clutch cable question

[LaceyDucati]

Just a couple of other tips:

The clutch cable should take a nice smooth route in a "S" shape and not be too short.

The cable should not be tied tight to the frame, as this is the cause of many a rough tight clutch. Any ties should act as guides and allow the cable to move freely.

The clutch centre adjuster should be adjusted so the lower part of the arm is just back from vertical. In opperation the lower part of the arm should move through the vertical at mid travel of clutch opperation, this is the most efficient use of the lever. The lever in the picture is too far out and will probably not even reach the vertical when fully in. If the lever is too far out there is also the danger of the lever fouling the back of the selector box when it is installed. I've solve quite a few slipping clutches that have have been resting on the back of the selector box, there was play at the cable but not at the lever. Once the centre is adjusted, any other adjustment should be taken up on the cable adjuster or the nipple moved if this is not achievable.

Check the arm and pin, as some can have unbelievable wear, leading to arm positioning not being ideal.

Ensure you have standard 250/350 springs as there should never be a need for anything heavier in any 250, either road or race.

Hope some of this helps

Nigel

[narrow_monza]

Hi Nigel,

Thanks for the tips, I will use it as a checklist.
I took apart the push rods and balls and made sure there were no obstructions or unusual wear.
I suspect the cable is too short. I ordered another cable. Is soldering the tip the best way yo cut it to avoid unraveling?
Is there an easy way to tell if the springs are too stiff for the bike?

Thanks

Adrian

[narrow_monza]

I received and installed the new cable. I shortened it a bit and still trying to figure out the optimal length.

Here a photo of the way it is currently routed:

clutch-cable.JPG

And here are a couple of video clips of it operating:

http://www.youtube.com/watch?v=M0dj0ou0FTk

http://www.youtube.com/watch?v=qT1tL9owzY0

Is that enough travel to engage/disengage the clutch?

Thanks

-Adrian

[JimF]

The cable length, the routing, the free play, the lever travel and the basket operation all look normal to me.

How heavy or light is the clutch pull now?

Is the clutch disengaging fully??

Your clutch pull should be easy now. If that throw is not sufficient to disengage I would check the clutch plates for flatness.


Jim

[narrow_monza]

Hi Jim,

Can I tell if the clutch is disengaging enough without the engine running?
It's going to be a while till the engine fires up, but I suppose I can put in in gear and pull the clutch to see if I can wheel it around...

The clutch is still a bit stiff but that's compared to my modern bikes. On such an old bike, I really have nothing to compared it to.

Thanks

_Adrian

The cable length, the routing, the free play, the lever travel and the basket operation all look normal to me.

How heavy or light is the clutch pull now?

Is the clutch disengaging fully??

Your clutch pull should be easy now. If that throw is not sufficient to disengage I would check the clutch plates for flatness.


Jim

[JimF]

Are your modern bikes equipped with hydraulic clutches?

I wish I could quantify the pull force for you. It should be easy to draw in, and nothing that you couldn't easily hold for a few minutes at a stop light.

No "Popeye" arm required.

Personally I would move on to something else as this may be a non-issue and may be too hard to gauge on a non-running bike.

I think that the only thing you could potentially have working against you is if your springs are not correct. It's hard to imagine some previous owner could have found a set of stiffer springs that would even fit, unless wide case springs are stiffer. Even still, why would somebody opt for stiffer springs unless it was a mistaken substitution.

[narrow_monza]

Hi Jim,

Yes my modern bikes have hydraulic clutches but even my 1968 Benelli 125cc 2-stroke clutch is easier to pull.
It's still manageable at a stop light though.
I'm going to move on to the ignition and the fuel system now. I hope I can locate my ignition timing advance unit, I only have one that I removed a few years ago
and now it's M.I.A. I'm not sure I can locate a source for a replacement.

Thanks

-Adrian

[Bevel bob]

I don't like to dissagree but it appears that the cable is far too long (outer and inner) and won't fit under the tank . Mine runs a much tighter path but is still an easy pull. However it was not always so!. It came to me with a set of new steel british levers that would possibly suit a BSA or triumph . It was awfull and worse than a Norton Atlas to pull.. Not able to source a set of original levers I looked around for levers with a distance of around 5/8ths of an inch from the center of the nipple to the center of the pivot , Not finding what I wanted I ordered a set of cheap alloy aftermarket scrambler levers to experiment with. These arrived as two clutch levers (not a pair) ,after complaining I got two free brake levers!.The levers were better than the brit ones with a lighter pull but still heavy to operate. Using a pillar drill I redrilled the holes on the levers (but not the perch) to give about 9/16ths of an inch ratio , did this on both clutch and brake.Looks more than a bit odd. Clutch now very easy to pull and brake stops as it never did before!. The reduced lever action however means that the lift on the clutch is also reduced,it was necessary for me to fit new (flat!) clutch plates and shim the springs to get a really even lift . Success at last. I will have to make up a blanking disc to tidy up the old holes but have so enjoyed riding the thing have not found the time.Your nice expensive levers are NBG! ,Sell them to someone and find some original ratio levers (difficult!) or do as I did.Perhaps someone with a set of orrig levers will check the dimension and post it for us . Anything over 3/4inch will be no use in my opinion. Nortons have a similar problem and where 7/8th inch levers work fine 1inch do not. Its that critical. A widecase Mod as Nigel suggests is also good, done this to my 860.

[LaceyDucati]

Bob
I did see your previous mention of the lever pivot to cable anchor position and would agree with all you say about that. I didn't mention it as I was only trying to add to what had already been said.

Adrian
That cable should be fine, but I route the cable between the frame and fork leg and the yokes on the right hand side. Then through the frame downwards in front of the front rocker cover and loop round over the top of the primary cover round the cylinder. Much as you have done but through the yokes and a slightly bigger loop at the bottom. Soldering the last bit of the cable as you suggested is the best way to avoid cable fraying.

For identification as new:

250 springs are approx. 31mm long and 2.0mm wire with 7 coils.
450 springs are approx. 27mm long and 2.2mm wire with 6 coils.

They will probably be compressed with use, much more than 1mm and they probably need replacing.

The only sure fire way to a lighter clutch is a longer lever as on a widecase as suggested by Eldert. There will be reduced travel at the clutch but as it is not a major problem on a widecase and every thing else is the same..............

As for advance units, if it is a standard Ducati unit you require, I do have quite a number of both types. If you are stuck let me know.

Regards Nigel

[amartina75]

A few thing I would check are:
Make sure your plates are flat, they get worn and develope burs on the edges
Bench them flat on a surface plate with fine sandpaper
Make sure you eliminate slop in the system
Clutch levers arms get worn where they pivot and rob
You of some mechanical advantage
Same with the Hand levers if they are worn
You can drill them out and put in a bushing.
Good luck