There's a possibility one of your rollers is sticking, or has a flat spot on it, not allowing your shift weights to move all the way out. Your shift weight might even have a rough spot on its back side, Be missing a piece of metal, or be missing one of its bushings. To raise engine RPMs, you need to lighten the shift weights, or keep them from fully extending. (as far as clutching is concerned).
If you pull your cover, then belt (note direction), then using a pry tool, gently spread the primary sheaves together, until you can put your finger in between the roller and shift weight, so you can manually spin the rollers.
Be careful to either use something to hold the sheave together, or make sure your pry tool is secure, so you don't get your finger caught in there. This tool will help:
UTV - Tools - Sheave Clamp Tool - Starting Line Products
Have you blown a belt, and not get all the debris out of the sheave? With the cover off, and the belt removed, start the engine and cycle the RPMs a few times so you can visually inspect that the sheaves are opening and closing properly. I recommend facial protection, because it has the possibility to fling debris out of the sheave with violent force due to the high RPM required to get the sheaves to open.
Here's a link for the spider nut socket:
UTV - Tools - Drive Clutch Spider Nut Tool - Starting Line Products
PS, don't lubricate any of the clutch pieces in a way that some of the lubricant could come into contact with the belt or sheave's belt contact area! Centrifugal force can/will fling stuff everywhere!!!