Over the last week or so I have tried different chain tensions, from tight to loose, and the problem persists. The chatter is only really evident when starting out in first gear and when rolling on the throttle at slow speeds. When watching it run on the stand, the chain pops and jumps on regular intervals, like you'd expect it to if it had a messed up link. Only thing is...I can't visually find a problem. I'm thinking at this point that I'll just order new chain and sprockets. I have been considering trying a 17 or 18 tooth up front anyway.