Camel - Draggy Clutch

Camel, Sahara, Kanguro, Coguaro
Butch
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Re: Camel - Draggy Clutch

Post by Butch »

OK. Watched the video (thanks, as always). Liked the look of the tool, which of course I don't have, applied some penetrating fluid and left overnight. This morning I took the biggest and bestest of the flat blades in my impact driver kit and Dremeled the middle out of it. Then applied some heat and then tried again. Tore the nuts. Both studs do move, but only slightly before gripping again.

Which put me at that go/no go point of buttoning it all up again for now or getting destructive.

Picked up the Dremel and cut the flanges off the two spring retaining cups, after which I could strip the clutch OK, albeit with all the bits still tight on two of the studs. Centre nut retaining the inner clutch drum wasn't overly tight so came off OK without the special tool (plain plate with some strip welded to it I guess).

Observations:
The tab washer in there was on its second bend so someone has passed this way before.
And I'd say, done up those nuts way too tight.
Plates are heavily contaminated with oil, which will have been the problem I'd imagine.
Clutch push rod is marked up where it runs through the seal, so I think that must have let go.
I can't see how the two slightly loose studs can be made tight again.
Tangs on the plates and the slots in the clutch drums all look good.

Anyone had any luck boiling oil out of clutch friction plates?
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Re: Camel - Draggy Clutch

Post by EVguru »

The lifter mushroom is often worn. I don't think they're available NOS, so unless its really bad, smooth out any ridges so it moves smoothly.

The oil leak can come from either of the main seals, or the lifter seal, but often is down the centre of the clutch basket sleeve. That's where you need the carefully applied Hylomar.

If you're lucky, you may be able to re-peen the ends of the clutch studs. If that doesn't work, they'll need drilling out and that has to be done with absolute precision. I have a sleeve that goes over the stud and is held in the lathe tailstock chuck, whist I use a twist drill in the headstock assuring perfect alignment.

Buy yourself a big can of brake cleaner. Don't use Petrol, the modern stuff is really toxic and can cause chemical burns.
Paul Compton
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72degrees
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Re: Camel - Draggy Clutch

Post by 72degrees »

Strange that they should over tighten the spring nuts but not tighten the centre nut properly. I've never managed to loosen them without my DIY special tool (old plain plate and a bit of silver steel flat stock screwed and bolted to it - needs a good drill bit!). Then I always use a torque wrench on the centre nut (after checking the end play first). Did the spring nuts that came off show signs of corrosion?

This presumably already has the later type nut with replaceable oil seal, which may be the main culprit, but you will be best replacing the other two seals while you are in there.

Weevee used to weld the loose studs somehow to reclaim centres if I remember correctly. I tried it myself once but it was beyond my limited welding skills and ancient arc welder.

I've also tried reclaiming oily plates by hot ultrasonic cleaning with limited success - then they were well worn anyway. Another plus point for the clutch spring 'assist' washers is that on the 375 (that I've recently robbed them from for the project) the seals could go quite badly to the point that oil was dripping from the little notch at the bottom, but still not slip or drag. Just dismantle, quick wipe down of the plates with clutch/brake cleaner and reassemble with new seals.
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Re: Camel - Draggy Clutch

Post by EVguru »

Broken clutch stud removal; https://youtu.be/jVN1_Iijy-8
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Re: Camel - Draggy Clutch

Post by EVguru »

72degrees wrote:Weevee used to weld the loose studs somehow to reclaim centres if I remember correctly. I tried it myself once but it was beyond my limited welding skills and ancient arc welder.
The centre is chilled cast Iron, or some other quite hard cast ferrous material.

I don't think you can successfully weld the studs to the hub. TIG brazing with Silicon Bronze would probably work.
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72degrees
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Re: Camel - Draggy Clutch

Post by 72degrees »

EVguru wrote:
72degrees wrote:Weevee used to weld the loose studs somehow to reclaim centres if I remember correctly. I tried it myself once but it was beyond my limited welding skills and ancient arc welder.
The centre is chilled cast Iron, or some other quite hard cast ferrous material.

I don't think you can successfully weld the studs to the hub. TIG brazing with Silicon Bronze would probably work.
Well I did say my attempt was unsuccessful! It's a long time since I saw the back of a reclaimed (for just loose not broken studs). It looked as if some kind of welding/brazing had been used then ground back.
Butch
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Re: Camel - Draggy Clutch

Post by Butch »

So I ordered a whole load of stuff from NLM and that turned up on Friday. Amongst that were two new studs, two new (but OE style) slotted nuts and two used cups. Looking at the back of the clutch hub I could see that the two studs with the nuts et al still attached were working loose in the hub. So I centre popped the middle of the back of each stud and then put a large drill in there using the pillar drill to take out just the peening. Then I could fit my slotted tool (the one from the impact driver) into the pillar drill chuck and clamp the clutch drum down on table. Now with plenty of downward pressure applied I could spin them out. Which then released the springs, which were the only bits I still needed. I loctited the new studs in, then peened over the backs and cleaned up with the Dremel. Out of interest I then tried undoing one of the nuts usineg the bench vice. That was unbelievably tight, and no corrosion in there either. Phew.

A question ... NLM seem to think I can change all the oil seals without removing the inner casing. Both the manual and the You Tube clip (thanks) suggest otherwise. Even with the four screws removed the outer clutch drum doesn't seem to want to come off. And the point about Blue Hylomar duly noted. Have I now got to order and wait on a gasket, and decant all my lovely fresh oil out of the sump?
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Re: Camel - Draggy Clutch

Post by EVguru »

It is possible to change the seal with out taking off the side case. Self tapping screws into the seal casing are the usual trick.

Getting the new seal into the right position is the next issue.

The clutch basket has a pair of dowels and the usual way to separate the basket is to knock the dowels back into the primary gear (the hole in the basket is semi-blind). In situ, you'd then have the problem of pulling the dowels back out.

NLM have a basket puller to avoid taking a side casing off and I made one up; https://youtu.be/MbWJp4EiB8s
However, I ended up not needing it as the basket was loose in this case and the whole side had to come off to fix the worn dowel holes.

Going back together, you have the slight worry of the dowels getting pushed in.

Time is money in NLM's workshop, so it's worth them being set up for seal changes without taking off the side case. I prefer to put in a little extra work most of the time and clean up inside whilst I'm at it.

Do be very careful of the oil pump feed seal!
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Butch
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Re: Camel - Draggy Clutch

Post by Butch »

Actually that all went OK. I fashioned a little slide hammer that was just enough to get the clutch basket off from the outside, thus revealing the two seals I was most concerned about. As the video shows, the little seal on the inside of the basket has a nasty step to go over, and I ended up making a tapered nylon bushing to help it over as things went back together. On other notes - I seem to have a half thickness friction plate in my replacement set and which I put in first. I'm putting the original plain plates back in though I have one which is quite dished and so I put in last. That one may be adding to the clutch dragging issue. Not sure if I'll be able to buy one on its own if that becomes necessary to swap out.
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72degrees
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Re: Camel - Draggy Clutch

Post by 72degrees »

The 'dished' plate is the famous conical plate that is intended to be so. Evguru recommends it is put in first (like the half thickness plate which is also 'standard'), not last as the manual states.
Butch
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Re: Camel - Draggy Clutch

Post by Butch »

Hmmm, I've not much truck with dished plain plates. In my experience they dish further under heat and expand the clutch pack, introducing unwanted slack at the lever. I guess they are there to give some 'snap' to the release, but in my opinion they're a solution looking for a problem.

Meanwhile, lying in bed this morning I recollected very clearly having failed to fold up the lock washer before I built up the clutch pack yesterday. Too excited about checking end float I suppose. But in fact, with everything now assembled as it should be it was the work of moments to go back in this evening and remedy it.
Steve Brown
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Re: Camel - Draggy Clutch

Post by Steve Brown »

I think most people would say to use that dished plate. It does sound an odd way of fixing something but I suppose the best way to prove that is to try it with a plain plate fitted instead?
I found it made a nice difference fitting it in the opposite position from the manual advice. It isn't the only known mistake in the book :)
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Re: Camel - Draggy Clutch

Post by EVguru »

The conical plate is there is give more progression and make the clutch less grabby. It was a modification over the earliest clutches which had all plain plates.

The manual isn't wrong on the assembly procedure and it probably wouldn't make any difference to the action of an all new clutch assembly, but having the conical plate as the first steel plate in moves the whole clutch pack, spreading the wear and encouraging the plates to separate.

The assembly procedure was revised in the Cagiva era engine manual.
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Butch
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Re: Camel - Draggy Clutch

Post by Butch »

Not much improvement detected on my run out tonight - still pretty s41te. With little slack in the cable the bite point is quite close to the bars so maybe I need to move the 'fruit bowl' plain plate to the back of the stack. Probably didn't help that the shift action has stiffened up enough that it needs light pedal assist to get it back to the middle after each change.
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Re: Camel - Draggy Clutch

Post by EVguru »

Sounds like you may have slightly warped steel plates.
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