Speedo cable wrapped around axle

Mart UK

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Oh dear, I've turned it into an oil thread! :)
IDK, it's done now. Quick blast, still waving at me, +/- couple mph. Don't mind living with it now I know my speedo only costs £59!
 

marshg246

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Oh dear, I've turned it into an oil thread! :)
IDK, it's done now. Quick blast, still waving at me, +/- couple mph. Don't mind living with it now I know my speedo only costs £59!
Not sure we started at the beginning of your problem (hope I didn't miss it). If you disconnect both ends of the cable and turn it with your fingers, it should turn smoothly with a little resistance. If not you need to clean and lub, or re-route, or replace. If it does, then you can use a drill to spin the speedo to see if it is smooth or not. If it is smooth, better have a good look at the speedo gearbox, if not, speedo not good.
 

L.A.B.

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In answer to my query re: lubrication and routing of a new Mk3 speedo cable:

Apparently, you do not need to oil the cable but if you want to, then use a light lubricating oil. I use 3 in 1.

Apparently!? :oops:They don't seem too sure.
According to AN's website their 06.7904 speedo cable: "featuring an improved inner cable" so might be improved in a way that doesn't require lubricating although doesn't say specifically how it is "improved", even if that were the case it wouldn't apply to existing cables.


Sounds more like AN could have been quoting from the old Venhill control cable maintenance instructions (below). A standard speedo cable needs to be lubricated in my opinion!

file:///tmp/CableInstallationRecommendations-1.pdf
"Road bikes – At the beginning and end of the summer, remove the cables and flush through with WD40.
Once clean, lubricate the cable with a light 3 in 1 general purpose oil and lubricate nipples where required
with Copper grease. Note barrel nipples must be free to rotate in the lever blade."
 
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Tornado

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The drive depth of the '71-on gauge spindle (below) is approximately 0.735" so should have been fine with an inner cable of 0.45" as the inner cable only needs to be just less than the drive depth of the gauge.


Chronometrics and pre-'71 magnetics (the one below), however, have less drive depth (approx 0.546")...


...'71-on, therefore, are 9/16" (0.5625").
a_Correct-cable-fitting.jpg
Regarding these cables, my '74 850 with fading green dot speedo has an inner cable that looks the same at both ends save for one end has a brass ferrule swaged to its square end section...sort of a limiter to how far into speedo or drive receiver the sqaure section can go, or perhaps its there to better control lateral wobble against the drive or speedo abutements? Unsure which device this brass end is meant to go into. Trying both, speedo does seems to run, but much less sensitive to jumping needle syndrome when the brass lives at the speedo end, at least when using my power drill to run cable at the drive end.
 
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The brass bit goes to speedo end. I'm pretty sure it is to get the amount of inner cable that goes into the speedo head controlled as it locates against a shoulder in the outer cable end piece.
 

L.A.B.

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Regarding these cables, my '74 850 with fading green dot speedo has an inner cable that looks the same at both ends save for one end has a brass ferrule swaged to its square end section...sort of a limiter to how far into speedo or drive receiver the sqaure section can go,

Unsure which device this brass end is meant to go into.

There should be a brass ferrule at the upper end of the speedo and rev counter inner cables.

You should find the length of inner cable that extends from the brass ferrule is longer than the depth of the spindle recess (so I recommend you don't grind it down as it would then be too short!) as its purpose is as Nortoniggy says so the brass ferrule locates against a shoulder inside the outer cable fitting.

 
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L.A.B.

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...Also...I suggest you fit the drive gearbox end of the cable first especially if it's a new cable or drive gearbox (or fit the outer then insert the inner from the gauge end) as the upper end of the inner cable could be forced into the gauge if the inner cable is tight in the drive gearbox which would go unnoticed if the cable is fitted to the gauge first.
 
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If you fit the top hat spacer directly into the wheel bearing before you fit the speedo drive it holds the speedo drive off the rear hub cover, it stops the speedo drive being distorted and failing when the axle is tightened and it fills the gap between the axle and the bearing so that the bearing is in contact with the axle.

Fitting the rear wheel spacer between the speedo drive and the swinging arm does not require levers etc. No other shims need to be made. Speedo drives do not get dished and fail or seize.

This is how my bike was assembled from new. I bought it in 1975 in a box ready for export to the USA but the Mk3 came out and Elite Motors of Tooting sold the MK2a off at a discount. That is how the rear wheel was assembled when I did my first puncture repair in France in 1976.

There are many, many threads describing a variety of failures in this area. The key observation is that the axle is undersized relative to the wheel bearing. If the top hat is fitted through the speedo drive per the drawing, the axle passes through the bearing without touching it. Norton may have made some errors but not something like that. Drawings can be incorrect.

And, should the assembly be ordered as I suggest, what risk are you taking. No one describes a speedo drive failing because it was running off centre or floating as it is in the scheme I describe. All the discussion is of dished speedo drives, new spacer dimensions and crushing of the speedo drive or top hat components. If drawings are sacrosanct have a look at part number 06.3369 and then the drawing. Mistakes happen. I know I've made quite a few.
 

L.A.B.

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If you fit the top hat spacer directly into the wheel bearing before you fit the speedo drive it holds the speedo drive off the rear hub cover, it stops the speedo drive being distorted and failing when the axle is tightened and it fills the gap between the axle and the bearing so that the bearing is in contact with the axle.

The key observation is that the axle is undersized relative to the wheel bearing. If the top hat is fitted through the speedo drive per the drawing, the axle passes through the bearing without touching it. Norton may have made some errors but not something like that.

What you describe doesn't seem possible because the bearing runs on the shoulder of the bearing spacer that protrudes from the bearing on the speedo drive gearbox (timing) side as shown in the pic below, so there is no "gap between the axle and the bearing" (there couldn't be), therefore, I fail to see how the top hat can "fit directly into the wheel bearing" but only into the outer end of the 06.7704 inner spacer as the inner end of the spacer locates over the bearing spacer shoulder.

flowerpower_000166-jpg.43635


If drawings are sacrosanct have a look at part number 06.3369 and then the drawing.

https://andover-norton.co.uk/en/shop-details/16071
Part number:
"06.3369
SECURING CLAMP - OIL FILTER"

This drawing? Some other drawing?
Shows the oil filter clip?
 

Tornado

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So after disassembling my speedo cable, thoroughly cleaning inner cable and outer sleeve, putting it back together, brass fitting end into speedo, test ride today gives no needle movement whatsoever. I tried undoing drive end at road side to see if turning into end by hand gave any needle flick, it did not until I pushed/pulled inner end within the sleeve. Found it could be pushed well into sleeve, leaving only maybe 1/8" protuding.
Refitting to drive, I could see inner being turned as I spun wheel before fully seating inner, so I know drive is turning. But still no needle movement after fully threading nut in place.
Will need to pull speedo end and have more inspection. Can't do that now as i'm still out riding last sunny day for much of coming week.
 

L.A.B.

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I tried undoing drive end at road side to see if turning into end by hand gave any needle flick, it did not until I pushed/pulled inner end within the sleeve. Found it could be pushed well into sleeve, leaving only maybe 1/8" protuding.

If I understand correctly that there is only approximately 1/8" of inner cable protruding from the outer cable sleeve end (not including the knurled nut?) then that would be the problem as it wouldn't even reach the drive spindle (approx 0.140") inside the speedo.
 
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Tornado

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If I understand correctly that there is only approximately 1/8" of inner cable protruding from the outer cable sleeve end (not including the knurled nut?) then that would be the problem as it wouldn't even reach the drive spindle (approx 0.140") inside the speedo.
Only when I push inner fully into the sleeve. Unsure on exact length protuding, will get proper meaasue later. I can pull inner out of sleeve fair amount, maybe half inch?
 

L.A.B.

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Only when I push inner fully into the sleeve. Unsure on exact length protuding, will get proper meaasue later.

You should be seeing a similar length of inner when pushed fully into the sleeve as my previous pic.
Again, here:

I'd say there should be a minimum of 3/8" protruding because at least 1/8" of the engagement is lost as the spindle doesn't extend to the very bottom of the gauge but only as far as the brass ring in the pic below:
 
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What you describe doesn't seem possible because the bearing runs on the shoulder of the bearing spacer that protrudes from the bearing on the speedo drive gearbox (timing) side as shown in the pic below, so there is no "gap between the axle and the bearing" (there couldn't be), therefore, I fail to see how the top hat can "fit directly into the wheel bearing" but only into the outer end of the 06.7704 inner spacer as the inner end of the spacer locates over the bearing spacer shoulder.

flowerpower_000166-jpg.43635




https://andover-norton.co.uk/en/shop-details/16071
Part number:
"06.3369
SECURING CLAMP - OIL FILTER"

This drawing? Some other drawing?
Shows the oil filter clip?
Its too late to take the wheel out and show a photo - not sure I'm able to post photos anyway. Try tomorrow.
Re the drawing - see the direction of the worm drive - its drawn across the oil filter clamp, not along the clamp as it has to be to work. Just an example of a small error in the drawing
 

L.A.B.

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Its too late to take the wheel out and show a photo - not sure I'm able to post photos anyway. Try tomorrow.
The rear wheel drawing isn't wrong, though, as I'm sure other members will agree that the top hat spacer cannot fit inside the bearing if the shouldered spacer is there.


Re the drawing - see the direction of the worm drive - its drawn across the oil filter clamp, not along the clamp as it has to be to work. Just an example of a small error in the drawing

That was it! Ok. There are several more errors I could point out so I'm under no illusion regarding the accuracy of the drawings.
 
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