That sprocket looks pretty bad. I would expect it to slip. I never owned a motorcyle but lots of gokarts and what always tears the chains up is bad wheel bearings and/or loose motor mounts. And also when your building 12+hp single cylinder engines and still using the small #35 chain too. Its like a jackhammer on the chain But i dont think ive ever cleaned one of my chains before and they never really wear out. The master links always snap tho...wish i had a chain tool back in the day