Cycle World on Norton's race dominance and the Commando twins

Good stuff. My son sent me this a couple of weeks ago, but I just got around to watching it due to this prompt. I have always enjoyed Kevin Cameron. I have been reading his articles since the late 70s (a guess), and I understood a bit more each time I read one of his articles. I'm no engineer, and I appreciate how he teaches. And Mark Hoyer is a great guy as well. How can we not love a video that warms our mechanical-leaning hearts about Nortons, told so well?
 
gpzkat said:
Good stuff. My son sent me this a couple of weeks ago, but I just got around to watching it due to this prompt. I have always enjoyed Kevin Cameron. I have been reading his articles since the late 70s (a guess), and I understood a bit more each time I read one of his articles. I'm no engineer, and I appreciate how he teaches. And Mark Hoyer is a great guy as well. How can we not love a video that warms our mechanical-leaning hearts about Nortons, told so we
Click to expand...

I have also been reading Kevin Cameron for many years and am always amazed at his knowledge of motorcycles and the way they operate.Sometimes it is way over my head but he manages to make it understandable.It broke my heart when that magazine went only digital but that’s life.
Mike
 
That is an excellent video but I have some “alternative facts” -
Regarding the cylinder head port design of the twin engine imparting swirl, this was not the case with the early head with the integral inlet manifold.
In one of my discussions with Doug Hele I asked what power improvement the downdraught inlet ports gave and Doug replied “none at all, the downdraught angle was so that the carburettors would clear the central oil tank”
 
hybridracer said:
That is an excellent video but I have some “alternative facts” -
Regarding the cylinder head port design of the twin engine imparting swirl, this was not the case with the early head with the integral inlet manifold.
In one of my discussions with Doug Hele I asked what power improvement the downdraught inlet ports gave and Doug replied “none at all, the downdraught angle was so that the carburettors would clear the central oil tank”
Click to expand...
I believe Cameron and Hoyer were talking about the Commando head and the way the long side curve of the port gave the intake charge a different approach / downward path to the intake valve, so it did not get sucked out of the exhaust valve on overlap. Like the how to hop up your Commando showed when porting the head on your Commando that Norton published the specs and how to do tech on. The swirl is induced by the placement of the valves. But either way the 28 degree timing and the small combustion chamber works wonders as well as the cooling ability of the air flow thru the head and between cylinders. The head is work of art and a pleasure fora pro porter to work with. And a "kid" like me can make a real race winning machine from his street bikes and make his dream a reality.
 
If you look at the path the intake port follows compared to a Triumph looking from above, the Norton is offset to the center of the cylinder while the Triumph's is centered. I think this offset induces swirl via a corkscrew effect which gives better cylinder filling.
 
Here's an example of the Commando's dominance, Its smooth powerful delivery of speed and launch control gives you maximum velocity to get you off and racing. In the wet with a fast start means, You are the dry line and others are trying to get through traffic and get on board. In the dry you get up front and start to pull away. A big advantage either way.

1) Jerry Wood #3 looks a little pensive on where he will go, BUT he has already started the charge forward 2) then he sees a slight space between the two bikes in front and Wood put the old squeeze play on. 3) On cruise control and running his own race.

Cycle World on Norton's race dominance and the Commando twins
 
Carl H said:
I believe Cameron and Hoyer were talking about the Commando head and the way the long side curve of the port gave the intake charge a different approach / downward path to the intake valve, so it did not get sucked out of the exhaust valve on overlap. Like the how to hop up your Commando showed when porting the head on your Commando that Norton published the specs and how to do tech on. The swirl is induced by the placement of the valves. But either way the 28 degree timing and the small combustion chamber works wonders as well as the cooling ability of the air flow thru the head and between cylinders. The head is work of art and a pleasure fora pro porter to work with. And a "kid" like me can make a real race winning machine from his street bikes and make his dream a reality.
Click to expand...
So you do not believe in the Kadence effect in exhaust systems ? The first mistake many people make when building a race motor is to enlarge the inlet port. I never believed in my 850 motor, and that was my biggest mistake. WE all become conditioned by bullshit. If you look inside a Manx Norton engine, the squish band goes right around the piston. In the Commando engine, it is at the back of the combustion chamber, so the squish effect is towards the exhaust valve. Losing mixture through the exhaust valve happens every time the valve opens, then it gets stuffed back by resonance in the exhaust pipe. A 2 into 1 exhaust system gives more and smoother power than separate pipes with megaphones. But the opening at the end of the collector is important, and the length of the tail pipe must be a multiple of the length of one of the header pipes. The tail pipe resonates at twice the frequency of one header pipe. Jim Schmidt's little ramps which fit just after the exhaust valve are an excellent idea. During WW2 German aircraft were using fuel injection. American aircraft became faster when they were turbocharged. I think the aircraft of both sides had blowers, but the Yanks added exhaust-driven turbos. The biggest thing which might stop a Commando engine from being fast, might be the belief that the power is not there to be had. Using petrol as fuel should deliver more power than methanol - petrol has a 30% higher calorific value. Methanol hides up the tuning errors, due to latent heat of vaporisation. The differences in bigger jets are not as critical. The main trouble with carburetors is the needles are usually lowered in steps - not by smooth adjustment. An electronic ignition system should be able to compensate for rich mixture.
 
My qualifications are in industrial chemistry - NOT engineering. My approach to problem solving is different - all engineering is based upon science. Most of my life has involved making weapons. In one of my jobs, I was involved in closed vessel testing of gun propellant - octane rating of fuel is a similar concept to 'brisance' in gun propellant - a measure of acceleration of the combustion process. Methanol fuel has unlimited antiknock. With petrol, we are limited in how lean we can go. Lean is faster - complete combustion delivers more power. When methanol is run rich, the exhaust gas stings your eyes. In Australia, the pits at race meetings often involve sheds.

 
Last edited:
acotrel said:
So you do not believe in the Kadence effect in exhaust systems ? The first mistake many people make when building a race motor is to enlarge the inlet port. I never believed in my 850 motor, and that was my biggest mistake. WE all become conditioned by bullshit. If you look inside a Manx Norton engine, the squish band goes right around the piston. In the Commando engine, it is at the back of the combustion chamber, so the squish effect is towards the exhaust valve. Losing mixture through the exhaust valve happens every time the valve opens, then it gets stuffed back by resonance in the exhaust pipe. A 2 into 1 exhaust system gives more and smoother power than separate pipes with megaphones. But the opening at the end of the collector is important, and the length of the tail pipe must be a multiple of the length of one of the header pipes. The tail pipe resonates at twice the frequency of one header pipe. Jim Schmidt's little ramps which fit just after the exhaust valve are an excellent idea. During WW2 German aircraft were using fuel injection. American aircraft became faster when they were turbocharged. I think the aircraft of both sides had blowers, but the Yanks added exhaust-driven turbos. The biggest thing which might stop a Commando engine from being fast, might be the belief that the power is not there to be had. Using petrol as fuel should deliver more power than methanol - petrol has a 30% higher calorific value. Methanol hides up the tuning errors, due to latent heat of vaporisation. The differences in bigger jets are not as critical. The main trouble with carburetors is the needles are usually lowered in steps - not by smooth adjustment. An electronic ignition system should be able to compensate for rich mixture.
Click to expand...
I thought this is what I said: " The head is work of art and a pleasure fora pro porter to work with. And a "kid" like me can make a real race winning machine from his street bikes and make his dream a reality." I took pride in the fact that my basic Commandos could be a Class Champions and very reliable. I didn't care to do anymore as I let the top guns from the USCRA ride and make up for any short coming in my low tech.

And as far as the legends go, they had enough brains not to bust their ass on the very dangerous Laconia track, but enough skill to ride very fast and stay on course and out of the ER. But you'd have to talk to the guys that finished behind my" streetbikes", I think they would have a whole different take on how it felt to try to beat one with Wood, Henning , Nichols or Duhamel riding them. I'm no expert, I only know the tracks in New Hampshire and I understand the basics of racing there. Apparently, I did something right.
 
Carl H said:
I thought this is what I said: " The head is work of art and a pleasure fora pro porter to work with. And a "kid" like me can make a real race winning machine from his street bikes and make his dream a reality." I took pride in the fact that my basic Commandos could be a Class Champions and very reliable. I didn't care to do anymore as I let the top guns from the USCRA ride and make up for any short coming in my low tech.

And as far as the legends go, they had enough brains not to bust their ass on the very dangerous Laconia track, but enough skill to ride very fast and stay on course and out of the ER. But you'd have to talk to the guys that finished behind my" streetbikes", I think they would have a whole different take on how it felt to try to beat one with Wood, Henning , Nichols or Duhamel riding them. I'm no expert, I only know the tracks in New Hampshire and I understand the basics of racing there. Apparently, I did something right.
Click to expand...
Carl, don't feed into it. A Cotrel has been on meth most of his adult life. The side effects are just coming to light.https://www.bing.com/search?pglt=427&q=side+effects+of+meth&cvid=56ed0757288e47e4807a45ce49bc2c2e&gs_lcrp=EgRlZGdlKgYIABBFGDkyBggAEEUYOTIGCAEQABhAMgYIAhAAGEAyBggDEAAYQDIGCAQQABhAMgYIBRAAGEAyBggGEAAYQDIGCAcQABhAMgYICBAAGEDSAQkyMDM3MWowajGoAgCwAgA&FORM=ANNTA1&PC=U531
 
3rd year university physics and maths are actually useful when discussing wave mechanics. - what Ashley calls 'techno-babble' - inverted snobbery ? - Information was meant to be free'.
 

Similar threads

pantah_good
Cycle World: 50 Years of Commando
Replies
6
Views
2,788
Danno
Danno
R
  • Locked
New Kiwi member
Replies
6
Views
1,409
Matt Spencer
M
VintAge
  • Locked
Commando editorial in Cycle World
2
Replies
33
Views
3,684
SteveA
SteveA
Back
Top