What is the 2020 best solution for the parts in a P11 clutch?

Curious as to what parts make up the best wet or dry clutch combination on a P11 today? I've read the older P11 clutch posts. My clutch is wet and mostly Barnett with heavy springs. My motor combo is kind of healthy compared to a stock P11 and the clutch has tough time holding if I turn the wick up too quick. I'm not sure what oil is in the primary case. Probably a combination of everything given how long it's been sitting. I have always had to let the motor idle for about 5 minutes pulling the clutch in occasionally before I can get the clutch to release. I have free play in the cable. I don't mind the cold drag during warm up at all. It's the slipping I can do without. I have a taller gearbox sprocket in it. Haven't counted it. Probably 21T since I was doing some HWY miles and pretending to keep up with 916s in the twisties on the street in the early 1990's.

Something weird happened with the message box interface locking up while I was writing this up and I ended up only being able to post it or delete manually. I posted it

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Yes indeed. something weird happened. My reply is running into your post.
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AFIK, Barnett plates have the best coef. of friction with oil. Type F ATF is said to provide 35% more coef of friction than motor oil, so I would recommend you run Type F ATF.

I have Barnett plates in my Atlas, and with ATF I am able to back off the springs 1 1/2 turns from flush with studs, and no problem with slipping.

I have found it necessary, with Barnett plates, to free up the clutch before cranking up.

Slick

Mine was in standard tune, though I did have the head cleaned up by the cylinder head shop in Wimbledon UK (still in business 30+ years on)
I had lighter springs custom made as I reckoned the standard atlas clutch could cope with a heavier frame, pillion passenger AND drag a sidecar around if need be, so my skinny ass was well within it's capabilities.
Even accelerating hard up the local 1 in 7 incline didn't promote slip at all...
Rest was stock.

texasSlick said:

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Yes indeed. something weird happened. My reply is running into your post.
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AFIK, Barnett plates have the best coef. of friction with oil. Type F ATF is said to provide 35% more coef of friction than motor oil, so I would recommend you run Type F ATF.

I have Barnett plates in my Atlas, and with ATF I am able to back off the springs 1 1/2 turns from flush with studs, and no problem with slipping.

I have found it necessary, with Barnett plates, to free up the clutch before cranking up.

Slick

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I use to free up the clutch with the kick starter holding the front brake, but since I have to warm up my motor anyway before the idle stays steady, I let the motor do the work.

In my case backing off the springs might not get me out of my uphill driveway. he he
It works fine as long as I ride like an old man. It shifts really nice as well.

It had ATF in it when I put it away, but like an absent minded dope I forgot to drain the oil out of it, and a lot of it ended up in the primary case. I think it was about half full when I fired it up after it sat for I guess 27 years. I thought it was 30 years, but found a receipt for some parts from 1993. I have two 8 foot long oil stain stripes on my driveway (one going out and one coming back) from what came out of the back of the primary. What a mess. I'm lucky I made it to the end of the street and back. Fortunately all my turns were left handers. If they had been right handers, the ass end might have stepped out a little. I sorted that all out and actually put 5 miles on it since. And I did drain the sump and put oil in the tank before starting it after sitting for years. What I didn't do, was drain the primary, since I thought I had drained the oil out of the oil tank. Surprise

Anyway, probably going to get in there and check it all out. I need to replace my old hand cut primary gasket and reinstall those darn countersunk screws holding the inner case on, but this time use better sealant. They definitely weep. I thought I'd see what people were using for clutches and install something better while I have it apart. I probably have what I need and just need to clean it up.

The fun really never ends with the Unapproachable Norton. I'm not complaining. It keeps my mind occupied.

Thanks

Schwany said:

Anyway, probably going to get in there and check it all out. I need to replace my old hand cut primary gasket and reinstall those darn countersunk screws holding the inner case on, but this time use better sealant. They definitely weep. I thought I'd see what people were using for clutches and install something better while I have it apart. I probably have what I need and just need to clean it up.

The fun really never ends with the Unapproachable Norton. I'm not complaining. It keeps my mind occupied.

Thanks

Click to expand...

I found that ATF is tough on sealants. My primary case was oil tight for 2 years, then failed catastrophically overnight. Found half my primary ATF on the floor. After some research, I found Permatex #81180 is specifically recommended for auto transmissions. That is what I used to seal my primary now, but it has been only a matter of weeks, so I cannot attest to how well it will hold up.

Slick

Mind you, when I put the clutch together I ported and polished everything, making sure there were no burrs, bumps or notches to hold things up, even polished the spring cups and posts for free movement. And always set the springs by tying the lever to the handlebar and going round the pressure plate with a feeler gauge, size of the gap wasn't as important as making sure it was constant all round for a clean, square lift..

FWIW on another forum, somebody had experienced problem with clutch drag using ATF oil.
I,m at present trying with a modern synthetic motorcycle oil, JASO MA2, in a couple of primaries. So far seems to work ok.
Reason is that those oils are designed for wet clutches.

Thanks for the additional input gents. Much appreciated.

Any belt driven dry clutch P11 bikes out there? My P11 is not a restoration, so I'd be open to going that route.

I know it's been done on other Atlas 750 featherbed or custom frame race configurations, but I'd like to keep the stator where it is. Of the Atlas 750 configurations I've seen, I don't think any are using the stator because of the offset caused by the belt drive and inability to use the outer primary case. Been wrong many times before though, so could be wrong about that.

Isn't a chain case spacer needed? Any belt is going to be wider than the OE primary chain, so footrests may need moving too, perhaps?
I'd have filed under: 'Too much effing about!!'
But that was then, maybe the stuff's out there now for those who want it..

Schwany said:

Thanks for the additional input gents. Much appreciated.

Any belt driven dry clutch P11 bikes out there? My P11 is not a restoration, so I'd be open to going that route.

I know it's been done on other Atlas 750 featherbed or custom frame race configurations, but I'd like to keep the stator where it is. Of the Atlas 750 configurations I've seen, I don't think any are using the stator because of the offset caused by the belt drive and inability to use the outer primary case. Been wrong many times before though, so could be wrong about that.

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AFAIK, belt drives have been added to Atlas primary cases. The stator is handled by using a Commando stator mount, and a Commando rotor nut. The outer case can handle the wider belt .... I once had a Commando triplex chain and Cdo clutch in my Atlas with no interference problem.

Slick

Schwany,

Try searching for postings by user 'AgentX'. who fitted a belt drive to his Norton N15. The thread is approx. 6 months old (look in the folder "Other Nortons"). Primary drives of N15/G15 and P11 are virtually identical.

Personally I would stick to chain and the standard clutch. They can be made to work if the correct parts and assembly procedure is employed.

-Knut

RGM are now offering belt drive components with a 20mm belt, but again there might be issues with the matchless alloy chain case......

Knut,

Thanks, I'll look for that info.

I'm starting to think along similar lines about sticking with the standard clutch and keeping things simple, but I haven't got the whole shebang out yet to see what the overall condition is. Stalled at the darn tighter than heck stator wire going through the now hard as a rock rubber grommet in the center of the inner case. Need to get some heat on it tomorrow and pull it free. Then see what's going on.

The primary chain has been grinding the heads of the 3 little countersunk bolts fastening the inner case to the crank case. Gonna be fun getting those out of there. My primary chain has a half link in it, which I don't remember putting in there at all. Probably what
has been chewing on the little bolt heads. It's also kind of sloppy, but looks great.

Time to consult my blended liquid oracle.

Read AgentX's Bob Newby belt the clutch report. Not going to make a spacer, so that probably won't happen. Norvil claims their belt drive kit works on the N15CS. I'm waiting for confirmation on whether or not that is with a spacer.

Anyone try an NEB wet clutch in a P11 G15, N15... etc? Certainly looks like it was designed after WWI unlike the P11 clutch. he he

Speculation
I think part of the minor issues I'm having with my clutch are due to the spring cups having some healthy ridges dug into them. The friction plate media is getting pretty slick as well.

Anyone ever radius the top edge of shock absorber cover? Seems like that might help a little with reducing the ridges being cut into the spring cups That and new shock absorber rubbers. I tried a search and got nothing related to putting a radius on the cover.

I won't be rebuilding the stock clutch with all new parts. A new modern design clutch is cheaper. I will put a radius on the shock absorber cover, get new spring cups, and put it all back together, while I continue researching clutch options.

My engine sprocket is acting like it is welded onto the crank. My cheap two jaw puller is about to snap. It's hammer tapping time.

Get a blow torch on it....

I've had heat on it. The puller is junk. Also tried a junk 3 jaw puller. Both are apparently too weak. I bent the bolt on both of them using a 32-inch breaker bar. If my pitman arm puller was wider, I'd be done. Got another puller coming.

Neighbor came by and said hook the positive and negative from a stick welder onto the sprocket. It'll get hot. I don't think I'll do that. I probably over torqued it and didn't put enough lube on it when I put it on. I've had it off before, so it's a little puzzling. Maybe the P11 is trying to tell me to leave it alone and just ride it.

There's heat and there's heat and you have to be brutal... When I asked a well known dealer here: 'How hot?' his reply was: 'Smoking!' And yes, cheap pullers aren't worth a light. I roasted mine with the puller as tight as and then a smart clout and off it shot... But let it cool before you pick it up or you'll be cancelling your violin lessons

Schwany said:

I've had heat on it. The puller is junk. Also tried a junk 3 jaw puller. Both are apparently too weak. I bent the bolt on both of them using a 32-inch breaker bar. If my pitman arm puller was wider, I'd be done. Got another puller coming.

Neighbor came by and said hook the positive and negative from a stick welder onto the sprocket. It'll get hot. I don't think I'll do that. I probably over torqued it and didn't put enough lube on it when I put it on. I've had it off before, so it's a little puzzling. Maybe the P11 is trying to tell me to leave it alone and just ride it.

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You need the orginal Norton sprocket puller from RGM at £22.

Re clutch slip; did you ajust the centre push rod ajuster when you installed those Barnett clutch plates? ( Read leaving pushrod slighty loose)Also oil level plug maybe to high, you only need to lube the bottom half of the primary chain.