Friction plate ID please

tomspro · Nov 3, 2014

Opened my primary case for the first time since I bought this Combat 10 months ago.
I am looking to seal some persistent oil leaks [yea- i know... good luck with that!]
Just removed clutch to clean and inspect and found these.
def not Barnett. replace? (clutch was working ok.)

comnoz · Nov 3, 2014

Here is two Barnett plates- the left was purchased about 5 years ago and the right was around 10 years ago. They look pretty similar to me. Jim

Hobot · Nov 3, 2014

Look like my Al plate standard issue Barnetts. BTW did we ever determine what accelerates their teeth becoming pointy.

comnoz · Nov 3, 2014

hobot said:
Look like my Al plate standard issue Barnetts. BTW did we ever determine what accelerates their teeth becoming pointy.

The plate on the right has 35,000 or so on it. Notice the friction material is down to the wear indicators.

The plate on the left was around 20,000 miles.

I used a Norton for a pit bike one time and after idling it around the pits for several days in a row I was rewarded by the loss of all the clutch teeth on a fairly new set of Barnetts. They didn't like rattling around at low speed for sure.

grandpaul · Nov 4, 2014

comnoz said:
Here is two Barnett plates- the left was purchased about 5 years ago and the right was around 10 years ago. They look pretty similar to me. Jim

The difference in those two is that the teeth on the one on the left are in better shape, they have a distinct "\_/" shape with no point. The one on the right has it's teeth worn almost to "V" points.

If you don't slip your clutch a lot, you won't wear out the friction material as fast. aluminum-based plates are lighter, but the teeth wear faster.

tomspro · Nov 4, 2014

comnoz said:
Here is two Barnett plates- the left was purchased about 5 years ago and the right was around 10 years ago. They look pretty similar to me. Jim

Thanks Jim & Paul!
Guess I should have said they are def not the CURRENT Barnett plates.
Was not aware they had wear indicators, and the teeth look pretty good, so I guess I will clean them up and re-install.
tomas

grandpaul · Nov 4, 2014

I don't recall whether the Norton manual has a specified friction plate material thickness, and the wierd thing is the Triumph manual specifies wear should not exceed "X", but doesn't give the original thickness!

As long as you have significant material thickness, and your overall clutch plate stack height is close to the optimal thickness, you should be good to go if the teeth are not excessively worn.

tomspro · Nov 4, 2014

grandpaul said:
I don't recall whether the Norton manual has a specified friction plate material thickness, and the wierd thing is the Triumph manual specifies wear should not exceed "X", but doesn't give the original thickness!

As long as you have significant material thickness, and your overall clutch plate stack height is close to the optimal thickness, you should be good to go if the teeth are not excessively worn.

Paul - as usual, Fred has that covered!
https://www.oldbritts.com/ob_clutch_info.html

comnoz · Nov 4, 2014

Was not aware they had wear indicators, and the teeth look pretty good, so I guess I will clean them up and re-install.
tomas

I don't think the later plates have the wear indicator -or at least I have never seen them on the newer plates. Jim

Rohan · Nov 4, 2014

There is not a rivet buried at the bottom of those 'wear indicator' holes ?

grandpaul · Nov 6, 2014

Rohan said:
There is not a rivet buried at the bottom of those 'wear indicator' holes ?

no.

Brooking 850 · Nov 7, 2014

What about the diaphragm?
My road bike has a 32mm Maney belt drive in it, race bike has a Maney 40mm belt drive with the clutch basket the same depth on both.
The road bike has an extra steel plate in it as the first one loaded, and this leaves just enough room for the pressure plate , diaphragm and circlip. %The diaphragm is just slightly concave at rest.
The race bike has no extra steel plate ( I have tried )and the diaphragm is slightly convex at rest. i did experience some clutch slip in the race bike the last meeting, but by day two it had come right ( I had over greased the sealed bearing in the clutch basket and it spun grease onto the first bronze plate) perhaps different thickness pressure plates.
So what is the ideal state for the diaphragm, slightly convex , concave or dead flat at rest?
Regards Mike

comnoz · Nov 7, 2014

Brooking 850 said:
What about the diaphragm?
My road bike has a 32mm Maney belt drive in it, race bike has a Maney 40mm belt drive with the clutch basket the same depth on both.
The road bike has an extra steel plate in it as the first one loaded, and this leaves just enough room for the pressure plate , diaphragm and circlip. %The diaphragm is just slightly concave at rest.
The race bike has no extra steel plate ( I have tried )and the diaphragm is slightly convex at rest. i did experience some clutch slip in the race bike the last meeting, but by day two had come right ( I had over greased the seled bearing in the clutch basket and it spun grease onto the first bronze plate) perhaps different thickness pressure plates.
So what is the ideal state for the diaphragm, slightly convex , concave or dead flat at rest?
Regards Mike

The diaphragm should be slightly concave at rest. It should go slightly convex when the lever is pulled. Jim

Friction plate ID please

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