Clutch Spring Adjustment

[muskrat]

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

[RichardL]

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.

[bsa-bill]

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.

[redbeeza]

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...

[redbeeza]

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.

[RichardL]

Despite some folklore to the contrary, you really won't learn anything about the clutch by taste testing the chaincase lubricant.

[chaterlea25]

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

[redbeeza]

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

[muskrat]

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

[groily]

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!

[chaterlea25]

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

[iansoady]

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.



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.

[redbeeza]

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

[BSA_54A10]

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

[muskrat]

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?)
Cheers