Clutch Spring Adjustment

[redbeeza]

But if the springs and or cups aren't right, or the tangs are catching on the drum etc. how have I been able to ride around on the bike with a sweetly operating clutch for 80 miles or so?

I did all the deburring and checking that the plates moved freely when I rebuilt the bike not that long ago.  I've had the clutch apart twice in the last three days and have studied the plates, the tangs, I've had them on a sheet of glass to check for flatness.  I've run the right amount of SAE 40 oil in the primary.  I've had the pushrod out and checked it for straightness and had a look at the ends (the pushrod is a one piece item Bill; no ball bearings); both ends have a slight dimple in the centre, the rod slides smoothly.  The actuating arm is not at a leery angle, nor is the adjuster nut/screw.  The adjuster is about midway on the threads.  I have about a 1/16" slack on the clutch cable.  I have the bigger fulcrum clutch lever.

I can pull out the pushrod and tell you the length of it.  I could measure/photograph a spring and cup.

I can't think of anything else at the moment...

Cheers,
Terry

[chaterlea25]

Hi Redbeeza,
SAE 40 is way too heavy for the primary, 10/40 motorcycle oil (wet clutch) or ATF
To add to all the other advice 
the angle of the clutch arm / cable should be less than 90deg when the lever is slack, (clutch engaged) (driving pos)
the lever should move through 90deg till just past 90 as the handlebar lever is operated
the same applies to the adjuster in the gearbox,
Ie, it must push the rod towards the clutch without trying to push it sideways
there is a certain amount of adjustment with the threaded pusher,
make sure the ball in the threaded adjuster  isnt lost 

HTH
John O R

[RichardL]

But if the springs and or cups aren't right, or the tangs are catching on the drum etc. how have I been able to ride around on the bike with a sweetly operating clutch for 80 miles or so?

As I read it, you've created the correct spring force on the pressure plate for comfortable riding, but the problem is one of concern for the nuts coming off. Changing the springs or the cups (or both) may allow you to achieve the same force while the nuts are further home.

I don't know if this has been discussed before (or if it even matters here), but for any given slippage of the clutch, the distance from the backing plate to the pressure plate will be the same regardless of spring pressure.

Ricahrd L.

[bsa-bill]

Puzzling one this, I had a very similar problem when I put mine together,ntuts habging on by one thread - scary, solved in the end , but memory won't give me the answer how.
However tomorrow I need to take the clutch off so will measure cups and springs for comparison
IT has to be something that has been done recent if it was working well before.

[groily]

Dunno for the life of me why it did the 80 good miles Terry, but in light of all you say and looking at the 2 pix again I'd say it HAS to be a spring and/or cup problem. In the first pic they're quite close to coil-bound, in the second they're probably a bit the other way - hence the ultra-light one finger operation. Can't think of anything else given all the checks you've done on the operating mechanism and pushrod, the drum and the centre. Those nuts on the springs really should be close to flush with the pressure plate, with lightish and smooth operation at the handlebar. But they're not, despite your having eliminated all other likely causes of grief. When all other things have been ruled out, what remains must be the truth, however improbable (or whatever Sherlock actually said). Be very interested to see what Bill's measurements are and what your bits come in at.

[bsa-bill]

Just noticed Terry, on both photos the chain keeper is on the wrong way round, not that that has anything to do with your problem.

[RichardL]

Terry, et al,

Ya know, I think I comment on things for different reasons (maybe too much). Sometimes I think I understand something, or, have experience with it, or, maybe I have a different view, or, maybe I just need to be tought something. Right now, I think the last will apply.  In looking at the 4-spring clutch I am confused as to why the pressure plate runs against a plain plate and why the pressure plate appears to have so little surface area. I went to the Haynes manual to see what gives and there it does look like steel runs against steel in the 4-spring. Is that right? Also, Haynes seems to be saying that there should only be four inserted plates which, I think, is one more than in the clutch-of-fame.

Please enlighten and free me, as this topic has me in its clutches.

Richard L

[trevinoz]

Richard,
                   Steel on steel is correct for the pressure plate.
There are 5 friction plates and 6 plain steel plates.

  Trev.

[RichardL]

Trev,

Doesn't the steel-on-steel negate something said here about running dry with the cover off? This is pure mechanical curiosity for me. I hope to come out of this a fulfilled human being.

Richard L.

[trevinoz]

Dunno, Richard.
                           I tend to think that the designers knew a bit about what they were doing, up until the idiocy of bringing in aircraft engineers.
Anyway, it's a Triumph design so couldn't possibly be as good as the 6 spring clutch which it replaced, being one of BSAs finest efforts!

  Trev.

[RichardL]

Not that I have experience with other clutches, but my 6-spring seems to work a treat (a.k.a., "great"). Never had any trouble, and can find neutral often enough.

[trevinoz]

Yeah, mine is the same on the Flash. Always find neutral when stopped and no crunch selecting first.
Maybe it's just the remnants of earlier owners abuse that sets current owners against the sais clutch.

  Trev.

[Brian]

Terry I think you need to go back to the start here before you change anything.

Firstly I take it the clutch worked well without any problems but the actuating lever was worn in the gearbox cover. You had the lever bushes repaired and since you have put it back together the problems have started. The problem has to be with the set up of this lever.

The first picture you posted of the actual clutch showing the brass screws roughly level with the threads is about where they should be.

Now back to the lever in the gearbox cover. When you put the small piece with the ball bearing in it on the splined end of the lever was it approx in line with the lever at the top that the cable attatches to, it should be. It may be necessary to alter it a spline or two either way but as a starting point it should be in line.

Now without the cable attatched to the lever at the top of the gearbox where is this lever positioned when there is no slack in it. Looking down from above the lever should be at about 5 o'clock. with the cable attatched and the clutch lever on the handlebars pulled in the lever on top of the gearbox should move to the 6 o'clock position.

When you pull the clutch lever on the bars in and the lever on top of the gearbox moves from the 5 to the 6 o'clock position the clutch plates should lift freeing the clutch. Once you have it doing this then you need to check the clutch plates are lifting square and if not adjust the spring tension so they do.

If the clutch worked well before and the only thing you have changed is the lever in the gearbox then the problem has to be with the set up of that lever.

[muskrat]

Richard, the last plain & pressure plate on a 4 spring act the same as the pressure on a 6 spring.
Here's a few pics of my spare 4 spring. The nuts are done up to where they normally sit.
Cheers

[RichardL]

So, the last plain plate is not driven, correct?

P.S. Sorry if I'm being thick about this but I think it is a thickneth with a cure.