I was driving my xt40 today and suddenly a loud clank and it died. Started up, fine if I go slow, a bit faster, same thing. Afraid to break something-- I get it in the shop, and find that the pin that goes thru the brake plate, the one you can push in by hand, (don't know what its called) was loose on the firewall. both sides were loose, I tightened them up, but it still has the problem. I am wondering if the drive chains are too tight or what would make this happen. I'm not sure what to do, since the pin mounts are stable now. Am I about ready to see something nasty happen?