Speedo cable wrapped around axle

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During my last ride the speedo stopped working. I thought that the cable had disconnected from the gauge as I've had that happen before. When I got home I saw that wasn't the case. I have a new cable on the way and hopefully the drive is ok.

Not sure what causes this, rear axle not tight enough?
 
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Never heard of this before. I've had my entire drive disintegrate but nothing like that in my history of WTF things take place.
 

L.A.B.

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Not sure what causes this

 

texasSlick

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I have had a worn speedo drive rotate but not that badly. I found the ring gear of the speedo drive was so worn the worm gear snagged it, rather than meshing with it.

Slick
 
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Those big old axle nuts do loosen with time. I have to check mine once in a while, but my bike shakes and rattles more than a Commando.

If you get the speedo shim setup right, you can crank the axle down tight without worry.

I made a mistake shimming a new speedometer drive unit when I first put a speedo on my Norton. Rear wheel locked up. Cable didn't wrap around the axle, but it snapped at the speedo and was dragging behind the bike. The speedo housing got jammed up on the hub drive, and stopped the wheel from spinning. Your axle must have been a little loose at some point, or the speedo housing would/could have stopped spinning around wrapping up the cable and instead locked up the rear wheel. Well, maybe anyway.
 

BERT

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Those big old axle nuts do loosen with time. I have to check mine once in a while, but my bike shakes and rattles more than a Commando.

If you get the speedo shim setup right, you can crank the axle down tight without worry.

I made a mistake shimming a new speedometer drive unit when I first put a speedo on my Norton. Rear wheel locked up. Cable didn't wrap around the axle, but it snapped at the speedo and was dragging behind the bike. The speedo housing got jammed up on the hub drive, and stopped the wheel from spinning. Your axle must have been a little loose at some point, or the speedo housing would/could have stopped spinning around wrapping up the cable and instead locked up the rear wheel. Well, maybe anyway.
Hard not to smell something burning
 

gortnipper

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These things happen quickly.

I refurbished my speedo several years ago, giving it a good clean out, pulling the spiral gear, straightening out the slightly caved in body, repacking.

Early this year on a local ride, speedo stopped working. Stopped to have a look and had the grease death star and the speedo was detached from cable+nipple and rotated almost 60°.

The cable end had sheared off, and the ring/spiral gears were jammed. No repair possible. End of life. Which came first? Who knows. Cable was only a couple years old. New speedo was needed.
 
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Those don’t explain why after ten years it decides to pack up. If it hadn’t been shimmed correctly it wouldn’t have lasted this long.
 
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Did you check your speedo gearbox? If the worm gear and its mate locked up ?
That's the only thing that I can think of when the smith gearbox would spin with the wheel? I would wash it down with diesel and have a good look at the gears.
 
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850cmndo

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These things happen quickly.

I refurbished my speedo several years ago, giving it a good clean out, pulling the spiral gear, straightening out the slightly caved in body, repacking.

Early this year on a local ride, speedo stopped working. Stopped to have a look and had the grease death star and the speedo was detached from cable+nipple and rotated almost 60°.

The cable end had sheared off, and the ring/spiral gears were jammed. No repair possible. End of life. Which came first? Who knows. Cable was only a couple years old. New speedo was needed.
The "Death Star" doesn't mean immediate failure. In my experience it results from too much lubricant. The fact that things shear is puzzling. The speedo froze?
 

gortnipper

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WTF? That's nuts. It sheared? Never had a cable disconnect from the gauge either.
The cable was still attached to the brass nipple which inserts into the drive. That had pulled out, and the cable end sheared off ~1/4". I didn't notice that until I installed the new drive and the speedo wnd of the cable did not spin.
 

gortnipper

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The "Death Star" doesn't mean immediate failure. In my experience it results from too much lubricant. The fact that things shear is puzzling. The speedo froze?
Yes, I had just done a seasonal relube, so most likely too much grease. Speedo drive gears were locked, either that or the drive twisting sheared the cable tip.
 

RoadScholar

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The grease nipple doesn't look like it has had a squirt in a while, just an observation, not something I would debate, and if you say it has received regular lubrication, so be it.

In any event it needs to come off and be examined, clearly it seized. In my experience part # 06-0317, "speedo drive lockring"
can get knackered for a number of reasons preventing the two ring gear teeth from "floating" due to manufacturing tolerance. The ring gear teeth should not bottom in the two slots of the lockring. With the spacer and "hat" and some modeling clay the depth of the of ring gear teeth can be checked and shimmed if needed. The lockring can be cleaned up, radiused and polished if it is not too far gone; I suggest that new lockrings get radiused and polished as well as checked for ring gear teeth seating depth.

I hope you will follow-up with some of the excellent pictures you take and post so well. I suspect that whatever caused the failure, once laid out, will greatly benefit forum members that have no idea of how complex a Norton can be.

Best.
 
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Never heard of this before. I've had my entire drive disintegrate but nothing like that in my history of WTF things take place.
I've seen it on my mates commando. Spun and pulled cable at a rally. My drive disintegrated or rounded out so I didn't lose the cable as his did. Mine, It just stopped working during a NYNO rally. Part of the maintenance. Shit happens.
cheers,
Tom
 
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