Just opened up a primary and found a triumph clutch lurking amongst the oil and grime.
Having taken it apart, it has the flange (or whatever you engineers call it) on the clutch centre which effectively stops the first plain clutch plate from ever coming into contact with the chainwheel, and leaving it to “wobble” on the rollers.
If I remember rightly the trick is to turn this off, right?
Do I then start with a plain plate or one with inserts (not sure if the slots in the chainwheel go down far enough for this and it’s not cold and dark in the shed so I’m not going out to check).
Why was this clutch made like this? BSA have inserts in the chainwheel, which seems sensible, and the whole lot locks into a unit when the clutch is driving whereas the Triumph seems to rely on the rigidity of that first plain plate sitting on the flange. 
Or have I totally misunderstood what’s going on…wouldn’t be the first time!
email (option): petercomley@web.de
I've not done that mod myself, though I have heard of it...Consequently I'm not familiar with what it's all about...
One thing to check though is that you do have the correct clutch rollers fitted...
Triumph rollers are not .250"x.250" as you would think...The length is actually 244"....Longer (standard 1/4"x1/4") rollers allow everything to rattle about a bit...Ian
got the right rollers, first thing I checked
I bought a complete "Triumph for BSA" clutch kit from Kiddiminster MCs a while back but I can't remember if the centre had the flange or not. And I'm not stripping it out of the B31 to find out!
Ian, I'm about to strip the M21 gearbox for something to do over Xmas. Sad git that I am! I've got the stuff from the technical section and any other tips that have appeared over the past few years but if you have any particular advice..I'm all ears! 
. I'm putting a sealed bearing in to stop it dribbling when on the side stand, at least I hope that the reason it's leaking!
Cheers
Pete
I fitted new Triumph clutches to the B30 and my '51 B33 and I have one for the sprinter and one for the T120R....All have the 'lipped' center...
If the sprocket is rattling around I would imagine you either have wear in the sprocket roller track, rollers, or the back of the clutch center...or a combination of the three...
On the B30 I converted the clutch to a sealed ball bearing and dispensed with the loose rollers...That pretty much eliminated the entire problem though it did involve some machining work...
If you have the previous posts on gearbox rebuilding you must pretty well have it covered...
Go for the thin inner cover gaskets to cut down on shimming...and take a look at my fairly recent post on wear at the sleeve gear end of the mainshaft splines...
Remember with these boxes it's all about setting and shimming them correctly and avoiding 'lost movement'..Either through wear/excessive play in the selector forks, sliding dog grooves, selector fork arm pin tracks and pins or through slack shimming of the shafts, wear on the mainshaft splines etc..
Mail me off forum ref. some further gearbox info...Ian
Thanks Ian.
I'd thought about the possibility of putting a sealed bearing in the clutch (probably read an old post from you) but couldn't see how to fit one into the 1/4 inch space available. Any tips on how to do it? I've got a lathe and a couple of fairly large hammers
cheers
Pete
Hi Pete..The B30 was a different set up due to the shorter mainshaft used in that bikes gearbox...So, in that application I used a modified M20 clutch sleeve, not the triumph clutch adapter you will have fitted...
The first thing you have to do is check the diameter of the splines on the clutch center to determine whether they are a bigger diameter than the roller track...I'll come back to that issue in a minute..
I pressed the hardened ring out of the clutch sprocket and bored the sprocket out to give a lightish press fit on the bearings outer diameter...You need to note before commencing work how far above the rear face of the inside of the clutch sprocket the bearing track edge sits....This will determine how far the bearing protrudes above that back face when fitted...
Using that figure, the thickness of the bearing and the thickness of the rear wall of the sprocket it is then possible to calculate how far the bearing will protrude from the back of the sprocket when fitted...
With that information I then turned up an alloy 'top hat' holder that had an internal diameter that was a press fit on the bearing and a depth that matched the distance the bearing protruded from the sprocket...
The bearing was then pressed into this and then pressed into the back of the sprocket until the 'top hat' rested against the rear face of the sprocket...
I then drilled and tapped through the housing and screwed it to the back of the sprocket with 4 x 5mm screws...
There is sufficient space behind the sprocket for the bearing to protrude without touching the casing...But check this on your own machine...
You might have to modify the sliding plate...
You will also have to have some material ground from the clutch adapter...Firstly the flange diameter behind the bearing track must be reduced to jut below the outside diameter of the inner bearing track...
Then the shoulder must be ground back to allow for the extra width of the bearing protruding from the back of the clutch...This shoulder cannot be completely removed as you must have a 'backstop' for the bearing....
Check that there is sufficient material for this alteration on the adapter shoulder...
Now we come back to the clutch adapter splines...If they are a smaller diameter than the roller track then you will have to press a sleeve over the roller track to bring it up to the inner diameter of the bearing...This sleeve would pass over the splines.
However, when I used the M20 clutch adapter the splines were larger than the roller track...In that case I turned up a ring that was a sliding fit on the track and in the bearing inner and then cut this in half to make a 'collet' of the correct diameter for the bearing...
This I fitted around the roller track and then slid the bearing/sprocket assembly over it...The collet is held in place by the back of the clutch center when fitted...
Get in touch off forum if you decide to do this mod, I'll sort out the bearing number for you....Ian
I agree..In a new clutch movement of the sprocket is minimal...certainly not problematic...
Wear in the other components is the likely cause as noted in a previous post...
The bearing conversion was necessary when I built the WB30 as there were no new clutch sleeves available for that model and even if there had been I didn't want to fit a 6 spring BSA clutch (original fitment for that model)...
I also did the same conversion for the same reasons to a 1940 B29 Silver Sport..
I think the conversion could be carried out to the BSA/Triumph clutch set up...and even to the single spring M20 clutch and it eliminates all the wearing parts that cause the problem...
However, I personally think it's only really worth doing if you can't get new replacement parts...which you can for the Triumph clutch....
It is a lot of work simply as a strategy to avoid buying readily available parts...
Saying that though, sometimes it's enjoyable to try these things just because you can..and you learn a lot as you go..
For example...I never had to tune an engine but I found out a lot about the engines design, its limits and its capabilities by doing it...Ian
Agreed!
Although I do enjoy messing about for the sake of it I will make a note of this info and dig it out again when I hit retirement and have more time. There's a few basket cases in the cellar that may benefit from such attention.
For now I think I'll just bung it all back tgether with the requisite replacement parts and enjoy life.
Many thanks Ian for the information and time taken to impart it. Most interesting.
Cheers
Pete