P11 gets the JSM treatment

Fake progress. This is a mock up head bolted on barrels to check that the valves don't bang into the pistons. They clear and I probably could use a thinner head gasket, but will stick with the .040 for now.


That lump on the side of the head is a oil pressure gauge fitting. If I could find my 4th stainless rocker spindle outer cover, I'd use it.


Sooty exhaust ports. I did not clean them out. Probably lose some insignificant amount of HP for a few months from leaving them dirty. Spigot exhaust mounts for the Bubb pipe headers.

I misread the P11 Red book. I was only looking at the paragraph on removing the head. Apparently, and I find it hard to believe, the engine can be put into the frame with the head on. It does however have to be done as a unit with the gearbox in the mounting plates. It is a heavy proposition for me these days but my son is still around to help, so I will try it.

After I get the oil tank back in the frame I won't have any excuses for not finishing up. No predictions on completion. I'll find something else I have to fix that doesn't need fixing before I'm done.

I have repeatedly heard that the way to install the engine is to lay it on its side on a bench, then lower the frame over it very carefully, put the bolts in and then stand it up. Doubtless this works better if your frame is bare!

What approximate C.R. do you think you'll have with those pistons?

elefantrider said:

What approximate C.R. do you think you'll have with those pistons?

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Sorry figuring that out is above my pay grade. One of the guys into knowing the numbers would have to do the math. Squish band clearance with those flat top highish CR pistons is .038 with the .021 base gasket and a .040 head gasket I'm using. It is a 74mm bore. The combustion chambers are untouched stock shape. I'm more of a backyard wrencher tuner rider and actually don't think about the numbers that much. As long as it all fits together and I won't bend a valve, I know I can make it work, or die trying. Uneducated guess is over 9, but not over 10.

My biggest issue after I get it all together will be controlling the froth that is going to want to escape through the breather system. I need to come up with a tall thin filtered to atmosphere canister with some volume and an easy to use drain. Then mount it on the frame in front of the drive side shock. I believe Ludwig made one that is a good model. I don't have a mig welder or the experience to use one, so will have to backyard engineer something, or get lucky and find one online.

Prop the engine up so a plug hole is vertical. Get that piston to TDC with the valves closed.
Measure the amount of oil it takes to fill the combustion chamber to the first one or two threads. That’s your combustion chamber volume (CCV).

To calculate your static CR the formula is (CCV+Swept volume) / CCV.

Junglebiker said:

I have repeatedly heard that the way to install the engine is to lay it on its side on a bench, then lower the frame over it very carefully, put the bolts in and then stand it up. Doubtless this works better if your frame is bare!

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I'm going to attempt it in the rolling chassis. I've done it before, but was 30 years younger. If it looks like too much of a pain, I'll do it with the head off.

Fast Eddie said:

Prop the engine up so a plug hole is vertical. Get that piston to TDC with the valves closed.
Measure the amount of oil it takes to fill the combustion chamber to the first one or two threads. That’s your combustion chamber volume (CCV).

To calculate your static CR the formula is (CCV+Swept volume) / CCV.

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Thanks for the info on how to calculate static compression. Addition and division broke my brain meter unfortunately.

After staring at the frame for half an hour yesterday wondering if I should do it the hard way. I put the engine next to the frame (wheels and tires on) with the head off and stuffed the motor in the frame. Gearbox was loosely fit in the cradle before I started. Supposed to install the motor and gearbox as a unit. No thanks. The engine would have fit with the head on it, but it would have been a lot of shenanigans dealing with the weight, and I didn't feel like pulling it out and starting over. I used a rolling transmission jack to scoot the motor over next to the frame. Used my son to help me balance the motor on the trans jack prior to moving it into the frame and while it was on the floor jack under the frame when I was installing mounting bolts. I can't see the paint under the motor but I'm sure it got scratched some.

I finished up the head install next day. Removed the exhaust rockers and rubber banded the push rods up in the head to make the job slightly tolerable. Screwed up on seating the last exhaust rocker I put back in. Noticed something was way off when doing the valve adjust. Hope I didn't bend a valve. I wasn't forcing anything, but it locked up a little. Might have been the odd angle of the ball of the rocker against the side of the cup. I could have sworn it was in place. Oh well, I guess I'll know if the exhaust valve is tweaked when I start kicking it over.

Side note: As it turned out there really is not enough room to install the cNw breather on the back of the driver side case where it is supposed to work better. The two cross members in the frame that the middle of the cradle mounts to are in the way in the P11 frame. So it will remain at the back of the timing side. It quacks a lot louder than it did previously turning it over slowly by hand. More compression and bigger holes into the case on the timing side.

Pushrods test. They stick up way too high to get the head under the downtube.



Getting there. Should be running in 4 or 5 days if I didn't bend a valve.

Schwany said:

Side note: As it turned out there really is not enough room to install the cNw breather on the back of the driver side case where it is supposed to work better. The two cross members in the frame that the middle of the cradle mounts to are in the way in the P11 frame. So it will remain at the back of the timing side.

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Thank you for your comment on location bottleneck at the drive side crankcase. I guess this will affect the G15 too as the powerplants are almost identical. It's surprising that no one has mentioned this before, AFAIK.
A dry assembly of the powerplant on the workbench is required to find a workaround (I want to retain the ignition in its default location).

- Knut

mdt-son said:

Thank you for your comment on location bottleneck at the drive side crankcase. I guess this will affect the G15 too as the powerplants are almost identical. It's surprising that no one has mentioned this before, AFAIK.
A dry assembly of the powerplant on the workbench is required to find a workaround (I want to retain the ignition in its default location).

- Knut

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Knut

The G15 and P11 frames are not alike. You might have the room down there. If I could have fit the cNw breather on the rear of the drive side case, I might have done it. There is about 5/8" between the case and cross member. To fit the cNw breather you need a minimum of 1.25". Otherwise, you'd never be able to get a tool on the breather with the motor installed. If you fit the breather and attached it onto the case on the bench you need 1" clearance. You would have to be very careful installing the motor though.


Breather would be installed below what you see at an angle pointing back right into the frame cross member. Hey, there's some of that scratched up paint patina down there.

If you have the motor apart you could dry fit the cases no crank and so on to see how it all lines up in the frame. If I had a brain I would have thought of that for my build. It just turned out that I was right all along that it would not fit down there.

I could use a NYC Norton breather that goes into the sump hole if I had a twin exhaust and not the 2 into 1. It would just fit, but I would have to be real creative with the outlet. It wouldn't fit with the outlet turned straight up.

The breather on the timing case does work if you have enough exit holes in the timing side case. I know everyone thinks the holes need to be plugged and a breather installed anywhere but on the timing side, but they may not have tried it and are just parroting what they've been told.

Notes:
I ran into a situation that caught me off guard with the JS2 cam.

Not being up on the latest greatest Norton aftermarket performance parts I did not realize that many (all?) aftermarket cams are threaded on the timing side for a 1/4-28 bolt to secure a points AAU or a stator for modern ignition. I screwed the old Norton cam lip seal protector thingie I have into it and it started out fine, but got real difficult to turn eventually. I took it out and knew something had to be wrong. I tried a 1/4-28 bolt in there and it would not go either. I jammed up the threads about half way in. So I contacted Jim and asked what the thread is supposed to be. Once I got the right information about what the thread was supposed to be, I ran a tap in all the way in and was able to use a 1/4-28 bolt without any problems. Point is if you get any resistance at all trying to use an old Norton bolt in the timing end of any cam, that cam is probably threaded for a 1/4-28 bolt.

Just passing it along in case somebody is swapping out an old Norton cam with a newer aftermarket cam and doesn't instinctively know the threads for the AAU on the timing end are 1/4-28.

Schwany said:

Notes: Not being up on the latest greatest Norton aftermarket performance parts I did not realize that many (all?) aftermarket cams are threaded on the timing side for a 1/4-28 bolt to secure a points AAU or a stator for modern ignition. (snip).

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I'm a little lost here. Is it required that you fit a Commando primary cover to use points on the cam end in a P11 engine? My only experience with cam mounted AAU and points system* starts with the 750 20M3S engines (Commando) that only came along in mid-1969 - some time after the last P-11 was built.

What's the solution here?

On a different note, 1/4" is one of the most confusing sizes in British motorcycles. It's almost impossible to tell the difference between a 1/4" Cycle threaded screw (26 Tpi), a 1/4" BSF threaded screw (26 Tpi), and a 1/4" UNF threaded screw (28 Tpi) just by looking at them. The 1/4" UNF screw is entirely incompatible with the other two -- trying to fit the two together will result in damaged threads -- but the two British standard screws seem compatible because they will appear to screw together properly but the thread cross-section pattern is different and the resulting thread interaction will give a lower level of strength and reduced service life. (Something in the back of my head tells me that Commandos suffered a similar issue with the change in cam thread during its production life, but I don't trust those voices any more.)
Thanks, BY

(* Ok, you know that the "points" aren't fitted to the cam but are in conjunction with it - you know what I mean.)

Blewdy Yaink said:

I'm a little lost here. Is it required that you fit a Commando primary cover to use points on the cam end in a P11 engine? My only experience with cam mounted AAU and points system* starts with the 750 20M3S engines (Commando) that only came along in mid-1969 - some time after the last P-11 was built.

What's the solution here?

(* Ok, you know that the "points" aren't fitted to the cam but are in conjunction with it - you know what I mean.)

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Sometime between 1989 and 1993 I put a 2S cam in the P11 cases. I'd have to study my receipts to figure it out. When I did that I also decided that I did not want to run the Lucas K2F magneto and instead use points in the timing cover and coils. Can't be done with the stock 1967 P11 timing cover. Short answer is yes a Commando timing cover is required with modification to the P11 timing side case t do what I did. Both cases have to be modified for the higher lift cam as well.

The AAU for the points is fitted to the cam end. Did mean to confuse anyone.

I could have done it a different way I suppose, but what I did is what I came up with at the time.

Anywho, all things considered it's not much of a stock P11. It's a P11 special now with special needs.

Schwany said:

Sometime between 1989 and 1993 I put a 2S cam in the P11 cases. I'd have to study my receipts to figure it out. When I did that I also decided that I did not want to run the Lucas K2F magneto and instead use points in the timing cover and coils. Can't be done with the stock 1967 P11 timing cover. Short answer is yes a Commando timing cover is required with modification to the P11 timing side case t do what I did. Both cases have to be modified for the higher lift cam as well.

The AAU for the points is fitted to the cam end. Did mean to confuse anyone.

I could have done it a different way I suppose, but what I did is what I came up with at the time.

Anywho, all things considered it's not much of a stock P11. It's a P11 special now with special needs.

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Perfectly understandable, and I can see exactly what you mean in my mind's eye (it's about 20/50 like my other two are at my age). It sounds like a nice mod for that engine (or an Atlas engine)..

You said "The AAU for the points is fitted to the cam end. Did mean to confuse anyone."

Yeah, my comment was fuzzy. The AAU is attached to the cam - the points and backing plate is attached to the timing cover. But it appears that that's all just like the Commando engine (later models). Do you run a tachometer? If so, how is the drive set up?

Thanks, BY

Blewdy Yaink said:

Perfectly understandable, and I can see exactly what you mean in my mind's eye (it's about 20/50 like my other two are at my age). It sounds like a nice mod for that engine (or an Atlas engine)..

You said "The AAU for the points is fitted to the cam end. Did mean to confuse anyone."

Yeah, my comment was fuzzy. The AAU is attached to the cam - the points and backing plate is attached to the timing cover. But it appears that that's all just like the Commando engine (later models). Do you run a tachometer? If so, how is the drive set up?

Thanks, BY

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At the time it was a good modification. I do not recommend it though. It kind of ruins a kinder gentler street ride.

No tach.

I look once in a while to see if I can find a small automotive electrical tach that will tolerate the positive ground. Changing the bike electronics over to negative ground is in theory simple, but I keep putting it off.

At the time it was a good modification. I do not recommend it though. It kind of ruins a kinder gentler street ride.

Schwany said:

No tach.

I look once in a while to see if I can find a small automotive electrical tach that will tolerate the positive ground. Changing the bike electronics over to negative ground is in theory simple, but I keep putting it off.

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Thanks for this. My college roommate in 1968 rode a P-11 (or "Ranger", it seemed to be called both and I don't think that it matters to the specification much) and so I'm still very fond of the model. By the time I had enough $$ together to buy a Norton, the "S" model Commando was out so that was my first Norton purchase (1969). So my real experience with Nortons is almost entirely Commando but I do enjoy hearing about other riders' experience with the earlier models and learning more about them.

Getting close. Maybe 1.5 hours till buttoned up, but pre-procrastinating on when I'll start it. 39 degrees in my driveway. I won't take it for a ride in cold weather. No need to prove to myself I'm a rough tuff man and ride in the cold. My experience says it's not that safe with cold tires and old man reflexes. If I were Australian I'd obviously do it buck naked, kick start it with my arm, and take off front wheel in the air.

How many people break in their Norton motors in the driveway?



Some comic relief: My clutch rod condom. Works too.

Funny looking thing is all dressed up, sans foot pegs and shifter, and no place to go.



I won't be starting it. Although I must admit the urge is strong to do just do it. Unfortunately, a couple of days ago about 4 hours after torquing the head down I realized I screwed the engine build up. I got ahead of myself and forgot to safety wire those 4 damned screws for the lifter tabs. A check list might have been handy is an understatement. I went ahead with the bike assembly anyway because I had a few things I wanted to plumb around and rewire. The screws might hold with the little dab of locktite they got, but having them fall out would be a bad day, and possibly my last day on earth if leaned over in a favorite 80 mph sweeper when they fall onto the cam and jam up the works.

Anywho, going to have to pull the head and barrels and do that part of the build over again. Should not be a big deal. I'm just a bit disappointed that I didn't realize I had reached my level of incompetence earlier like when I was holding the barrels over the crank case and about to install them.

Not sure when I'll get around to tearing it down. I've got some catching up to do around the house.

Schwany said:

Funny looking thing is all dressed up, sans foot pegs and shifter, and no place to go.

I won't be starting it. Although I must admit the urge is strong to do just do it. Unfortunately, a couple of days ago about 4 hours after torquing the head down I realized I screwed the engine build up. I got ahead of myself and forgot to safety wire those 4 damned screws for the lifter tabs. A check list might have been handy is an understatement. I went ahead with the bike assembly anyway because I had a few things I wanted to plumb around and rewire. The screws might hold with the little dab of locktite they got, but having them fall out would be a bad day, and possibly my last day on earth if leaned over in a favorite 80 mph sweeper when they fall onto the cam and jam up the works.

Anywho, going to have to pull the head and barrels and do that part of the build over again. Should not be a big deal. I'm just a bit disappointed that I didn't realize I had reached my level of incompetence earlier like when I was holding the barrels over the crank case and about to install them.

Not sure when I'll get around to tearing it down. I've got some catching up to do around the house.

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Your bike looks brilliant but I have to say I don't like that silencer mount
Would you be adverse to adding another lug to the frame above the existing one and forming a triangular plate ?

Schwany said:

Funny looking thing is all dressed up, sans foot pegs and shifter, and no place to go.

I won't be starting it. Although I must admit the urge is strong to do just do it. Unfortunately, a couple of days ago about 4 hours after torquing the head down I realized I screwed the engine build up. I got ahead of myself and forgot to safety wire those 4 damned screws for the lifter tabs. A check list might have been handy is an understatement. I went ahead with the bike assembly anyway because I had a few things I wanted to plumb around and rewire. The screws might hold with the little dab of locktite they got, but having them fall out would be a bad day, and possibly my last day on earth if leaned over in a favorite 80 mph sweeper when they fall onto the cam and jam up the works.

Anywho, going to have to pull the head and barrels and do that part of the build over again. Should not be a big deal. I'm just a bit disappointed that I didn't realize I had reached my level of incompetence earlier like when I was holding the barrels over the crank case and about to install them.

Not sure when I'll get around to tearing it down. I've got some catching up to do around the house.

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Ok, I’m gonna say it, I’ve been called all sorts of names before so I can take it…

So, at the risk of sounding like an utter heathen…

IF those tappet guide screws were properly tightened… and IF they were loctited… I’m struggling to see why they’d come loose…?

I‘m pretty sure I’d at least start the thing and give it a shakedown run. Or three.

You’d be mightily p*ssed off if you stripped it down to lockwire the screws, and rebuilt it again, and ran it, and realised you need to strip it AGAIN to re balance the crank !

Fast Eddie said:

Ok, I’m gonna say it, I’ve been called all sorts of names before so I can take it…

So, at the risk of sounding like an utter heathen…

IF those tappet guide screws were properly tightened… and IF they were loctited… I’m struggling to see why they’d come loose…?

I‘m pretty sure I’d at least start the thing and give it a shakedown run. Or three.

You’d be mightily p*ssed off if you stripped it down to lockwire the screws, and rebuilt it again, and ran it, and realised you need to strip it AGAIN to re balance the crank !

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You sound like somebody on the interweb voicing an opinion.

I did try that screws won't back out easily logic when considering starting it up as it is, but wasn't convinced that the screws wouldn't come loose on a longer ride. Particularly if it does need to be rebalanced. I used Blue Loctite, which is not that strong. I've already started the top end teardown, so is what it is.

Anywho, getting pissed off doesn't last that long at my age. However, pulling the motor out of the frame again would be a PITA. Not as much work as previously when it was filthy and I also pulled the gearbox, but annoying it would be.

The P11 is never going to feel like it's that well balanced in a solid mount frame. It is also possible that it could be better balanced with the new parts. I freely admit I should have bought Jim's race book and at least checked the crank balance, but I'll be able to live with the "didn't get it rebalanced mistake" if it turns out to be a mistake. If it doesn't turn out to be a mistake, I'll be sure to say so.