Triumphrat

Hoping to clear up confusion re: Speed 4 clutch cable rumors. The clutch cable does not stretch, as it is not under any undue strain or stress. Think about it logically; there's no heat or heavy clutch springs; what would make it stretch? Why would it be any different from the millions of other clutch cables that don't stretch? If it were stretching from such duress, it would surely break and fairly soon. The material has no memory and would just keep stretching until it breaks or could not be adjusted enough to disengage the clutch plates. The clutch itself has troubles outlined in my other posts, with information straight from factory mechanics. It gets grabby when it's hot and the cable has nothing to do with it. There are issues with the clutch basket on some bikes and the 'bullet' on the end of the clutch pushrod that needs replacement, as well.

I'd argue that point a little bit. Saying that the cable doesn't stretch is misleading, if not completely wrong.

Since the cable is a wound metal cable, the ductility of the metal, coupled with the initial "stretching" action of the cable is inevitable. The cable is attempting to tighten itself up, up to the point that it reaches it's maximum tightness as a function of it being wound.

Using the "it doesn't stretch logic," would translate to the same things with bicycles (which I'm more than competent at wrenching on). If cables didn't stretch, then you wouldn't need to adjust cables after initial rides when installing new derailleur and brake cables. As a matter of fact, on every bicycle that I've re-cabled, I've needed to adjust the cables a few times after the initial installation, due to the stretching. However, after the "cable break-in" period, zero adjustments need to be bade (unless something comes out of whack).

With bicycles, it's more pronounced... as there is more tension affecting the ductility function of the cable, and making the time it takes to "tighten" itself into itself much shorter. Since a clutch cable isn't in as much tension as a derailleur cable on a bicycle, it just takes longer to fully seat.

I think saying that the Speed Four has a faulty clutch is a little like Chicken Little saying that the sky is falling. But, either way, be cognizant of what's happening around you.

Ldogdotcom is right there will always be some stretch as the steel wire is put under tension, it will also "try" to unwind a bit. However IMHO more usually there is compression in the cable outer (which gives the same effect of reducing the amount of action that you get when you pull on the cable). This is the same in any use of Bowden cables: Snow mobiles, tractors, boats, bicycles, cars or bikes.

The cable outer is a spiral of wire supported in plastic & fibres. Outer cable compression can occur whenever the cable run bends so the spiral opens up on the outside of the curve & has gaps in it. It is more likely if the cable has sharp bends or kinks, if the load being pulled by the cable is high (brakes or clutches) and when the supporting plastic & fibres get hot so holding the spiral less tightly in place.

For this reason most cable companies I have found in US & UK offer so called "non compressible outers" to reduce this effect in heavy duty applications. These are heavier duty & sometimes use square wire -I once found an old cable with a twin spiral of trapezium cross sectioned wires.

The easiest way of spotting cable outer compression is if the cable twists or flexes as you pull on the lever. They all do a bit, but after a few years you get a hunch about what is acceptable and what is "too much".

IMHO tHis was all much more critical on old european bikes as some had appaling clutch leverage and rubbish cables so the lift all but disappeared when you pulled on the lever.... and then the linings would begin to heat up & swell taking the rest of hte lift with them!

However Trispeed I dont know about your bike - my S4 has a poor clutch lift a very hot engine and a weak cable. So there is a slight reduction in lift with a hot engine which worsens the low speed gearchange. On my bike this effect is much reduced with a heavier duty clutch cable (like the venhill one). I notice Triumph put a hydraulic clutch in the D6 whcih gets rid of the problem - until the hose or seals start to bulge...

Still each to their own
Jon

burgessa23

Hey, johnny, where you been?

you seem to have had the same issues as me, grabbby, clunking clutch when hot at low revs, bad cable lift, what's your opinion about the 'bullet' thing?

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thanks,
-Andrew

there is so little strain on the clutch cable, how is it stretching? Maybe the outer sleeve is a weak spot? The clutch springs are so light on the Speed4, it's nothing like a brake cable, even on a bicycle. The common thread with everyones' stories is that the situation gets worse with a hot engine. The cable temp. never changes much, so it is out of the equation. The plates are dragging a bit and when they heat up and expand a little, it makes clutch dis-engagment difficult.

Well Trispeed I'll go some of the way with you... :-g coz I have had a beer or two and that makes me a bit more reasonable!

I think the design gives insufficient lift as a starter.

your pegaso, wing & vstrom should all be better at getting a fully lifted clutch than the s4 ¿¿¿ :???: ??

But given that there is too little lift divided by 12 or 14 clutch plates I want to preserve every last mm (or 32nd of an inch).

By the way on mine the the cable temp does get very high. Check yours by the top right of the cam cover: when the engine is hot - 106ºC and you can squeeze the plastic casing with your fingers!!

Hiya Burgess
As regards the "bullet" well you can lose lift by losing clutch push (or pull)-rod material. Be it a button or a mushroom or a bullet or a rod! It has happened to me twice. 1958 Royal Enfield bullet & 1974 Honda CB250k4

Both times the hardening was failing & the non hardened metal could not handle the spin of the clutch itself & ground away. However these were fairly "catastrophic" failures... like 100 miles of noise & losing clutch adjustment. Then dead. Oh & it does not get better when it cools down!

So I don't understand how failure of the clutch lifting "bullet" can give a predictable repeatable drop-off in clutch lift every time the bike gets hot which gets better when cold & stays stable over 2k miles! If any of those, fully lubricated & metal, components in the clutch operating train start to go.. They ain't comin back

Cheers now Jon

Here's the first thing I tried ( the day I bought the bike, about 2 miles down the road, service was closed, so I didn't return it that day) I thought that the clutch was not dis-engaging fully, so I took all the slack out of the cable, then even pre-loaded it a bit to get a huge amount of dis-engagement. Absolutely no difference. Can't be a clutch lift problem then, per se. I believe the guys that BUILD the bike. The factory mechanics say two things. Clutch basket needs de-burring and/or the bullet at the end of the pushrod need the updated part. This is what updated parts are for; to fix a problem inherent in the system. There is no updated cable. The faulty bullet allows for UNEVEN dis-engagement. It changes position and makes the problem seem intermittent. Hope this helps, I'm just waiting for the parts to arrive, but several people have had the problem fixed this way.