F.1 sport clutch

[fogrider]

My sport has been unused for several years as I got sick of the clutch judder. Richard Negus helped me replace the cush rubbers which made a big difference, but it still juddered an annoying amount when setting off. ( it was a favour so I did'nt like tell him it was'nt the full cure he expected !).
The plates have all been checked over on a surface plate and seem to be true.
A Commando owner recently suggested replacing the bronze plates with fibre ones, need advice on that ! Apparently the bronze ones can be troublesome.
Richard suggested leaving a friction plate out, have'nt tried it , not sure if that would stop judder.
Someone I met at Stafford 2 years ago ( from Andover Norton ) suggested replacing the outer ring and circlip as any distortion on them may cause the diaphragm to run off. Seems feasable.
Just gathering all the ideas and suggestions together before I start dismantling - I don't want it to be in bits a long time and I would like to take it to the Norton Gathering at Pocklington in May.
Any and all ideas welcome !

Regards all, Terry.

[James]

My Classic clutch engages in a very small lever movement . I read all the posts about that and the consensus was the diaphragm type spring and the type of lifting mechanism was to blame . Both cannot be changed without much effort. One person said to change the lift mechanism steel ball with one that is larger. My Commandos are just fine, with that type of spring.

[fogrider]

Thanks James,
Maybe the ball is not running true in the lift pin, worth a look at whilst it's apart. I'm wondering if the fingers of the diaphragm are not equal height so giving a bias to the pressure plate ?
Not familiar with diaphragm clutches, my other bikes are all normal springs.

[fogrider]

Having a look up about diaphragm type clutches, found loads on the Commando with references to diaphragm finger heights. Seem to be needing to be within .010" of each other, THAT will be a vital thing to check.
Not sure who has new parts for our rotary's these days..........

[James]

https://andover-rotary.co.uk/rt/shop-de ... agm-spring

[Anthony Duffield]

Terry,

My experience is solely Commander.

As the clutch lever is released and the clutch plates compress the take up of drive should be smooth, if the clutch plates do not move freely in the sprocket assembly there could be juddering as the plates eventually fully compress, perhaps removing the clutch plates and checking for wear in the clutch assembly would indicate if there was a problem.

It could be the diaphragm that's weak I would not think they are expensive, my advise is not to change everything at once as you will not know what solved the problem

As you have changed the cush rubbers it is unlikely they are the problem, my Commander has cush rubbers in the rear wheel main sprocket is this the same on your bike? if so it could be worth a look.

Tony

[fogrider]

Thanks Tony,
A call to Andover resulted in the purchase of a new diaphragm , spacer and outer clip. Very reasonable price too.
The next day, when looking for the clutch special tools, there was a pile of Commander clutch parts I forgot I had !
Good diaphragm, starter ring, plates, basket etc. Oh well.
The bronze plates are all dead flat but look thin, any idea what the new thickness should be , anyone ?

Shall have a very close look at all the parts and check for clearance/burrs etc as you suggest.

I hope this is the last time the clutch has to come down !

I know you do big mileage on your Commander, out of interest - what oil do you find best in the primary ?, Paul at Andover once told me a M/C specific 10/40, Richard said a plain/cheap 10/30 and others swear by ATF. The mileage you do, I expect you have a proven opinion.

Regards all, Terry.

[Anthony Duffield]

Terry,

I have used ATF for many years, it seems to work ok no problems so far, I do strip the clutch every winter for an inspection though, I have a selection of clutch plates, when I get home from my current trip to the far east I will measure a plain plate for you.

Do you still own a Commander, if not and if you cannot use the parts you found in your F1 I might know someone who would be interested.

Tony

[fogrider]

Thanks Tony,
ATF it will be.
I don't have a Commander, I bought an engine/gearbox around 15 to 20 years ago to build a special but, as usual, too much got in the way. After being unused for years, Richard bought the engine to convert a Classic to water cooled. The gearbox bits were sold to someone he knew short of good bits. The primary stuff was shelved.
I struggle with heavy things now, when my son gets back from a contract in the Persian Gulf in a week or so ( hopefully), he will help get the bike onto the lift bench and the work can be done.
I assume my 'heavy' mechanical bits in the primary will be OK. Once mine are proven, the bits will be available. Have checked them over , the starter gear looks as new, can't fault the clutch basket or the pressure plate either, bronze and plain plates look very useable.
Andover sent me the new bits ASAP, I was impressed, then found I had a good diaphragm and pressure plate anyway !
I blame old age......
You will have first pick when I get to that stage.
Hopefully all done for the Norton do in May at Pocklington.
Fingers crossed.
Regards all, Terry.

[Anthony Duffield]

Thanks Terry, yes first dibs for the bits please, I'm currently in China due home next week then back here again 9th April, pleased the flights are avoiding Iran etc, I hope your son gets home OK.