Comet Clutch Centre damaged splines

Vic Youel

Well Known and Active Forum User
Non-VOC Member
Here in the Dolomites my Comet went well up and down the Stelios pass as well as many others. Some 500 to 600 miles in the first three days of the superb "Cols des Alpes" rally organised by Jean Marie duBonneville.

Apart from the main jet working loose and my new cheap (non VOCS) pattern silencer coming adrift..... welded by a local garage, all was going well until the drive disappeared and alarming noises transmission appeared.

Upon dismantling I found a loose clutch with rollers scattered over the chain case. The centre nut and lock washer had come off and the splines on the clutch centre had all but disappeared........terminal!

Any thoughts from the forum on whether this is a common fault and any advice on what I might do better? Meanwhile I have ordered a new PR50-2X from the VÖCS plus locking washer becasue the inner shaft splines look ok.

Thanks in anticipation



Well Known and Active Forum User
VOC Member
Comet clutch woes

Best thing I've done for my Comet clutch was to discard it and fit one of Colin Jenners Honda clutch conversions. Even hauling a sidecar for three years hasn't worried it, and I haven't even looked at it since fitting it.
The original Burman clutch is still hanging around my garage if there are any bits you could use....
I hate to say it, but I did recommend putting three bikes in the van !


Well Known and Active Forum User
VOC Member
Comet clutch

Rapcom has it right, the Honda clutch is a vast improvement, even the gear box feels better.
The only down side with the one I fitted to a 600 Comet is that on first assembly it was very tight on the splines. Yet a few hundred miles later the alloy nut supplied with the kit backed off and the clutch was then slack on the spline. On re-assembly it was tight on the spine again, I can only think that the steel adaptor in the back of the clutch has a poorly cut spline.
Next job will be to make a steel nut and think of some way to lock it in a positive manner. John.

Ian Savage

VOC Vice President
VOC Member
Comet Clutch Centre

Yes it is common, when I ran my Comet hard (as a youth!!) I must have destroyed 3 or 4 centres, I even hand filed slots in the centre and made keys one weekend to keep it going when I couldn’t find a replacement.
The centre failed on Ute Augustine’s Comet at the Italian rally last year and Gordon Hart has just had one fail last week.
The lock washer is not ideal as you can only attach it to the bit that you’re trying to secure, the centre, and using a high grade locktite gives a problem when you need to remove the nut. I made a clutch locking tool from a couple of old plates so I could really torque up the nut on the shaft with locktite.
Ian S

Piston Pete

Well Known and Active Forum User
VOC Member
comet cutch

Hello Vic

I too have had the Comet clutch give up ,as a result of wear on the splines - the centre nut undid itself .....and you can guess the rest . Must be something about Burman clutches and hills -for mine expired on the Wickow Gap ,one of the few "passes" in Ireland (small ,but its the best we can do)-. I posted a thread in Oct /Nov ,and got lots of helpful advice .I fitted a Conways clutch Kit and its been great . I cannot recommend it highly enough !! SInce then I have covered about 3500 miles .:)

Graham Smith

I had trouble with the clutch on my Comet a couple of years ago, and was all but resigned to the fact that I was going to have to order a clutch conversion kit from Conways to improve things.

However, upon speaking to Dick Wheeldon, he assured me that there there was no reason I couldn't get the original Comet clutch working properly, and he came round to help me.

After cleaning everything up and adjusting everything properly, it's been fine ever since. All that's non-standard is the basket that's been reinforced.


Forum User
Non-VOC Member
Like so many I have had problems with the Comet clutch, onetime packing the splines with slivers of cat food tins, to cut down on backlash.-fit them on the over run position.

On my current bike I have fitted a thick, stainless, washer, which is dished, like a Bellville washer. This is fitted concave side to the clutch centre.

To lock the nut I made a special tab, this has a vernier effect. One side gives 5 different positions, turn it over and you have another, different,5 positions. Fit a small spring over the tab to hold it in position.

A problem with any tab washer fitted under the nut is that I found that the washer spread out over time and allowed the nut to loose its grip. With such a short length of thread there is very little extension of the thread under the nut. Compare this with a cylinder head nut where you have a long length of stud to spring and a little loosening of the nut still gives you plenty of grip.

The plate you can see in the photo is to give support to the first plain plate and is fitted from the back of the centre. This works very well.


  • 'A' clutch centre.jpg
    'A' clutch centre.jpg
    86.4 KB · Views: 98

Vic Youel

Well Known and Active Forum User
Non-VOC Member
Comet Clutch and Burman Gearbox

Well I finally fitted my Honda clutch from Conways. The splines took a little fettling to get a fit and initially all was ok although I too do not like the aluminium retaing nut. I also had to remove the gearbox to repair the adjuster bolts and threads. First signs are really good so the old clutch and spares is now on Ebay.

I went on a local run today and suddenly in top gear I got this horrible screaching noise. I glided to a halt with the clutch in. I no longer have a top gear.....but 1st 2nd and 3rd are fine. Clutch has also got really sticky even though I used SAE5 fork oil in the chaincase.

I wonder what is wrong with my loss of top gear? Oh well I must pluck up the enthusiasm to remove the whole primary and gearbox yet again......grrrr....

So I think I will go back and properly road test my twin clutch after further treatment in the Old Windsor clutch clinic for the early part of the week. Good job I have a Triumph and a Matchless to provide reliable motorcycling! Wish I had not said that :confused::confused::confused::confused:



Well Known and Active Forum User
VOC Member
Colin makes the splines a little tight to make up for all the wear everybody has on their shafts , many are worn uneven from running loose clutch's over the years or even worse,if you measure your shaft front to back I bet it is different.
missing top gear and having the oither gears should be nothing to do with the clutch , let us know what you find on the inside
Peter Allen

Vic Youel

Well Known and Active Forum User
Non-VOC Member
Burman Gearbox

I totally agree that the sticking clutch is nothing to do with the gear problem.....was using fork oil SAE5 synthetic by the way and the clutch was full of oil on dismantling the engine and very sticky.

So the jury is out for a while on my clutch saga.:confused:

I will start a new thread on the gear problem.