Clutch Spring Adjustment

[bsa-bill]

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?

[redbeeza]

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

[muskrat]

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

[redbeeza]

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

[muskrat]

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

[redbeeza]

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

[bsa-bill]

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

[redbeeza]

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.

[RichardL]

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.

[redbeeza]

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

[bsa-bill]

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

[wilko]

There certainly are different cup lengths,or maybe the springs are too long.

[muskrat]

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 
Cheers

[RichardL]

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.

[groily]

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!