Correcting for wear in clutch plates

Boxerfan · Feb 22, 2015

In search of the reason for the heavy clutch in my Mk3. I've had the plates out and measured them. It looks like i've lost about 20 thou' off each sintered friction plate, with them measuring around the 0.123" mark. Is it acceptable to put another plain plate in, which handily would take me back to pretty much a new stack thickness? if so, is the convention to put it under the basket end or the main pressure plate at the outboard end of the clutch?

Bits everywhere at the moment, the aim is to change the final drive sprocket & fix the sprag clutch before buttoning it back up.

comnoz · Feb 22, 2015

Boxerfan said:
In search of the reason for the heavy clutch in my Mk3. I've had the plates out and measured them. It looks like i've lost about 20 thou' off each sintered friction plate, with them measuring around the 0.123" mark. Is it acceptable to put another plain plate in, which handily would take me back to pretty much a new stack thickness? if so, is the convention to put it under the basket end or the main pressure plate at the outboard end of the clutch?

Bits everywhere at the moment, the aim is to change the final drive sprocket & fix the sprag clutch before buttoning it back up.

I don't think the bronze plate ever measured much beyond .123.

Set you clutch stack height by observing the installed diaphram spring.
It should be slightly concave when at rest and slightly convex when you pull the clutch lever. Jim

L.A.B. · Feb 22, 2015

Boxerfan said:
It looks like i've lost about 20 thou' off each sintered friction plate, with them measuring around the 0.123" mark.

I make that 2 thou, not 20 (sintered plate thickness, 0.125")

http://atlanticgreen.com/clutchpak.htm
http://atlanticgreen.com/ndnsclutch.htm

Boxerfan · Feb 22, 2015

Hmm, the factory Mk3 workshop manual says 0.148/0.142" is the spec for a new plate. The bike is showing 36000 miles and I have records back to 19000 with no record of new plates being fitted in that time. I'm guessing that they may be the originals?

comnoz · Feb 22, 2015

L.A.B. said:
Boxerfan said:

It looks like i've lost about 20 thou' off each sintered friction plate, with them measuring around the 0.123" mark.

Click to expand...

I make that 2 thou, not 20 (sintered plate thickness, 0.125")

http://atlanticgreen.com/clutchpak.htm
http://atlanticgreen.com/ndnsclutch.htm

I kinda figured that. It would take a lot of engines and trannys to wear .020 off a bronze clutch plate.

L.A.B. · Feb 22, 2015

Boxerfan said:
Hmm, the factory Mk3 workshop manual says 0.148/0.142" is the spec for a new plate.

Unfortunately the information is wrong, as it applies to the earlier 4 fibre clutch plate thickness.

Boxerfan · Feb 22, 2015

Looks like my wear is minimal - my stack is 1.165" against a nominal of 1.175" from Dyno Dave's website. Thanks for the link!

Hobot · Feb 22, 2015

The expensive expert way is have several pressure plates thicknesses or renew whole stack but hillbillies shade tree just stick appropriate plain plate against the back of clutch basket and not tell anyone here.

kerinorton · Feb 22, 2015

one of the problems associated with replacing just one plate is the wear on the splines. A new plate wont be worn, so until its been worn in, it will be taking up all the load?????????

Hobot · Feb 22, 2015

Yeah your probably right and why I stated experts have pressure plates on hand or buy new stack. So far I aint' been able tell it was a bad practice or not nor my ride buddy sharing some my excesses.

Correcting for wear in clutch plates

Boxerfan

comnoz

L.A.B.

Moderator

Boxerfan

comnoz

L.A.B.

Moderator

Boxerfan

Hobot

kerinorton

Hobot

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