06-3979 Clutch center wear

I'm working on a 1974 Commando for the original owner. The bike shows 32,000 miles on the speedo. The bike has developed a sticky clutch. I would like to know if the wear on the clutch center could be the problem. Can these be dressed out to some degree with a file? I will be checking primary chain adjustment so that it isn't too tight etc. Everything else looks normal, the clutch sprocket does not wobble, so I think the clutch location circlip is good and the nuts are properly torqued on each end of the main shaft. Thanks for your replies!

Jonez69 said:

I would like to know if the wear on the clutch center could be the problem.

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Yes, it's worn and should be renewed.

Jonez69 said:

Can these be dressed out to some degree with a file?

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It should be the hardened type so it's unlikely anything can be done to improve it with a file so it should be renewed.

Probably needs friction plates as well.

Here is the good Hardened type from cNw.

In the bad old days I would repair these with a file. You need a good file with a safe edge. And good technique.
I would do it cause I had more time than money. Or because I wanted to put it together today, not 2 weeks from today.
I doubt it would make sense for you to do it for customer.
Re: LAB's comment. I am not sure which would be harder, the file or the "hardened" center. I would guess the file.

Stephen Hill said:

Re: LAB's comment. I am not sure which would be harder, the file or the "hardened" center. I would guess the file.

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I'd think it would need a good file as I've tried filing but that does little more than shine the surface and doesn't really cut anything. I suppose if anyone were to work at it for a week with a sharp enough file then it could possibly be improved but if the plates have worn through the hardening then there seems little point to me in trying to repair it.

Thank you all for the help! Next question, can I service this part without removing the clutch sprocket? I have only been in to a Norton primary to this degree one other time (last spring) and cannot remember if the clutch center separates once the fixing nut is removed.

Jonez69 said:

Thank you all for the help! Next question, can I service this part without removing the clutch sprocket? I have only been in to a Norton primary to this degree one other time (last spring) and cannot remember if the clutch center separates once the fixing nut is removed.

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Yes, the center will pull off once the nut is removed.

Edit: Sorry, I completely screwed this up - mis-read the question. The clutch will come off with the nut removed, not just the center. So, the engine sprocket must come off as well.

Jonez69 said:

can I service this part without removing the clutch sprocket?

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You need to remove the engine sprocket and clutch as a complete unit (after the plates have been removed) to gain access to the circlip at the rear that releases the clutch centre from the drum and bearing.

marshg246 said:

Yes, the center will pull off once the nut is removed.

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The bearing inner circlip must be removed from the rear of the assembly so the complete clutch must be removed.

L.A.B. said:

You need to remove the engine sprocket and clutch as a complete unit (after the plates have been removed) to gain access to the circlip at the rear that releases the clutch centre from the drum and bearing.



The bearing inner circlip must be removed from the rear of the assembly so the complete clutch must be removed.

Andover Norton - CLUTCH BEARING INNER CIRCLIP - 06.0753

CLUTCH BEARING INNER CIRCLIP

andover-norton.co.uk

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Correct - sorry, mis-read the question.

L.A.B. said:

I'd think it would need a good file as I've tried filing but that does little more than shine the surface and doesn't really cut anything. I suppose if anyone were to work at it for a week with a sharp enough file then it could possibly be improved but if the plates have worn through the hardening then there seems little point to me in trying to repair it.

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The point I made.

It's a good idea to fit a new mainshaft circlip, either the correct item or some owners prefer to fit a thinned down 06-8072 circlip (2nd link) as it is a little stronger and retorque the nut with Loctite to 40 lbs. ft. not the original 70 lbs. ft. as that can damage the circlip. Some owners prefer not to fit the tab washer. Also according to the parts book the hardened steel 06-3447 washer goes between the tab washer and the nut as I think maybe your picture shows it between the clutch centre and the tab washer.

To follow up on my own thread, I cleaned the plates and cleaned all the gummy build up in the clutch center and sprocket splines. Next I used an oil can to lube the clutch bearing, that and changing gear box oil, cleared up the sticky and jerky feel I found while turning the rear tire and holding on to the clutch center. After adjusting the primary and drive chains, I reassembled the bike and took it for 40 mile test ride. Things improved immensely. When the bike was first brought to me, it would not shift into first cleanly and would creep and die once it was in gear. All those symptoms have disappeared. It took a couple of readjustments to get the clutch action just right. Now it finds neutral easily and is for the most part, normal. My friend does not wish to put more money into his old bike due to his age, which I understand. So for now he can ride and enjoy the fall season. He and I are discussing my purchasing the bike when the season is over. It will need some TLC and $$$ to be a dependable rider though. Original paint and seat with 32,000 miles!
Thank you, everyone for your help!