i was on this stright away i toped it out and it felt slower than useual then i raced some other dude with a 350rancher he is 140-150ish pounds and he had mud lites tires and he barley takes care of his bike i have a 350rancher i take good care of it and i am 180 pounds i have dunlop quadmax tires the lugs are deeper than the itp mud lites we draged race and he won he was a head by like 4 inches how the hell did this happen is my motor wearing out

 

I wouldnt jump to that conclusion, on just loosing one race.
Swap tires and wheels for a race...and see who wins. It could also be the weight difference of the riders,condition of the air filters, valve adjustments, depth of lugs on tires, and shifting styles. Could be alot of things, but Id say the tires and wheels have alot to do with it.