My belt starts slipping when water gets to the floorboards. I replased the cover gasket. The plastic plate that the cover bolts to is a little loose. Is this the problem? Also i went from a 36t to a 30t sprocket in the rear and added an epi s/u clutch kit and uni air filter. However i did not use their weights or there secondary clutch spring and its set with the greatest tension. So i figured these products would give me more speed and acceleration but it only goes 61mph and the acceleration feels the same. What happened?

 

Your clutch kit is only for acceleration, lighter helix/weights and tighter spring makes you engage at a higher R. But go back to your 36 tooth, you'll notice a substancial notice. As for the uni filter throw it out and go purchase a K&N it makes a great deal of change.

 

Well my belt slips when water gets to it too. But my clutch cover doesn't go all the way on, I have to leave one of the screws out, or the housing hits the pulley. I dont understand this, but I don't like water anyways! So your not the only one with this problem.
A buddy of mine had a scrambler just like mine, and he kept getting a wet belt, and he could not stay out of the water so he put silicone around his clutch housing as a gasket, and he has never had a wet belt since, but he did say that it is a pain in the but to get the housing off when he needs to, and it is hard to get all the silicone off. You might try putting silicone around it, but if your clutch upgrade isn't doing what you want it to, then I would wait until you get that situation delt with, if you decide to put silicone around it.
As for your performance modifications, I called Hot Seat Performance, to order one of their clutch kits, and I told the guy what kind of riding I did, and he told me not to put a clutch kit in it. He said that if you do any trail riding at all, not to put a clutch kit in it. He said that you should only modify your clutch system if you are doing flat drag racing, and nothing else. So that might answer your question, but the kit should give you more acceleration and speed, if you are in a flat field, or something.