The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: Howard on 31.05. 2011 22:53

Title: Clutch Spring Adjustment
Post by: Howard on 31.05. 2011 22:53
I`m sure this will have been covered before, however, I have just fitted the clutch (6 spring) to my 51 A7 which I brought as a basket case and I`m not sure how far to tighten up the 6 spring nuts. I don`t want to fit the primary cover and then have to remove it all if they are not adjusted correctly. Would it be best to leave the cover off, get it running, make sure the clutch clears etc then fit the cover ??  thanks, regard Howard
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 01.06. 2011 06:59
G'day Howard,
                   I do mine up till the base of the nut is level with the cups. Then use a zip tie to hold the lever in to the handle bar and turn the motor over and check the pressure plate is lifting square. Adjust nuts till it is, say within 10thou. I use a dial gauge but any sort of pointer will do.
Cheers
Title: Re: Clutch Spring Adjustment
Post by: Howard on 01.06. 2011 11:19
Thanks Muskrat, appreciate the info...Regards Howard
Title: Re: Clutch Spring Adjustment
Post by: tombeau on 01.06. 2011 11:35
Glad to see questions like this covered.
It can be frustrating to come across things in manuals like "ensure the springs are properly adjusted" with no further info, cant it?
Title: Re: Clutch Spring Adjustment
Post by: BSA_54A10 on 01.06. 2011 13:32
The trick with the clutch is to adjust it for equal lift then readjust it for  strength then go back and check the lift.
The settings in the "book" are usually way too hard but BSA had to do this so that the clutch did not slip & an owner got flattened on their bike.
The aim is to have the lightest spring pressure that dose not slip.
This will not only be a pleasure to use but substantially reduce wear to all the pivot points.
Usually I put the front wheel against something solid ( like a brick retaining wall ) , pop the bike in 1st then apply pressure on the kick starter. If the clutch slips, tighten all of the nuts 1/4 turn and try again, if it dose not slip then loosen them all 1/4 turn. when you find the spot where the clutch just slips, do them all up 1/2 to 1/4 turn, start the bike , engauge 1st then feed out the clutch. If the engine loads & stalls then you are there, if not , then just a little tighter.
From here, put the pointer back on and check for truth.
Because the pressure plate is a pressing and because it has a random alignment with regards to the rolling direction it may distort differently after you add more weight to the springs so the need to true it again.
Title: Re: Clutch Spring Adjustment
Post by: Mosin on 02.06. 2011 13:42
It's perfectly acceptable to ride the bike with the primary cover off while you make rolling adjustments to get the clutch spot on. But if you are doing so, just remember to leave your trusty 'flares' in the wardrobe before you start!
Title: Re: Clutch Spring Adjustment
Post by: Goldy on 02.06. 2011 16:22
BSA_54A10 is spot on with what he says. It,s a combination of having the nuts tight enough so that the clutch does not slip, but not too much that the clutch lever is too difficult to operate.
Title: Re: Clutch Spring Adjustment
Post by: Topdad on 08.06. 2011 13:46
Never could get the hang of this type, liked the plunger unit and very Interesting reading what I should have been doing all these years and never did with 6 springers , I can't get the memory of the little bearig ring always giving up the ghost at the worst poss time so i reverted to 4 spring type and threw the other  bloody useless thing's in the bin best wishes Bob hebdon.
Title: Re: Clutch Spring Adjustment
Post by: BSA_54A10 on 09.06. 2011 14:49
Hey,
Don't get me wrong.
BSA 6 spring clutch is an engineering atrocity and the world would be better off if they all went to Japan and came back as 1.5 Toyotas.
OTOH if that is all you have then you may as well adjust it properly.
I have only ever found one that ran what I would call "sweet" and that was no a bike owned by a fanatic who adjusted his lift with a tickler gauge to +/- .002".
Apart from being bad engineering the pressure plate is pressed out of straight rolled steel so is asymmetrical stiffness wise.
Pressure plated should be either cast ( spun cast by preference ) , pressed from cross rolled steel or made from a laminated material.
Title: Re: Clutch Spring Adjustment
Post by: trevinoz on 09.06. 2011 22:13
I have good results with the 6 spring clutch with a bit of work.
First I set up the sleeve on a main shaft and fit the splined plate.
Set up in the lathe and machine the face true to the shaft.
I get the plain driven plates machined flat by a friend who has made a device to hold them.
Assemble on the bike and set the spring pressures, I use a dial guage but that is probably over-kill.
Also, ensure that the clutch lever is 1 1/16" fulcrum.
With all of this, I have a clutch which allows me to select neutral after stopping and which allows selection of first gear while standing without a crunch.
But it is a cheap and nasty bit of gear!

  Trev.
Title: Re: Clutch Spring Adjustment
Post by: wilko on 09.06. 2011 23:17
It's easy enough to get nil runout for the pressure plate but you'll never get it for the basket, wobbling around on those narrow ball bearings.Even with the 1/4 rollers on most other brit clutches you'll have a hard time.
Title: Re: Clutch Spring Adjustment
Post by: trevinoz on 10.06. 2011 00:37
Yeah Wilko,
                       But the wobbling basket doesn't matter a bit if you have enough square lift.
How much does it really wobble with the engine running?

 Trev.
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 10.06. 2011 04:59
My plunger clutch wobbles about 1/16" at rest and a little running but nil when the lever is pulled in.
The lytedrive on the cafe is nil in or out.
Cheers
Title: Re: Clutch Spring Adjustment
Post by: wilko on 10.06. 2011 23:33
Yeah, i know it doesn't matter, in fact it's needed to help separate the plates. I was just explaining to people who might be trying the impossible.
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 09.07. 2011 16:51
I'm having trouble resetting my clutch after a minor problem.  I had the clutch working lovely; it lifted square, it was light at the lever, no problems with slipping or creeping, and I could select neutral OK most of the time.  My minor problem was the disintegration of a bodgy shim I'd made out of thin alloy sheet (beer can) to take up slack where the clutch arm pivoted in the gearbox cover (the hole had worn oval).  When the 'shim' crumbled during a ride, the clutch stopped working and after a few crunched, clutchless gearchanges I stopped and that was the end of the ride.

I took the 'box cover off and sent it to Groily who did a grand job of making up and fitting a bush to the clutch arm hole (thanks again Bill).  Clutch arm now nice and smooth with no wobbles.  Trouble is I can't get clutch adjusted right again now (maybe it was a fluke I got it right first time!).

I've had the clutch apart and checked the plates for flatness.  The centre nut is not loose.  The nut on the end of the gearbox mainshaft is not loose.  The rod is ok and moves smoothly.  The splines are set right and parallel with the clutch arm.

I've set the plates up to lift squarely; first time with the screws screwed in roughly how they were before the problem occured (approx 12 turns in).  When I did this the pressure plate or a screw head fouled the inside of the primary cover (when kicked over the action was stiff and scraping sounds came from primary side, also very light scoring on inside of primary cover).  Even so, clutch would not engage (when in first gear with clutch pulled in couldn't push bike).

So, I wound screws in a few turns and set up to lift square again but the clutch will still not engage (same trouble, can't push it in gear with clutch pulled in).

I've attached a photo of spring/screw settings as of now.  There is one screw that is always in a very different position to the others.  In order that the screw does not stick out too far and foul the cover, I have to wind the other screws in a fair way to get the plate to lift square.  Do I need a new set of springs now?  And the fact that it worked so well before was just flukey??

Regards,
Terry
Title: Re: Clutch Spring Adjustment
Post by: bsa-bill on 09.07. 2011 17:16
Hi Terry
noway should you hear scraping sounds, sounds like the clutch cant disengage as its up against the primary cover.
two things spring to mind (sorry for the pun)
1. for some reason the clutch is too far into the primary chain case - doubtful if it was working previously
2. you have too many plates in your clutch, how many are there?
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 09.07. 2011 18:03
Hi Bill,

Yes, Groily suggested there might be a plate too many but they're right (6 plain, 5 friction). Nothing catches now I've wound the springs in more.  I think it must have been the one errant spring/screw that has to stick out more than the others so that the plate lifts square....even though the scoring mark seems to fall between the circle described by the screwheads and that described by the drum.... The scoring might be a red herring and have been there for years...it's just that I was looking for possible scoring and then noticed it...

Cheers
Terry
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 09.07. 2011 18:51
G'day Terry,
                that one screw hasn't turned a tad and the square head is sitting up on it's groove at the back of the clutch center ? Try pushing on the nut while turning 1/8th of a turn to see if it pops out.
Cheers
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 09.07. 2011 19:26
Hi Musky,

Sorry to read of your spill and very pleased to hear from you, seems you've bounced back unfazed, a fine example to us all!

I had been thinking along the same lines as you and checked that all the screws were seated as they should be when winding the screws down, but I will check tomorrow on that one screw, thanks.

But what are your views on replacing the springs?  When on the bench they all measure the same length, though I forget what that measurement is, and one does seem to be 'stronger' than the other three.  They look like a matching set...

Terry
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 09.07. 2011 19:56
Thanks mate.
Unless YOU fitted that set you really don't know if they are a matched set. A new set will put your mind at ease as far as that goes. Still have the one short screw issue, and it worked fine before. Make sure all the tangs on the plates are good (no burrs) as well as slots in chainwheel and center. If the plates were mixed up (not in their original position or direction) can also cause problems. I always mark each plate so it goes back in the same spot.
Cheers
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 10.07. 2011 13:20
Have checked that the clutch spring retaining screws are seating correctly on the back of the drum and they're ok.  Also had a re-read of my 1st post and the last paragraph is confusing.  What I meant to say is that one of the spring retaining nuts, not screws, is always threaded out further than the other three in order for the plate to lift squarely.  It's as if that spring is stronger than the other three.  If I slacken off the other three nuts to lighten the pressure on the plate, the fourth one ends up sticking out too far (I think), and maybe catching the primary cover.

Anyway, I've been reading archived posts on clutch adjustment and will go and have another try now.  I spent a while yesterday wrestling with the problem and no matter what I did (such as extreme adjustments) I couldn't get the clutch to lift enough to be able to push the bike in gear with the clutch in.  Am I missing something or not thinking straight?  It has been known...

Cheers,
Terry
Title: Re: Clutch Spring Adjustment
Post by: bsa-bill on 10.07. 2011 13:38
Just a thought Terry
You mentioned the work done on the gearbox cover to take up play on the clutch arm. obviously the clutch arm has to come off to do this, it is attached to the pushrod actuator (for use of a better word) by a spline, is this connected correctly so as to allow maximum travel of the pushrod, you may have to turn it around a spline or three, can be done with the cover on if you have small nimble fingers.
Hope you can understand what I mean
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 10.07. 2011 15:15
Hi Bill,

Yes, that's one of the things I've checked and it's right.  I've been following the guidance on adjustments.  I have the front wheel up against a wall, bike in first gear, trying to get it to kick over to get the clutch to slip, unwinding spring retaining nuts 1/4 turn at a time (yes, I've already set the plate up to lift square).  The nuts are now wound almost all the way off and will shortly ping off the bolts, and still the clutch won't slip.
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 10.07. 2011 17:17
Even so, clutch would not engage (when in first gear with clutch pulled in couldn't push bike).

So, I wound screws in a few turns and set up to lift square again but the clutch will still not engage (same trouble, can't push it in gear with clutch pulled in).

Terry,

If this just turns out to be a language thing, I apologize, but this is how I've read your post: You are thinking (or, at least, saying) that the clutch is "engaging" when the lever is pulled in. In fact the clutch is disengaging. This word mix-up might mean nothing, except you say you wound the screws (nuts) in while attempting to improve actual disengagement, which is opposite to your intention. However, tightening the nuts should not affect the clutch's ability to disengage, as long as operating the lever does not bottom the springs. What you would get, barring other problems, is a much stiffer lever and a jumpy clutch action.

Here are some possibilities I don?t believe have been mentioned:

1)   Your pushrod is too short (nothing personal). This can be fixed by cutting the rod in two and running a ¼? ball bearing into the tunnel to sit between the two halves, as is mine. You might need to trim one of the halves if too much length is added.
2)   The adjusting screw on the actuating lever needs to be, as they say, adjusted.
3)   Position on the splines was, indeed, mentioned, but the possibility of said position allowing the ball end of the adjusting screw to fall off the end of the pushrod should be checked.
4)   When I bushed the clutch arm on mine, the alignment in the bore was not perfect and I was concerned that looseness of the pushrod in the tunnel would allow the rod to move away from the pusher ball. I used my Dremel grinder to create a depression in the rod end to assure contact was maintained. (Though, I?ve no doubt Groily probably did a better bush job than job than I, even though he is in France and not Oz.)
5)   The ball is gone off the end of the adjusting screw.
6)   As mentioned above, the springs are bottoming on lever action because they are too tight.

Well, that?s a lot of palaver. Please keep us informed as to progress.

Richard L.
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 11.07. 2011 08:36
Hi Richard,

Thank you for your response, I hadn't considered the issue of the ball on the adjuster screw slipping off the end of the rod if the adjuster was a little off square so I had a check of that and it is seating OK.

You're right about the engage/disengage thing, I can't seem to find a way of remembering which is right.  I'm the same with whether a clutch is 'in or 'out' or which is a cars 'nearside' or 'offside' (to me it depends where you're standing! What's wrong with left and right?).

You're right as well about my tightening the nuts when, if I wanted to get the clutch to slip, I should have been loosening them.  The trouble is in my explanation and my approach to the problem.  I was trying to resolve two related problems at the same time.  Originally, after I had refitted the operating/actuating arm after Groily's mod, I refitted the primary cover (I'd taken it off whilst trying to understand what had gone wrong with the clutch before discovering the sloppy actuating arm).  After I'd tightened the primary cover down, the kickstart was very stiff to operate and there seemed to be a graunching sound coming from the primary.  I hadn't touched the clutch springs at this time and I reasoned that the clutch would obviously need to be readjusted after the mod because the actuating arm would be pivoting in a different place. I thought one of the spring nuts was fouling the inside of the primary cover, so I tried screwing them in and reset the pressure plate square and refitted the primary cover.  This did cure the graunching/stiff kickstart but off course I'd forgotten about adjusting the clutch to actually work.

Anyway, after thinking about things a bit more I decided to do one thing at a time: get the clutch to work, then find out why something was fouling.  This was when I started to loosen the springs bit by bit with the front wheel against a wall etc.  To me it seemed that I was having to loosen the screws too much, and still the clutch wouldn't 'work', hence my later post.  I continued to loosen them anyway for lack of any other ideas, and early yesterday evening the clutch finally operated correctly with barely any adjustment left on the nuts (and on one nut in particular).  I re-squared the plate and I now had a nicely operating clutch with an incredibly light action (one finger on the lever).  I rode the bike around the yard with the primary cover off and my trouser leg tucked in my sock and the clutch worked well.

Trouble now is the nuts are so far threaded out (see photo) I fear one will ping off on the next ride out and I'll be calling my neighbour out with his fruit and veg van to come and fit the bike in amongst his trays of melons and cherries again!

What I'm currently thinking is this:  Groily's excellent mod has positioned the pivoting point of the actuating arm a little bit inboard to where it was; hence I've had to wind the spring nuts dangerously far out to get the clutch to work; hence, to alleviate this problem, I need to shorten the pushrod, say 1/16" or so?

What do you think?  I'd appreciate Groily's view on this train of thought also.

Regards,
Terry
Title: Re: Clutch Spring Adjustment
Post by: bsa-bill on 11.07. 2011 09:32
Hi Terry
There are different depths of spring cup, you'd need to measure one and someone will be able to tell you if they are the deep ones.
Also different spring tensions, springs are not expensive and someone like C&D would advise   you as to the right ones for your bike.

Kind of sounds like you maybe had plates stuck together or binding
Title: Re: Clutch Spring Adjustment
Post by: wilko on 11.07. 2011 10:02
There certainly are different cup lengths,or maybe the springs are too long.
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 11.07. 2011 10:52
The springs there don't look to be compressed very much. So I think the problem lies elsewhere. Something not sitting right, tangs on plates binding in slots on chainwheel/center. Someone swapped your primary oil for contact glue  *eek*
Cheers
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 11.07. 2011 11:01
I suppose you are quite capable with internet research, nonetheless, here is a clip from the BASMOTOR catalog showing the differences between springs and cup lengths. Not sure if this is comprehensive.

edit: Added the rest of the cups shown on BASMOTOR site.
Title: Re: Clutch Spring Adjustment
Post by: groily on 11.07. 2011 11:15
Excellent you've got the clutch to work again Terry, but you're right, things do look a bit perilous and not a solution, yet!

The fact that the operating arm is now back near enough to where it started life (give or take a few thou, inevitably) shouldn't, probably, affect the pressure plate/springs end of things, although it would clearly affect pushrod adjustment as you and Richard rightly observe, and there's an outside chance the pushrod now seems too long.

Starting on the offside (or right!) You need a little bit of slack before the lever starts to bear on the pushrod. If you've got that, if the ball bearing is about central on the pushrod, and you say it is, and if the spline position for the lower operating arm looks good and the adjuster and locknut are in a sensible 'mid-point' configuration, that end should be OK. (My fingers aren't nimble enough to play with that spline with the outer cover on, I have to say apropos one previous comment!)

However, moving to the pushrod  . . .
Suggest you check what angle that bottom operating lever is at to the pushrod when a) there's the right amount of slack at the operating lever and b) the clutch spring nuts are done up flush with the ends of the studs (to squeeze the clutch plates to roughly normal operating position). If it's absurdly far back from a right angle, then the rod is too long and you might not even be able to get the little cover back on the gearbox. That would require a bit of grinding to shorten the rod -  assuming it is seating right in the pressure plate of course, AND that someone hasn't already done the Richard ball bearing mod somewhere up the mainshaft to make the rod longer to compensate for the worn operating arm. Suggest you extract pushrod if you haven't already to check what's in there!

The clutch plates seem from the pic to fill the basket about right. The tangs of the outermost plain or friction plate can't disengage from centre or drum when the clutch is disengaged, nor is there so much space between the pack of plates and the outer end of the clutch centre that the pressure plate can't bear on the outer plain plate. Ergo that part of it all looks OK to me.

I reckon if all is OK on the operating mechanism and the pushrod is set right, the problem most probably lurks in the springs and cups department (which others are saying while I labour through this screed). Although they can't have been fully coil-bound if you had lift on the pressure plate yesterday with things screwed down very tight, there's something not right. Either that, or the plates aren't able to move freely in their grooves on the centre or inside the drum.

Nothing very new here I fear, but maybe some pointers. And I'd definitley look at the rear inner primary case mounting when it comes time to chase the graunching noise (if it persists) . . .

Despite the pain factor, it WILL pan out OK!


Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 11.07. 2011 19:10
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
Title: Re: Clutch Spring Adjustment
Post by: chaterlea25 on 11.07. 2011 19:41
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  *conf*
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  *eek*

HTH
John O R
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 11.07. 2011 20:42
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.
Title: Re: Clutch Spring Adjustment
Post by: bsa-bill on 11.07. 2011 20:58
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.
Title: Re: Clutch Spring Adjustment
Post by: groily on 11.07. 2011 21:44
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.
Title: Re: Clutch Spring Adjustment
Post by: bsa-bill on 11.07. 2011 22:22
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.
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 11.07. 2011 22:58
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
Title: Re: Clutch Spring Adjustment
Post by: trevinoz on 11.07. 2011 23:36
Richard,
                   Steel on steel is correct for the pressure plate.
There are 5 friction plates and 6 plain steel plates.

  Trev.
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 11.07. 2011 23:40
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.
Title: Re: Clutch Spring Adjustment
Post by: trevinoz on 11.07. 2011 23:47
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.
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 11.07. 2011 23:51
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.
Title: Re: Clutch Spring Adjustment
Post by: trevinoz on 12.07. 2011 00:03
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.
Title: Re: Clutch Spring Adjustment
Post by: Brian on 12.07. 2011 02:05
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.
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 12.07. 2011 04:08
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
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 12.07. 2011 04:35
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.
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 12.07. 2011 05:07
No it's driven just like the 6 spring pressure plate. I think the reasoning behind it is so there is no driving affect on the pressure plate it self.
With a 6 spring if there is binding of the drive tangs this will affect the lift of the pressure plate, not so with the 4 spring.
Clear as mud.
Cheers
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 12.07. 2011 06:46
Thanks Musky. I got it now. I had forgotten the driving relationship between the hub and the pressure plate being the same as the driven plates. Hence, no slippage between last plain plate and pressure plate. Duh! (This can go on my list of reasons for humility.)

Richard L.
Title: Re: Clutch Spring Adjustment
Post by: bsa-bill on 12.07. 2011 10:36
Aha Musky beat me to it.
There are various incarnations of this clutch cush, no cush, also 4 plate and 5 plate, you might have a combination of parts, defo different cups for four plate and five plate.

anyway here are the size of my cups and springs, I use a Lyfords alloy pressure plate which needs no modification to the push rod so every thing should be the same, but it wasn't in my case, I also had a cush drive centre that did not match the clutch basket and gave no end of problems with getting the correct centre nut.
the threads on my spring studs don't come right out flush with the spring nuts they stop about one thread in behind the screwdriver slot.

Keep at it there's an answer here somewhere and we'll all benefit from knowing it.
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 12.07. 2011 12:16
Thank you all very much for your help and the photos.  When I get the chance I'll whip out my parts and measure them to compare with yours (!).  I keep thinking along the same lines as Brian: i.e. it worked fine before the actuating arm mod so trouble ought to lie in that area.  It is possible though, I suppose, that a former handler messed with the standard spring/cup/pushrod set-up to overcome the worn actuating arm assembly.  I'll get back to you after further investigation.

Must get on with fitting that kitchen door though, I've already deviated to search for fibre washers to try and stop the new fuel taps from leaking whilst on the bread run...
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 12.07. 2011 18:00
Bill,

Thanks for spotting the split link on the wrong way round, I'd taken the chain off to try rocking the clutch drum around as part of my investigations.  And I've put the bleedin link on wrong...Should have had a tea break earlier.

I've had stomach bug today and don't feel like dragging myself to the bike to do anything tonight.  Well, actually I've been told by other half that I won't be visiting the bike tonight.

Will be back on the case soon.
Title: Re: Clutch Spring Adjustment
Post by: RichardL on 12.07. 2011 19:21
Despite some folklore to the contrary, you really won't learn anything about the clutch by taste testing the chaincase lubricant.
Title: Re: Clutch Spring Adjustment
Post by: chaterlea25 on 12.07. 2011 22:59
Hi All,
Does anyone know if the spring studs are different between 4 and 5 plate clutches?
(talking about ""Triumph" type 4 spring)

Regards
John O R
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 14.07. 2011 15:49
Still feeling too rough to work on bike but have taken photos of various clutch bits to show: 1. position of actuating arm 'at rest' and 2. with handlebar lever pulled in (little gearbox cover is off so you can see position of adjuster screw for end of push rod); 3. amount of thread showing on adjuster screw outside the locknut; 4. another view of adjuster screw and locknut and position of end of pushrod; 5. clutch spring and cup.

The spring and cup look to be the same type and size as you've shown me.  I'm beginning to think it must be an adjustment problem and (after further thought and drawing little diagrams for myself to help understand the relationship of the parts of the clutch mechanism) it wouldn't be helped by cutting bits off the pushrod.  There must be a plate getting hung up somewhere, or the squareness of the pressure plate lifting needs ultrafine tweaking...I don't have a dial gauge but I'm beginning to understand why some of you use them.  I've set the clutch up fine before without one though.

Another thing I don't get is how come the clutch still isn't slipping despite such a very light spring tension.

By the way, when I unscrewed the loosest spring retaining screw to take the photograph, I found it was still 4 full turns away from pinging off the end of the bolt, so not as perilous as I imagined.

I forgot to take a photo/measure the length of the pushrod, would that help?

Cheers
Terry
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 14.07. 2011 18:17
All looks good there Terry. The kick start cotter pin is backwards.
Like you say, it's strange that you don't get slip with the springs set so lightly. Are you sure of all the plates are in correct position, steel, friction, steel, friction, steel, friction, steel, friction, steel, friction, steel & pressure plate. The pressure plate should lift at least 1/8" and all the tangs slide in their respective slots freely.
Don't let it get the better of you.
Cheers
Title: Re: Clutch Spring Adjustment
Post by: groily on 14.07. 2011 20:22
All also looks pretty good to my less well-tuned 'Beesa-eyes' than Muskrat's, Terry. The adjuster may be a bit far out I thought, but things look really quite good from what can be seen.
I did have a look at a thing called a Haynes manual this afternoon (had to get it out of its wrapper to be honest) and it did raise one Q which intrigued me. On p72 it shows 4 spring clutches with only 4 friction plates, but shurely shome mishtake as your pressure plate would probably hit the inner drum without squeezing the pack tight enough to drive anything if you pulled a plate? The 4 spring jobs on my A and my B both have 5 friction plates anyway  . . . . but maybe there were variants and if there were, someone here will know for sure. 6 and 5, says Haynes, are for plunger and rigid 6 springers, 6 and 4 (the rear of the outer drum being lined) for swing-arm 6 springers, and 4 friction, unspecified plain, on 4 springers. Must be dubious?
Darned if I know either why the thing didn't slip though, with everything so loosely done up.
Does the pushrod easily move a good 1/8th of an inch at the clutch end when you operate the handlebar lever with the pressure plate removed? Ie under no load? If it does, the hassle has to be with the clutch itself; if it doesn't something's sticking on the way across or there's a lack of clearance somewhere when thing are assembled. But I'm back to the clutch end for whatever the problem is, having seen the pix. I await better and wiser comments, as I feel a strong kindred interest in this thing working!
Title: Re: Clutch Spring Adjustment
Post by: chaterlea25 on 15.07. 2011 01:05
Hi All,
Firstly to answer my own question!
Yes the spring studs are different for 4 and 5 friction plate clutches !!

Redbeeza , By any chance did you fit new roller bearings to the clutch chainwheel?
were they the correct ones? they need to be 0.225 long not the common 1/4 x 1/4in.
Fitting the longer bearings causes the clutch to bind up!! (grip wit no spring pressure???)

HTH
John O R
Title: Re: Clutch Spring Adjustment
Post by: iansoady on 15.07. 2011 11:16
The kick start cotter pin is backwards.
Cheers

That's the way round I always put them - and is the way it's shown in the handbook.

(http://i43.photobucket.com/albums/e398/iansoady/a10/th_cotter.jpg) (http://s43.photobucket.com/albums/e398/iansoady/a10/?action=view&current=cotter.jpg)

If you put it the other way round when you use the kickstart it'll tend to loosen the cotter pin.

I must say I'm not a great fan of cotter pins holding kickstarts.
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 15.07. 2011 11:24
Hi chaps,

Yes, I've got the plates in the right order, and the kickstart cotter pin isn't the wrong way round, even the Haynes manual and BSA parts list show it fitted like that, so...

I didn't replace the roller bearings but don't remember what size they were, didn't bother measuring them.  I think I'd have had a problem before now if they were wrong.

On the Haynes manual stuff, that book really is a mixed blessing isn't it.  I've got an old secondhand one and it's full of owner added information about left hand threads where it says right hand (and vice versa), and the gears being wrongly numbered.  It doesn't even mention the four spring clutch in mine, despite having the drawing from the parts list illustrating it as an alternative (and the drawing shows the correct number of plates but the text doesn't correspond).  The photos on the engine rebuild bit only show the six spring.  I've used the drawings in the BSA parts list (supposedly for my year of bike) as the main guiding force for what's needed and what goes where.  And Roy Bacon's book has been helpful as well as the Gold Portfolio A7/A10 book (when you have no history of having these bikes in your youth you have to start somewhere!)

I'm still under the weather so haven't done anything else to bike yet.  Don't worry Groily, I'm sure it's nothing to do with your repair job, it must be something snagging in the clutch drum and an adjustment issue, probably the lifting square thing.  I actually felt a lot happier when I finally got the clutch to lift.  I just didn't know what I was doing wrong and was concerned that something serious had gone wrong like a sheared off gearbox mainshaft or something.  Turned out I wasn't doing anything wrong, I was just expecting the clutch to lift where it should have done with the adjuster screw heads closer to the bolt ends.

When I did finally get the clutch to lift/disengage/work? I was having to adjust each spring tension a real knat's cock of an increment, none of this 1/4 turn business.  Maybe when I left it in that persons yard for a few days after it broke down, he installed a Velocette clutch for a laugh...

Cheers,
Terry
Title: Re: Clutch Spring Adjustment
Post by: BSA_54A10 on 15.07. 2011 11:28
Quote
That's the way round I always put them - and is the way it's shown in the handbook.

If you put it the other way round when you use the kickstart it'll tend to loosen the cotter pin.

I must say I'm not a great fan of cotter pins holding kickstarts.
The thickest portion of the pin goes in the side that takes the thrust. or at least that was what I got taught.
Thus the pin is in correctly AFAIK


Title: Re: Clutch Spring Adjustment
Post by: muskrat on 15.07. 2011 13:18
When I find that old pushbike builder I knew as a kid I'll tell him he was wrong. Funny how little things you are told as a kid stick for life. (Sorry Mum, what did you say?) *red* *red*
Cheers
Title: Re: Clutch Spring Adjustment
Post by: redbeeza on 19.07. 2011 19:20
I think I've sorted it out.

It just seems to have been an adjustment thing, but I think a plate or two must have been sticking or jamming somehow when I first started to set up the clutch and that complicated matters.

To recap:  I'd got the clutch to work (with the primary cover off) but the nuts on the clutch springs were unscrewed an awful long way.  I'd also had trouble with the kickstart sticking, accompanied by a graunching sound, after I'd put the primary cover back and tightened it down.

When I had another think about the clutch and drew a few diagrams to help me understand the relationship between the various different adjusters I decided to approach the problem from the other direction.

The clutch was working and lifting square but the screws were too slack and I couldn't understand why the clutch was still not slipping.  Instead of fiddling with the spring tension again, I screwed in the adjuster at the gearbox end half a turn: the clutch then slipped.  I then started to screw the springs in 1/4 turn at a time and regularly checked the pressure plate was lifting square, readjusting when necessary.  I got the clutch spring nuts screwed back down to almost where the threads were beginning to show and the clutch was still slipping, so I went back to the adjuster at the gearbox end and slackened it of gradually until the clutch stopped slipping.  A little bit more tweaking on the spring nuts and a bit of slack put in the cable by adjusting the handlebar lever and we were there:  spring nuts down to where they should have been; light lever operation; clutch spins freely on the kickstart when the lever's pulled in.  Still haven't road tested it yet but I think I'm there.

Coming to the graunching sound.  From one of my photos, Groily noticed there was a spacer missing from where the inner primary cover bolts to the frame at the rear.  This spacer pushes the inner cover out at this point.  I thought that by adding a spacer here, my problem with the tightening kickstart action and the graunching would be worse because I had convinced myself that something was catching on the inside of the outer primary cover.  I thought this because I had discovered a light scoring on the inside of the cover where the clutch rotates.

I thought I'd give the spacer a go though because there should be one anyway.  I had noticed that the outer primary cover didn't sit very flat on the inner before tightening and could be rocked maybe 1/4", so I tried adding different thicknesses of washers to where the spacer should sit to try to reduce this.  I got the gap down to about 1/8" and left these washers in in place of the spacer on reassembly.

On tightening down the outer primary cover screws and checking kickstart action: nice and free and no graunching sound.  I can only think that the primary inner case was catching on the back of the clutch drum somehow and causing the trouble... all would be hidden from view, and that the scoring I had seen on the inside of the outer cover was a historical red herring.

Can anyone tell me the thickness that said spacer should be on a '62 model A10?  My inner cover is now spaced out about 5mm in new money.

Thanks for all the help.  It led me to sit down and understand exactly how the whole mechanism of the clutch works together, and saved me from sawing a bit off the pushrod...

Regards,
Terry
Title: Re: Clutch Spring Adjustment
Post by: muskrat on 19.07. 2011 20:46
Glad you've finally got it sorted Terry. I know sometimes I (we) dive in looking for major problems when it can be something as simple as plates stuck together. At least now you have a good understanding of how the clutch works.
As for the spacer. If the inner cover is still flat (not warped) it's just a matter of doing up the 5 screws (use spacers on the front 3) and use washers or a made up spacer to fill the gap. It could be 1mm or 10mm, it varies.
Check that the outer cover is flat on a piece of glass or other flat surface. If it is bolt it up to the inner before working out the spacers required.
Cheers
Title: Re: Clutch Spring Adjustment
Post by: groily on 19.07. 2011 22:31
Brilliant Terry, this is Good News. Wasn't sure if a spacer was missing or not, but from bitter experience I know that stressing the cases to close them up is BAD and that there has to be something (usually) to get the alignment correct.  Quarter inch says 'yes', something needed doing - and when I had the same hassle light years ago it seems now, the noise was at the back not the front of the clutch. Excellent if a washer or two will serve, but as Musky says, no golden rule as far as I know on How Thick. The main thing is it's all looking good and you'll be out there again frightening the natives. I hope!
Title: Re: Clutch Spring Adjustment
Post by: shabashow on 10.08. 2011 15:02
Glad you managed to get a resolution to your problem.
The combined IQ of our BSA experts on the forum must be astronomical, and whatever the problem, someone will come up with a solution, or at least helpful comment.

slithly off topic - back to the kick start cotter pin -

I had it in the 'reverse' direction for a short period a while back (worried about it dropping off due to the nut loosening off) and thought it didn't make any real difference until I went to open the tool box on my 52 plunger. With the pin in the wrong direction, the kickstart lever sits slightly more angled to the rear, which fouls the toolbox lid when it is opened. I turned the cotter pin back around the 'right' way, with the nut on the top and releived my fears of the nut loosening off by liberal application of locktight and using two nuts to lock them together.
Title: Re: Clutch Spring Adjustment
Post by: cyclobutch on 31.08. 2011 15:53
Yeah - I've always inserted cotter pins so that you push in to the taper. Still running them front and back on my tandem.
Title: Re: Clutch Spring Adjustment
Post by: Joolstacho on 18.04. 2013 09:28
Just in case others may have a similar problem. While setting mine up (4-spring) I found that one spring was fouling it's cup, -at high lift, a coil on the spring was spreading slightly, just enough to drag and 'catch' in it's cup.