75 850 ES clutch

L.A.B. · Apr 9, 2010

pvisseriii said:
It's that extra plate in the back that seem questionable.

If the plates are being squeezed together because of the extra plate so that there's no space at all for them to separate then it wouldn't surprise me if that was the cause of the problem?
Measuring the stack height of my own Commando's clutch previously (including pressure plate [Edit] and spring) at .055" below the circlip groove, there wouldn't have been room for it to take an additional standard thickness (.080") plain plate.

pete.v · Apr 9, 2010

L.A.B. said:
) at .055" below the circlip groove, there wouldn't have been room for it to take an additional standard thickness (.080") plain plate.

This is as it should be?

rick in seattle · Apr 9, 2010

Kevin,

During my Mk3 rebuild last year I, like you, reused the existing friction plates, since they appeared to only need cleaning. During the debug phase, I found, like you, that I could not "clear" the clutch prior to starting. That is, with the clutch pulled in, it took several full kicks to release the plates. I found that old plates, in spite of their appearance, were unusable and unreclaimable, and finally, after many cleanings, spent the 60 bucks and installed new friction plates. Problem solved; the clutch clears on the first kick. My only regret was spending as much time as I did trying to reclaim the existing plates. I installed the Dave Comeau rod nut as well. Its been a year now and I never think about the clutch. Do yourself a favor and install new plates.

ATM is a poor choice in the primary of a Mk3. The hydraulic adjusters need an oil with more heft, like 20/50.

rick in seattle · Apr 9, 2010

Make that ATF, not ATM. Must have cash on my mind.

click · Apr 9, 2010

pvisseriii said:
Hey Click, how about a close up of the clutch arm inside the inspection cover. Maybe the lockring is loose.
You sould have 5 bronze, 4 drivers and 1 pressure plate. You may want to mic everything and add it up. If you have a digital vernier measure from the snap ring base to the bottom of the basket and compare the measurements.
It would seem the you got the diaphram on ok. When all are stacked up in the basket, what is the measurement from between the diaphram and the circlip groove. Old Britts shows about .1 of an inch. I would say mine is around .05.

Hi,

Here are some shots of the arm, difficult to get the right angle!

click · Apr 9, 2010

Hi Lads,

I really appreciate all your help & input on this.

I think I have found the cause of the problem, as usual it was my rushing through things as I had it in my head all I needed to do was clean the plates & all would be well.

Just some stats before the pics.

The combined stack height of the 5 bronze & 5 plain plates is 1.043 (without the thicker pressure plate)

Stack height with 5 bronze & 4 plain plates is 0.958 (without the thicker pressure plate)

Here is a pic of all 10 plates (5 bronze & 5 plain in the clutch basket)

OK now the pics, you guys can tell me if the wear on the centre splines is acceptable or not (I think the answer will be not!)

pete.v · Apr 9, 2010

Rick is right about the oil. No ATF for you. I also agree with rick about getting new clutch plates.
That Center looks not so good. Time for a new center and some Barnett plates. Sorry

L.A.B. · Apr 9, 2010

The lifter arm looks OK.

The centre could be worn, but I doubt it is as bad as mine was (see photo, back on page 1) and that didn't cause any drag problems if the engine wasn't running.

But, I do suggest you try it without that extra plain plate?

click · Apr 9, 2010

pvisseriii said:
Rick is right about the oil. No ATF for you. I also agree with rick about getting new clutch plates.
That Center looks bad. Time for a new center and some Barnett plates. Sorry

Hi,

I presume you are refering to the clutch actuating arm & not the splines

If the consensus is to replace the centre clutch part then I will also get new plates.

Kevin

pete.v · Apr 9, 2010

Yes arm looks good. New plain plates won't hurt but the old ones may be usable. Research this for proper thickness for your bike.
I did update the earier post when I saw the new pictures of the hub come through.

click · Apr 9, 2010

L.A.B. said:
The lifter arm looks OK.

The centre could be worn, but I doubt it is as bad as mine was (see photo, back on page 1) and that didn't cause any drag problems if the engine wasn't running.

But, I do suggest that you try it without that extra plain plate?

Hi L.A.B.,

Thats very interesting about your centre splines!

I'm just about to put the clutch back together without the extra plate. I'll post my results in a little bit.

Kevin

L.A.B. · Apr 9, 2010

click said:
The combined stack height of the 5 bronze & 5 plain plates is 1.043 (without the thicker pressure plate)

Stack height with 5 bronze & 4 plain plates is 0.958 (without the thicker pressure plate)

http://www.oldbritts.com/ob_clutch_info.html
"850cc:
Friction plate is: 0.121”
Plain plate is: approximately 0.080"
Pressure plate is: 0.102”
Total clutch plate thicknesses (5 friction, 4 plain and 1 pressure) is: 1.027” "

(original bronze plates seem to be slightly thicker at .125" compared to the latest AN bronze plates.)

click · Apr 9, 2010

chris plant said:
hi click,i could be wrong here,but your way of testing for clutch drag is wrong{clutch pulled in bike in gear kickstart depressed}i think you,ll find that even with no clutch plates fitted,bike in gear depress kickstart and the back wheel will turn,could be wrong its been a while,best way is as swoosh said

Hi Chris,

I might owe you an apology :roll:

I tested the clutch as L.A.B. suggested with the extra plain plate removed but it was still the same.

I then remembered what you had said & removed all the clutch plates & attempted the 'test' I was doing to see if the clutch plates where sticking (bike in gear, clutch pulled in, rear brake applied & kick the bike over) and guess what . . . . exactly the same, rear wheel moves under a lot of pressure from the kickstart!!!

Obviously the gearbox is directly connected through the front sprocket to the rear wheel via the chain when in gear regardless of the clutch.

It's what you where saying above, the test I've been doing is flawed.

The only true test is to put everything back together, start her up & see what happens!

As I said the 'test' I was doing gave the impression the clutch was grabbing but it cannot be the clutch when I've removed it!!

Silly mistake on my behalf.

Is my logic correct? Any comments?

Kevin

L.A.B. · Apr 9, 2010

click said:
Obviously the gearbox is directly connected through the front sprocket to the rear wheel via the chain when in gear regardless of the clutch.

Yes that's right, if it's in gear, and the kickstart is operated, then the rear wheel will turn, regardless of whether the clutch is engaged or not.

swooshdave · Apr 9, 2010

L.A.B. said:
click said:

Obviously the gearbox is directly connected through the front sprocket to the rear wheel via the chain when in gear regardless of the clutch.

It's what you where saying above, the test I've been doing is flawed.

Click to expand...

Yes that's right, if it's in gear, and the kickstart is operated, then the rear wheel will turn, regardless of whether the clutch is engaged or not.

swooshdave said:
There may be some slight drag and that might cause the rear wheel to turn. I'd put it in gear (on the ground) and see if it will roll with the clutch lever in. If so, start and see if you still see the drag. I don't get worked up about a little drag until the bike is warmed up.

As someone said earlier (it may have been me) put it in neutral. Then kick it. (Way back on page 3...)

Hortons Norton · Apr 9, 2010

Never mind I should have read the whole post.

KEV-C · Apr 9, 2010

:wink:

click · Apr 9, 2010

L.A.B. said:
click said:

Obviously the gearbox is directly connected through the front sprocket to the rear wheel via the chain when in gear regardless of the clutch.

It's what you where saying above, the test I've been doing is flawed.

Click to expand...

Yes that's right, if it's in gear, and the kickstart is operated, then the rear wheel will turn, regardless of whether the clutch is engaged or not.

Hi L.A.B. and everybody else!,

OK might have been a bit of mis-communication on my side, the 'test' I've been doing all along is with the bike in gear.

I'll need to button everything up & start the bike or at least put it in gear, pull the clutch in & push the bike.

What I'll also try is put the clutch back on, pull the clutch in with the bike in gear & see if I can turn the rear wheel, this should be a true test to see if the clutch is grabbing.

Kevin

click · Apr 9, 2010

KEV-C said:
:wink:

Yea it's a real Homer Dooh!!!!! moment

For some reason I thought, wrongly, that the 'test' I was doing was actually testing the clutch!! Now you all know why I'm on this forum :mrgreen:

Kevin

L.A.B. · Apr 9, 2010

click said:
I'll need to button everything up & start the bike or at least put it in gear, pull the clutch in & push the bike.

What I'll also try is put the clutch back on, pull the clutch in with the bike in gear & see if I can turn the rear wheel, this should be a true test to see if the clutch is grabbing.

Or, as Grandpaul (I think?) mentioned, with the gearbox in neutral, and the clutch lever pulled in, if you operate the kickstarter, then all you should feel is the return spring tension?

75 850 ES clutch

L.A.B.

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