Throttle cables replacement

My throttle cables have rust dripping out of them, so I assume I will have to replace them very soon. I've never done this before but from what I can tell its a relatively simple job that doesn't require the removal of much (only the headlight and left side fairing I think?).
However I noticed the 'official' GRiSO throttle cables cost 65€ each, so 130€ for both the open & close cables. I've never bought throttle cables before but aren't these normally relatively cheap parts in the range of 20-30 bucks for a set? Anyone know if there is a good alternative?

In 14 years of working on Grisos I've only ever replaced one cable.

Do you still have the rubber boots over the adjusters up by the twistgrip? If so where can water be getting in to cause rust?

Is the throttle getting stiff or refusing to close when you release the twistgrip? Are the cables fraying at the nipples? Top and bottom? If not I'd just leave them alone. Give the bottoms where the inner exits a spray with silicone or lanolin spray, NOT a mineral oil product, and ride.

Pete Roper wrote:

In 14 years of working on Grisos I've only ever replaced one cable.

Do you still have the rubber boots over the adjusters up by the twistgrip? If so where can water be getting in to cause rust?

Yes, and I'm not sure. Maybe the cablecoating has been compromised somewhere through abrasion?

Quote :

Is the throttle getting stiff or refusing to close when you release the twistgrip? Are the cables fraying at the nipples? Top and bottom? If not I'd just leave them alone. Give the bottoms where the inner exits a spray with silicone or lanolin spray, NOT a mineral oil product, and ride.

When I don't ride it for a couple of days the throttle is stiff and doesn't reset itself when I let go. After giving gas a couple of times that goes away. No fraying cable at the nipples. But there is brown rust-fluid coming out of the bottom ends of the cables.

Be careful when ordering throttle cables. I had broken the nipple at the end of the cable and ordered a new Moto Guzzi replacement, but it wouldn't fit! It was a different size and there was no way to make it work. There must have been different sizes used. I ended up fixing the old cable and never used the new one. See if you can get a measurement before ordering one!

GuZeee wrote:

Be careful when ordering throttle cables. I had broken the nipple at the end of the cable and ordered a new Moto Guzzi replacement, but it wouldn't fit! It was a different size and there was no way to make it work. There must have been different sizes used. I ended up fixing the old cable and never used the new one. See if you can get a measurement before ordering one!

Thanks for that warning! Trying to make the existing cables work first, but so far no luck. No matter how I adjust the cables the throttle only returns from the full 85 degrees to 30 degrees or so by itself when released but to get it back to the default 4.8 degrees I need to manually twist the throttle.

After 3 hours of labour I managed to get the throttle working again correctly. The open-throttle cable was stuck between the edge of the guidance channel and the housing (handlebar side). But even after fixing that, it didn't solve the problem.
Eventually after ruling out anything else I concluded some sort of blockage mid-cable was giving so much friction that the throttle body spring was unable to close the throttle by itself. Liberal application of ACF-50 and WD40 on both ends followed by pulling both cables (while loose) on both ends intermittently, and suddenly it worked once again.

Then I had a ride and got pulled over by the police on the highway as my headlight bulb had apparently burned out

WD40 was a terrible choice.

Pete Roper wrote:

WD40 was a terrible choice.

What would have been better? For next time.

edit: nvm I googled it. Teflon/PTFE spray next time then.

Any mineral oil will cause the nylon inners in the cables to swell and grab. I'd buy those new ones now.

mgcycle.com has the cable assemblies for about $35 each: search for GRiSO throttle cable.

Prior to Pete's judgement that you have ruined your nylon cable inners, I might have suggested a visit to flanderscables.com to acquire new cable (w/o the housing) and cable ends.

But $35 each for the full assemblies is not terrible.

Moto

If you end up wanting to change the cables, you may find my experience useful.

I recently made a set of replacement throttle cables fro my 2014 Stelvio NTX as I have lifted the handlebars quite a bit. The throttle pull cable was just too short and was pulling on full right steering lock I decided to basically replicate the cables but made then 10cm longer.

I used a Venhill universal kit:
Venhill Braided double throttle kit

You can get cheaper non-braided versions and even different coloured outers. You can buy these directly from Kenma in Australia and they had stock locally. Kenma

It comes with a range of bends, connectors and end nipples (none of which work as the NTX end pieces are specific for the bike.

Tip 1. Do 1 cable at a time so you don't get them mixed up as the pull and push cables are different. Leaving 1 in place also shows you the cable run. Make 1 cable and fit it and then remove and do the second.

Tip 2. once the cable is removed, Pull the inner to one end and measure the length of free inner. This is the target you need to hit. I made the outer 10cm longer and made the inner free length the same and got a perfect result.

The metal end pieces are crimped on the standard cables so I just used a Dremel to cut around the crimped bit. This leaves the metal parts and the cable socket. Cut the new outer to the desired length. I needed to exactly cut one of the 2M outers supplied to get what I wanted so I have an entire 2M outer left over.

Assemble the components and thread them on the inner cable - rear mount, ferrule, outer, ferrule, rubber cover for adjuster, top bend with adjuster. I used the preinstalled nipple on the throttlebody end and soldered the nipple on the throttle end but you can do it eather way. Cut the cable so you have the EXACT amount of free play as standard. Fit the nipple and "birdcage" the cable end.

This is easy if you buy the expensive Venhill tool but I used a soft jaw vice and a punch with a concave head. Look on the Venhill site for videos on how to do this. Solder it on.

This is hard if you use a soldering iron as if you overheat the inner cable it will anneal and get really brittle. It is very easy if you use the dip in molten solder method.
I used isopropal alcohol to clean the cable - just spray it on the end of the cable and nipple.

Cover the birdgaced part of the cable with electronics resin/flux - do not get it further up the cable.

I heated non-resined solder (from plumbing supplier) in a metal cup with a propane torch and and when molten, just dip the nipple in the molten solder and hold for a few seconds. Do not dip in any deeper and you DO NOT want solder running up the cable. This will prevent flex and it will break in use. Clean it up with a file and reassemble. Adjust both adjusters and jobs a goodun'!

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