I have a NE5 and my belt slips only when I get caught in the rain. It seems like after about 5 minutes of moderate rain when I throttle up the belt slips..I think the rear belt slips. How tight should these belts be? Can I over tighten them? I don't want to put too much on the bearings.. I replaced the belts last year with the notched ones. I still had the problem before and after belt replacement. Anybody else have this problem?