Triumph 4 spring clutch (non cush type)

[trevinoz]

Bob,
            Nothing that some previous butchers do surprises me now.
Trev.

[Mosin]

Hi Kiwipom,

You might want to take a look at this thread: http://www.a7a10.net/forum/index.php/topic,2689.40.html

I had almost exactly the same problem when fitting a four spring clutch. Go straight to the last couple of posts for the solution!

Good Luck

Simon

[kiwipom]

hi simon, thanks for your input and i have looked at the similar problem that you had, your solution will not fix my problem strange though it may seem as you will see from the pics my bearing has an 11.5mm built in to take the place of a spacer. i need to find 4-5mm from somewhere, apparently the spacers are 10-12mm wide but i cannot source one from here so may have to have one made. if i leave the clutch in the position that it is in at the moment that means that i will have to move the engine sproket out 4-5mm, to do that i believe that i will have to have a spacer 10mm wide so as to engage the oil seal and then take 5mm off of the origonal bearing piece that will put the middle of the sprockets about 18-20mm out from the primary casing, any other solutions would be welcome,cheers,
Bob.

[Brian]

Bob looking at your bottom photo (clutch centre) it looks like the clutch centre is the problem. It should sit further into the sliding plate than it does. You can see quite a lot of the scroll, most of it should be in the sliding plate bush. Do you have any other centres to try or get some measurements from someone, maybe someone on the forum has one apart at the moment and could measure how much thread on the mainshaft is sticking out.

If you start spacing the whole assembly out you may run into clearance problems with the outer cover.

[bsa-bill]

Interesting Bob - looks like a fair bit of thread out through the centre, maybe not as much in http://www.a7a10.net/forum/index.php?action=dlattach;topic=2689.0;attach=7121;image but not far off, worth giving yours a measure as in the photo.
Your primary case looks to be where it should be also.
Possibilities left are
Gearbox not where it should be (engine plate?) unlikely and you can punch me for suggesting it, if you ever meet me
Wrong mainshaft - unlikely but given the funny set at the engine end !!
Key holding the centre from tightening up onto the taper
Wrong centre - could be a duff one

Keep us posted

[jjbsa]

What an interesting thread is this!  I have been to somewhere quite close to this place myself very recently.  BTW I call the thing that fits on the taper the clutch sleeve and the inner part of the clutch that fits on it I call the clutch centre.

I feel that Brian (reply number 18) has hit the nail on the head with your problem kiwipom.  The photos do suggest that the clutch sleeve is sitting too far out.

My problem initially was that when the clutch centre was tightened down then the clutch chain wheel would not spin freely.  This turned out to be because the clutch sleeve had been driven up the taper when the clutch centre nut was tightened and it had stretched where the internal keyway is cut into it.  This meant that the race the rollers run on had become oval, about half a thou oversize at 90° to the keyway ( and explained why the rollers didn?t want to go in).  The rollers were pinching on this part of the clutch centre.  

Also, because the sleeve was too far up the taper, the chain wheel was inboard of the engine sprocket (a situation I had never seen before).  I ended up deciding to buy a new sleeve, which also ended up giving me good sprocket-chain wheel alignment.  

An interesting difference that I noticed between the new and the old sleeves was that the clutch centre nut tightened up against the clutch centre when the new clutch sleeve was being used, but with the old clutch sleeve the nut tightened up instead against the clutch sleeve, with the clutch centre remaining about a half millimetre below the sleeve, which meant that the clutch centre was free to chafe around (I hope that all makes sense[pls also note I've edited this after my initial post as I'd used the word "centre" in a few places where I meant to say "sleeve"]!).  I presume that the new clutch sleeve has things tightening up the right way?

[trevinoz]

JJ,
         The washer under the nut has a recess which ensures that the centre is tight regardless of the sleeve height.
Trev.

[bsa-bill]

An interesting difference that I noticed between the new and the old centres was that the clutch centre nut tightened up against the clutch centre when the new clutch sleeve was being used, but with the old clutch sleeve the nut tightened up instead against the clutch sleeve, with the clutch centre remaining about a half millimetre below the sleeve, which meant that the clutch centre was free to chafe around (I hope that all makes sense!).

JJ - this is even more interesting, I had exactly that happen to me, the old centre was the cush type, I had all sorts of configuration of nuts and washers but it still always had a just discernible bit of play, I bought a new (nos) non cush centre and the problem was cured.

[chaterlea25]

Hi Bob and All,
From your photos, I'm almost certain that the cush assembly you have is the Wrong one
The inner sleeve looks to be from an earlier semi unit engine????
As pointed out it also looks as if the clutch adaptor is not sitting in far enough????
Do you have the spacer and 2 gaskets fitted between the crank and primary cases, these make up near enough 1/8in.
I can see from the pics that no spacer is fitted between the lower rear mount and frame??? usually theres need for some washer or spacer here?? DO not force the primary outwards by omitting any spacers needed

I can take some photos tomorrow of different centres on a mainshaft, must set a reminder to myself

HTH
John O R

[kiwipom]

hi guys thanks for all the input. what i would really like is the distance that the primary chain is away from the case then i should be able to work on the bit that is not right, it seems to me that the engine sprocket is too close to the case so if anyone could supply centre of chain to back of case measurment i would be gratefull. I am sure that some of the parts must be wrong but they came with the bike so i am not sure which ones, as a matter of interest i have one quite thick gasget for the primary case/crank case (fitted) ,that was in the kit so don`t know about two, can`t see the point of two anyway but if i have to i will make one, thanks guys
Bob

[kiwipom]

hi guys me again, just a couple of pics of the clutch centre with measurments,cheers
Bob

[BSA_54A10]

What an interesting thread is this!  I have been to somewhere quite close to this place myself very recently.  BTW I call the thing that fits on the taper the clutch sleeve and the inner part of the clutch that fits on it I call the clutch centre.
I feel that Brian (reply number 18) has hit the nail on the head with your problem kiwipom.  The photos do suggest that the clutch sleeve is sitting too far out.

BSA used the same tapper on every box ( that had one ) it ever made and these include ones for cars, stationary engines ( reduction & right angle drive boxes), invalid chairs , farm equipment ,,,, the list goes on.
They all look very similar but they differ in the size of the hole.
As it is a tapper, the bigger the hole, the closer it sits to the gear box.
AFAIK there are 4 commonly used on bikes, 2 long ( for big clutches ) & 2 short ( for small clutches ), one with a big hole for tin primaries and one with a slightly smaller hole for alloy primaries. The difference in hole size has the clutch sitting between 1/2" & 1/4" out of alignment.
Oddly enough there only seems to be big & small listed in the parts books but I have a box  of them dating from the early days when I did not know any better and shoved all of the sleeves from all of the clutchs together in an oily box for storeage.
It took weeks to find the correct combination of sleeve & center to replace the single spring clutch for a 6 spring on the M20

[Mosin]

hi guys thanks for all the input. what i would really like is the distance that the primary chain is away from the case then i should be able to work on the bit that is not right, it seems to me that the engine sprocket is too close to the case so if anyone could supply centre of chain to back of case measurment i would be gratefull. I am sure that some of the parts must be wrong but they came with the bike so i am not sure which ones, as a matter of interest i have one quite thick gasget for the primary case/crank case (fitted) ,that was in the kit so don`t know about two, can`t see the point of two anyway but if i have to i will make one, thanks guys
Bob

A lot of my problems stemmed from measuring the distance things were from the Primary Inner case and assuming that this was a fixed point. This can be extremely misleading as it's easy for the case to become slightly twisted one way or the other and creating the optical illusion that other things are either in line or out of alignment. I know it's a hassle, but I would really recommend removing the inner case altogether so it can't act as a confusing distraction. You can then take the time to get everything nicely lined up with all your spacers and shims and what-not in the right places, your sprocket and clutch aligned and your chain running smoothly. Once you are totally happy with it, it's not too difficult job to whip the whole lot off again, replace the case and then put it all back together.

As regards the two gaskets, these sit one either side of a quite thick spacer (I don't have the part number to hand sorry) between the primary inner and the crankcase, and the three together serve an essential job in ensuring the inner case lines up correctly. (A washer or two may be needed at the other end as has already been mentioned just to keep things true). Apart from anything else, without the spacer in place there is the very real danger that the three large bolts at the front end of the primary outer case will reach too far through the crankcase and actually foul the crank itself!

Good Luck!

Simon

[chaterlea25]

HI Bob,
Here are a couple of pics of the location of 3 adaptors on the same BSA shaft
The first one is an original BSA part,
second is one of the "Crap" pattern ones with the scroll going the wrong way
third is a NOS 6 spring adaptor
The total length of the adaptors varies a bit, original 38.75mm, pattern 38mm and the 6 spring 37 mm
they all sit within a reasonably tight tolerance on the shaft as seen in the pics
I know Simon has gone through all this when he rebuilt his bike, his advice and description are good

You definitely need the correct cush drive and sprocket  assembly to sort your problems

Regards
John O R

[kiwipom]

Hi guys, back on the four spring clutch again. Received new bits from S.R.M. which included the new clutch centre, the only difference between the one I had and the new one is that S.R.Ms. has a thrust washer but in any case only moved the clutch 1mm closer to the primary case.  I managed to procure a two lobe Cush drive set up for the engine and as you can see in the pic the Cush sleeve has no built in spacer like the 4 lobe, this is what I wanted so I would just get a spacer made to suit the clutch set up, my measurements tell me that I need a spacer that is 13.7mm wide.
O.k. you will note in my second pic that I have the old original Bsa 6 spring clutch (munted) the S.R.M.centre (middle) and the clutch centre that I am replacing (left) my question  is this which way does the oil scroll have to be? To my way of looking at it the S.R.M. centre will scroll the oil outwards where the other two will scroll the oil towards the clutch, I can`t imagine that the Bsa one was the wrong way around.  I am going to e-mail S.R.M. for their opinion, cheers
Bob