P11 basket case

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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?
You could. I think the crank cases would have to come apart and be drilled and tapped for the standoffs, and who knows what else. Too much work for my cranky old bones. Easier to clean up the dribble and refill the primary for me, but heck yeah it's doable. Some great examples out there already on similar bikes and the P11.
 

Junglebiker

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Couple things:

1.) cush drive--in my case I went with a rear wheel that has a gigantic cush drive, just because of the warnings from people on here. I went with a 1975 or so Kawasaki KZ750B (the big twin) rear wheel, mainly because it has a somewhat "british" look to it in my mind. Scroll up to see it, maybe you'll see what I mean.

2.) oil passages--funny you should mention that, Motorson and I were just talking about that today. Mine is an early P11 and apparently did not have high pressure to the head. However, I have a set of finned Webco oil passages that bolt to the sides of the head and which can be used to duplicate the Commando oiling, though of course I will have to switch to Commando rocker shafts and will have to add a banjo bolt to the timing cover down there near the PRV.

I've had the PRV apart and cleaned it out thoroughly, what might need to be changed in it?
 

mdt-son

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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?
Yes, it has been done and there was a report in the Jampot magazine of the AJS/Matchless Owners Club. Basically you need to make a banded spacer for the outer cover, about 1/2" thick.
If made of aluminum, it will be fragile and should be bonded to the inner cover. The stator may have to be moved inwards, whitch is no problem if a suitable spacer and longer studs are fitted.

The belt drive modification works best for the "native" AJS/M models. The P11's left side footrest may have to be modified.

- Knut
 
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mdt-son

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2.) oil passages--funny you should mention that, Motorson and I were just talking about that today. Mine is an early P11 and apparently did not have high pressure to the head. However, I have a set of finned Webco oil passages that bolt to the sides of the head and which can be used to duplicate the Commando oiling, though of course I will have to switch to Commando rocker shafts and will have to add a banjo bolt to the timing cover down there near the PRV.

I've had the PRV apart and cleaned it out thoroughly, what might need to be changed in it?
The 6 start pump, large oilways and high-pressure lubrication of the cylinder head was introduced in February 1966 across the line of NHT. This was one year before the P11 was launched, and your P11 certainly had this feature.

The 6 start oil pump will deliver more pressure than the 3 start, and even though I haven't verified the numbers, I do think NV changed at least the PRV spring. You need to look up the 1965 & 1966 part lists.

A proper P11 cylinder head will have the same plain rocker shafts as found in the Commando heads, even though oil banjo bolts connects to the top of the cylinder head. The only reason Norton attached them to the sides of the later cylinder heads was due to the large head steady NV devised for the isolastic engine mounting.

There can be a number of changes to timing covers made between say 1957 and 1967. I am somewhat surprised you want to fiddle with this old cover. Obtaining the correct timing cover for a P11 doesn't cost a fortune (beware there are two versions).

- Knut
 
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Junglebiker

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The 6 start pump, large oilways and high-pressure lubrication of the cylinder head was introduced in February 1966 across the line of NHT. This was one year before the P11 was launched, and your P11 certainly had this feature.
The 6 start oil pumpp will deliver more pressure than the 3 start, and even though I haven't verified the numbers, I do think NV changed at least the PRV spring. You need to look up the 1965 & 1966 part lists.

There can be a number of changes to the timing covers between say 1957 and 1967. I am somewhat surprised you want to fiddle with this old cover. Obtaining the correct timing cover for a P11 doesn't cost a fortune (beware there are two versions).

- Knut
It is entirely possible that the head I have is an older Atlas head. I have no way of knowing, I only know that it came from a partially disassembled engine (top end removed) that was stamped "P11 12XXXX". I'll have to confirm with motorson, but I think the crank may actually have had a 3 start oil pump drive gear, but no oil pump was on it, IIRC. Mismatched parts? Seems possible--the engine had definitely been apart before.

As for the timing cover, it's not a matter of not being able to find the correct timing cover. It's just a matter of liking this cover better. The oil passages line up alright, nothing is rubbing, all the screw holes line up, and if the PRV isn't correct, I can replace it with a correct one. I will most likely use a Commando banjo bolt and oil line from the timing cover.
 

mdt-son

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It is entirely possible that the head I have is an older Atlas head. I have no way of knowing, I only know that it came from a partially disassembled engine (top end removed)
You have actually. A proper P11 head would have been furnished using a Birco "25319" casting. Of course you can't verify rocker spindles unless you dismantle the head. If untouched, you can be confident the head has plain rocker spindles.

The earlier head casting Birco "23166" may be used IF special spigot substitution rings are fitted (and scrolled rocker spindles replaced with plain ones, for use in the uprated engines). These rings are hard to find now.

- Knut
 

Junglebiker

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You have actually. A proper P11 head would have been furnished using a Birco "25319" casting. Of course you can't verify rocker spindles unless you dismantle the head. If untouched, you can be confident the head has plain rocker spindles.

The earlier head casting Birco "23166" may be used IF special spigot substitution rings are fitted (and scrolled rocker spindles replaced with plain ones, for use in the uprated engines). These rings are hard to find now.

- Knut

The one I have definitely does not have or need the spigot rings. It also does not have the oil lines going into the sides of the head like a Commando does.
 
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If I were to go to the trouble of fitting a belt drive clutch on a P11, I would not leave the stator in the outer primary, but that is just me. I'm not exactly an incompetent mechanic. I'm still working on getting my incompetent mechanic badge. However, I don't think it's worth the effort. It's much easier to install a belt drive on models that have the stator on standoffs bolted into the crank case.

Norvil told me 2 years ago that they have a version of belt drive clutch that just bolts right up to a P11. That told me one of two things: They don't know much about the P11. Or their definition of "bolt right up" and mine differ a lot.
 

motorson

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Another picture of Andrew's bike in my garage.
 

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Junglebiker

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A motorcross bike with disc brakes at both ends? Is there a weight advantage by this conversion?

- Knut

It started with my unwillingness to pay for original wheels coupled with my desire for better brakes. Please let's not restart the disc brake discussion over here. I've many examples of both, I prefer discs. As my bike was missing all of these parts, I saw no reason not to go ahead and install what I wanted rather than trying to do another restoration.
 

mdt-son

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Junglebiker,
Sorry, I didn't realize it was your bike pictured by "motorson". You have a huge rear disk there. Nice set of forks btw. Which bike are they from?

- Knut
 
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Junglebiker

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Junglebiker,
Sorry, I didn't realize it was your bike pictured by "motorson". You have a huge rear disk there. Nice set of forks btw. Which bike are they from?

- Knut
Motorson has a garage and I don't, that's why he puts up pics from time to time. The rear disc is actually a little smaller than the one I was originally going to use, and in truth I would like it to be smaller yet, but it will do for now. It is the disc that would originally have been fitted to that wheel--in fact the swingarm, rear hub, and rear brakes all came from early 1970's Kawasaki KZ750B's, (the twin cylinder KZ750, not the four). The swingarm is about 3 inches longer than the P11 item. I laced the rear hub with Buchanan's spokes into a repro 18" Akront. I actually had to ask Buchanan's to make me a custom set of spokes, but they were very easy to deal with on this.

The front fork, (including the triple clamps/yokes), is also Kawasaki, it came from a 1992 KZ1000P (police bike). I chose it because although it is a 1992 front fork, it looks right and should be easily supportable for years to come. I may have to change the springs, we'll see what it is like once the engine is in.

The front wheel is a Honda CB500 front hub laced with Buchanan's spokes into a repro 18" Akront. The CB hub fits the KZ axle with no mods, (same size). I have not investigated the front wheel fitment too closely yet, the spacers are going to need some fiddling to get right, I may have to make news one, we'll see. Not 100% certain what I am doing for the front brake caliper yet.
 
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What are your plans for a speedometer? Or is this P11 going to be dirt only?

It could be a unique Dual Sport bike. A real crowd pleaser with open high pipes.

The longer swing arm will help when you go over the Widowmaker in Utah. ;)
 

Junglebiker

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The forks look right at home on your bike, and so does the front fender. Where did you get it? Is it aluminum?
Front fender is one of those things I spent money on--it is aluminum and I had it made by 7 Metal West. He can make fenders out of aluminum, copper, brass, can't remember if can do steel. I believe his usual customers are chopper builders. Anyway, he can make fenders/mudguards in various widths and lengths and in any radius you want. I had one full length front one made and one short one for the rear. He can also make them in various thicknesses; for durability's sake, I went with a full 1/8th inch thick, (.125"), which I believe is the thickest he can do. At the end of the day, I doubt I spent any more than I would have done for a nice set of original ones.
 

Junglebiker

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What are your plans for a speedometer? Or is this P11 going to be dirt only?

It could be a unique Dual Sport bike. A real crowd pleaser with open high pipes.

The longer swing arm will help when you go over the Widowmaker in Utah. ;)
Believe it or not, at this point the bike is already registered! When I had the title transferred over to me in TN, I automatically got registration as well. So as long as I get it ridable before March 2023, I should be totally legal to ride it, provided it has lights, horn, the usual street equipment. You can see that I have already fitted a mirror.

Well, since I am using a Honda front hub and speedo drive, I could use any Honda speedo. I think I can use a Yamaha speedometer as well, and I would like to use an early 1970's Yamaha DT unit. I have a very very nice one of these, but of course I accidentally left it in Papua New Guinea. Looking at similar ones on eBay, I see that they have skyrocketted in value, so I'm not 100% certain what I am going to do yet. I may go with a cheapy mini speedometer from eBay as a temporary measure and then will bring back my nice Yamaha one next time I come back from PNG.

On the swingarm, I see that the one on Mike Patrick's race bike has been extended by an inch or so, and somewhere along the way I understood that this was a common mod for P11's which were raced in the desert. To my eye, the original swing arm looks super short--with the KZ swingarm I still have a wheelbase of around 56", which for a dirt bike is longish, but not uncommon, at least not on newer ones.

Right now I have about 12" of ground clearance and a seat height of 37", which is high, but I am a large, heavy man, so it will work okay for me, plus I plan (maybe this will be a longer term plan) to modify the suspension in such a way as to incorporate some pre-sag, like newer bikes do.
 
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