NEB wet clutch for P11

mdt-son said:

The surface is hard all right, but the base material still has the modulus of aluminum. The designer of the clutch overcame the problem of dissimilar materials by enlarging the pressure area acting on the aluminum. In their design, only a small fraction of the pressure load acts on the spline ends. Essentially, the small washer is there to ensure the large washer stays flat. It's a bit complicated to explain - load distribution is a product of area and modulus of the backing material.

In your loading scheme, virtually all pretension load and running load will transfer via the nut and small spacer into the splined ends, and there is very little pressure on the hub pushing its splines towards the tapered end of splines, which is the real design intent.
I fear you will see abnormal wear and clutch drum "wobbliness" before long. I guess you will just have to monitor the clutch assembly as miles stack up.

- Knut

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I'm thinking you are wasting your time in the message box and should be writing a dystopian science fiction novel.

On the plus side of this experiment, nothing gets modified to the point that going back to the AMC clutch can't be done easily.

Given how little I actually ride the P11, I doubt I'll have any issues with the NEB clutch other than banging the gears some without any cush rubber in the clutch center hub or my rear wheel hub. Shifting into first from neutral might be a bit crunchy.

By the way, I think the AMC clutch also fastens with the nut pretension load on the shouldered end of the spined shaft. I'll be checking on that soon. If it actually tightened up on the taper spline cut, I would need a clutch puller to get the AMC clutch off. However, the clutch slides on and off after the nut is removed. The main difference is the little spacer is not part of the NEB hub like it is on the AMC clutch. It actually free floats in there. So I suppose it is possible that things could loosen up and trash the alloy splines if not torqued down tight. I'm not going to worry about it.

Schwany said:

I'm thinking you are wasting your time in the message box and should be writing a dystopian science fiction novel.

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Haha! Engineers should always conceive what can go wrong in a particular design. It helps avoid some pitfalls, but not all.


- Knut

Schwany said:

By the way, I think the AMC clutch also fastens with the nut pretension load on the shouldered end of the spined shaft. I'll be checking on that soon. If it actually tightened up on the taper spline cut, I would need a clutch puller to get the AMC clutch off. However, the clutch slides on and off after the nut is removed. The main difference is the little spacer is not part of the NEB hub like it is on the AMC clutch. It actually free floats in there. So I suppose it is possible that things could loosen up and trash the alloy splines if not torqued down tight. I'm not going to worry about it.

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No, it doesn't. See picture in #1:

The spider has provision for using a puller (the theaded boss).

- Knut

mdt-son said:

No, it doesn't. See picture in #1:

Norton AMC gearbox 4th gear bushes

I have read somewhere that the bushes 040062 in the (M4) main gear 040422 can be had in two lengths....and the longer bush are recommended. I want to replace mine. Can anyone help on the part numbers, removal replacement procedures, and any special tools required? I have not disassembled this...

www.accessnorton.com

The spider has provision for using a puller (the theaded boss).

- Knut

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The NEB is fastened up against a shoulder at the front of the splines the same way the AMC is. That picture is deceiving. I'm sitting here looking at the clutch and the mainshaft. The rear of the clutch does not hit the 4th gear sleeve shoulder. If it did it would not function as a clutch. It's close though. It butts up against a step shoulder on the front clutch side of the mainshaft splines. I could circle where it butts up in the picture, but have more important things to do. Basically the AMC clutch is fastened the same way that the NEB will be fastened. No sense for NEB to reinvent the wheel. Not to put too fine a point on it, but if you had both clutches in hand like I do, you'd see how it all works. It's also possible that we are on the same page in different books.

The NEB clutch does not want to slide on the splines like the AMC clutch does. My guess is a machine work error though and not an intentional tight fit. It should slip right over the splines. I have to find what is hanging it up and clean it up with a file. I don't want to beat it into place, because I'd never get it off.

A clutch puller is not necessary for the AMC clutch on my P11 even though the hub center is threaded.

I wondered about that. Mine is the same way, I have to tap it on with a hammer and then very carefully pry it off to remove it. Perhaps it was a slip fit before the hard anodizing?

Junglebiker said:

I wondered about that. Mine is the same way, I have to tap it on with a hammer and then very carefully pry it off to remove it. Perhaps it was a slip fit before the hard anodizing?

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I thought similar about the anodizing, but don't know enough about anodizing (without using google) to have a clue how much difference it could make to the dimensions. Anodizing is a pain to remove that much I know. Currently I'm trying to get the NEB clutch on and off by hand without a hammer with the inner case removed.

This is the kind of stuff that always bugs me about so called performance upgrade parts. They often require too much fiddly hack work to make fit. I don't have a machine shop at my disposal, so everything I do is hack work.

What were you carefully prying the clutch off with?

Pry bars, but I would apply a little pressure, rotate 100 some degrees, apply a little pressure, rotate, apply, rotate, apply, etc. Took forever.

I ended up making a simple puller (not pictured) for the NEB clutch so I could install and remove the clutch repeatedly when test fitting for the right size shim to prevent the back of the clutch hub from hitting the 4th gear bush sleeve, or whatever that sleeve is. When torqued down to no more than 35 ft lbs without a shim the hub hit the sleeve locking up the clutch and making it direct drive and nonfunctional. It won't be nonfunctional when I get done. The shim does not go behind the hub. It is actually inside the spline ID of the hub and butts up against the spacers in front of the hub. The puller uses the three threaded bolt holes on the front of the hub. It's a piece of 5/16th aluminum with three holes in it, some spacers, and three long M5 bolts that screw into the hub and pull the clutch forward enough to take off by hand. I could make a sophisticated one that bolts up to the hub and uses a larger center bolt arrangement to push against the end of the mainshaft, but what I did was the quickest to make. It also causes the least harm to the mainshaft. That's my theory anyway.





The tight fit on the splines I was whining about earlier is not a machining error. The clutch goes on smoothly with a nut and wrench. The tight fit should prevent the alloy clutch hub splines from getting beaten up by the steel mainshaft or wobbling once torqued down. To get the clutch on the mainshaft during the test fit process, I pushed the clutch on by hand until there was enough thread showing inside the hub to start a spare shouldered alternator rotor nut on top of a big washer. Once the clutch was up far enough on the mainshaft I could use the standard clutch nut against the NEB spacer stack on top of the hub.

This NEB clutch as delivered would not work on my P11 if torqued to 50 ft lbs, which I consider about right for an alloy final drive component with a nut the size used for the clutch. It can be installed and work with less torque on the nut and feel tight and secure, but I'd rather be sure. I'll be using a star washer similar to what is used on the rotor and not the big OEM lock washer. Not enough thread showing for the big lock washer.

Today I'll find out if the primary chain run aligns with the clutch and engine sprockets. If not, I may not be using this NEB clutch. I've been messing around with it too long already, and the wear life of an alloy sprocket is short enough, but if the chain run is not aligned it will be really short lived. The old AMC clutch works without all the drama.

I'll remember your puller solution. If I had known that I was going to be installing/removing it so many times, I would have gone ahead and made something better than what I had. But each time I installed it I thought, "There! That's sorted." Only to realise a little while later, "oh. That needs to come off again." This has been how I have been learning about Nortons! Endless repetition.

I was about to give up on this NEB clutch install, when I said to myself F... it, I'll make a 5/16th thick shim and stuff it in there to see how it goes. Reason for going big is I could not get the primary chain on the clutch chain gear because the NEB clutch chain gear is not a 1/4" offset gear like the AMC clutch. It is completely flat. There was not enough clearance between the gear and the inner primary to get a chain on. I needed another 1/8". I don't know how Junglebiker got so lucky, but this clutch was not even close to working on my P11 as delivered. I have the chain gear in the same alignment location now as the AMC clutch, so in theory it should line up with the engine sprocket.

Negatives are the NEB clutch is out there on the mainshaft splines further than it should be. Fortunately, it weighs less than the AMC clutch. I may be able to get away with it. If not, it will be a nasty destructive lock up when it breaks the mainshaft. Remains to be seen. I also have to use a thinner nut. Current plan is to cut my spare rotor nut shoulder off and use the remaining nut. Bigger nut, but a thinner nut. Also it is very likely that oil in the primary will splash up and out of the hole in the inner primary for the mainshaft. It does anyway, but it now has a full 1/4 inch of open space between it and the back of the clutch chain gear. On the plus side the hub bearing will get plenty of oil on it.

I do have reservations about continuing with this clutch, but as they say no risk no reward. I've come this far, I might as well try it. Yippee

That's the spirit! Never say die!

Clutch installed with a cut off rotor nut and thinner outer washer instead of the bolt on spacer, and the clutch pushrod condom. Scary for an engineer, but me not so much. It all fits behind the outer primary.

Buttoned up waiting for the gasket sealer to cure. Should be able to ride it tomorrow and get a feel for what it is like without a cush in the rear hub.



My thoughts alone based on owning this bike for a long time is the clutch pull on the 6 spring NEB clutch once adjusted is no stiffer than the AMC clutch with 3 Barnett springs in it. That said, I do not need a 2 finger pull clutch to be happy riding a motorcycle. I'm not that evolved.

Took the P11 for a ride with the NEB clutch in the primary. Only 15 miles. I forgot my wallet and phone so had to turn around and take it easy on the way back home. What a maroon

Clutch worked great. No crunch at all into 1st and the rest of the shifts were as good as they were with the AMC clutch.

I have no idea if the lighter weight did anything for making power quicker. The bike felt smoother running, but I corrected a timing issue and went back to the stock gearing in the primary and gearbox to rear hub. Less weight has to be easier on the motor and gearbox. The stock gearing keeps the motor in a meatier part of the JS2SS cam profile on the street. Really a nice short ride other than the 95 degree weather when at longer stop lights in a black leather jacket.

One nice feature of this NEB clutch so far is it frees up very easily when stone cold after sitting for a few days. A new AMC clutch would probably be similar, but mine was old and sometimes took a couple of kick through strokes to free up.

Went for a slightly longer ride and goosed it a couple of times in second gear. Didn't snap off the mainshaft or come loose, so all good to date. I don't use a tach, so have no idea how many RPMs I hit, but it was just enough to get the JS2 cam to start to wake up. Maybe 4300 RPM

Forgot to mention if I take my time shifting and don't try to rush the shifts like it's got to be a quick shift, the shifts are smooth like a normal clutch. If I rush the shift at higher RPM I can feel the gears shift on my shifting foot and barely hear the gears coming together. No big Harley crunch, but not as smooth and stealthy as the slower toe shift.

When the motor came into the cam so to speak it did accelerate like it was spinning a little easier with the lighter clutch. Still no 3rd gear power wheelies though. No before the NEB clutch and after the NEB clutch dyno runs, so as usual whatever I say is all motorcyclist on a bar stool BS for the most part.

Buzz kill

NEB clutch farted out at around 270 miles. It didn't want to consistently disengage the gearbox from the engine, and the clutch stopped freeing up entirely. The engine started stalling sitting still in first with the lever to the bar, and shifting in general was not good which to me is typical with symptoms caused by excessive glue like drag. Not a clutch cable adjustment issue, not a gearbox issue, not gear lube leaking into the primary past the clutch rod. The simple stuff has all been checked.

Not exactly sure what went south, but it may have had something to do with how the frictions responded to ATF and didn't want to let go of the steels, or the hub bearing doesn't get enough lubrication and eventually gets hot and starts to drag. Anyway, whatever the case, it is a bit of a disappointment on my P11 because the NEB clutch weighs half what the AMC clutch weighs, and while it was working it was really good. Although it was noisier than the AMC clutch all the time. The AMC clutch only rattles a little when the lever is pulled and the steels start talking.

The NEB never really fit in my primary correctly to be honest. The chain was not aligned that well even after making a .270" shim to get it about as close as I could without putting the clutch too far out on the mainshaft to have threads to attach the clutch, and the chain scraped the primary inner cover a little toward the rear behind the clutch gear. If the shim was machined with better tolerances than a hacksaw and file can produce , the chain may not have scraped the inner primary. The clutch basket did not run exactly true. Had a miniscule wobble caused by the shim not being perfect. I don't think that contributed to the drag factor. It did make the clutch a little noisier though with the chain tapping on the inner primary.

I put the old AMC clutch back in where it goes. The engine and clutch gears align, and the chain is not scraping anywhere. The clutch also disengages the gearbox from the engine like it should. All good

Thanks for saving me a ton of frustration. Plus, no belt conversion or NEB clutch means money I can spend elsewhere on the bike.

Schwany said:

Buzz kill

NEB clutch farted out at around 270 miles.

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Long thread and lots of thought has gone into this attempt of a conversion. Athough I was sceptical at the outset, I am really sorry to hear of your mishap.
It would be interesting to research the cause of why the clutch failed, and how worn the parts are now. Maybe a winter project?

- Knut

Longtimegone said:

Thanks for saving me a ton of frustration. Plus, no belt conversion or NEB clutch means money I can spend elsewhere on the bike.

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My results may not be typical. It'll be interesting to see how Junglebiker's NEB clutch works out when he gets back to his P11 project. His apparently lined up and does not scrape on the inner primary without modification.

mdt-son said:

Long thread and lots of thought has gone into this attempt of a conversion. Athough I was sceptical at the outset, I am really sorry to hear of your mishap.
It would be interesting to research the cause of why the clutch failed, and how worn the parts are now. Maybe a winter project?

- Knut

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You skeptical, no way.

It was an interesting experiment.

Cleaned up plates and a new hub bearing, and the NEB clutch would be better than it was new.

Truth: The bearing was notchy when new right out of the box. It spun slightly better when lubed. Because it is a pressed in bearing and not that much fun to replace, I was hoping for divine intervention taking over and fixing it after installing and put into service. Unfortunately, I should have replaced the bearing before installing it. The bearing did not fail completely. The notchy feeling was gone, but it did not spin that smoothly on examination after removing the clutch. The gear misalignment did contribute to excessive alloy wearing off the back side surface of the clutch gear. That ground off alloy was everywhere in the primary oil and on the bearing and turned into a fine sticky paste in the ATF on several of the plates.

I never should have run the clutch once I discovered I could not get it aligned close enough. It was nearly 1/8" out of alignment over that short distance between the engine sprocket and clutch sprocket after making the shim. Had to try it anyway, as dumb an idea as it was.

For a better fit my engine and gearbox would need to be aligned in the cradles specifically for the NEB clutch. Laying the AMC clutch and NEB clutch on a flat surface gearbox side down, the AMC gear is a full gear width higher off the flat surface. Hard to make that up and not lose too much thread on the mainshaft without changing the engine and gearbox alignment.