Speedo drive AGAIN!

Went to go meet the guys for a early canyon ride to a very secluded little place for breakfast but noticed that dreaded grease had come out of my speedo drive & the rear wheel was not spinning freely. I had adjusted the chain a few days ago so I guess the junk speedo drive & Top hat spacer must have gotten squished? Again. I know some people get rid of them & put in a spacer but I like my stock speedo. What is the trick to longevity for these things? I am careful not to over tighten the axle, follow the books process of left axle (stub) first then the right side while deppresing the brake to center the drum/shoes, this was a used but good drive with a new top hat spacer. What's the trick?

Same way you preserve tires, you just don't ride on them very much or hard. All's I know ya can do is try to keep the fixing rivets tight or replace by more robust very short length bolts and lube as best ya can while constantly keeping an eye out for spares at a good price, same as tires over about same mileage till worn out again.
Any cycle over 250cc is pure luxury ongoing expense, even more so on a big ole Commando so get over it or get off them. Ya don't need to nip up axle any more than to keep the nut from coming off or tends to strain the dumb axle stress risers and the speed crush prone nature. Only thing else I can add on designed in decay of a number of factory items is - ugh.

I cut the center out of the pot metal housing to the inside diameter of the steel retainer. Then machine a steel spacer to fit with a shoulder that rests against the steel retainer on the inside and use a large diameter washer on the outside to pinch and hold the drive in place. If you do that and then lube it with oil instead of grease they will last a long time. Jim

I am no engineer but could not Norton have come up with a much better speedo apparatus?

I removed my speedo drive and cabling 15 years ago, but left the speedo in its holder next to the tach for looks.

Horrors!

It just does not interest me to know how many actual miles an hour I am going, the tach does just fine for me.

I see the stock speedo drive as just another source of potential problems, including freezing up and grabbing the cable and ripping it, to dismantling and lubing intervals.

As my wife says of many things, "I mean, why bother"?

I am no engineer but could not Norton have come up with a much better speedo apparatus?

I am sure they could of but not for the 1.95 they had in the budget for such extraneous items. :? Jim

I've been though 4-5 speeds on two bikes now so predict about 4-6 miles before about used up. If Comoz or such could supply beefed up drives for say $200 it'd be a bargain in long run. Part of this hobby fascination and obstination is how much to do - fixing real Norton items or jumping ship and tradition. Both paths have same appeal pressure, only solution I've come to is get two Cdo's for each type of zeal.

Ok Jim that sounds like a good idea & I may be able to have a friend make the parts for me but can you tell me what is locking up the wheel when I tighten the axle? Is the drive unit deforming and rubbing on the hub??? Thanks, Glenn.

gtsun said:

Ok Jim that sounds like a good idea & I may be able to have a friend make the parts for me but can you tell me what is locking up the wheel when I tighten the axle? Is the drive unit deforming and rubbing on the hub??? Thanks, Glenn.

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What usually happens is the soft metal deforms and causes the flat side of the drive to get convex and the drive moves over and contacts the hub. It also mis-aligns the gears and makes them short lived. The only way to avoid this without a steel center is to reduce the torque on the axle which causes other problems. Jim

What is the solution for the speedo drive woes? I do like to have a speedo since it is the best way I know to try to stay somewhere near the speed limit when the authorities are monitoring my speed. The Norton always seemed to have more spirit than the law allowed . . .

Vintage Paul

hudson29 said:

What is the solution for the speedo drive woes? Vintage Paul

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New electronic (cableless) speedo replicas of the original Smith clock are available from RGM.

Mick

Any chance of posting pictures of the parts in question and the recommended fix? I have been reviewing the old workshop manual but it has limited views of this set up.
Thanks, Gary

Yes, please; I'd appreciate that also.

BrianK said:

Yes, please; I'd appreciate that also.

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Me to. I think we're talking to comnoz. :mrgreen:

"New electronic (cableless) speedo replicas of the original Smith clock are available from RGM.
Mick"
+1, Cj

I will get some pictures but it will probably be after the rally. Jim

I got down into the Norton over the weekend (maintenance per the manual) and have had the black star of death on my rear hub for the last couple of weeks. I pulled my rear wheel apart, took off the bearing cap and pulled the felt ring and top hat out. They looked ok so I cleaned the bearings up and put lithium grease in them and put it all back together. I noticed when putting my speedo back on it was turning fine but I put my grease gun on it before installing it and noticed that grease was coming out from between the ourter race and the inner part that connects to the hub to spin. The clearance is about 2-3 mm and it lets plenty of lube through, is the speedo supposed to be sealed so the lube does not leak out? It is wearing on my hub plate, gouging the surface at the center.

Has anyone ordered one of the re-pops from India that are supposed to be steel? If not will probably just get one from Norville or Old Britts.

As for the bearings, they are good but would like to go ahead and do sealed since they are only about $5.75 each. Has anyone done this without a press? And if you have replaced the bearings with sealed did you use the felt ring or just leave it out. I read on Old Britts site you could leave it out since it was no use with sealed.

Just a reminder I have a 74 Roadster.

Thanks

The speedo gearbox should not contact the rear hub cover plate. You either have too much grease on your box, or it is heating up from rubbing on the cover plate and melting the grease. Some like just to put oil in there. It doesn't take much, you don't want to fill it, just lube it a bit every year unless you really put the miles on it, the decal says every 5000 miles. I think comnoz had a fix for the gearbox and it's tendency to bend in a recent thread.

The bearings, you can get sealed ones, no pressing required, but you will have to knock them out somehow. The manual covers that pretty good, I think you can use the front spindle. Note one side is a double row and you can get that at FairSpares or Walridge for less than $40, no machining required. I think the felt seal is optional, I put it in just to take up the empty space and cleaned all that old grease out of the centers, just put a light amount in to keep things from rusting.

Dave
69S

Electronic speedometer from RGM?

Sounds great, how much money?

thanx

mcns said:

Electronic speedometer from RGM?

Sounds great, how much money?

thanx

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Hi,

I contacted SRM in Wales: http://www.srmclassicbikes.com/news/new ... -and-tacho

Their plan is to get the grey faced clocks shipping first, then black, then green dot (no plans to do the Norton/Triumph vector logo)

I was told towards the end of this year they hope to be shipping product.

The electronic speedo drive is just a housing for a HE sensor and will only work with the electronic speedo.

Also I think the electronic speedo will only work with a neg earth system.


I have this setup on my Christmas shopping list :mrgreen: I have a 75 MK3 so I'd really like the original Norton/Triumph vector logo, I'm looking into options on getting custom clock faces made up, more anon.

All the best

Kevin