Speedometer drive flinging grease

My speedometer drive is flinging grease all over the hub. I found a post from 2013 that talks about "drive spacer collapsing" as the root cause by creating heat and melting the grease.

Has anyone else had grease flinging everywhere and rectified the situation? Is it cause by a drive spacer (part no?) collapsing or a failure of the felt gasket?

Thanks!

Geoff

geoff1971 said:

Is it cause by a drive spacer (part no?) collapsing or a failure of the felt gasket?

Click to expand...

More likely to be the speedo drive spacer.
https://andover-norton.co.uk/en/shop-details/17202/speedo-drive-spacer-nm-13270-b2-660-

I had my speedo drive go slightly dome-shaped (presumably from PO over-tightening the axle), which forced the felt seal against the polished aluminum hub cover. The combination of grease and aluminum dust created quite a nasty mess across the face of the cover. I took a chance at reforming the speedo drive by carefully squeezing it in the bench vise, and it's lasted two years and counting.

Nathan

I don't know if you ran across this thread in your search but it at least gives you a good look at the various parts in the speedo drive.

Smiths Speedometer drive Rebuild Explained...

You are probably faced with one of four options should you discover that this problem is due to the failure of one or more drive parts.
1.) Buy another unit, used or new. New is about 90 bucks.
2.) Get clever and figure out how to repair it. You could then potentially become the forum expert on this topic.
3.) Collect up a bunch of damaged units and put together a good drive from the pieces and become the forum expert on this topic.
4.) Move away from mechanical gauges to electronic ones.

Is your speedometer still working correctly? If so, then LAB is probably correct that it is a Norton part and not a Smiths.

Russ

Get over it.
If you grease it, it wont wear out quickly. It will leak grease out though. Tough.
Don't grease it and it will stay clean but will be stuffed in about 6,000 to 10,000 miles.
I grease mine before every long ride.
Best still, if you want it to stay clean, dont ride it.
Dereck

L.A.B. said:

More likely to be the speedo drive spacer.
https://andover-norton.co.uk/en/shop-details/17202/speedo-drive-spacer-nm-13270-b2-660-

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Thanks L.A.B. - the link was most informative!

This problem just recently surfaced, and even though my Commando will not win any cleanliness awards, having the rear hub and tire covered in grease in a short ride goes beyond the norms for a British bike. If it turns out to be an irreparable problem with the drive I have been drooling over electronic gauges for sometime now.

geoff1971 said:

Thanks L.A.B. - the link was most informative!

This problem just recently surfaced, and even though my Commando will not win any cleanliness awards, having the rear hub and tire covered in grease in a short ride goes beyond the norms for a British bike. If it turns out to be an irreparable problem with the drive I have been drooling over electronic gauges for sometime now.

Click to expand...

I'm not sure I posted the "informative" link, however, you need to ensure the wheel isn't rubbing against the speedo drive gearbox even if it means adding an extra spacer/shim.

Slinging grease is not normal.

After 85K miles, mine began to sling some grease, creating a few 4 to 6 inch long streaks, which I paid little attention to. Next thing I knew, my gearbox was gouging the center hub disk as Nathan describes above. Like Nathan, I found the GB to be domed shaped, which I do not think axle tightening had anything to do with. Like LAB, I think the top hat spacer may have something to do with it.

On disassembly, I found the worm and particularly the ring gear to be worn.

If you can get the parts, these things are easily rebuilt. NOS units are still available, but pricey if you can find them. Used original units are readily found but condition is ?. There are reproduction units, reasonably priced but I have heard they do not last long in service. That info is several years old, so perhaps someone can bring us up to date.


Slick

There are some very old threads on this subject. I was probably involved in some of them. In my case the gearbox case around the mountings lost some parts, got thin and started rubbing on the aluminum shield. I think I found some washers to build up the area and stiffen the assembly. It's sort of a weak spot.