Unfortunately the new clutch presents both the problems outlined by Ian in his piece in the technical section.
Firstly the clutch nut wouldn't screw hard up, cured by shimming.
The big problem is the play between the centre & the outer chainwheel. Ian describes the remedy for this . Ian (I hope you're reading this),you describe machining the clutch centre. As I understand it, you mean removing material from the section that also forms the inner bearing race- remove material closest to the splines?

It's best to ensure that we are both using the same terminology and are therefore talking about the same part...

The clutch sleeve is the part that fits first onto the main shaft and on which the clutch rollers run (effectively the inner race...) The clutch sprocket holds the outer race...The clutch centre goes on after the sleeve, rollers and clutch sprocket before the clutch plates are added...

In the back of this part is a recess and the material should be removed from the face of that recess....Ian

email (option): ian@wright52.plus.com

Ian
Thanks for the reply.
All work here has paused as I've been in hospital with pneumonia & sepsis. Not pleasant. When I can understand what's written in front of me once more I'll restart.
Bob

I fitted the new clutch after the machining. On the shakedown ride it seemed to be bedding in nicely. There was a bit of drag which was disappearing. Putting it in gear for the ride home, there was a godawful clang, the bike shot a couple of feet forward & stalled. I could pull the clutch lever in as normal but the clutch didn't work.
Got home, took the cover off the clutch & didn't see anything wrong. The plates seemed to be freeing up. Then it started working, I could start the bike on the stand & put it into gear.
All I can think of is that a couple of the steel plates, a fairly tight fit in the new clutch, jammed somehow & stopped the clutch freeing.
I'll reassemble it with a slight smear of grease on the surfaces that bear on the clutch plates.
Any other ideas?
The basic symptom was that I could pull the handlebar lever in as normal but the clutch didn't work.

Something similar happened to me once! On a ride out I was gradually losing the clutch. In the end I had to park the bike in someone's drive and hitch a lift home and collect the bike in my van. The problem was simply that the center nut (the one the push rod goes through) was undoing itself. Some filing might be required if plates are hanging up in the basket?? Ron

email (option): ronpier@talk21.com

Thanks for the quick reply Ron.
The centre nut was fine, but I've just reassembled the plates & spring & the bloody drag's back. The plates are'nt the originals but are almost new & worked fine in the previous clutch. But there is a bit of wear on the tongues, I'll file them down & see what happens.

Bob I've also seen a slightly bent push rod hanging the clutch up. Ron

email (option): ronpier@talk21.com

I've also had corrosion on a 'straight' push rod that took up the clearance in the main shaft hole, resulting in a tight pushrod. I always oil the rod with some light machine oil when fitting...

Is your clutch operating arm set correctly?..IE. When the clutch lever is pulled in the operating arm is vertical...If the arm is incorrectly set maximum lift is not achieved...

Also, do the plates lift squarely?..If the spring ends are not parallel to each other the clutch won't lift squarely causing incomplete separation of the plates (dragging)...

It's always worth leaving out the last two plates as well...That gives more room in the basket for the plates to separate and won't affect the functionality overall..Ian

email (option): ian@wright52.plus.com

While you're there Ian. What would be a reasonable starting point for how far to screw the springs down on my new Triumph clutch? So far I've got the nuts flush with the tops of the threads.....Very light clutch so far. I only had to cut 3/8" off the end of a new silver steel push rod , I just need to harden and temper it. Ron

email (option): ronpier@talk21.com

I go about an 1/8" beyond the end of the thread as an initial setting....It is often the case the setting will not be identical on each adjuster to achieve even lifting of the plates..Ian

email (option): ian@wright52.plus.com

Got it! Cheers Ian.

Ron

email (option): ronpier@talk21.com

Thanks for the input folks. Another stripdown looms. Thank goodness I've got the spring compressor tool.:face_with_rolling_eyes:

I've improved things a bit but it's a bodge.
There's bad scarring on the contact area of the clutch basket where it contacts the fibre clutch plate. Probable corrosion in storage? I hadn't thought this would be an issue. But perhaps this is causing the drag? I've put 2 fibre plates in before the metal plate to hopefully reduce friction. I think this may have helped.
The basket from the old clutch is in reasonable condition & perhaps I'll try fitting this.

Bob did you try Ian's suggestion of leaving one steel and one fiber plate out of the stack?

I'm currently fitting a Bonny clutch to my special for no other real reason than it's "cush" hub. I've ran this bike for 6000 miles on a standard M20 single spring clutch with two plate removed..... It's far more powerful than an M20.

I also run my WM20 (600cc) with the two plates removed.

I can't really think how the friction plates can hang up? More likely the steels if they are worn or a poor fit?? Ron

email (option): ronpier@talk21.com

Ron
Yes, I tried leaving out the two plates. It made no difference to the drag. I agree that it'd be hard for the plates to hang up but it was all I could think of. In fact I can see them moving when the handlebar lever's pulled in. I'll try the basket from the old clutch tomorrow & see what happens. Other than that I haven't a clue.
Incidentally, my pushrod was way too long to work with the 2 plates removed. Can you remember what length pushrod you use? Mine's about 12 13/16" though the bearing surface would be a bit less because of indentations at each end.

Well I just prepared a new push rod for the Bonny clutch and the old one is still on the bench. It's 12 5/8".

Ron

email (option): ronpier@talk21.com

Thanks Ron.

The standard length for a WDM20 clutch pushrod is 12.740"-12.750", so nominally 12 3/4".

On that basis Ron's 12 5/8" would be about right with two plates removed as the thickness of one fibre plate (.093") and one steel plate (.048") is .141" ..Ian

email (option): ian@wright52.plus.com

Well, I seem to've fixed things simply by fitting the spring from the old clutch. I know springs can be variable. I'd looked at the new spring & as accurately as I could measure it seemed true, not so it seems. But I find it hard to believe the new spring could be so bad as to cause that much drag. Repeating, I could pull the handlebar lever in & the clutch simply didn't work.
I've put all the plates in to fit the pushrod, I'll sort a shorter one & try taking out the 2 plates.