belt rides on the face of the variator. Be sure all 3 slides are fitting nicely into the variator backing plate, replace if necessary.


Clutch/clutch bell: uneven surface or scratches will affect the performance of the clutch shoes. Check the clutch shoe thickness.

To remove the clutch shoes you will need a spring compressor.

1. Remove the big nut holding the clutch to the secondary slider.

2. Removing the nut

3. Remove the shoe and the center spring.

You can check the rear pulley slide guide rollers by removing the center spring collar. If they are worn or grooved replace. Also check the pulley bearing at the base and top of the rear pulley, put grease before assembly.

Be sure to clean all the parts before putting them back together.

When putting back the parts put first the last part you removed and so on.

INSTALL HINT:
 Put the belt on the rear pulley halfway on the rear clutch first before putting it back on the engine to make it easier. Hold at the middle part of the belt and keep them together to hold it from returning at the top of the rear pulley. Put back the driveface and the nut on both pulleys, tighten them properly. Install the kickstart cover. Start the engine try to idle the engine after putting all the bolts back. Make sure theres no knocking sound on the engine.

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