Shim on speedometer drive?

brian4.2 · Dec 27, 2018

I have assembled the wheel, all new parts, bearings in the proper place. I am using one Dons 1 piece axle.

When I fit the speedometer drive to the wheel, there is a chaffing that I can hear. Its not terrible but I dont think there should be ANY contact with the Hub-Cover. I can see some wear marks on the inside of the drive, this must have been happening before I took it apart.

Is this a common problem?

Almost like the spacer #31 is .010" to short.

Has any one fit a shim to the inside of the speedodrive?

If so, does anyone have a part number? I think .010" should do it

Deets55 · Dec 27, 2018

Could it be the steel cover that holds the felt in place that’s rubbing?
And yes, on my MKIII I needed a .30” shim because it would bind up when I tightened the stub axle.
Pete

texasSlick · Dec 27, 2018

I had a similar problem. The speedo drive somehow became distorted and the center portion was bulging outward. I placed it in a vice with a socket for a spacer, and pressed it back to shape.

I had a dimension for the thickness of the speedo housing, but it has escaped me ..... I want to say it was 0.8" without the top hat bushing, but I cannot say for sure.

Slick

Update: Just measured my old speedo drive ... thickness is 0.825".

Ron L · Dec 27, 2018

As Slick says the drive can be distorted. I believe this often is the result of levering the wheel to get the spacer between the drive and the swingarm. The drives are easily deformed.

The other cause is the crushing of the "top hat" spacer in the drive. A new spacer or a small shim is the remedy here.

johnm · Dec 27, 2018

I had exactly the same problem when fitting the one piece axle last week. I had also replaced the hub cover. Looking at the old hub cover you could see a deep groove had been worn in it by the speedodrive.

I installed a thin spacer (about 40 thou (- 1 mm )) to space the speedo drive out from the hub cover. I shortened the axle spacer on the right side by the same amount to give the same spaceout between the swinging arms.

HoveToo · Dec 28, 2018

It looks like you have omitted the speedo drive spacer, part number 06 7629. I know about this because I did the same and went through many drives before I checked the manual and the rear wheel parts diagram. After I bought a replacement I found the original in my Norton left over bits box.

Ron L · Dec 28, 2018

HoveToo said:
It looks like you have omitted the speedo drive spacer, part number 06 7629. I know about this because I did the same and went through many drives before I checked the manual and the rear wheel parts diagram. After I bought a replacement I found the original in my Norton left over bits box.

The spacer is clearly present in the photos (inside the speedo drive).

brian4.2 · Dec 28, 2018

Thanks all, yes the spacer is present and I have another new one on the bench. I think I will compress it in the vice, as I am only looking for .010". I would prefer to shim it but it seems an impossible size to find. I only have crude machining ability here.

HoveToo · Dec 29, 2018

Ron L said:
The spacer is clearly present in the photos (inside the speedo drive).

Ah yes, I was looking at the wheel. Just a thought, is the spacer inside the speedo drive or outside, fitted through. I only ask because the exploded diagram shows it outside when it should be fitted between the speedo drive and the bearing spacer.

Deets55 · Dec 29, 2018

brian4.2 said:
Thanks all, yes the spacer is present and I have another new one on the bench. I think I will compress it in the vice, as I am only looking for .010". I would prefer to shim it but it seems an impossible size to find. I only have crude machining ability here.

https://www.mcmaster.com/shaft-shims

I think this was the set I bought.

There are probably other options, possibly Tractor supply or NAPA?
Pete

brian4.2 · Dec 29, 2018

HoveToo said:
Ah yes, I was looking at the wheel. Just a thought, is the spacer inside the speedo drive or outside, fitted through. I only ask because the exploded diagram shows it outside when it should be fitted between the speedo drive and the bearing spacer.

This is new information. I'm not sure it will go inside. It seems to be outside going thru the hole in the drive, as the drawing suggests. It was stuck there so I thought it was a part of the drive and ordered another spacer.

texasSlick · Dec 29, 2018

brian4.2 said:
This is new information. I'm not sure it will go inside. It seems to be outside going thru the hole in the drive, as the drawing suggests. It was stuck there so I thought it was a part of the drive and ordered another spacer.

That spacer is called a 'top hat' spacer. It is pressed in from the outside until the 'brim' of the 'hat' meets the flat of the drive.

The function of the spacer is mainly to adapt a universal drive housing to several sizes of bike axles and designs.

Slick

texasSlick · Dec 29, 2018

brian4.2 said:
Thanks all, yes the spacer is present and I have another new one on the bench. I think I will compress it in the vice, as I am only looking for .010". I would prefer to shim it but it seems an impossible size to find. I only have crude machining ability here.

The thickness of the Speedo drive from the outside flat (without top hat spacer) to the inside cover containing the felt washer, should be 0.825" +/-. Apply a little heat and squeeze in a vice using a socket to push around the bore hole. The material is not brittle and yields easily.

Slick

HoveToo · Dec 30, 2018

The top hat spacer should be fitted directly into the bearing spacer before fitting the speedo drive. That is why you have scuffed the dust cover on the wheel as the speedo drive is forced against the wheel rather than held off by the spacer. With time the speedo drive will fail. I bought two before discovering that I had left the spacer out during a protracted repair.

850cmndo · Dec 30, 2018

Never heard that one before.

brian4.2 · Dec 30, 2018

Im off by .010". If I moved the "top hat" spacer to the inside, .062" for the top hat and around .040" for the thickness of the drive. I would be worried about engagement on the drive. There doesn't seem to be any positive locating going on inside.

Ron L · Dec 30, 2018

Slick is correct. The tophat spacer is fitted from the outside of the drive. If the drive scrapes the wheel disc, the tophat spacer is is either crushed or (more likely) the speedo gearbox is not flat, but bowed out in the center.

HoveToo · Dec 31, 2018

Well I guess we agree that the speedo drive is too close to the wheel and needs some kind of spacer to hold it off. Threads back to 2009 describe the same problem including the damage to speedo drives that I have suffered. Only the top hat spacer is shown on the wheel drawing. It is a matter of minutes to try it in the position that I suggest.

cyclegeezer · Dec 31, 2018

HoveToo said:
Well I guess we agree that the speedo drive is too close to the wheel and needs some kind of spacer to hold it off. Threads back to 2009 describe the same problem including the damage to speedo drives that I have suffered. Only the top hat spacer is shown on the wheel drawing. It is a matter of minutes to try it in the position that I suggest.

I think an easy test would be to loosen up the long axle bolt and see if the swingarm spreads out at all. Wouldn't the stack height of all the components be less than the space provided if the top hat belongs on the inside? For the record, I had the scuffing problem when I got my bike a decade ago, and now that I have the top hat on the inside of the drive I no longer have that problem. The speedo drive is about .035" from the face of the aluminum wheel cover.

texasSlick · Dec 31, 2018

For the third time, measure the thickness of the speedo drive. It should be no more than 0.825 inches not including the top hat spacer. If it measures more, the center part is bulged out. This bulge causes the inboard side of the drive to encroach on the wheel hub cover.

Apply some heat to the drive housing, and squeeze it to size in a vise using a socket of approx 1.25" outside diameter bridging the hole.

No spacers other than the proper top hat spacer are required. The spread of the swing arms is not a factor.

Slick

Shim on speedometer drive?

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