Norton Commando John Player Peter Williams replica build

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Bernhard said:
Only the lap times on the stopwatch.
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The reason I said dyno is because I suggest you’d need a very accurate way of measuring the difference, because it’ll be tiny, if that.

There‘s no way turning the baffle tubes around will make any difference to lap times !
 
Fast Eddie said:
Agreed. I dyno’d bigger bore pipes, open megas, etc, etc on mine only to conclude that standard 1 3/8 downpipes with fluted peashooters out performed them all.

The only exception was the Maney / Brooking 850 2:1. But even that only out performed peashooters when long duration cams were used.

Having said all of that, a production racer from the day told me they used to cut open the pea shooters, turn the fluted baffle around, and re weld / re chrome them. Their logic being that would increase the flow of the peashooters! But they didn’t have access to a dyno to prove / disprove their theory.
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That fluted baffle didn't do much silencing.....nor was it much restriction...mine has teh standard fluting and was no quieter than those with absolutely nothing inside the can.....a long reverse cone mega after all....
 
Fast Eddie said:
The reason I said dyno is because I suggest you’d need a very accurate way of measuring the difference, because it’ll be tiny, if that.

There‘s no way turning the baffle tubes around will make any difference to lap times !
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I never suggested there was.
The fact that Norton kept 2 commandos specifically for the Indy circuit at the 'Hatch that lapped 2 seconds a lap quicker than anybody else was not disputed for years until PW let the cat out of the bag, just shows you how devious some of those proddy racing boys where.
 
SteveA said:
Specific rules were mostly broken!

When I production raced a standard 1970 Fastback my fellow racers had 33mm carbs fully flowed heads, high compression (and long kickstarts) and 4S cams...I could still beat some of them with standard compression and cam, 28mm ports 30mm carbs and a twin leading shoe brake....sometimes outbraking them because I simply could not stop quicker!

Most peashooters used had nothing in them....mine were as they came to me...and whistled on the overun...please remind me why I sold that bike!

Oh yeah!....it was to help fund racing the following year! And now it is lounging in someone's shed in the UK on an off road notice.
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That’s very true Steve. I think production racing always has been, and always will be, as much about who can be the most ‘creative’ with and around the rules as it is about the action on the track.

And followers / supporters are no better... when it’s someone we like we say they were being ‘creative‘ or at the worst ‘cheeky’... when it’s someone we don’t like, well, they were cheating !
 
Seeley920 said:
The crankcases and gearbox were both spigotted. The holes were line reamed slightly oversize to be properly parallel, and an oversize stud that was a tighter fit was fitted. This was slightly shorter than the width of the case. and threaded internally for a bolt.. A top hat bush was fitted to the engine plates from the outside and a bolt through the bush into the stud secured them. One of the main reasons was to prevent the early crankcase halves from "shuffling" when the power went up (the cases with the small dowel compared to later ones). and o keep everything parallel

Which JPN are you referring to, a PR replica or a "proper" JPN in a special frame??
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Thanks for that John. I understand what is meant by spigoting now. New info after 40 years. Great stuff.

And like the outrigger I wandered off thinking about, another thing you don't need to do with Maney cases and a TTi gearbox!
 
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Bernhard said:
I never suggested there was.
The fact that Norton kept 2 commandos specifically for the Indy circuit at the 'Hatch that lapped 2 seconds a lap quicker than anybody else was not disputed for years until PW let the cat out of the bag, just shows you how devious some of those proddy racing boys where.
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Like BMW fabricating frames that had 1" more ground clearance. There was only one man that tended to measure them, John Milligan!
 
Fast Eddie said:
That’s very true Steve. I think production racing always has been, and always will be, as much about who can be the most ‘creative’ with and around the rules as it is about the action on the track.

And followers / supporters are no better... when it’s someone we like we say they were being ‘creative‘ or at the worst ‘cheeky’... when it’s someone we don’t like, well, they were cheating !
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Having tasted Historic Rallying...it was ever thus...write a rule book and someone with a big bank balance will 'invest' in 'gaining an advantage!'

They don't 'alf get upset when someone with 'a heap of junk' finishes in front of them!
 
But back to the OP, we have discussed and questioned what he wants to build....he has said, 'yes that'...but perhaps he will post his own picture of his dream.

I am still sure it can be done with less emphasis on period works 'hidden' modifications and more off the shelf parts and a good paint job.

The only bespoke parts might be the exhaust down pipes and mountings!
 
SteveA said:
Like BMW fabricating frames that had 1" more ground clearance. There was only one man that tended to measure them, John Milligan!
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When Triumph did that with the production race triples they were being ‘creative’. Or perhaps ‘cheeky’ underdogs defending the realm...

They weren’t cheating...
 
Fast Eddie said:
When Triumph did that with the production race triples they were being ‘creative’. Or perhaps ‘cheeky’ underdogs defending the realm...

They weren’t cheating...
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Milligan measured Ray Knight's Triumphs too......but he always seemed to bring the same ones back....

Maybe the clue was in the name of the race club Milligan ran....the 'British Formula Racing Club'....
 
Fast Eddie said:
Agreed. I dyno’d bigger bore pipes, open megas, etc, etc on mine only to conclude that standard 1 3/8 downpipes with fluted peashooters out performed them all...
Click to expand...

Maybe true on a production racer. But my friend Chris Scott had a motor tuned by the great CR Axtell. Flowed head and Axtell #3 cam with the hot 102 degree lobe centers (difficult to fit without valve clash). It ran like stink. When he quit racing he put in on the street and let me take it for a ride - asking me why it didn't have any top end. Everything was the same as his race bike except for the peashooters and headers. The headers didn't matter and he was using the same Mikuni flat side carbs that he raced with. The power band went flat around 5 or 6000 RPM. I told him it was the peashooters. He didn't have any choice but to run mufflers on the street. They do look sexy. But when it comes to an all out pumped race motor the peashooters are restrictive in my opinion.
 
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jseng1 said:
Maybe true on a production racer. But my friend Chris Scott had a motor tuned by the great CR Axtell. Flowed head and Axtell #3 cam with the hot 102 degree lobe centers (difficult to fit without valve clash). It ran like stink. When he quit racing he put in on the street and let me take it for a ride - asking me why it didn't have any top end. Everything was the same as his race bike except for the peashooters and headers. The headers didn't matter and he was using the same Mikuni flat side carbs that he raced with. The power band went flat around 5 or 6000 RPM. I told him it was the peashooters. He didn't have any choice but to run mufflers on the street. They do look sexy. But when it comes to an all out pumped race motor the peashooters are restrictive in my opinion.
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We seem to be agreeing. Radical head jobs and cams may well work well with, even need, radical exhausts.

But as you say, a production racer is different.

And the bike in question is a production racer after all.
 
jseng1 said:
But when it comes to an all out pumped race motor the peashooters are restrictive in my opinion.
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There are HUGE differences in restriction levels of various brands and models of what APPEAR to be 'identical' peashooters...
 
lcrken said:
Update. The Butcher/White number 2 bike is in the British National Motorcycle Museum, along with one of the first John Player F750 race bikes, the blue and white number 22.

Ken
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Not sure how much of them are original after the big fire. Norman would know, as he rebuilt a lot of them.
 
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