P11 basket case

Hello all. I am new to the site, but have at least one good friend who is active here and who has mentioned Access Norton to me many times over the years. Certainly his Commando is a nice one.

I am here because I was recently given a P11 basket case. All that is there is the frame, the crankcase (matching numbers), a fuel tank, and maybe a few other bits-n-bobs. I'd include a photo, but I am currently working in Papua New Guinea and my P11 is in the US. I've seen it, but only in pieces scattered around a workshop.

I am very interested in resurrecting this bike. Since so many pieces are missing, I thought I might take the opportunity to resurrect it as something somewhat non-standard. I know the purists will boo and hiss and I do apologise to them, one and all, but surely one non-standard P11 will only increase the value of the others?

I am interested in this bike as a rider, not as a trailer queen. To that end, I would like to improve it's performance, but I'd like to do it in a way that makes it look as though maybe it was built by a desert rider in the early 1970's. Maybe by some guy who really loved his old P11, but understood that improving the brakes and suspension and losing weight would only make it more usable.

So! What was available in terms of aftermarket disc brakes in say, 1973? What was the best available off-road suspension at that time?

I want it to be street legal in the USA, so for lights I am thinking of going with late 1960's style small diameter, bottom mount Bates style headlight and something similar for a taillight/signals. Haven't decided on the clocks yet, I am thinking I may leave the tach off and just go with a speedometer. An old aftermarket desert seat might be cool, but then, I really like the P11 short seat, too. I'm not sure what to do about the oil tank--originals are pricey and the reproductions are too. I may resort to a custom one since I know a couple of good welders and could probably have one made in aluminium or in stainless.

Anybody got a pics of P11's with period modifications for desert racing?

Just to be clear--I'm not planning any modifications that would be irreversible, so whoevber gets it after me could always restore it back to OEM spec if they wanted to.

Somewhere between this (which I really like):


and this (and yes, I do know that this one is a completely different frame):


I'd like to end up with something a lot closer to the first picture. For example, I know I want to keep the original type seat and tank. I don't want suspension quite a long as the yellow bike, in fact the original type P11 front suspension might be fine and I'd only go an inch or two longer than stock on the rear shocks. I do like disc brakes and alloy rims. I'm thinking to stick with the original 18" and 19" sizes, (or maybe both 18", jury is still out on that). While I like the high mount front fender, in my mind it is difficult to really get a high mounted metal front fender to look quite right. I'll have to experiment to see what looks right to me.

I like your concept, it will make a fun play bike that you can take off road. I'd recommend Betor or Cerriani forks for a more period correct look with better performance than Teledraulics. Alternatively, you could adapt other Euro or Japanese off road forks but that would be harder to do. Good luck and keep us posted

Yowza, new Hungarian Cerianis are pricey! Lots of old Betors on ebay, but they are off of Montesas. Can a set of Cerianis or Betors that were originally intended for a Butaco or Montesa be retrofitted to a P11? I know that there is a big weight difference between P11 and say, a Frontera, so obviously a P11 would need heavier springs, maybe different fork oil, but would Cerianis or Betors originally fitted to a Bultaco/Montesa actually be made any lighter (like, to the point where strength becomes a concern), than the aftermarket ones that might have been available for a P11 back in 1973?

I admit that my experience has mostly been with Japanese stuff from about 1970 on, and my experience with anything British or European is pretty limited, but that is slowly changing.

Junglebiker, it's not clear to me what you are trying to accomplish.

Lighter forks? Teledraulics are pretty light at the outset, and you could improve them further by fitting lighter yokes made out of aluminum (actually, some or all G3C trail bikes had aluminum yokes of a somewhat different design).

Improved damping? OK, but what are your specific complaints about Teledraulics? If there are any, can the OEM design be improved upon?

Extended travel? Hard to achieve without raising the bike's ground clearance and in doing so, you would probably want to extend the wheelbase and the rear fork as well ..... longer travel necessitates longer stanchions, which necessarily means larger OD, unless you want to compromise fork stiffness. We are probably talking about constructing a different chassis.

Fitting a disc brake up front? Upgraded stanchions to 35-36mm OD will be necessary. Use slider(s) of greater wall thickness capable of supporting a disc caliper. Maxton/Ceriani is a possibility.

One immediate measure is highly recommended, unfortunately it's not reversible: Alter the steering head to take sealed ball bearings a la Commando. This will probably cure the bike's tendency to high-speed weaving. AMC's steering head support design is really unsuitable for anything but offroad work.
There are recipes with the AJS/M Owner's Club how to do this. Special tooling and bracing is required. I have been planning to do this mod on my P11 for some time.

-Knut

mdt-son said:

Junglebiker, it's not clear to me what you are trying to accomplish.

Lighter forks? Teledraulics are pretty light at the outset, and you could improve them further by fitting lighter yokes made out of aluminum (actually, some or all G3C trail bikes had aluminum yokes of a somewhat different design).

Improved damping? OK, but what are your specific complaints about Teledraulics? If there are any, can the OEM design be improved upon?

Extended travel? Hard to achieve without raising the bike's ground clearance and in doing so, you would probably want to extend the wheelbase and the rear fork as well ..... longer travel necessitates longer stanchions, which necessarily means larger OD, unless you want to compromise fork stiffness. We are probably talking about constructing a different chassis.

Fitting a disc brake up front? Upgraded stanchions to 35-36mm OD will be necessary. Use slider(s) of greater wall thickness capable of supporting a disc caliper. Maxton/Ceriani is a possibility.

One immediate measure is highly recommended, unfortunately it's not reversible: Alter the steering head to take sealed ball bearings a la Commando. This will probably cure the bike's tendency to high-speed weaving. AMC's steering head support design is really unsuitable for anything but offroad work.
There are recipes with the AJS/M Owner's Club how to do this. Special tooling and bracing is required. I have been planning to do this mod on my P11 for some time.

-Knut

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Knut,

Here's the deal: I've recently gotten my hands on a P11. I say "P11", but really it's just a P11 frame with matching numbers crankcase. That's pretty much it. Oh, and a set of engine plates. I am going to resurrect it, but since so much is missing, I figure I may as well improve it a bit along the way. I've decided that I want it to look like somebody's last desperate attempt to take on the 2 strokes in around, say, 1973, which is when I was born. I'm certainly not interested in trying to make it into a WR450F or anything like that--I really like the look of the original P11, but I also like being able to stop and having good suspension.

To complicate matters further, I am currently in Papua New Guinea, but my bike is int he US and it will be a couple years yet before I even have a chance to get started on it, so at this point I'm just trying to decide excatly what I want to do.

Oh, I also have a fuel tank. Forgot to mention that.

Just build it to stock first. It sounds like you have time to find the missing parts. By dirt bike standards, these bikes are heavy monsters off-road and you are not going to be able to improve on that much -if at all. You'll lose the bike's good looks and value the further you deviate from stock.

Junglebiker said:

Oh, I also have a fuel tank. Forgot to mention that.

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Finding a genuine P11 gearbox should be fairly easy. They are advertised on Fleebay quite often. Otherwise, British Only or Baxter Cycle are your premier sources. Genuine forks is much harder to come by. Please note that the "triple tree" is special to the P11 series.

-Knut

I understand that the mounting points on the P11 gearbox are different from those of a Commando, and that the P11 gearbox uses the AMC type case rather than the Norton case. Is this correct? What are the differences internally compared to a Commando GB? Wider ratios? Closer ratios?

elefantrider said:

Just build it to stock first. It sounds like you have time to find the missing parts. By dirt bike standards, these bikes are heavy monsters off-road and you are not going to be able to improve on that much -if at all. You'll lose the bike's good looks and value the further you deviate from stock.

Click to expand...

If all he has is a frame, engine crankcases, and a fuel tank, collecting the necessary parts to return it to stock will be quite expensive. It might be much less expensive to find a set of forks (and triple trees and wheels) from a Japanese dirt bike. Recently P11 wheels have been bringing as much as $400 each with junk spokes and rims!

As for the gearbox. The AMC "competition" gearbox case (and N15, G15, P11) are all the same. The internals of the P11 gearbox are identical to the Norton Atlas. The mainshaft is different than the Commando mainshaft, but all other components are identical.

Ron L said:

If all he has is a frame, engine crankcases, and a fuel tank, collecting the necessary parts to return it to stock will be quite expensive. It might be much less expensive to find a set of forks (and triple trees and wheels) from a Japanese dirt bike. Recently P11 wheels have been bringing as much as $400 each with junk spokes and rims!

As for the gearbox. The AMC "competition" gearbox case (and N15, G15, P11) are all the same. The internals of the P11 gearbox are identical to the Norton Atlas. The mainshaft is different than the Commando mainshaft, but all other components are identical.

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Thanks, Ron L. Your thoughts on restoring it to stock are the same as mine; I've been checking prices and have found that yes, I could spend a fortune building it all back up to original, at which point it would be just like everybody else's stock P11. And it's true that I'd be able to say "numbers matching" but in my mind it'd be a farce.

The downside, of course, is that someday somebody will look at it and wonder who "screwed up" a matching numbers P11, but I reckon it will have to be my heirs who will have to deal with that, as I have no intention of selling it. It was given to me by a close friend and is only the second British bike I've owned (the first is an Armstrong MT500 army bike, Rotax engine, so it sort of doesn't count).

Likewise, the final dollar value of the bike is less important to me than whether or not I like to ride it. And I do definitely intend to ride it! A lot!

So going back to stock is pretty much not in the cards. At the same time, I'm not interested in grafting on all the latest and greatest in brakes and suspension. I'm used to riding mid 1970's Japanese bikes on road, and 1980's Japanese bikes off road. If I can get the P11 brakes and suspension to be "better than average" or maybe even "high zoot" by 1973 standards, I'll be happy with that. If a Ceriani fork and Works Performance, Ohlins, or similar quality rear shocks end up being just completely outside of my purchasing capabilities, then I'll reevaluate. Like I say, it looks like I've got plenty of time to decide what I want to do.

I think I can do all the work myself, (except boring cylinders if I end up needing to do that). Everything else I think I can handle, especially with the help of the guy who gave me the bike.

How much suspension travel did the P11 come with? Let's start there.

You would be lucky to get 4 inches of suspension from the front teledraulics and less on the rear Girlings. Racers back in the day would say "I only have 4 inches of travel but it's a good 4 inches."

How much suspension travel did the P11 come with? Let's start there.

jerrykap said:

You would be lucky to get 4 inches of suspension from the front teledraulics and less on the rear Girlings. Racers back in the day would say "I only have 4 inches of travel but it's a good 4 inches."

How much suspension travel did the P11 come with? Let's start there.

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Do you (or anybody else reading this) know why Mike Patrick preferred the Road Holders on his race bike? I've read that he did, but never heard anybody say why he did.

Mike rode many other brands of English bikes on his way to becoming AMA District 37 champion on his P11 and then again on Yamaha's. At one time he rode Atlas scramblers. I think it was then that he developed an acceptance of them as being better than the others? I remember distinctly asking Mike about them and he replied his P11 was the only bike that didn't put him on his head. I also asked abut the feeble way the front brake torque stay was affixed to the left fork leg with 1/4 " X 20 studs in the left hand fork slider. His was beginning to break away in this area, and he replied, I didn't need much front brake, engine compression, the big rear sprocket and the rear brake gave plenty of stopping power.

Junglebiker said:

Do you (or anybody else reading this) know why Mike Patrick preferred the Road Holders on his race bike? I've read that he did, but never heard anybody say why he did.

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Very interesting! The guy I got my P11 from is planning to go to the Vintage Festival later this year--I was going to ask him to try to get lots of good detail pictures of Mike's bike. I really like the fact that it has survived more or less as it was.

Forgive me if these questions have all been asked before, but what kind of air filter is that on MP's bike?

Hi Junglebiker,

I'll be going, once again, to the Barber Vintage Festival...it's too much fun to miss.

But you can see quite a lot of the details of Mike Patrick's championship P11 on the internet. Over the 15 years that I was custodian of this great bike I documented most everything I could with my camera. There's quite a lot of pictures here, the ones at the end show the most detail when I replaced the head gasket: https://mymotolife.shutterfly.com/3409 It's actually very highly modified by Mike back in the day. Also there's a couple of videos to look at too.

Let me know if this works for you. Happy to help another have fun with his P11

C-ya, Jer

Junglebiker said:

Very interesting! The guy I got my P11 from is planning to go to the Vintage Festival later this year--I was going to ask him to try to get lots of good detail pictures of Mike's bike. I really like the fact that it has survived more or less as it was.

Forgive me if these questions have all been asked before, but what kind of air filter is that on MP's bike?

Click to expand...

Oh yeah, the air filters...Mike took Harley Davidson air cleaners (from an XLCH?) and adapted them using 90 degree bends made with the right diameter radiator hose. Effective and accessible.

Junglebiker said:

Very interesting! The guy I got my P11 from is planning to go to the Vintage Festival later this year--I was going to ask him to try to get lots of good detail pictures of Mike's bike. I really like the fact that it has survived more or less as it was.

Forgive me if these questions have all been asked before, but what kind of air filter is that on MP's bike?

Click to expand...

jerrykap said:

Oh yeah, the air filters...Mike took Harley Davidson air cleaners (from an XLCH?) and adapted them using 90 degree bends made with the right diameter radiator hose. Effective and accessible.

Click to expand...

Ah, that's pretty much exactly what I suspected--the chrome looked like an old Harley item and I assumed that there must be some sort of 90 degree bend in there.

If you've been to the Vintage Fest before, then maybe you've bumped into my friend--he's a member here and his user name is Motorson. He tries to go every year, not sure if he'll make it this year but I hope he does. I was in the US last year and wanted to go with him, but I couldn't get a bike out of storage, up and running and registered in time to make the trip. And it wouldn't have been a Norton, because I didn't have one yet.

Thanks for the link to the pictures!