Clutch performance questions

I have a sportsman 335 and the power was a little low for me so i recently threw n a jet kit and a k&n air filter but now it seems like the engine is to powerful so the clutch cant grip the belt well enough and it just slips. I was just wondering if there was any cheap/easy way to get the clutch to pinch the belt better and prevent it from slipping. Iv read about clutch kits but i really don't want to spend the extra cash right now. any ideas?