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Clutch stack heights

Submitted by bob_southall on Fri, 12/03/2021
Forums
Commando

The forum is full of articles suggesting that the clutch stack height is critical to both slip and lever weight. Articles refer you to the WS manual. However my Mk111 workshop manual does not appear to have this data along with the incorrect data for the friction plate thickness.

Can any please quote the stack height or suggest where the data can be found?

Thanks

 

Submitted by john_holmes on Fri, 12/03/2021

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Base data

http://atlanticgreen.com/clutchpak.htm

I played around by adding extra plates and using thicker pressure plates and then taking for test drives until I got the combination of lightest lever pull and no slipping, just don't ask me what that setup ended up as. 

More info

http://atlanticgreen.com/ndnsclutch.htm

Submitted by katherine_scott on Sat, 13/03/2021

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Hi Bob

I also have a MK111, I started the search for stack height Nirvana  by adding an extra plain steel plate they are roughly 2mm thick. The extra plate made the clutch lighter in operation however the clutched slipped under hard acceleration at 5000 rpm. I then discovered that RGM sell a 3mm thick steel plate, I removed the extra steel plus one 2mm steel and fitted the RGM 3mm plate the clutch operation was lighter with no slip.

Best regards 

Katherine Scott 

Submitted by andrew_mackenzie on Sat, 13/03/2021

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Hi Katherine,

Are you using five standard, scrolled, sintered friction plates?  Also, is your primary drive standard, or are you running it dry with a belt?

Andy

Submitted by david_comeau on Sat, 13/03/2021

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John has sent you to my website which is OK.

Having sold over 1200 MKIII starters I tend to get a lot of MKIII feedback over the last 15 years.

I will however add that I have recently become sensitive to the MKIII, if using fiber clutch plates, slowly contaminating the primary oil and possibly aiding the sprag's clutching action misbehave with eventual failure. I now work  exclusively with the bronze plates to make them function as intended.I will certainly keep an eye on developments as data comes in slowly...

 

 

Submitted by ashley_cutler on Sat, 13/03/2021

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I have substituted a steel plate with a 3mm one and sintered plates. No slip and lighter clutch action. The bike has a large amount of torque from 2500 rpm as well, this was found on the dyno. Happy with my set up. 

Hi Andrew 

I am running the later AN plates.  I really don't think running a MK3 starter drive mechanism dry is a good idea. 

I use the duplex primary supplied by the chain man jason@the-chain-man.co.uk 

Best regards

Katherine 

Submitted by bob_southall on Mon, 15/03/2021

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Thanks for all the advice.

When I bought the bike 9 years ago the clutch was either engaged or free with no in between making it a pig in traffic. I undertook a complete restoration of the whole bike and in the process fitted the old four fibre plate setup. This worked fine but the lever has got heavier and heavier as the plates wore. It has however been lovely and progressive with no slip.

I have it in pieces at the moment and the four fibre plate set up has a stack height 0.5mm less than the sintered plates. I have ordered an RGM 3mm plate and am trying to decide whether to stick with the fibre plates or go back to the sintered.

Has anyone tried adding one fibre plate in place of a sintered unit to aid progression?

Cheers

Bob Southall

 

 

 

 


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