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Tacho cable size

Posted: Wed Jun 04, 2025 11:37 am
by IanHood
The tacho drive I have on my yellow desmo appears to require a cable end that is a 3mm square but the cable I have has a 2mm square.

Do I have the wrong cable (or maybe the wrong drive)?

Ian

Re: Tacho cable size

Posted: Wed Jun 04, 2025 12:07 pm
by Duccout
Hi Ian,

I had this trouble with my 250 and my 900 when I bought new cables and found that the square end was too small for the ferrule. I fitted the old inner to the new outer on the 900, but the 250 required a new inner cable which I had made by Carrot Cycles (who I believe are now retired). This is all part of the pleasure of owning classic motorcycles!


Cheers,

Colin

Re: Tacho cable size

Posted: Wed Jun 04, 2025 1:13 pm
by Boxprod
When dealing with the rev counter cable on my 350, I found this to be the most cost-effective route:

https://www.louis-moto.co.uk/en/louis-parts-repair-kit-for-speedometer-cable-10058992?filter_article_number=10058992

No idea if it will be appropriate for yours, but it worked fine for me - until the rev counter itself didn't, at which point I went electronic.

Good luck,
Pete.

Re: Tacho cable size

Posted: Wed Jun 04, 2025 5:45 pm
by blethermaskite
Had this issue a couple of times.......so my remedy (as long as everything else is the correct size) is to make a small sheath for the squared end of the cable from biscuit tin tin ;) you just wrap a small strip around the end and squeeze it tight into a square works a treat. I think I have had my own rev counter cable done like this for the last 20 years so a proven 'dodge'. Cheers, George

Re: Tacho cable size

Posted: Wed Jun 04, 2025 6:51 pm
by IanHood
Excellent idea, thanks George!

Ian

Re: Tacho cable size

Posted: Thu Jun 05, 2025 2:14 pm
by IanHood
…and now sorted. Biscuit tin was too thick so aluminium can was substituted.

Ian

Re: Tacho cable size

Posted: Thu Jun 05, 2025 2:34 pm
by ranton_rambler
A bit of Coke can? - in the best tradition of "Zen and the Art..."

Re: Tacho cable size

Posted: Thu Jun 05, 2025 5:37 pm
by IanHood
:D Must classier - Fever Tree tonic water can

Re: Tacho cable size

Posted: Thu Jun 05, 2025 6:39 pm
by blethermaskite
"It's not what it is, it's what it might be" ;) Cheers George

Re: Tacho cable size

Posted: Sun Jun 08, 2025 7:19 am
by Jordan
I have a non-Ducati bike that had the speedo drive gearbox mounted on the rear wheel, but I need to move it to the front wheel.
I could probably buy a custom made shorter cable, but also I could make it myself if only I had a suitable press tool to make a square profile on the end of the inner cable. This message thread inspired me to do something about it.

The needed square has 3mm sides.
Material of the tool dies is ordinary mild steel - good enough for several cables I think.
I have a mill/drill with a tilting head and an hydraulic press.

The photos show how it was done.
I was surprised just how much pressure was needed to produce the square shape - about 5 tons.

Result of first attempt is fair, usuable.
It could to with silver soldering the end to prevent fraying.
The fit is a little tight, probably because of spring back of the cable wires. Slightly smaller die groove depth should fix that, not hard to adjust.

It won't be used much, but if such a thing was to be used in production, a flame hardenable steel like S1040 would be used, then hardened and tempered.

Total time was about 4 hours - I'm a slow worker.