I finally figured out what that intermittant noise around my feet is, the stupid chain! According to the manual the chain needs to be cleaned and lubed every 600 miles. One week of riding to work is a little over 600 so I clean & lube every weekend. Apparently this isn't enough because the chain starts knocking about mid week. I got lazy this weekend and didn't do it so I just sprayed on some lube and everything's quiet. I would love to get rid of the chain altogether and go with a belt.