Clutch Stack Revisted

ludwig said:

swooshdave said:

Because not everyone has access to a lathe? Sound incredible but it's actually true..

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Some spend money on tools , others on fake PR parts .
Different priorities , I suppose ? ..

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Yup, one makes the bike look good the other makes it 4 grams lighter. :roll:

Whilst my input to this thread is not about stack height, i did remove a lot of the inner diameter of the steel plates that do nothing when used with the narrow band bronze plates. I plan on drilling the area of the bronze plates inboard of the friction surface i.e. between the bronze and the splines. Got to be some scope for loosing some weight there.

ludwig said:

Pete .v ,
If you ever have the chance , install your complete clutch on a mainshaft , put it in a lathe and spin it to 3000 rpm .
You will likely get an idea of the forces involved .
A standard 850 clutch , with the extra steel plate as often recommended , weights 6 kg .
With a little effort , you can bring that down to 2.5 kg or less .
That makes a huge difference in rotational energy .
All you need is 3 narrow steel an 4 fibre plates , an alloy back plate and a thin alloy pressure plate .
It will all fit in a 30 mm wide basket .
Instead of adding weight to get to the correct stack height , why not removing it ?

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To be honest, I wasn't' sure if your were serious or not so my response earlier was a bit facetious. I'm sorry.

Anyhow, the RGM hubs are soooo light in comparison to stock stuff that cutting them down wouldn't offer a significant enough advantage for my trouble. After all, it is still just a street bike. I will however put I on the list of things I can mess with if I become so inclined.
Ludwig, I really appreciate your input and doing stuff like that is certainly in my wheelhouse.

gripper said:

Whilst my input to this thread is not about stack height, i did remove a lot of the inner diameter of the steel plates that do nothing when used with the narrow band bronze plates. I plan on drilling the area of the bronze plates inboard of the friction surface i.e. between the bronze and the splines. Got to be some scope for loosing some weight there.

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It would be a lot faster and save even more weight to switch to the Barnett plates. They are very reasonably priced too.

swooshdave said:

gripper said:

Whilst my input to this thread is not about stack height, i did remove a lot of the inner diameter of the steel plates that do nothing when used with the narrow band bronze plates. I plan on drilling the area of the bronze plates inboard of the friction surface i.e. between the bronze and the splines. Got to be some scope for loosing some weight there.

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It would be a lot faster and save even more weight to switch to the Barnett plates. They are very reasonably priced too.

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I think this is relative to the topic. I also think the Barnett plates are a weight savings reasonably priced, along with wear well and easy to replace. They may or may not be more sensitive to oil but what me worry.

It worked!

I bought the 060746/KIT Commando Drive Plate Assortment "shim kit" from OldBritts. It comes as three shim plates; one 0.060", one 0.070" and one 0.078" thick. OB will take back and refund the plates that you don't need, obviously so long as you don't damage them.

So Dave and I tried all three and decided that the 0.60" shim was the best fit and immediately upon fitting the plates we noticed a huge difference in the clutch pull action. The thicker 0.70" plate was just a little too thick and took the spring too far over center. The .060" seemed to be the best size so fitted the shim at the very back of the clutch basket and reinstalled the clutch.

Attached below are some pics of the process.

Step 1. Shim Kit from OB:


Step 2. Empty clutch basket:


Step 3. 0.060" shim added first to the rear of the clutch basket:


Step 4. Final (lighter) Barnett plates added:


Step 5. Final pressure plate added:


Step 5a: Another pic to try and show that the pressure plate is flush with the outside 'teeth' of the clutch basket:


Step 5b: Another pic to try and show that the pressure plate is pretty flush:


Step 5c: Another pic to try and show that the pressure plate is flush:


Step 6: A pic to try and show the gap between the spring diaphragm plate and the groove for the circlip that holds the diaphragm plate in:


Step 6a: Another pic of the gap between the diaphragm plate and the groove for the circlip:


Step 7: Clutch reassembled and adjusted and immediately noticing the clutch action improvement!


Step 8: Go for a little ride around the neighborhood to test the clutch...

Step 9: ....keep riding for 20-30 miles because you're so happy with the clutch action!!

Step 10: Come home a very happy chappy!


Thanks for all the advice guys!
Cheers
Mike

Fun for the rest of us seeing successful trial error mechanicing. Do Note the foldover tab is too soft alloy not to crush down over time loosing clamp force you just fine tuned so make a decoration of it and get a hardened washer of your own or mimic one off special wide hardened washers both solid or bowed spring themselves.

What is interesting is that I had to remove a plate to fix my bike and Mike had to add one.

I wonder if DogT just tried to swap his OB shims with a plain plate when he should have added one.

For all of you with stiff clutches, it doesn't have to be that way. Two fingers, that's it.

+1
Two fingers is about right if its set correctly.
Cheers,
Thomas
CNN

swooshdave said:

What is interesting is that I had to remove a plate to fix my bike and Mike had to add one.

I wonder if DogT just tried to swap his OB shims with a plain plate when he should have added one.

For all of you with stiff clutches, it doesn't have to be that way. Two fingers, that's it.

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You just might be right about that.

DogT said:

swooshdave said:

What is interesting is that I had to remove a plate to fix my bike and Mike had to add one.

I wonder if DogT just tried to swap his OB shims with a plain plate when he should have added one.

For all of you with stiff clutches, it doesn't have to be that way. Two fingers, that's it.

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You just might be right about that.

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If you have an extra plain plate you should throw it in just to see if it helps. If it gets really light and slips then get the thin plate from OB.

Hi Mike T.
If that red stuff oozing out around the clutch pushrod is gearbox oil then the 'real' slipping clutch test will be when that stuff works its way through the clutch plates. You will know then if you have the best balance of clamping force versus lever force.
Ta.

needing said:

Hi Mike T.
If that red stuff oozing out around the clutch pushrod is gearbox oil then the 'real' slipping clutch test will be when that stuff works its way through the clutch plates. You will know then if you have the best balance of clamping force versus lever force.
Ta.

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Probably grease. Helps to block the gearbox oil.

swooshdave said:

DogT said:

swooshdave said:

What is interesting is that I had to remove a plate to fix my bike and Mike had to add one.

I wonder if DogT just tried to swap his OB shims with a plain plate when he should have added one.

For all of you with stiff clutches, it doesn't have to be that way. Two fingers, that's it.

Click to expand...

You just might be right about that.

Click to expand...

If you have an extra plain plate you should throw it in just to see if it helps. If it gets really light and slips then get the thin plate from OB.

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I remember thinking about that after I'd sent the kit back, but I did buy a Barnet plain plate which is .075 and it makes the clutch slip. So like Deet says maybe I need a thinner friction plate and a thicker plain plate to bring up the stack maybe .030. I really can't complain about my clutch action or pull, but it would be nice if it were a 2 finger like some.

Glad yours worked out for you. Someone has to do it right.

If you cut the push rod to put a bearing shouldn't you heat treat the cut ends?

Very old school clutch rod oil path mods, neck down a rod section near AMC shell wall to allow oil to drip off - or - slice section of rod out and place ball bearing in to also allow oil flow to mostly drip off before weeping into clutch plate and some even put a o-ring neat end of rod. Packing with grease is also common aid - as long as it lasts in slight oil flow that splashes up that far. But on the other hand for those lazy dazy ones not wishing to alter away from stock might try ATF in AMC so don't matter if some gets through plates into primary...

ludwig said:

That clutch rod is a very sloppy fit .
I wonder how long a DD CR seal will last with such a rod wallowing around .
IMO , a better solution is to cut about 3 cm of the rod and add a bearing ball and a precision fit end piece :

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Well in excess of 20,000 miles then you can put a new 10 cent oring. AN dash 010

The ball bearing mod is not nearly as effective IMO...along with over 5000 sold? how bad can it be?

Dyno gave hobot one his 1st clutch seals I fitted to Peel and then stupidly ran living snot out of about 3 AMC's and finished off a triplex chain with obvious clutch wobble, then through a couple belt drive belts and horrendous OVER REV event - Dyno's seal held tight 2000 miles afterwards - so put it on plain Jane Trixie since 2006 with triplex chain and gear lube in AMC, but after suffering through a number more clutch removals [for non drive train issues] its o-ring stil sealing and waiting to go back on later this year. I'd quess one would go through about 5 first gear bushes before Dyno's seal might need another o-ring. Nortoneers are so nic picky for such a sloppy contraction.

Shouldn't the push rod be stationary and have no load when the clutch is engaged?

If I had a lathe I'd cut a spiral groove in the pushrod so that when it was spinning it would draw the oil back to the gearbox. :mrgreen:

Added bonus of being lighter than ludwig's solution. :lol:

swooshdave said:

Shouldn't the push rod be stationary and have no load when the clutch is engaged?

If I had a lathe I'd cut a spiral groove in the pushrod so that when it was spinning it would draw the oil back to the gearbox. :mrgreen:

Added bonus of being lighter than ludwig's solution. :lol:

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"...spinning pushrod..."? relative to what to create a slinger effect?
The endcap with o-ring is simplicity engineering that delivers what is promised.
Oh, and the o-ring is well lubricated by the gearbox oil it retains!
Ta.