I've got a SunTour Cyclone rear derailleur w/ a six-speed freewheel on my 23-year-old Bridgestone 600.
Lately whenever I backpedal the chain dumps off the upper jockey wheel towards the inside. It doesn't actually get stuck between the jockey wheel & the cage, it still moves freely, but it makes a hellacious racket, plus of course it totally screws up the efficiency of the drivetrain.
Any ideas what might be causing this?
In the past I've noticed while cleaning my chain that the rd would sometimes swing forward when I backpedalled, as if the chain was somehow not moving freely through the cage & instead was tugging on the rd...this would happen when I was gripping the chain w/ a rag. So now it would seem there's some sort of tension/load on the chain during normal operation? Or something like that...?
My wife says "Just don't backpedal." Thanks, honey.
Other suggestions appreciated.