Snapped throttle cable

[Henk]

I am at the point of admitting that I've grown a serious throttle cable issue. My car seems to eat them. Mostly at most inconvenient occasions. The first snapped during a weekend of intensive driving at the Ardennes. A cord taken from the pants of my aunt solved that one temporarily. The second one snapped just in time, the evening before a 2000 km through Europe. The third one sheared off yesterday in Luxembourg on my way back from France. Fixed it by tieing the two parts together (which was an awful solution, but I didn't find a wire connector in spare parts collection in the boot). Idling could be tuned back to 2000 rpm and driving it with barely touching the accelerator pedal did the trick.
My solution from yesterday:
https://drive.google.com/file/d/0B75bFW ... JWUUE/view

The cable sheared off just beneath the cable stop (no idea what the correct Dutch word for this part is, let alone the English translation of that word):
https://drive.google.com/file/d/0B75bFW ... RrTWM/view

My idea about the problem:
1. cable is cut by sharp edge on this part (in the middle of the picture) but no sharp edges found.
https://drive.google.com/file/d/0B75bFW ... E2V1k/view
As a solution I came up with this idea:
https://drive.google.com/file/d/0B75bFW ... RsVG8/view
No sharp edges anymore, the 'ring' protects the cable. But shoud I really modify this system that much?

2. pedal stroke is too much for the carb linkage, so when the pedal is floored the cable is under large tension (cable only measures 1,5 mm diameter)?

Then I realised that the pedal operation is increasing heavy when reaching the floor. With disconnected cable pedal is moving fine without much effort. Cable itself slides really smooth. Carb linkage is turning fine by hand, spring tension isn't overly heavy. So probably my second guess (see above) is correct?




https://drive.google.com/file/d/0B75bFW ... sp=sharing
https://drive.google.com/file/d/0B75bFW ... sp=sharing
https://drive.google.com/file/d/0B75bFW ... sp=sharing
https://drive.google.com/file/d/0B75bFW ... sp=sharing

[misterp]

Thats quite a few cables!

As far as Im aware there is nothing inherently wrong with the design as the forums and such are not filled with stories of cables snapping regularly.

The only thing I can think of from your pics is have you made sure the 'keeper' (the receptical for the carb end of the cable) rotates?
Once the throttle cable nipple is seated, it should rotate and keep the cable linear as you press the throttle.

Cant see from your pics, but looks like theres a pin or R clip there...is it too tight perhaps?

[Henk]

Thanks for the helpful thinking. Yes I thought about that keeper too, but it freely rotates. Going through the system this evening.

[soe8m]

They don't snap regulary. You can use this cable. These do fine and are teflon lined. There should be a bolt on the pedal to adjust and stop the excess travel. Make sure the progressive mechanism between the carbs is adjusted properly before fitting the new cable.

Jeroen

http://www.ebay.co.uk/itm/WEBER-DELLORT ... SwPCVX6osl

There are more sellers but this cable is it. It does slot in the original fitting of the carb mechanism. You will need a clamp at the pedal.

[Henk]

Thanks Jeroen, that cable is exactly the one that was installed. I now purchased a inner cable which suits the existing outer cable. I'm not aware of the adjustment bolt so I will investigate.

[Henk]

I found a plate with a hole at te lower end of the pedal. Mounted a bolt in it. Is this arrangement with a bolt the right solution?

[soe8m]

Jah.

Jeroen

[Galileo]

Good to see that you bury the throttle in the carpet often enough that you snapped the cable!

[Henk]

Once everything is warmed up I like some spirited driving!


Alright then, this seems solved: bolt is in placed and limits the pedal stroke. Thanks guys!

[misterp]

Hopefully you have it sorted although cant see why over travel on the pedal would cause the cable to snap just before the nipple, it might just be that due to the forming process that point becomes the weakest spot?..dunno

One thing to check and its a 1 in a million..but I have seen it where the main earth strap to a motor has come off/broken, and the throttle cable then glows red as the thin bit of wire then becomes the only way to earth the engine.
Might be worth checking or at least verifying that the block is earthed with a digital multimeter?

[GrahamFountain]

I'm not certain I understand why you need this bolt as a stop. Is it that if you take most/all the slack out of the peddle at the top of movement - i.e. so the lightest touch on the peddle takes it off tickover -, the cable is going tight before the peddle is fully down?

If that's the case, surely there's something wrong somewhere, possibly in the linkage? Mind you, I've have expected wear to have the opposite effect, i.e. that with all the slack taken out at the top of travel, the butterflies wouldn't be fully open with the peddle to the metal.

Graham