Bouncing Speedo

[Pin_Head]

I doubt that a bad cable would make the needle bounce, unless it was binding up and winding up inside the tube and then letting go. If the needle bounces, it usually means that there is dirt/oil inside the drum inside the speedo unit (if it does it regularly) or there is a bad bearing on the drum or magnet if it only does it when you hit a bump.

Check out eddy current speedometer at to see how it works:
Howstuffworks "How Speedometers Work"

 

[CruisinMT]

well I seem to have fixed my problem, I took the speedo apart and replaced the odometer with one i know works. The old one was brittle and the gears starting breaking off. I replaced that and the speedometer cable as well. everything works and there is no bouncing anymore. So far everything works and I'm pretty stoked about it. The first time in 7 years that I can tell how fast I'm going.

 

[CruisinMT]

well my speedo worked right for about a day now when I get to 40 it makes an awful spinning sound and shoots up to 80 mph. WTF is going on?

 

[KOOTENAY KRUZER]

sounds like the drum and magnet in the speedometer are touching each other at times.

 

[Pin_Head]

sounds like the drum and magnet in the speedometer are touching each other at times.

X2 the spinning magnet is dragging on the drum. Either the drum is contaminated with oil/dirt/junk or the bearings are worn, allowing the magnet to touch the drum.

 

[CruisinMT]

ok I get that so how do i know if its the bearings or not?