Tach cable too long?

[berniebee]

My '83 SP1000 project has a T3 style console :





The tach cable appeared to be about 2 inches too long, so I ordered the MG Cycle T3 tach cable - but it was exactly the same length! There is plenty of slack even when the handlebars are at full right lock. The inner cable  length is 23 1/4" (59cm).

The cable is presently routed straight down from the tach, hits the lower triple tree plate and goes rearward to the engine.




When the handlebars are straight, the cable makes a fairly sharp turn at the lower plate and there is a big loop of excess cable out to the side:


 
When the bars are turned left, it's ridiculous.

Is this "Guzzi normal"?  Should I route the cable differently?
I lust looked at the MG Cycle site, a tach cable listed for the LeMans 850 is 21 3/4" inches, so about 1.5 inches shorter.  Could I use this one?
https://www.mgcycle.com/index.php?main_page=product_info&cPath=135_149&products_id=621
 It has a slight bend in the metal sheath, which I don't think will be an issue, but are the LeMans tach cable ends a different size or style?

[Antietam Classic Cycle]

Tach cable routing is always "fun". The Le Mans cable is the same, only shorter (and with the kinked end) and may work for you.

[centauro]

I did that very same modification to my SP. I simply removed the 90 degree angle drives on both tach and speedo, and the original cables routed just fine on both instruments.

[guzzista]

Based on Gutsibits tach cable descriptions LM1 is the shortest at 21.57  inches and one of the V50 variants  (Monza) is at 22+ inches.
I had the same issue  and used a V50 cable I had ( only descriptipn I had on the bag, no part #) and it was approx 21  inches. Matched it to a LM1 cable and the LM1 was longer. Guzzi dilemmas...

[n3303j]

Seems most cables I buy are size two. Either 2 long or 2 short.
So now I just get them all 2 long and cut them down for a perfect fit.

Speedo & tach cables are easy enough. You just need to make the inner wire cut end square again.

I clean the area thoroughly and then Flux it and saturate it with silver solder. Then a bit of careful filing and I have a new square drive end.

[berniebee]

Antiem: "Fun" LOL. So I'm finding out.

Rodekyll:  Thanks, but I've tried a right angle drive (it came with the bike.), it worsens the too long cable issue.

Centauro: The bike didn't come with the original console and so the tach cable might not be original either. Maybe that's why mine is too long.

Guzzista: Too bad there's no part number. On the MG Cycle site, they lump the V50 together with the T3. In other words it's the cable I ordered from them, which is 23 1/4". (It's a shame they don't list the length of this cable, I wouldn't have ordered it. I know, I know, I should have asked.)

N3303j:  You're solution definitely appeals to my DIY side, because I now have two good cables which are too long. But I was told that silver solder doesn't fill gaps and I don't have silver solder or flux. You think that copper pipe solder might work?

I've found a Utube video which describes shortening a cable
https://www.youtube.com/watch?v=WZ21dGNIbJw

and another which talks about making a die to square up the cable end.
https://www.youtube.com/watch?v=z82RtQZGZ9c







 

[n3303j]

Antiem: "Fun" LOL. So I'm finding out.

*SNIP*
N3303j:  You're solution definitely appeals to my DIY side, because I now have two good cables which are too long. But I was told that silver solder doesn't fill gaps and I don't have silver solder or flux. You think that copper pipe solder might work?

I've found a Utube video which describes shortening a cable
https://www.youtube.com/watch?v=WZ21dGNIbJw

and another which talks about making a die to square up the cable end.
https://www.youtube.com/watch?v=z82RtQZGZ9c

Properly cleaned and fluxed silver solder will fill the gaps as long as you don't overheat the joint.
But filling the gaps isn't necessary. It's just important that all the wires are joined to each other by the silver bonding agent.
I wouldn't trust lead plumber's solder to bond well to the steel wire.
No reason those video processes wouldn't work. That's probably how it's done in the factory (but with much neater dies).
But my method is sufficient and quick.
I measure the square with a micrometer. I measure the round with a micrometer. I compute the difference divided by 2. That is the amount to file off each side to make the round into a square.
I have a good vise with ground jaws. I grab the cable in the vise and file the first flat. Watch to keep it even width (so that it is even depth). Measure it and file until the first flat is parallel with the unworked side of the cable and is the correct depth (it's actually easier than it sounds, just don't rush.
When done grab the cable in the vise so the first flat is against the stationary jaw. Now file the second flat parallel to the top of the vise. This establishes the 90 degree form. Use the two finished flats fastened against the fixed jaw of the vise to set up for filing side 3 and 4.
Takes less time than watching the videos.

[centauro]

Properly cleaned and fluxed silver solder will fill the gaps as long as you don't overheat the joint.
But filling the gaps isn't necessary. It's just important that all the wires are joined to each other by the silver bonding agent.
I wouldn't trust lead plumber's solder to bond well to the steel wire.
No reason those video processes wouldn't work. That's probably how it's done in the factory (but with much neater dies).
But my method is sufficient and quick.
I measure the square with a micrometer. I measure the round with a micrometer. I compute the difference divided by 2. That is the amount to file off each side to make the round into a square.
I have a good vise with ground jaws. I grab the cable in the vise and file the first flat. Watch to keep it even width (so that it is even depth). Measure it and file until the first flat is parallel with the unworked side of the cable and is the correct depth (it's actually easier than it sounds, just don't rush.

Never shortened these type of cables, but, something worth considering is finding a brass button from a ball point pen, flatten it into a square shape, and see if it fits the back of the gage. If it does, maybe solder it to the inner tach cable. Almost free to try it.....(Guzzi content!)
When done grab the cable in the vise so the first flat is against the stationary jaw. Now file the second flat parallel to the top of the vise. This establishes the 90 degree form. Use the two finished flats fastened against the fixed jaw of the vise to set up for filing side 3 and 4.
Takes less time than watching the videos.

[centauro]

Or, you could change the angle or raise the instrument console a little higher; either of these actions will take up the extra length of the cable without shortening.... I am just thinking outside of the box?

[berniebee]

Thanks Ron: My mission now will be to find the correct solder and flux. Maybe there are fluxed rods.

Centauro: The cable is at least an 1.5" too long, moving the instruments console up that much would (I think) look a little strange. I'm going to to try to cut/solder/file (If solder doesn't cost too much.) and my plan B is to buy a shorter cable..

[n3303j]

There are fluxed rods. Welding supply might sell you just one?

[n3303j]

Don't overthink the flux.  I use the same little tube for everything I solder.

Silver likes borax.