I thought my Ratty Cimatti had a catastrophic tranny failure this weekend during the MopedLar Ride. Upon closer inspection yesterday, I found that the only thing wrong was the nut holding the drive sprocket was gone and the sprocket was just spinning on the shaft.
This is at least the third time this has happened to one of my Minarelli powered peds. Do yourself a favor and check that nut. A little loctite wouldn't hurt either.
Long live the Ratty Cimatti! (edited)