Comet clutch

[Hugo Myatt]

Yes correct.An interesting point here is that in my collection of Burman clutch plates I have a thick plain plate that has the splined section thinner than the plate section to allow the stack to be position slightly nearer to the chain wheel, maybe to stop the top plate coming out. Also the shoulder at the rear of the clutch centre can be too thick and I have had to slim this down in the lathe to make a stack fit. Finally if you buy clutch springs at a show there are at least 2 or 3 different lengths available, if I remember correctly the difference is whether the inserts are cork or Ferodo, I use the longer prewar type and I can now squeeze blood from a stone. .John

I,too, have this extra thick recessed innermost plate. I was told it came from an early AJS 7R which used a Burman gearbox. It is very stiff but because of the recessing it stands no more proud than the standard plate.
Hugo

 

[redbloke1956]

I,too, have this extra thick recessed innermost plate. I was told it came from an early AJS 7R which used a Burman gearbox. It is very stiff but because of the recessing it stands no more proud than the standard plate.
Hugo

Hi Hugo, my Comet, AJS and Matchless all came with the thicker recessed innermost plate, of course I cannot be certain that any are absolutely standard.
Kevin

 

[Hugo Myatt]

Hi Kevin,

That's good to know. I have always thought they were very rare but perhaps they were used much more extensively so they may well be more available second hand.

Hugo

 

[redbloke1956]

Hi Kevin,

That's good to know. I have always thought they were very rare but perhaps they were used much more extensively so they may well be more available second hand.

Hugo

Hi again Hugo, I have just looked through the spares manual for a '56 AJS and it only shows one size steel plain plate (makes no mention of the thicker recessed one?) it also mentions two different clutch centres - a four plate centre for the 350 and a five plate for the 500. The lack of a thick plate could be a mistake in the manual or maybe a modification? Anyone elses guess would be as good as mine.

Regards Kevin

 

[RedRyder]

I like what I read in KTB so I went with one less plate (4), since I was using "modern" ones, and lighter is better, so they say. Besides, with all new plates the 5 would not fit! Result with 4 was clutch slip. So, I went back to 5 and used a couple old and thinner plain steel plates. The stack just did fit and works the charm, no mo' slip!

I've just been reading KTB, looking for pitfalls since I'm building a big-bore Comet: new plates are thicker than old plates, with results noted here, but it suggests that four modern plates work as well as five old ones, particularly if used with the thinnest (0.031") steel plates where possible. The stack height should be made up by steel plates under the pressure plate, taking care that the top one doesn't escape the splines on full lift. The implication is that the first plate into the basket should be a thick steel one. (VOC spares sell them.) I haven't tried this yet, but expect I'll have to when the 572cc Comet makes the jump from "basket of bits" to "motorcycle that may one day run". Lots of potentially useful dope on Burman clutches in KTB, recommended.

 

[timetraveller]

OK chaps, as no one offered to make the pieces needed to fit a needle roller thrust race into the outer plate of the Burman clutch I have had all the parts made and assembled them. I can now start and send them out. I have 3 for Derek Sayer, 2 for Bill Thomas, 1 for Peter Holmes and 2 for Steve Ebbs in the USA. It works out that the price of each assembly is £30. There will be a postage charge of about £5 for the UK, no matter how many you are having and I do not know the charge to the USA yet. Please just let me know that this is acceptable and I will get them into the post.

 

[Gene Nehring]

OK chaps, as no one offered to make the pieces needed to fit a needle roller thrust race into the outer plate of the Burman clutch I have had all the parts made and assembled them. I can now start and send them out. I have 3 for Derek Sayer, 2 for Bill Thomas, 1 for Peter Holmes and 2 for Steve Ebbs in the USA. It works out that the price of each assembly is £30. There will be a postage charge of about £5 for the UK, no matter how many you are having and I do not know the charge to the USA yet. Please just let me know that this is acceptable and I will get them into the post.

You reckon they would work on the Honda conversion?

 

[Hugo Myatt]

I don't think there is sufficient clearance in the Honda clutch to fit it.

 

[oexing]

Some Jap clutches got a mushroom type lifter like some here have fitted a modded engine valve for this purpose to fight wobbly outer plates. Have one or two balls in between clutch push rod sections and this is good enough for the job. No real need for axial bearing, you got other places in the clutch assembly that cause drag for loud first gear shift at standstill. I think of poorly lubed bronce bushes in clutch baskets on gearbox input shaft - not fully designed I´d think.

Vic

 

[timetraveller]

For the benefit of others I replied to Gene pointing out that I do not have access to a Comet at all at the moment so that I cannot be sure what the clearances are. However, the part of the needle roller thrust race assmbly which pushes into the outer plate can be shortened to that no part of it will protrude further than the outside of the plate. Whether that is useful I don't know.