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Big ray

BSA M20 Clutch Plates.

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Hi Folks, I need a new set of clutch plates for our sons M.20, any ideas where I can obtain same, present ones seriously effected by oil ingress, have had the oil problem solved now. I also believe that you can fit a wet clutch from the B40 into the M20......... any thoughts on that one, maybe you have already done that???

Thanks in anticipation for any help.

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Hi Folks, I need a new set of clutch plates for our sons M.20, any ideas where I can obtain same, present ones seriously effected by oil ingress, have had the oil problem solved now. I also believe that you can fit a wet clutch from the B40 into the M20......... any thoughts on that one, maybe you have already done that???

Thanks in anticipation for any help.

 

Hi Ray,

I have no idea about the B40 clutch fitting, but just wanted to warn you about replacement clutch plates for the WM20. A few years ago, I had to renew all the plates on a customers WM20. The new ones were obviously not original BSA, fitted then, correct number and order and found the clutch would not free. Having by chance the REME Inspection Standards for the bike, the original thickeness of these plates was listed. Measuring them i found they were all thicker than plan size and the accumulation of oversizes amounted to one extra plain plate. A rang the parts supplier who immediately told me there was no problem, then without hesitation said to remove one plate! This was going to be my solution but had not told him that. Do not ask me how I did this as it is too long ago now, but it worked perfectly and I seem to recollect telling another M20 owner and he had done the same.

 

regards, Richard

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Hi Ray,

I have no idea about the B40 clutch fitting, but just wanted to warn you about replacement clutch plates for the WM20. A few years ago, I had to renew all the plates on a customers WM20. The new ones were obviously not original BSA, fitted then, correct number and order and found the clutch would not free. Having by chance the REME Inspection Standards for the bike, the original thickeness of these plates was listed. Measuring them i found they were all thicker than plan size and the accumulation of oversizes amounted to one extra plain plate. A rang the parts supplier who immediately told me there was no problem, then without hesitation said to remove one plate! This was going to be my solution but had not told him that. Do not ask me how I did this as it is too long ago now, but it worked perfectly and I seem to recollect telling another M20 owner and he had done the same.

 

regards, Richard

 

Thank you very much for your quick response, I had heard that there could be a problem with none-genuine plates (Thickness) That seems like the solution to that problem, thank you again for the info.

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Don't know if it's any help but..

...there's a fella name of Adrian Moss from Stroud who builds awesome old British bikes into competition machines and he knows his onions especially with old BSAs...He was a great help to me when I was rebuilding my B44 Scrambler. He may be able to shed light on your idea of retro fitting a B40 clutch??

anyways.....worth a call maybe if only for some further advice???

http://www.rickman-motorcycles.com/about-rickman-motorcycles.php

PS: As you can see.... he also owns the rights these days to the world famous 'Rickman Motorcycles'

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For 20 odd years now I have run my M20 (now 600cc) with one steel and one friction plate removed. It makes for a much lighter clutch and no slip or drag. Ron

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The modern friction plates in many clutches, in some cases as a replacement for cork, are arguably far more hard-wearing and resistant to oil, etc......but the compromise usually is greater thickness...........both the Ariel W/NG and 16H Norton use modern friction plates but both with one less steel and friction than originally specified.......but the end result is a trouble-free, lighter clutch that is almost "fit-and-forget"........

 

These changes may require some time spent playing with push-rod lengths and cable adjustments, etc, but is really is time well spent............

 

I wouldn't dream nowadays of refurbishing old cork clutch plates, which is both time consuming and expensive when modern replicas are available........whilst I'm a firm fan of originality, on occasions practicality overrides authenticity...:-D

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But Steve, I think the M20 clutch plate were always the Ferodo type. With the bowler hat cover to keep the oil out.

 

Ron

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But Steve, I think the M20 clutch plate were always the Ferodo type. With the bowler hat cover to keep the oil out.

 

Ron

 

You are right Ron, all the ones I have worked on are Ferodo type plates.

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