if your tiller is burning up belts you may need to dress the pulleys. i recnently purchased an 8hp horse that had not been used for awhile. i noticed some rust on the pulleys but figured i'd run with the old belt and let it clean the pulleys. it did good for about 3hrs of heavy tilling. i went to the local parts store and matched it with a Gates Powerated 6822. the belt fit fine, but after about 4hrs of tilling it was shot.

i used a small chaninsaw file and 60 grit sand paper to dress the pulleys. remember your just trying to remove the rust and not the metal.

after doing this i went back to the same parts store for another belt but i had bought the last of that size. i purchased a 6821 which is an inch shorter. at first i didn't think it would work, but it did fit. the only drawback is my ajustment block for the engagement lever is close to the top, but this should give me more potential for ajusting in the future. one other note is that the reverse disk is missing on my top pulley, so if yours has the disk it could cause it to stick in reverse due to the shorter belt.