Speedometer puzzle

[burvis]

Here's a brain teaser for the forum. I have burned through three speedo cables and still haven't figured this out.

Bought my bike as a basket case with a broken speedo cable. Once I finally got it running, I bought a used cable on ebay. When the bike got going, the needle started bouncing around like crazy, then the vintage cable snapped. I blamed the 'vintage' cable. So I bought a new aftermarket cable. The needle bounced around again. This time I noticed the speedo cable had gotten all bunched up between the fender stay and the wheel. I figured I'd routed the cable poorly and it got muched by the wheel. Bought cable #3 - watched it while going down the road. The needle started bouncing. Then the cable started to twist up in the middle like it was binding up internally.

I know that the speedo drive spin direction is different on different model years. I verified mine spins clockwise when the wheel is rolling forward. I hooked a working cable to a drill in order to test my speedometer gauge. Rotating the cable clockwise moved the needle in a normal way. I tested each cable as I put them on, all spun freely. My speedo drive is oriented properly, and the cable doesn't have to take a tortuous bend at the wheel.

I'm stumped. Bad speedo? Bad drive unit? Exceedingly bad luck with cables?

[burvis]

Hi folks,
this topic is pretty well covered already. I thougt I had searched this before, apparently not. Looks like I need to lube and recondition my speedo works, and use white grease on any new (4th) cable I try.

[paperslammer]

I am in the midst of disassembling mine because something was wrong. I found that the speedo cable had snapped, and the reason was the gears inside of the speedo had locked. So the wheel tries to turn the gears and snaps under the torque it has to use. I have taken it apart and seen where its rusted. So maybe that's something you could look at? Lube is recommended, but you may have to clean the gears up yourself...

[LOUD MOUSE]

If ya can even turn the part ya may want to put some "3 in one" or any Non-Detergent oil in a cap and set the unit into the cap so the oil will WICK UP the part.
Over night should do it. ....................lm

I am in the midst of disassembling mine because something was wrong. I found that the speedo cable had snapped, and the reason was the gears inside of the speedo had locked. So the wheel tries to turn the gears and snaps under the torque it has to use. I have taken it apart and seen where its rusted. So maybe that's something you could look at? Lube is recommended, but you may have to clean the gears up yourself...

[brewsky]

Hi folks,
this topic is pretty well covered already. I thougt I had searched this before, apparently not. Looks like I need to lube and recondition my speedo works, and use white grease on any new (4th) cable I try.

It's not that hard to do....unless it looks like this.....