Hey Trevor, I see that you have only had this belt for about a week. It does take around 10 hours of run time to break in a new belt. Its not uncommon to lose 1 or 2 mph after installing a new belt until it gets broke in. If you lost any more speed then that, then there is most likely another issue (dirty/greasy clutch faces, improperly lubricated clutch, or worn clutch). These belts also come with a 1 year warranty, so if there is some defect causing premature wear of the belt, it will be replaced at no cost. Average lifespan of these belts is easily 500+ hours. I have sent you an email requesting more information about your issues and some tips and tricks about belt and clutch maintenance. Thanks Jonas