Speedo Cable

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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Peter Morris
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Location: SURREY UK

Speedo Cable

Post by Peter Morris »

So 3500 miles after the speedo cable was fitted, my G15CS has decided that the cable does not go far enough into the speedo to actually make it work.

I have tried putting the inner cable in the vice and tapping the (speedo end) ferrule further down the cable but it won't budge, any ideas please?

I have a spare Doherty cable and the knurled nut (speedo end) won't even nearly fit.....won't even start on the speedo threads. I can't remember what bike the cable is actually for though, but definitely AMC.

Thanks
Peter
P.S. It's a Smiths grey face speedo, if that helps.
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clive
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Location: LONDON UK

Re: Speedo Cable

Post by clive »

Peter Morris wrote: P.S. It's a Smiths grey face speedo, if that helps.
Not really there were two types of grey faced speedos, one dished a chronometric fitted from 1960 onwards and the second a magnetic speedo which I imagine is on your bike. How about quoting the number. If is chronometric it will start SC or if magnetic SSM.

It's relevant because the magnetic and chronometric speedos need a cable with a different length tang, shorter for chronometric, so if you have a chronometric cable fitted to a magnetic speedo it may work for a while but the end of the tang or the internal square will wear and the cable start slipping. Incidentally if you go the other way and fit a magnetic cable to a chronometric speedo it preloads the internal drive cog and eventually wears it out.

Johnsons cables are a good bet for a cable, specify the length or year/model and whether it's chronometric or magnetic and you will get what you need. (I have no connection with Johnsons except that I have been recommending them for the last 35 years!)

So change the cable and hope the wear has not b******d the internal square of the drive in the speedo it should be ok.
clive
if it ain't broke don't fix
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Peter Morris
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Re: Speedo Cable

Post by Peter Morris »

clive wrote:
Not really there were two types of grey faced speedos,
Good point Clive, it's magnetic.

Thanks for your help, Johnson's it is then.
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