First, welcome to the forum. as for the backfiring/sputtering, I'd check the carb to make sure you have it adjusted right, you could be just that 1/4 turn off on the jet or pilot! also make sure your intake is all tight and you're not sucking air somewhere. As for the "slipage" check your chain, is it worn, does it need tighten, or are either of your sprockets showing excessive wear? hope this helps you some. anyone else
