P11 basket case

Junglebiker said:

Thanks for the encouragement--I have found so far that Nortons are generally simpler than I was expecting. The cam I am using is a JS0 cam, nothing too exciting; just a little better than stock, and I needed to get a cam that would work with the JSM radiused lifters. I also went with a compression ratio somewhere between 8:1 and 9:1, again, nothing extreme, I'm shooting for mild mannered, but respectable, reliable and smooth if possible.

I read up on your P11 a little while ago--I remember that your crank was set up with a balance factor of 62%, I assume that would have been with stock rods and pistons--with the JSM stuff your new balance factor is probably something over 62%, but obviously you are not suffering horrible vibrations, which is encouraging; the margin of error seems relatively high, unless one is building a serious race bike, which I am not.

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The JS0 cam is probably a good torquey ride. Your motor should last a long time.

The only thing negative about the JS2 cam I put in mine is I have to slip the clutch a little from a dead stop traffic light on the street with my gearing. Especially if I get stuck waiting a long time. I think the motor is getting hot sitting too long at idle during break in though. I should have put the bike in the back of my El Camino and trucked it up to where there are no traffic lights to break it in on the road. Cam break-in was done in my driveway.

I might have said this somewhere in my P11 build post, but not sure. Reason I did nothing about the crank balance in my case is I have always been under the impression that the crank is balanced separately from the parts that are being attached to it. Whatever I stick on the already balanced crank as long as the parts have been balanced; pistons same weight as each other, and rods same weight as each other, the rotating assembly will still be balanced. Balance factor will change with different parts, which I suppose could be problematic. However, it seems to work.

I have no clue what my compression or balance factor actually is. I will not get into Norton heaven due to excessive insincerity.

It works, you are happy with it, win win.

Got the guts of the timing chest in today. Actually need to pull it all apart again tomorrow as there is a shim/washer/bearing that goes behind the idler gear which I did not know about. Ah, the joys of starting with a bare crankcase that I didn't take apart!

Is the idler shaft removable from this side? If so, it'd sure be a lot faster and easier to do things like replace the magneto and cam drive chains. I have a new IWIS chain on the cam, but am running a worn chain on the mag--I have a better one I'll try tomorrow, but eventually I'd like to put another IWIS in there if they are available for the mag drive.

Some noticed that I had a tach drive on the end of my cam--in the above pic you can see I have replaced it with a modified one, but it still interferes with the cover I want to use, so it's been replaced again since this pic was taken.

I was concerned about the magneto--the lack of a woodruff key bothered me at first, but now I realise that it doesn't need one, and in fact having one could actually make things a lot harder. What I eventually did was put the crank at TDC, set the points cam at about where I would want it to be at TDC, (guesswork--I'll adjust it properly later, once I get my cylinders and pistons back from the machine shop), then installed the Auto Advance Unit. Like so many other things that I have been concerned about it was actually easier than I was expecting. Push the AAU mounting bolt all the way into the AAU, thread it on to the mag just a little ways (not tight, you need it to be able to move relative to the mag), adjust the chain tension, tighten the mag mounting nuts, make sure the points are where you want them to be, then tighten the AAU mounting bolt. It was so simple it blew my mind. Like I've said before, I'm used to Japanese bikes, and this is just different. I like it, and I'm excited to be gaining this experience.

So here's the timing cover I want to use--not sure what it was originally fitted to, but I like the simplicity of it and the little brass tag. I got it off of eBay ages ago:

I would leave that idler shaft alone and get that IWIS chain on the magneto while the barrels are out getting bored. It is a more work doing it after the motor is together.

So the older tagged timing cover now fits?

Is that NEB clutch the same height as the P11 AMC clutch?

Only reason I've not bought one is I never could get an answer from sellers of that clutch on whether or not the NEB will fit behind the stock primary cover.

Schwany said:

I would leave that idler shaft alone and get that IWIS chain on the magneto while the barrels are out getting bored. It is a more work doing it after the motor is together.

So the older tagged timing cover now fits?

Is that NEB clutch the same height as the P11 AMC clutch?

Only reason I've not bought one is I never could get an answer from sellers of that clutch on whether or not the NEB will fit behind the stock primary cover.

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Oh, you noticed my NEB, eh? Don't know yet if it will fit, we will find out! It's an Atlas style clutch, not a Commando one, as they are not interchangeable and the difference is more than just the drive chain. It looks to me like it will fit--if I remember, I'll put it side by side with a stock one and take some pics. Well, actually, I don't know for certain that the stock clutch I have access to is a P11 unit, it might be Atlas or ? The whole reason why I bought the NEB was because I was having trouble getting info about the stock P11 clutch. Rather than trying to piece together a lot of 50-60 year old parts that might not match, I decided to just get a whole new one. I was tempted to get a whole new transmission, too, but thankfully I got my madness under control before it was too late.

Older cover doesn't fit yet--it's close, but I still need to modify the nut I have on the camshaft before it will seat all the way down., I think. It does fit over the AAU.

Yes, I noticed the NEB clutch on the shelf. You also mentioned it elsewhere. I've not seen one sitting on its side like that. It looks shorter than I imagined and like it might fit inside the P11 primary.

Andover sells parts for the AMC clutch on the Desert Sleds page. Not cheap to rebuild entirely. The NEB is probably a better clutch. I'm not sure if it would last as long as the old AMC clutch if the gear is alloy, but it sure would be lighter and probably engage well with 5 springs.

Do you have the P11 timing cover? You might want to make sure all the oil passage holes around the pressure relief valve area are the same on the inside of the older cover. I'm not sure all the timing covers are 100% interchangeable without some modification. That is a cool looking timing cover though. Would be great if it all works out.

Andover has a desert sled page now? I don't think they did back when I was looking for a clutch. The clutch basket and sprocket are steel, not alloy, though I imagine the hub is alloy and the pressure plate is obviously billet aluminum.

I do not have a P11 timing cover, which is why I bought the one I have--if I can't make it fit, there is another here that I might be able to use.

Yeah, I've been looking at the oil passages, they look the same as Atlas and Commando covers that I have looked at here, but I will of course investigate more carefully once I have determined that I will actually be able to use it.

Junglebiker said:

Yeah, I've been looking at the oil passages, they look the same as Atlas and Commando covers that I have looked at here, but I will of course investigate more carefully once I have determined that I will actually be able to use it.

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I checked photos of one currently on eBay, and the oil passages appear identical to my P11 cover. There was also a 650 (?) model that had a small version of the P11 tank badge inset into the cover. But like your's, it does not accommodate tach drive. https://www.ebay.com/itm/175270889708?hash=item28cef588ec:g:3hQAAOSwU2JiJ40F

edit: link added

Longtimegone said:

I checked photos of one currently on eBay, and the oil passages appear identical to my P11 cover. There was also a 650 (?) model that had a small version of the P11 tank badge inset into the cover. But like your's, it does not accommodate tach drive. https://www.ebay.com/itm/175270889708?hash=item28cef588ec:g:3hQAAOSwU2JiJ40F

edit: link added

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One of the ones I have access to here is like that one, with the little "N" logo. They are pretty cool, but I really hope I can get this other one to fit.

Junglebiker said:

One of the ones I have access to here is like that one, with the little "N" logo. They are pretty cool, but I really hope I can get this other one to fit.

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You might have to shorten something you probably don't want to shorten to use that cover. When I had the P11 timing cover on my P11 I did not have the tach, but I believe the drive went through the cover. You could probably have one of those nuts you have machined down to 1/4" thickness and it would be enough meat to hold the cam gears on and might fit behind the cover. I'm making all that up because I don't have the parts in front of me to verify anything. Kind of how I roll in general. Fake it till I make it.

Just for those who are interested in the differences between a NEB clutch and what I guess is a stock Atlas or P11 clutch? I'm not savvy enough to know what the older one came off of. I said above that the clutch basket/sprocket on the NEB is steel, but I was wrong, it apparently IS aluminum. That is to say, a magnet will stick to it, but only weakly, and I think it was actually attracted to a steel drive plate on the other side. A magnet will NOT stick to the sprocket teeth.

There is a big difference in weight between the two--the OEM type is much heavier.

Got the timing cover to fit--part of it around one of the screw holes was bumping into the oil pump. I relieved it a bit and it fits a lot better now. I need to find some screws and see if it will snug down properly.

Junglebiker said:

Just for those who are interested in the differences between a NEB clutch and what I guess is a stock Atlas or P11 clutch? I'm not savvy enough to know what the older one came off of. I said above that the clutch basket/sprocket on the NEB is steel, but I was wrong, it apparently IS aluminum. That is to say, a magnet will stick to it, but only weakly, and I think it was actually attracted to a steel drive plate on the other side. A magnet will NOT stick to the sprocket teeth.

There is a big difference in weight between the two--the OEM type is much heavier.

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Well, sucks I have no more excuses for not getting one now.

Thanks, I really appreciate you taking the time to take the pics and show the similarities. My guess is that NEB clutch would make a positive difference. The motor should be a touch more responsive to throttle spinning a lighter clutch. Might also increase motor brake a little when getting off the throttle. I'd like the improvement. Guess I better go fill my cart.

Will be interesting to see what weight oil works well with that much spring pressure. One thing is certain it won't slip in a 750.

Does the clutch come with any printed information?

Junglebiker said:

Got the timing cover to fit--part of it around one of the screw holes was bumping into the oil pump. I relieved it a bit and it fits a lot better now. I need to find some screws and see if it will snug down properly.

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Don't forget the oil pump seal on final assembly. It gets compressed during assembly, so may feel like the cover isn't going on at first. I also suggest getting a hex head (Allen) bolt kit for the timing cover. Much easier to deal with than the slotted screws. JSM timing cover gasket as well. No sealer goo required. When not building a pristine restoration, I find it best to use parts that make the job easier.

I ordered the NEB clutch and blame you for my lack of judgement. Thanks for the unintended push.

Hahahahahaa, I hope you like it! I actually bought mine a few years ago, when I was just starting to build up my parts stash for this resurrection. I was overseas at the time and had it shipped to motorson's house. I don't remember ever seeing any printed info for it, but that doesn't mean I didn't get any.

Thanks for the heads-up on the oil seal, I'm aware of it--both the one tht fits over the crank and the one that fits between the crank and the pump need to be replaced in this engine.

You bought your clutch when they were priced right.

I think the NEB clutch will be a tight just fit behind the P11 primary. Very tight at the outer edge on top of that pressure plate. I'm hoping I don't have to radius it. Being a file and hacksaw back yard barn yard shade tree mechanic type without a lathe it will take all day.

The bonus of installing a new clutch is I get to try for the umpteenth time to stop the primary from leaking. I had high hopes, but automatic transmission ATF specific sealer doesn't work any better than no sealer at all on the gasket Andover sells. I stuff two folded up blue paper shop towels between the lower frame rail and under the near full length of the primary to prevent it from barfing a small silver dollar sized drop of ATF in the garage after a ride. Hard to see the towels unless looking for them and it does work. A rubber gasket would do the trick, or a dry belt clutch and a custom outer cover. Crap now I'm second guessing myself.

Junglebiker said:

Yeah, I've been looking at the oil passages, they look the same as Atlas and Commando covers that I have looked at here, but I will of course investigate more carefully once I have determined that I will actually be able to use it.

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I guess the timing cover you have there is off a 50's model 500 or 600cc engine. Even though oilways to the crankshaft fit, what about the high pressure exit for the top end lubrication which the P11 needs?
The PRV may have to be changed.

- Knut

Schwany said:

I ordered the NEB clutch and blame you for my lack of judgement. Thanks for the unintended push.

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It does look nice. The only drawback is you loose the cush center, which really makes up for the increased weight of the AMC clutch. Without it, you should consider fitting a rear wheel which incorporates a cush drive. Take advice from what Norton did on the Commando. On the other hand, I find the design of the Triumph T140 clutch inspiring - a logical development of the AMC clutch design. I guess that's the route I will take if I can't make the OEM clutch to behave.

- Knut

mdt-son said:

It does look nice. The only drawback is you loose the cush center, which really makes up for the increased weight of the AMC clutch. Without it, you should consider fitting a rear wheel which incorporates a cush drive. Take advice from what Norton did on the Commando.

- Knut

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Yes, I'm aware of the missing cush in the NEB clutch and the cush in the Commando rear hub. Probably won't do anything about it unless it clunks hard being all solid drive. It would have to be very annoying to make me want to install a new rear hub and rim. I don't know if I've ever owned another bike without a cush rear hub. It ill be interesting.

I talked to Madass140 a year or so back about his Trident conical rear hub, because I like the look, but the gearing is lower than I'd like and I'd have to figure out how to make it work. It is a narrower hub than the P11 hub and uses a smaller diameter axle. After thinking more, I had my doubts about the rim offset from the gear working on the P11. I put that out of my mind and stopped looking into solutions. If I do end up looking for a rear hub it more than likely won't be a Commando hub.

Also aware the alloy gear on the NEB clutch won't last as long. It will outlast me though.

Wonder if one could go with a belt drive and stock primary cover, by using longer fasteners with stand-offs, and a custom adapter to space the rotor out. Think it's doable?