Cutting the CDI will raise the rpm, so remember to change the drive boss to an unrestricted one.
After that you can check if the belt goes all the way out to the highest possible gearing by drawing with a permanent marker on the surfaces of the pulleys in the CVT and then go for a drive where you know you are going to hit max speed.
Then you take it apart and read it as here:
- The line are not fully removed on neither front nor rear pulley. This means that power is the main problem. An upgrade of spark plug to iridium and a 31.000V coil will give you the power to ignite the mixture as good as possible and removing the restriction in the air filter (where the white line is on the picture below) and getting the correct jet and rollers will get you the best possible running stock engine and you should definitely hit max gearing now.
- The line are fully erased on the front pulley but not on the rear: the belt are too long. Try a shorter one.
- The line are fully erased on the rear but not on the front: a longer belt will give you the higher end gearing you need. This was the case for me and a belt which was 2% longer gave me an extra 5 mph.