Nylon liners in control cables!

[themoudie]

Over the past few weeks the clutch pull required to operate the Ducati 450's clutch has become increasingly hard. It's a heavy clutch at the best of times, with 6 x 22Kg springs to be compressed in a distance of 5mm. Adjustment is via the clutch pressure plate central adjuster screw and the cable alone, the screws securing the springs being screwed tight.

Then last week the handlebar lever nipple cried "Enough!" and I was left to bring to a halt, in dense traffic, a torquey 450 single! Managed to come down the box, on the throttle and the traffic parted long enough for me to dart across the road into a lay-bye, where a temporary nipple repair was made to get us home.

Having purchased one of the "Motorcycle Stunt Clutch Lever Easy Pull Cable Systems" from eBay, Chinese manufacturer, as per Ian (SRX), a wee while ago, I decided to fit the "Easy Pull" and a new homemade cable, the latter using Venhill and Vehicle Wiring Products parts.

Upon stripping out the old cable of approximately 10,000 miles and 3 years use, it became very apparent that inspite of NOT applying any lubricant as advised by the suppliers, the nylon lining sheath had disintergrated and the peices of nylon were clogging up the cable ferrule ends. (SEE IMAGES) No wonder I was creating a Charles Atlas "Vice Grip" exerciser!    BEWARE OF STIFF TO OPERATE NYLON SHEATHED CABLES!

So, I made up a new cable, without the nylon liner/sheath this time and fitted the "Easy Pull". Bit of a juggle, with 4 cable adjusters to play with, one on the crankcase, two on the "Easy Pull" and one on the handlebar lever, having ensured that the pressure plate central adjuster screw was set up correctly.

The pull is now easier, but I am not sure about the "Easy Pull" making the exercise "50% easier" quoted by the advertiser. The difference in the internal leverage, on a common fulcrum, doesn't appear sufficient to gain that amount! I think more like 20% at best, but I haven't sat down and taken measurements and done the algebra, because I cannot be .......! 

Once I've put all the other bits back on the machine after some new tyres and a brake service, I'll see how the "Easy Pull" performs on the road.

Good health, Bill

[Itsme]

Hi Bill

I have never liked nylon lined cables and have always lubricated them against advice, but with good results.

As I have nerve damage in my left arm I find most clutches too heavy so usually make an extension piece for the operating arms to lighten the pull. I don't understand why manufacturers fit very short arms to operate the clutch, haven't they read up on levers and fulcrums?

I went with a friend of mine last week to look at the new Honda SCL500 as he is considering buying one and the clutch has clutch assist which makes the pull a literal one finger exercise. Absolutely lovely.

Ian

[Steve Lake]

all i can say is nylon liners work extremely well on my racing pushbikes.... a lot less muscle required but more importantly return spring effort required is less thus smaller & lighter spring. but ... i always prelubricated on assembly with very light silicone grease, my favourite time trial bike is 25 years old and the cables, well actually cable, as there is only one ( it's a fixed wheel bike so no gears and no requirement for a rear brake !) is as free running as the day i assembled it .... just saying 

[iansoady]

It depends who makes the cables. I always use nylon lined outers from Venhill when I make my own cables and have never had a problem. I do give them an occasional squirt with GT85 which seems at least to do no harm.

[Ian]

I always use "3 in one" oil and have never had a problem. I did read an article at some point, I believe it was endorsed by Venhill, and they said to only use  "a light machine oil" to lubricate control cables.
As Bill has rightly stated regarding the easy pull contraption, it does reduce effort but not the 50% as advertised. I fitted one as I wanted to extend the clutch cable as to extend the monoshock clutch cable is quite involved ( It has a 90° bend at the engine end) whilst fitting new handlebars. In that respect it has fulfilled my requirements. Less effort is a bonus for me. I may attempt at making a longer clutch cable over the winter but I think I would miss the less effort thingy 🤔