Commando Speedo Inner Cable

I have acquired a new cable, for my MkV 750, from Andover Norton, so assume that it is a genuine part. How far out from the end of the outer cable should the inner cable protude at the speedo gauge end. The new one extends approx 11/16" which seems a bit excessive. I understand that if the inner cable is too long it will damage the speedo internals. If I need to shorten the inner cable is there a best way to do it-eg grind off or cut?

Thanks for any help

Bazz

Bazz said:

I understand that if the inner cable is too long it will damage the speedo internals. If I need to shorten the inner cable is there a best way to do it-eg grind off or cut?

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Provided that the depth of the speedo spindle drive recess that the cable inner fits into is greater than the protruding length of the inner cable then there shouldn't be any problem?

Grind the end of the inner cable if it is too long.

I believe that the usual rule of thumb is that if the inner is properly seated (with the pressed on ring sitting on the ferrule) then the inner should not extend above the top of the knurled nut when the nut is raised up to the flange.

There is a difference between the clearances on chronometric clocks and SSMs (magnetics) They haven't sold you a Dommie cable have they ? I can't check this for you at the moment as the only chronometric that I have handy has a pre-war Jaeger drive.

Shortening this cable is another thing I tried, and failed at, a couple of years ago. I fitted a new cable to my 750 and noticed the inner wire seemed to be a bit too long, projecting above the ferrule as described above.

I tried to trim it with a cutoff wheel on a dremel, and the wire came apart on me :x It's actually not a wire but a spring, coiled up and tack welded on the end. I cut off the tack weld and SPROING! All I had for my efforts was a ruined inner cable.

So I bought another cable and installed it as it came. That was 5000 miles ago and everything is still working...

Debby

Bazz said:

I have acquired a new cable, for my MkV 750, from Andover Norton, so assume that it is a genuine part. How far out from the end of the outer cable should the inner cable protude at the speedo gauge end. The new one extends approx 11/16" which seems a bit excessive. I understand that if the inner cable is too long it will damage the speedo internals. If I need to shorten the inner cable is there a best way to do it-eg grind off or cut?

Thanks for any help

Bazz

Click to expand...

The length of the cable is critical and I don't think you can safely assume that any new cable that you buy is of the correct length. If you use a cable that is too long, you will start to see gold dust in your speedo and will ruin it in short order. Big $$$ to fix. Most of the speedo cables I have bought recently have been Barnett and they all have been too long. I am not sure about the ones from Andover Norton. Make sure the cable is well seated in the speedo drive before you do any trimming. The length protruding past the pressed-on brass ring needs to be about 7/16 of an inch for a Smiths magnetic speedo. I agree with 79X100 that with the cable well-seated in the speedo drive and the ring butting against the threaded cup, the end of the cable should be about even with the top of the cup. I haven't had any problems with the cable unwinding during trimming with a Dremel like Debby described but maybe I was just lucky! Wrapping the cable tightly with electrical tape before trimming works well for me. This technique also works for trimming control cables. I have, however, trimmed a speedo cable too short on one occasion because I failed to make sure it was well-seated at the speedo drive end.