Hi everyone,
This is for those who have been following the progress of my recently purchased WM20...

Well, today was the day I finally got to fiddle with everything clutch related :-)

I initially took the "new" (goodness knows where it was made!) clutch nut (15-4312) to my work where I managed to grind of about 1mm from it's outer edge so that it would fit inside one of the specialist tools I recently got hold of. Next, I had to grind out each of the castleations around the nut, because they were too shallow to fit onto the specialist tool I wanted to use to tighten the dammned thing up with...
Anyway, after about 1/2 an hour of grinding I finally got the bits back home. (progress 1)

Next I bit the bullet, and using another specialist tool, I pulled the clutch shaft (66-3811) out from the main gearbox shaft, making sure not to drop the special little "key" that fits in the groove.

I noticed that the cork seal (66-3813) looked a little tired, and so, I replaced it with the one I had recently purchased :-) (progress 2)

I then placed the clutch chain sprocket/basket (66-3809) on top of a clean tubular bucket thing I had on stand by & carefully arranged all those little annoying roller bearings (26-650) into their place on the sprocket/basket thing & made several attempts to carefully fit the shaft (66-3811) onto the bearings... After some time and many expletives, "CLICK!" Hey presto! (progress 3).

Basket, bearings and shaft were soon assembled in a temporary manner and fitted to the bikes main gearbox shaft again, making sire to line up that little key once more (progress 4)

To cut a long story short, everything was carefully put back together, making sure all seals and gaskets were carefully replaced and things that needed a blob of grease got a blob of grease. The new clutch dome (15-4315) was put in place, along with a new gasket and new screws/washers.
The chaincase was re-fitted along with a new cork seal, new screws & the oil reservoir was topped up again. Footrest replaced & clutch cable replaced and given the correct tension... Everything felt good (progress 5).

I took the bike outside - IT WAS SUNNY!!! (PROGRESS SIX!)

Fuel primed, engine kicked over a couple of times and she burst into life!!! (progress 7)

Took bike for a spin around the block, but the engine cut out going up an incline... This turned out to be a bit of crap in the fuel line I think, for after pushing her home and leaving her standing in the sun for half an hour or so, the fuel problem seemed to have gone away on its own (?) (progress 7a)

Took bike for a bit of a longer spin now, but this time, the clutch started to give signs of being "slack" so I pulled over and gave a bit of adjustment and off we went again, but as we trundled along, the clutch became less and less, until I had to crash through the gearbox to get back home & finally had to stall the bike to stop her! (failure 1) :-(

Looking at the way the bike was, it seemed that the clutch cable had very quickly stretched, but when I dropped the clutch arm that the cable attaches to (65-3160) the steel rod (15-4261(?)) was not protruding out, it seemed to be stuck inside the gearbox?? (failure 2) I wasnt sure what had happened, maybe something was broken? So I took my baby back to the workshop & opened her up.

Inside the clutch dome, the seal was intact, and everything inside was dry & the shaft that runs through to touch the small ball bearing (S9-3) was smooth, undamaged and moving freely, and at the other end, the same ball bearing (S9-3) was also rolling freely... Puzzled now! (failure 3)

I measured the clutch cable which from end to end is 136.3cm and I measured the steel rod (15-4261) and from end to end, it is 32.5cm long

What have I done wrong folks??

Best wishes from a very frustrated Ian

email (option): fozzie001@hotmail.com

Hi Ian...Have you fitted new fibre clutch plates?...This could be relevant as some pattern plates are too thick making the overall plate pile too high...This will effectively 'shorten' the clutch push rod in relation to the rest of the clutch...

Also check the ball is in place in the recess in the back of the clutch operating arm...

Regarding clutch adjustment ignore the cable...

The only function of the cable is to join the handlebar lever to the clutch operating arm on the gearbox...it plays no part in clutch adjustment...

All clutch adjustment is carried out using the adjustment screw in the bottom of the clutch operating arm..There should also be a single ball bearing fitted in the recess in the back of the arm between the screw and the clutch pushrod...

With the clutch cable in place and adjusted to give a little 'free play' pull the handlebar lever in all the way...

The clutch operating arm on the gearbox should now be vertical...If it is not disconnect the cable and slacken off the clutch adj. screw locknut...

If the arm is going past the vertical position screw the adj. screw IN a couple of turns...If the arm is not reaching the vertical position turn the screw OUT a couple of turns..

Next reconnect the cable to the arm, readjusting it to give the correct amount of free play...Now pull in the handlebar lever again and see whether the arm is vertical with the lever pulled fully in...

If it is not, disconnect the cable again and repeat the procedure...

If you run out of adjustment on the cable during this process you need a new cable...

I have written an extensive piece on the clutch that you will find in the 'Technical Section' of the website...Ian

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

Or is it possible that the nut that holds the clutch to the main-shaft has come loose and you are effectively pushing the whole clutch up the main-shaft with the handlebar lever. Ron

email (option): ronpier@talk21.com

I recently failed to correctly harden the ends of the clutch pushrod when working on my bike and it didn’t take very long at all before the one end got worn enough to make the clutch ineffective.

Cheers
Pete

Ian/Ron/et al have give just about all that you could have done wrong.

Only comments really are to mske sure that that with the hand lever released there is play I the clutch operating leaver on the gearbox.
I personnel have never seen a problem with push-rod hardening other than when there is no free play in push-rod/operating lever set-up.

One problem I have had is the hand-lever pivot to cable nipple-groove (don't know what else to call it?) distance ......

Later levers, re-pro levers and particularly 7/8" levers have a significantly smaller distance between pivot and nipple-slot than pre-war levers - reducing the cable travel and causing untold problems with clutch drag - as the plates are not fully separating.

Something to look for @ Auto-jumbles are the earlier levers with a bigger distance

email (option): ginantonik@tiscali.co.uk

It is imperative to note the importance of the fibre plate thickness as being a factor and you should check this if you have fitted new plates...

Original plates are .093" thick (3/32")...Many pattern plates are too thick by a substantial amount...As there are 8 fibre plates in this type of clutch this can result in a considerable increase in the overall height of the clutch plate 'pile'...

Not only does this affect the relative length of the existing clutch pushrod and thus the clutch adjustment, it also reduces the amount of space within the clutch basket for the plates to separate.

This substantially increases the likelihood of clutch drag occurring and is made worse if there is wear in the rollers or on the roller tracks and shoulders of either the clutch sleeve, clutch sprocket or the back of the clutch centre......

One way around this problem (if the parts mentioned above are not too worn)is to remove the last two clutch plates from the pile..One steel plate and one fibre plate...

If fibre plates which are too thick are fitted this will generally restore the clutch pile height to more or less the original dimension and has no measurable effect on the clutches overall performance in M20/21 applications...Ian

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

I agree...That should be checked first...

The other details are all things that need to be considered as well though to ensure the clutch is functional and set up correctly...

If the nut retaining the clutch to the shaft has come loose, put the bike in gear, press down hard on the back brake lever to stop the mainshaft turning and tighten it as hard as you can using a socket and 'T' bar.......Ian

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

And a spot of Loctite won't hurt either. Ron

email (option): ronpier@talk21.com

Hi guys - Blimey, thanks for ALL those great suggestions & ideas :-)

I do recall the centre nut being a bit of a pain to tighten, and I did the best I could with the limited resources at hand, so, that's worth checking as a "quick fix" so to speak.

Sadly, I cannot touch the bike till Saturday now due to having to work a couple of long and taxing shifts :-(

On another forum, my quote at the end of each message I post states "One day I'll get it right!" I think I should apply that to this forum as well ;-)

Once again, thanks EVERYONE for the input and ideas.. I'll let you know how stuipi.... er... I get on ;-)

Best wishes for now
Ian

email (option): fozzie001@hotmail.com

Ian, like many on this forum - we've all been doing this for many years and things seldom go right first time.

Guess that's why we stay in this fascinating hobby - the mental challenge?

As for Clutch-Center nuts - an internal problem, without some positive method of stopping the main-shaft rotating its always tricky.

A particularly crude method, occasionally employed by self - is to lift rear of bike off ground and place the bike in top gear - then poke a lump of wood through the back wheel, resting on the spoke nipples - turn wheel clockwise until said lump of wood is trapped against the s/arm or rear-frame.
This should 'lock' the main-shaft - allowing you to tighten the main-shaft nut up - usually until the wood splinters.
Then spend some time straightening bent spokes (joking - honest)
Job done .......

And worth investing in the correct tab washer (if ones fitted) or as Ron suggest Loctite - preferably BEARING-FIT grade (make sure the bugger doesn't come loose!).
Better still both !

I must admit I am proud of my record of not having bike failures either on the road or racing - I put this down to my consumption of Loctite (other makes are available)

What doesn't break you - makes you stronger .......

email (option): ginantonik@tiscali.co.uk

Nig,
One 45 gallon drum of industrial strength loctite now on order :-)

email (option): fozzie001@hotmail.com

Hee Hee

Dunk the entire bike ?

email (option): ginantonik@tiscali.co.uk

PROGRESS!!!!!

Thanks to you lovely people, I found out what the problem was with the clutch... The centre nut (15-374) was indeed loose - I hadn't tightened it enough :-/ So, I cleaned both threads with some petrol soaked onto a cotton bud or two, liberally applied some "nut lock" and with the aid of my trust impact hammer and a socket, I made SURE the dammned thing wasn't gonna budge again! :-)

Started bike & clutch worked lovely, so set out to put a few miles "locally" on the clock :-)

After a mile or so, my escort bike stopped me to tell me the side stand had fallen and was dragging on the road... my temporary bracket had snapped :-/ so a bootlace later and it was secured... Then a mile or so later he stopped me again to say my number plate had come off!! Screws had obviously vibrated loose, so again, a bit of bootlace & it was secured...

We got fuel from the local garage without problem...

Then disaster struck... The bike started to behave like the ignition was cutting out and power was being lost, till eventually the engine stopped... I got it started again and limped home... I think it's either an ignition fault or fuel starvation from a possibly blocked tap filter... I'll need to wait again till I can get a look at it... Typical that the fuel tank was filled up just before this problem raised it's ugly head :-(

One step forward, two steps back...

Ian

email (option): fozzie001@hotmail.com

Dunk the bike in Loctite - making sure none gets in one of the fuel filters......

Wonder if Loctite would stop flakes of rust falling off inside of tank ?

email (option): ginantonik@tiscali.co.uk

email (option): fozzie001@hotmail.com

Never thought of suggesting that - definite possibility.

All my old timer fuel caps leak like sieves, so its never occurred on any of them!

But I had a H2 which went ~5mph faster when I popped the cap on the IOM !
(36.5miles to the tank full .... yes I had to free wheel to a petrol station in Douglas).

email (option): ginantonik@tiscali.co.uk