Re: speedo problems

Posted by HH56 On 2012/6/16 10:46:33

Same applies. Those are two speedometers out of early 50's.

The second picture shows the U shaped magnet on the side of the round cup. Those do not touch but rather the magnet smoothly spins around and induces a field which the cup tries to follow. Anything such as a dry or kinked cable or dry bearing that hangs and then breaks free and allows the cable to whip so the magnet can suddenly spin rapidly, the cup will try to follow -- hence the jumping.

Best to take care of it now. If it gets too bad, the needle can jump so violently it hits the stops and either breaks or falls off or the hair spring jumps, gets twisted and damaged. Several have had that happen to theirs in the last couple of years.