'54 Plunger, 6 bolt clutch.
Please excuse the long post but I'm tearing my hair out here.
I've re-assembled my clutch and it's constantly in gear, despite the plates moving out.
Here's the back story.
All was fine with the clutch for the last year of owning this bike but last Monday, the clutch inner basket came off the shaft whilst out for a ride.
Got it home and removed the primary chain cover to fine the floating basket.
See image #1 for how it was assembled.
It had a "domed" washer fitted UNDER the basket, then the basket and finally the large conical nut that has the flat (presumably for a tab washer to lock it tightly?) Except mine had nothing locking the nut on, hence why it fell off.
Re-assembled it all today, putting the basket on first, then the "domed" washer and finally the conical big nut.
I tightened the out with an impact gun, not having a torque wrench and tabbed the washer over the flat of the conical nut, fitted the plates and started the bike in neutral.
Pulled the clutch, put it in 1st and it lurched forwards and stalled.
I found that the clutch, although the plates are moving out, is not affecting the gearbox.
Primary chain off, plates out of the clutch and I found that the inner basket does not move independently of the outer basket.
I've assembled it in order of the images below. (#2 #3 #4 & #5) but it would appear that it needs a washer / spacer UNDER the basket for the clutch to operate.
This is contrary to the parts diagram and there would be no space left on the shaft splines to fit the tab washer if a washer were to be placed under the inner basket.
Can anyone please tell me where I'm going wrong or what the problem is ?
I've got to get the bike running before the weekend.
Many thanks
Hi,
Before fitting any plates put the washer and domed nut on. Just do it tight rather than torqued up.
The centre should rotate quite feely as it turns the main shaft of the gear box. Likewise, unless you have the primary chain on, the chain wheel should rotate freely. These two parts should not touch in any way.
Dave.
Did you put the washer on curve inwards or outwards?
Quote from: DAVE BRADY on 13 May, 2025, 19:48 Hi,
Before fitting any plates put the washer and domed nut on. Just do it tight rather than torqued up.
The centre should rotate quite feely as it turns the main shaft of the gear box. Likewise, unless you have the primary chain on, the chain wheel should rotate freely. These two parts should not touch in any way.
Dave.
Thanks Dave.
I'd seen a YouTube video that said 60 ft/lbs but to me, if it's tight and the tab washer is locked, that should be OK?
Basically, what you've said.
I'll try just with it spanner-tight before locking the tab and see if that makes it work.
Thanks for your answer
Quote from: cdsdorset2 on 13 May, 2025, 20:00 Did you put the washer on curve inwards or outwards?
I put it on dished outwards (the outer lip raised, so I could get under it to bend it up to lock the big nut.
Did I get it wrong?
Im confused. In pic 5 there are obvious skid marks on the washer. How has that occured if it was locked onto the nut?
Quote from: cdsdorset2 on 13 May, 2025, 20:38 Im confused. In pic 5 there are obvious skid marks on the washer. How has that occured if it was locked onto the nut?
The marks will probably be from when the big nut was tightened down with the impact gun?
Should the washer have the lip raised outwards like I've fitted it?
Or inwards (towards the basket surface?)
Lip raised. But how hard did you tighten it to cause that much damage? Try tightening it with a torque wrench.
Quote from: cdsdorset2 on 13 May, 2025, 21:30 Lip raised. But how hard did you tighten it to cause that much damage? Try tightening it with a torque wrench.
Torque is supposed to be 60 ft/lb (according to YouTube) and my wrench only goes up to 40 so I used the impact gun (as advised by my local vintage bike breaker)
Have to admit ive never done that much damage to a lock washer at 60ftlb.
I know its a stupid question but the plate has been fitted behind the chainwheel hasnt it.
Quote from: cdsdorset2 on 13 May, 2025, 22:49 I know its a stupid question but the plate has been fitted behind the chainwheel hasnt it.
Not sure which "plate" you mean and by "chain wheel" do you mean the outer clutch drum?
Hi,
Number 23 is chainwheel/clutch basket/drum and you have this already fitted complete with bearings - squeeze a bit more grease in to these.
Now fit 16, the clutch centre, the washer 14 and the nut 13.
Do the nut up tight - final torque later.
Does the centre rotate freely and smoothly? If so then these parts should be OK.
Now assemble clutch plates individually making sure that they slide in to position.
As there is no pressure on the plates you should be able to turn the centre, probably need a socket, and the plain plates will turn with it.
Now fit the pressure plate and springs with the springs all done roughly evenly.
Does the clutch now disengage when the lever is pulled?
If so great now take the pressure plate off again and torque the nut and turn over the washer.
Refit the pressure plate and adjust the springs to get even lift of the pressure plate and no slip when turning the engine over.
Sorry if this seems patronising.
Dave.
Quote from: DAVE BRADY on 14 May, 2025, 07:59 Hi,
Number 23 is chainwheel/clutch basket/drum and you have this already fitted complete with bearings - squeeze a bit more grease in to these.
Now fit 16, the clutch centre, the washer 14 and the nut 13.
Do the nut up tight - final torque later.
Does the centre rotate freely and smoothly? If so then these parts should be OK.
Now assemble clutch plates individually making sure that they slide in to position.
As there is no pressure on the plates you should be able to turn the centre, probably need a socket, and the plain plates will turn with it.
Now fit the pressure plate and springs with the springs all done roughly evenly.
Does the clutch now disengage when the lever is pulled?
If so great now take the pressure plate off again and torque the nut and turn over the washer.
Refit the pressure plate and adjust the springs to get even lift of the pressure plate and no slip when turning the engine over.
Sorry if this seems patronising.
Dave.
Dave,
It's not patronizing at all.
I'm new to this so any advice is appreciated.
I'm guessing that I've over tightened the big nut?
I'll try again this afternoon.
What grease should I use in the bearings?
CV grease?
Thanks again
Hi,
Use a high melting point grease. Just push it in until all spaces are full and wipe off any surplus leaving just a smear across the bearing.
Unless you are using a very long lever you would be hard pushed to over tighten the nut. It locks all the centre bits together and they cannot be crushed. If you are using a socket with a standard length 'tommy' bar you will never over tighten it. If you can get a torque wrench that would be useful.
For the A65 the clutch centre nut is tightened to 70/75 ft/lbs which is quite a lot.
Unless someone comes up with and official setting then perhaps you could settle on 60 ft/lbs.
Dave.
You would be very hard pushed to overtighten that nut, chief thing is that there are no previous owners bodges as to why anyone would put the soft tab-washer behind the centre basket?
cdsdoorset2 was referring to the large dished washer that goes on before the chainwheel and centre bearing (this has contact with those corks on the backside of the chain wheel).
Just checking the centre but is the one with built in washer flange and a cutout for you to bend the tab washer over into?
Tighten with a moderately long lever should be fine, but your threads should be really clean and at final assembly (ie when you have confirmed that it all spins properly) I would use a couple of drops of Loctite Blue 243 thread locker (everyone with an old bike needs a tube of that to help avoid things dropping off!)
A point to make is that the two centre bearing cages can be assembled incorrectly on the inner race and it is also possible to have the inner race binding too (see text and pics re4ferred to below).
There is a useful thread here for a read and consideration:
https://www.britbike.com/forums/ubbthreads.php/topics/674773/bsa-6-spring-clutch
The author/poster can rather overdo the measurement/special tools bit but the pictures and information are very useful indeed.
I had to use an NEB clutch on my ABSAF 600 (too much power and torque for a stock clutch) but the same stock clutch with Surflex plates properly adjusted on my 57 Competition works beautifully.
Quote from: neil1964 on 14 May, 2025, 14:54 You would be very hard pushed to overtighten that nut, chief thing is that there are no previous owners bodges as to why anyone would put the soft tab-washer behind the centre basket?
cdsdoorset2 was referring to the large dished washer that goes on before the chainwheel and centre bearing (this has contact with those corks on the backside of the chain wheel).
Just checking the centre but is the one with built in washer flange and a cutout for you to bend the tab washer over into?
Tighten with a moderately long lever should be fine, but your threads should be really clean and at final assembly (ie when you have confirmed that it all spins properly) I would use a couple of drops of Loctite Blue 243 thread locker (everyone with an old bike needs a tube of that to help avoid things dropping off!)
A point to make is that the two centre bearing cages can be assembled incorrectly on the inner race and it is also possible to have the inner race binding too (see text and pics re4ferred to below).
There is a useful thread here for a read and consideration:
https://www.britbike.com/forums/ubbthreads.php/topics/674773/bsa-6-spring-clutch
The author/poster can rather overdo the measurement/special tools bit but the pictures and information are very useful indeed.
I had to use an NEB clutch on my ABSAF 600 (too much power and torque for a stock clutch) but the same stock clutch with Surflex plates properly adjusted on my 57 Competition works beautifully.
Thanks for the advice.
The whole bike has "previous owner issues" probably because it was used as a "show bike" and never ridden ::)
I've ordered a new soft tab washer and I'll assemble it as I did previously but I'll tighten it using hand tools and not the impact gun and see if the inner basket notes independently of the outer basket.
I'm also wondering about inserting the clutch plates . . . . .
Which goes in first?
Metal plate or friction plate?
(And which way do the raised "tabs" on the metal plates go? - facing the engine or outwards)
Sorry for the daft, newbie questions.
The link you provided was both interesting and mind blowing
You mentioned a domed washer next after the clutch drum . I cant remember that domed washer being fitted under the center . try it without it . If that indeed is how you fitted it .
Hi,
Number 23 it the washer and rather than 'domed' it has raised edge. It is a lock washer hence the tabs. The domed should have a flat on it so that once torqued up, the edge of the washer is turned up to add the the security of the nut.
Dave.
Quote from: DAVE BRADY on 15 May, 2025, 09:32 Hi,
Number 23 it the washer and rather than 'domed' it has raised edge. It is a lock washer hence the tabs. The domed should have a flat on it so that once torqued up, the edge of the washer is turned up to add the the security of the nut.
Dave.
Yes, I am referring to the nut (part 24 in the above diagram) that has a machined dome with a lip, so not a separate washer per se. The lip pushes the locking washer against the pressed steel basket and the space inside the lip allows space for the bearing and hub centre internally, hopefully avoiding the issue that you inherited.
Is it possible that you are tightening the Clutch Spring Nuts down too much..? They should not make the springs 'coilbound', and should each be individually adjusted to make the outer clutch plate lift off squarely.
Quote from: ducati2242 on 15 May, 2025, 09:24 You mentioned a domed washer next after the clutch drum . I cant remember that domed washer being fitted under the center . try it without it . If that indeed is how you fitted it .
Thanks
Quote from: DAVE BRADY on 14 May, 2025, 10:09 Hi,
Use a high melting point grease. Just push it in until all spaces are full and wipe off any surplus leaving just a smear across the bearing.
Unless you are using a very long lever you would be hard pushed to over tighten the nut. It locks all the centre bits together and they cannot be crushed. If you are using a socket with a standard length 'tommy' bar you will never over tighten it. If you can get a torque wrench that would be useful.
For the A65 the clutch centre nut is tightened to 70/75 ft/lbs which is quite a lot.
Unless someone comes up with and official setting then perhaps you could settle on 60 ft/lbs.
Dave.
I really can't recall how the clutch plates fit back in.
Do I start with a metal plate or friction plate?
(And does the lip on the metal plate protrude inwards, towards the engine or outwards?)
Thanks again
Hi,
If out refer to the drawing posted above, you will see that the clutch drum/basket has friction inserts so start with a plain plate and then a friction plate until they are all fitted.
In the drawing it shows the 'lip' outwards.
Dave.
your clutch drum seems to have a steel plate at the back of it so i wouldn't be too sure of copying the drawing you my have to start with a cork plate . remember the steel plates need cork plates either side of them the last one dosent matter as the pressure plate can act as a steel . Or it could be that there is already a plate in their .
That basket looks to have a complete friction ring, not steel.
An interesting pattern part.
The article I linked to shows how to set the springs.
Check the springs are of the correct length for your number of plates, decent springs with good plates ideally adjusted with a dial gauge to get even lift is invaluable.
Quote from: DAVE BRADY on 15 May, 2025, 12:28 Hi,
If out refer to the drawing posted above, you will see that the clutch drum/basket has friction inserts so start with a plain plate and then a friction plate until they are all fitted.
In the drawing it shows the 'lip' outwards.
Dave.
Thanks again.
I wasn't certain, especially about the lip on the diagram.
Job for tomorrow, rebuild & test the clutch
I hope I'm not leading you up the garden path here. I don't know much about these modern BSA's.
What is that ghastly looking mangled steel ring in the clutch hub? I suggest you remove it. There does seem to be some sort of "ring" here, probably as part of the hub, but it looks narrower than yours, and without a large chunk taken out of it. I imagine it's there to try to stop oil getting into the clutch. Maybe someone could post a picture of an original clutch hub?
In pictures 4 and 5, it looks to me that there is a grey friction disc fitted, with a beige friction disc fitted behind it.
According to the diagram, this is incorrect. Your clutch drum and the clutch discs should have friction inserts fitted into them. There are no friction "rings" fitted. These are only fitted on much earlier clutches.
Perhaps someone more knowledgeable than me can comment on the above?
Quote from: Steve.S on 16 May, 2025, 01:45 I hope I'm not leading you up the garden path here. I don't know much about these modern BSA's.
What is that ghastly looking mangled steel ring in the clutch hub? I suggest you remove it. There does seem to be some sort of "ring" here, probably as part of the hub, but it looks narrower than yours, and without a large chunk taken out of it. I imagine it's there to try to stop oil getting into the clutch. Maybe someone could post a picture of an original clutch hub?
In pictures 4 and 5, it looks to me that there is a grey friction disc fitted, with a beige friction disc fitted behind it.
According to the diagram, this is incorrect. Your clutch drum and the clutch discs should have friction inserts fitted into them. There are no friction "rings" fitted. These are only fitted on much earlier clutches.
Perhaps someone more knowledgeable than me can comment on the above?
Do you mean the thin metal ring that runs around the inside of the inner clutch basket? (Can't add another photo)
Quote from: DAVE BRADY on 13 May, 2025, 19:48 Hi,
Before fitting any plates put the washer and domed nut on. Just do it tight rather than torqued up.
The centre should rotate quite feely as it turns the main shaft of the gear box. Likewise, unless you have the primary chain on, the chain wheel should rotate freely. These two parts should not touch in any way.
Dave.
Hi.
I've done as you suggest.
Inner basket, then a new tab washer, then the domed nut.
Tightened up (not torqued)
Primary chain removed
Centre clutch basket is "locked" to the outer / primary chain sprocket and that won't turn without turning the back wheel.
If the centre basket should spin freely without contacting the outer basket, then there's something really wrong here.
I've no idea
Hi ,
Where do you live? Someone may be able to come and help.
Dave.
so starting from the nut you have the conical washer then the tab washer then the center then the basket nothing else . Does the center turn freely before you tighten the nut when out of gear .
Quote from: DAVE BRADY on 16 May, 2025, 10:13 Hi ,
Where do you live? Someone may be able to come and help.
Dave.
Sheffield (south-west side)
Hi,
Sheffield was the starting place for the BSAOC but no Branch these days.
There are Branches based in West Yorks. and South Derbs. but not on your doorstep. Lincs.may be easier to get to.
If not a member of the BSAOC, join up and contact your nearest Branch. It is likely that someone lives not too far from you.
Dave.
Quote from: DAVE BRADY on 16 May, 2025, 11:59 Hi,
Sheffield was the starting place for the BSAOC but no Branch these days.
There are Branches based in West Yorks. and South Derbs. but not on your doorstep. Lincs.may be easier to get to.
If not a member of the BSAOC, join up and contact your nearest Branch. It is likely that someone lives not too far from you.
Dave.
Hi Dave.
Firstly, I must thank you for all the help and advice but most of all, your patience with my lack of understanding.
I have finally either sorted the problem or put a sticking plaster over it but I've got a working clutch now.
I'll post a separate comment so you (and anyone else) can see easier, what the problem was.
Once again, sincere thanks
CLUTCH NOW WORKING - Here's the scenario.
With the help of a light misting of black paint, I deduced that the rivets on the back of the inner clutch basket were fouling on the outer edge of the outer race, embedded in the toothed "clutch outer"
With the aid of my power file, they now don't foul on the race and all is working well.
I do wonder though, if the outer race were a half-a-mil too "outward" then this would explain my problem.
It was only fouling on the very corner edge of the outer race.
Should the corner edge of the outer race be flush with the inside edge of the toothed clutch outer? Does it need pressing in by a fraction? (Which would also line up the primary chain drive and toothed clutch outer teeth a little better)
I've attached images showing the bright "wear mark" on the outer race corner and the offending rivet heads.
Any advice on the positioning of the outer race will be appreciated
Glad to hear you have got your clutch working.
I wonder if it might be worth taking a look at Vintage Bike Bird on You Tube. (Julie Diplock.) "1955 Us-spec BSA 650cc A10 Golden Flash Clutch Change."
Not the same bike, but the clutch looks similar to yours.
As you will have read in the thread I posted that if you have the bearing outer race incorrectly aligned the clutch will jam.
See the image with the chainwheel and feeler gauge.
Glad you have action from the clutch again!