Speedo cable

crusadersports said:

Brass ferrule on the inner cable goes into the clock and the ferrule is designed to stop it from going in too far.

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I'm not entirely sure it does, as the diameter at the upper end of the ferrule is generally smaller than the I/D of the brass ring inside the unit, but it would stop the inner cable from dropping too far.

Hmmm again. My clock ends with the stop ferrule on the inner cable, the tach has about 11/16" for the protusion, and about 9/16" protrusion for the speedo.



Looks like my clocks have the brass coloured caps, although it's hard to tell, but it doesn't look like L.A.B.'s left clock at all.

Speedo


Tach


All I can do is see if they work. Nothing looks damaged on the cable ends. Give me a few days for the weather to get cooler. I can't deal with this heat.

pv, your inner cable ferrule looks completely different than mine. May be a different clock input?

Dave
69S

I think you may perhaps have the wrong (later) cables for your instruments?

If I attempt to screw that type cable onto a 'brass cap' (Green blob) instrument, not only does the inner cable bottom out before the cable outer ferrule touches the cap (which can damage the instrument) but when I tighten the knurled fitting it runs out of thread before the outer cable is pulled tight against the instrument so the outer cable is still loose by 1/16".

[Edit] The brass cap instrument has approximately 6 turns of thread compared to the later one which has approx. 8 turns of thread.

Well, these are the only cables I ever had for this bike and they used to work fine. Only thing that has changed is 30+ years. I couldn't have mixed them up with some other bike because I don't have any others.

This is what I did, I put the cable ends into the clocks with the inner cable stop (ferrule) into the clocks, tightened the knurled knobs, so far everything seems fine. A bit of back and forth slop at the other end on the speedo cable. The tach drive I had to put the little tach drive adaptor into the cable so it's hard to tell about end slop. Then I put an electric drill on the ends in reverse, and all seems fine. At full speed on the drill on the speedo I get a steady 50 mph indication. On the tach I get about the same relative position, whatever rpm it is. If I have drop outs now, it's probably the gearbox off the rear wheel that is acting up. I'll find out when I get it started again.

I wonder if the 68-70 bikes had a bit of different cables and clocks.

Dave
69S

DogT said:

I wonder if the 68-70 bikes had a bit of different cables and clocks.

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Smiths instruments up to around 1970 (so Commando "Green blob/spot") appear to be the brass cap type with a cable recess depth of only just about 9/16", therefore a cable having 9/16" projection would have no end clearance in that type of instrument.
The 1971-on Smiths ("Green Globe" for Commando) are the type shown on the left in my photo, and those have a deeper cable recess of 3/4", so at least a cable with 9/16" projection has a reasonable amount of end clearance in that instrument.

My cables seem to go into the clocks fine without binding, maybe my picture has some paralax in it? L.A.B., can you inform me as to the date codes on the clocks?

Dave
69S

DogT said:

My cables seem to go into the clocks fine without binding, maybe my picture has some paralax in it?

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I suggest you carefully measure the actual amount of cable projection and also the depth of the recess inside the instrument, as there should be at least some amount of free space between the cable end and the endof the drive slot in the instrument. The amount of cable inner projection could also depend on the depth of the recess in the outer cable ferrule, so isn't just a matter of measuring from the stop to the cable end and ideally, the lower end of the cable needs to be in situ before measuring the inner cable projection.

DogT said:

L.A.B., can you inform me as to the date codes on the clocks?

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I don't know about any date codes? But an 'S' model would probably be fitted with a Smiths SSM 3001/02 1000 (MPH) speedo with BG5330/171 1.25:1 ratio speedo drive gearbox, and RSM 3003/12 4:1 tach. and both would be Norton "green blob" (solid green spot) items.

L.A.B. said:

I suggest you carefully measure the actual amount of cable projection and also the depth of the recess inside the instrument, as there should be at least some amount of free space between the cable end and the endof the drive slot in the instrument. The amount of cable inner projection could also depend on the depth of the recess in the outer cable ferrule, so isn't just a matter of measuring from the stop to the cable end and ideally, the lower end of the cable needs to be in situ before measuring the inner cable projection.

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I'll do that. I see what you mean.

L.A.B. said:

I don't know about any date codes? But an 'S' model would probably be fitted with a Smiths SSM 3001/02 1000 (MPH) speedo with BG5330/171 1.25:1 ratio speedo drive gearbox, and RSM 3003/12 4:1 tach. and both would be Norton "green blob" (solid green spot) items.

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I was asking about those numbers on the back of the clocks, like on mine 610 and 110 and on yours 518 and 119? I just assumed they were date codes, but I don't know. That's what others have told me.

I do have the green blob clocks. As far as I know they are original.


Dave
69S

DogT said:

I was asking about those numbers on the back of the clocks, like on mine 610 and 110 and on yours 518 and 119? I just assumed they were date codes, but I don't know. That's what others have told me.

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I'd guess the number probably identified the person or section within the factory that did the final quality checks and/or calibration?

Has anyone had a speedo cable with a green ceramic o ring under the brass? I have on my 74 stock cable.

Phil