75 850 ES clutch

click said:

Hi Lads,
Bike in gear, clutch lever pulled in, rear brake on, push down on kickstart, rear wheel moves!!

I assembled the clutch plates in the same order they came out. I'm going to check over all my work again to see if I missed anything.

I might pop up a video of the clutch operating. I'd like you guys to see if the clutch deflection is what you would expect.

No more work tonight. I'll wait till tomorrow.

More anon

Kevin

Click to expand...

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.

swooshdave said:

click said:

Hi Lads,
Bike in gear, clutch lever pulled in, rear brake on, push down on kickstart, rear wheel moves!!

I assembled the clutch plates in the same order they came out. I'm going to check over all my work again to see if I missed anything.

I might pop up a video of the clutch operating. I'd like you guys to see if the clutch deflection is what you would expect.

No more work tonight. I'll wait till tomorrow.

More anon

Kevin

Click to expand...

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.

Click to expand...

Hi,

I might try that tomorrow. As I said I have the rear brake applied while kicking over in gear with the clutch pulled in & the rear wheel still wants to move, I'm amazed the clutch is still 'sticking' under that type of pressure!

Tomorrows another day

Kevin

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

Gearbox in neutral. Clutch out. Kick over. What does rear wheel do? If it moves, how much pressure to prevent it?

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

Click to expand...

Hi,

Interesting! The only other brit bike I've had (and still have) is a Triumph T100. To free up the clutch I would kick it over with the clutch pulled in, sometimes in gear.

What is the difference between having the bike running pistons going up & down etc., in gear, with the clutch pulled in and exactly the same but manually moving the pistons up & down with the kickstart? The obvious answer is lots of vibration

I agree I could be missing something but at the moment I don't know what it is!

I just don't want to button everything down, new gaskets, oil in the primary & then find I have to strip everything again because I missed something.

One thing I have sussed is I have 11 clutch plates (see pic above page 2) The standard amount seems to be 10 for a 75 MK3.

The first plate as per workshop manual is a bronze plate, in my setup it a plain plate then a bronze etc. So the very first plate seems to be the extra one!

I know the stack height is very important in getting a good clutch action, I might try the clutch just with the standard 10 plates & see what happens.

We should call this place "The University of Norton" you sure do get an education :mrgreen:

Some of you have your PHd's, a large amount have their Masters, most have their undergrad degree's & guys like me are still doing their entrance exams to see if we can get in :roll:

Kevin

swooshdave said:

Gearbox in neutral. Clutch out. Kick over. What does rear wheel do? If it moves, how much pressure to prevent it?

Click to expand...

Hi,

Have not tried that yet, it's a but ackward to change gear on the 75 MK3 as the gear lever is in primary chainncase, I would have to button up the primary chaincase just to change gear & then take it off again, am I just being lazy! I could put a vice grips on the end of the gear crossover shaft!!!

I'll do a bit more testing tomorrow, I don't think my neighbours would appreciate a Norton kicking into life at 1AM in the morning :roll:

Kevin

I thought perhaps the tallish RGM sealing/fixing nut was the equivalent of the OEM fixing nut plus the Comeau sealing cap; I guess that's not the case.

By "clutch plates", you dont count the outer, heavily thickened pressure plate as a "clutch plate". Don't tell me your inner backing plate has come adrift from the clutch basket itself? That can't be good!

When you pull the clutch in, the kickstarter should slide through completely freely, except for the force of the return spring and just a bit of clutch restriction; hardly any force at all.

What you found out with the actuator arm is that the large ball in the lifter assembly can get jammed between the actuator arm and the recess in the body, not allowing the arm to set in it's proper place. A right proper jiggle will reset it.

grandpaul said:

I thought perhaps the tallish RGM sealing/fixing nut was the equivalent of the OEM fixing nut plus the Comeau sealing cap; I guess that's not the case.

By "clutch plates", you dont count the outer, heavily thickened pressure plate as a "clutch plate". Don't tell me your inner backing plate has come adrift from the clutch basket itself? That can't be good!

When you pull the clutch in, the kickstarter should slide through completely freely, except for the force of the return spring and just a bit of clutch restriction; hardly any force at all.

What you found out with the actuator arm is that the large ball in the lifter assembly can get jammed between the actuator arm and the recess in the body, not allowing the arm to set in it's proper place. A right proper jiggle will reset it.

Click to expand...

Hi Grandpaul,

I counted the heavily thickened pressure plate in my total of 11. So there should be 9 clutch plates (5 X bronze and 4 X plain)

I have 5 X Bronze & 5 X plain.

The extra plain plate is not the inner backing plate, I can see this, it has some holes in it which I presume are rivets holding it in place? You can see this in a picture on page 2 of the clutch basket.

Thanks for clearing up the clutch thing & kicking it over, I thought I was going mad. The little I know about how engines, clutches & gearboxes work tells me that the clutch should be 'free' when you pull the clutch in while in gear.

Because I have very little history with this bike I'm just feeling my way through the basics.

I'm cream crackered, going to bed soon

Kevin

Very often, people will stuff multiples of varying thickness plates to arrive at an optimum total stack height that results in an easy pull on the clutch lever to disengage; perhaps that's what you've got going on...

grandpaul said:

Very often, people will stuff multiples of varying thickness plates to arrive at an optimum total stack height that results in an easy pull on the clutch lever to disengage; perhaps that's what you've got going on...

Click to expand...

In your experience do you think the extra plate could cause the clutch to drag or just not disengage?

The clutch pull is quite light.

I'll pull all the plates again & inspect them, all I did was pull & clean them.

I'll check for warping & have a closer look at the clutch centre just in case I missed something.

Kevin

Your Commando's clutch certainly seems to have one extra plain plate.

So you could try removing one (the first and last plate you fit is normally a bronze one) and then see what happens, as the drag may disappear, but the clutch could feel heavier?

Also, have you measured the amount of clutch lift?




It should be somewhere around .125".

If it's around that figure, then I'd say the problem was probably with the clutch itself, and if the amount of lift is significantly less than .125" then the problem is more likely to be the lifter mechanism?

The workshop manual recommendation for backing off the adjuster by "one full turn" is often too much. With the cable slack or preferably completely unhooked at its lower end, screw the pushrod adjuster in until all play is removed from the operating lever, then back off the adjuster until slight play can just be felt at the operating lever, and then lock it up and reconnect and adjust the cable.

Yes I agree L.A.B. it may be the ramp is worn out on the clutch release arm, On one of the bikes I have it was worn down quite a bit.

One full turn is about a half turn too much.

Just a wiggle's worth of slack on the cable AFTER setting the adjuster with the cable set loosely on the handlebar.

I'll bet it frees off niceley.

As to the stack height, too many plates (or too tall of a stack) will not let you install the locking circlip for the diaphram spring; too few (or too short of a stack) will give you a REALLY stiff lever pull and/or possibly incomplete disengagement.

I know full well the clutch is a dry clutch, but having stripped it a few times over the past 15 years, it allways seem to be contaninated by oil, not drenched, but evident it is getting in there, ATF is fine but I'm not sure it is any better than other modern oil without friction improvers - ATF deteriorates quite nicely in auto boxes that are worked hard ie 4x4 with little cooling air flow over the oil cooler. Having been using the Commando recently I say it was an improvement - no slip on a cold clutch, and yes it gets abused despite its age - if it was an animal I'd be banned from keeping it. I work on the principle if it breaks I'll fix it.
On clutch operation, I found the Venhill cable a treat - the more expensive featherlight one, makes it a little easier.

Madnorton, Sorry I misread you. You're right about the Venhill cable. One finger!
But I am afraid Mr. Click has some strange issues. I am anxsious to hear from him to see what he has or has not discovered.

L.A.B. said:

Your Commando's clutch certainly seems to have one extra plain plate.

So you could try removing one (the first and last plate you fit is normally a bronze one) and then see what happens, as the drag may disappear, but the clutch could feel heavier?

Also, have you measured the amount of clutch lift?

It should be somewhere around .125".

If it's around that figure, then I'd say the problem was probably with the clutch itself, and if the amount of lift is significantly less than .125" then the problem is more likely to be the lifter mechanism?

The workshop manual recommendation for backing off the adjuster by "one full turn" is often too much. With the cable slack or preferably completely unhooked at its lower end, screw the pushrod adjuster in until all play is removed from the operating lever, then back off the adjuster until slight play can just be felt at the operating lever, and then lock it up and reconnect and adjust the cable.

Click to expand...

Hi L.A.B.,

I'm back to annoy everybody again!!

I've checked the clutch lift & it's 0.157 which I think is very healthy?

I'm just about to start stripping the clutch to check over the plates, ensure they are flat & to check the splines again, I did check them already but I want to have a closer look.

I also got a reply from RGM they want me to send them some measurements, length of clutch rod, distance between clutch shaft end & the start of the seal inside the nut they sent me.

More anon

Kevin

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 Lads,

To sum up.

1. I had a VERY sticky clutch. Bike would stall selecting 1st gear unless you revved her up a bit. It was also impossible to select neutral once the engine was running. Stop the engine no problem selecting neutral.

2. Attempted, unsuccessfully to clean the clutch with spray brake cleaner hoping it would work it's way into the discs (just in case anybody is as lazy as me :roll: )

3. Eventually stripped the primary case off & stripped the clutch. Lots of oil on the plates + I think I could smell gearbox oil on the plates.

4. Cleaned all the plates in petrol & then with brake cleaner (I think I'm adicted to this stuff )

5. Plates seems to be in good condition, splines etc. I also had 5 bronze plates & 5 plain plates (one extra plain plate at the back)

6. Outer clutch basket splines seem in good order as does the centre splines (I need to check these again as I rushed the first inspection)

7. Checked clutch lift and it's 0.157 which seem healthy?

8. Clutch is still sticking like bugger after the clean up & resetting the clutch as per workshop manual

Things I'm going to try:

1. Check plates are flat

2. Closer inspection on centre splines

3. Remove extra plain plate & see if it makes any difference

4. Pray to the God 'Norton' for divine intervention :mrgreen:

Now I'm off to the garage. I'll post updates as I potter along.

Kevin

It's that extra plate in the back that seem questionable. How much play was in the clutch lever on the handlebars? Is the adjuster screw set so it bearly touches the rod? Sorry for all the questions. Just trying to get my head around it.

pvisseriii said:

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

Click to expand...

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.