A few people have noticed with these bikes that a bolt inside the motor housing can work itself loose and start to make noise when pedaling. I think that has happened to me. It seems to be gradually getting more pronounced. I guess I'll take it into REI and have take off the motor cover and take a look. I'd like to be able to fix it myself in the future, especially if I go on a bike tour.
Also, a continuing issue I've had with my second topstone lefty is a very annoying squeek coming from the front brake. The first bike I had did not have this issue at all. It's really, really, really annoying. I've had the brakes adjusted, and they did some type of treatment which should have remedied the issue. However, it has not. I'm going to upgrade to the icetech discs and hopefully that will solve the problem.