Combat differences

worntorn said:

The strange thing is that the standard issue 750 Commando was quicker than the Honda 750 four.
It was likely the Kawasaki H2 Triple that Norton was chasing. That came out in 71. Then in 72 Kawasaki brought out the Z1. 82 reliable horses there vs 65 very unreliable horses with the Combat. No chance of winning that fight.



Glen

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You need to consider the times in which the Honda 4 and the Combat were current. In those days motor scooters, duffle coats and desert boots were the go. A Combat was a real motorcycle. That is not what was wanted. Most people could not ride a Norton 650ss or Triumph Bonneville 650 in the way in which God intended.
Norton's primary interest was racing, road bikes were secondary. Most race bikes do not make good road bikes, but something which resembles a race bike can feed a fantasy.
I have both raced and ridden road bikes. It is pretty much impossible to get fair dinkum on a road bike. You simply cannot use a road bike on public roads, in the same way as a race bike on a race circuit.
I think a Suzuki GSXR750 might be as close as anyone can get to having a thrill and staying sane. But even that might be too quick. One thing I would never do is road-race a modern motorcycle. The old ones are fast enough.

The Norton Twin was designed from the start as a road bike, the Manx was a dedicated race bike but what parts from the Manx made it to the twins other than the notable exception of the featherbed frame. And when presented with the Featherbed frame what manufacturer would not introduce it to the road bikes, the clue is in the nickname Featherbed.

MichaelB said:

"The Norton was sup-posed to have had a hot “Combat” cam in it, but our readings showed the magic stick to be a slightly worn SS cam instead"
Pulled this off the net. For those that don't know, the SS is the stock cam, the 2S is the Combat. Yes, confusing.

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Are you sure about that? I have a Combat and the cam was stamped SS. I thought people refereed to the two S's as 2S. Are you saying there's a 2S stamped cam.

Glad you're bringing this up.
The article references their measurments on the cam as being a SS, not a 2S.
I was just trying to clarify.
Here is Dyno Daves expose on Cams.

Also want to say I am NO expert on this...
With the Cam Id's and the various Mk's, Norton is quite successful in convoluting all this.

Bringing this up to this older post, but was the Combat sold as a seperate model, or was it offered as an available engine to the Roadster or some other model?

quawk said:

Bringing this up to this older post, but was the Combat sold as a seperate model, or was it offered as an available engine to the Roadster or some other model?

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AFAIK, the Combat engine was available from the factory in Roadster or Interstate only. There was no separate model.

marshg246 said:

AFAIK, the Combat engine was available from the factory in Roadster or Interstate only. There was no separate model.

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Any idea what the additional charge was for the optional Combat engine was from the factory?

Wasn't an option, it was the Standard engine for the Roadster and Interstate.
Hi Rider got the Non Combat.

acotrel said:

I might be a doubting thomas, but I would almost guarantee that when most guys skim a head to get more compression, they ride the bike without changing the jetting or ignition timing. It the motor is jetted slightly rich or the ignition is slightly retarded, increasing the compression will give an increase in power. Perhaps the same increase might have been achieved by optimising the jetting and ignition timing, without skimming the head ?
When you skim the head, do you worry about the squish band losing clearance ?

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Increasing compression within limits will always give more power when tuned properly.

There's a reason why moden automotive engines have static compression ratio in the high 11:1 range. They not only produce more power, but vastly increased fuel economy.

MichaelB said:

Wasn't an option, it was the Standard engine for the Roadster and Interstate.
Hi Rider got the Non Combat.

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So every '72 Roadster and Interstate were Combat engine equipped?

Every Interstate (within the Combat production series).
The Combat series wasn't introduced until 200976 so not all '1972' were Combats.

TomU said:

Are you sure about that? I have a Combat and the cam was stamped SS. I thought people refereed to the two S's as 2S. Are you saying there's a 2S stamped cam.

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It's complicated. The "SS" cam (called "ess-ess") was a cam developed for the 650 Norton twin variant called the 650SS. It was meant to be a fast-road-sporting or race cam. It was just about the perfect cam for a Norton (in the mid-60s) and it gained a well-deserved reputation as "the cam to have". By the time that the Atlas became twin/carb (maybe earlier), the SS cam became the stock cam and when the Commando was developed, it was carried over as the stock production cam for Commandos. Since it was "the cam" from 1968 - 1971, it wasn't marked with *anything* but it really was the old/very good SS cam grind.
In 1971, the "Combat" cam was developed. I'm not sure where or by whom (the later "three S" cams and subsequent cams came from the Norton Performance shop but the "Combat" cam would have been before the change to the John Player Norton team). Maybe Norman would know. Anyway, it was designated the 2S cam pronounced "two-S" or "double-S" but not on purpose because almost everyone except John Hudson had forgotten by 1972 that the stock Commando cam was the "ess-ess" cam. BTW, John Hudson hated -- I mean "pure HATED" the 2S/Comnat cam, he thought that it was far too hard on valve gear and gave poor powerband and torque characteristics for road use." I made the mistake of asking him one time!
One peculiarity is the the "2-S" cam was stamped "SS" on the cam. But it was not the "SS-ess-ess" cam, the stamping designated the 2-S cam. So the cam with the "SS" stamped on it is not the "SS" cam. Yeah, not good thinking but if you call the Combat cam the "2-S" cam and read the stamping as "2-ess", you're on the right track.

When we built my 850 Production Racer at the factory in the winter of '72/73, we skimmed the 850 head .040, ported it, and ran the stock cam. Great engine, loads of power, great match for the stock 4-speed box, and highly controllable!

L.A.B. said:

It's a '235' (Jan. '73) Hi-Rider, therefore, I would expect it to have a standard or RH1 (28.5mm inlet) head and 930 (30mm) carbs.

1972 750 Hi-Rider

Yes, I suspect that the hunting tooth is much more important on timing gears than sprockets and chains. Glen

www.accessnorton.com

https://www.classicbike.biz/Norton/Parts/1970s/Commando_Parts_73-74.pdf

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Yes. This is correct. To provide more info, I remember that the original "marketing plan" for the 1972 H*-R*d*r (AKA the "motorcycle sin that dare not speak its name" with apologies to Oscar Wilde) was for a standard engine and that would be baked into the price. By late spring/early summer, the boom in Norton sales in step with the introduction of the Combat engine was such that many dealers wanted Combat engines in the model. My memory is that this was done quietly in an plan to quietly sell off the existing motorcycles in the supply chain and then go with the Combat engine subsequently. But I have never been able to find any documentation of this; in discussion with Brian Slark, he has a similar impression as mine, but he cannot remember when/how many may have been sold through NVC in California.
So, if your hazy old memories are correct, there may have been a few Combat-engined H*-R*d*r Commandos built for a short time in 1972. Of course, the demise of the Combat engine on all models would have ended this sub-model as well.

I believe that all of the various s cams, other than the original ess ess cam, were designed by Peter Williams and his father. They were employed by Norton for the design work.
I'll guess that Peter Williams wasn't employed by Norton when he designed the PW3 profile.
The original ess ess cam was designed by Doug Hele.
BTW, great idea to call it the "ess-ess cam" as it should help to reduce confusion.

Glen

acotrel said:

You need to consider the times in which the Honda 4 and the Combat were current. In those days motor scooters, duffle coats and desert boots were the go. A Combat was a real motorcycle. That is not what was wanted. Most people could not ride a Norton 650ss or Triumph Bonneville 650 in the way in which God intended.
Norton's primary interest was racing, road bikes were secondary. Most race bikes do not make good road bikes, but something which resembles a race bike can feed a fantasy.
I have both raced and ridden road bikes. It is pretty much impossible to get fair dinkum on a road bike. You simply cannot use a road bike on public roads, in the same way as a race bike on a race circuit.
I think a Suzuki GSXR750 might be as close as anyone can get to having a thrill and staying sane. But even that might be too quick. One thing I would never do is road-race a modern motorcycle. The old ones are fast enough.

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I noticed Worntorn's comment about the horsepower of the Z1 Kawasaki being in the 80s and the Commando being in the 60s. That does not mean that a Z1 Kawasaki cannot be beaten by a Commando on a race circuit. There is an old saying 'torque wins races'. Most race circuits are not fully composed of long straights and sweeping bends. The difference between a short circuit and a big one is the gearing. But on a big circuit handling does not matter so much. At high speed the suspension pumps down and the bike becomes much more stable, top end power becomes more effective. When racing a Commando against large capacity four cylinder bikes - the lengths of the straights and the shapes of the bends are important.

worntorn said:

I believe that all of the various s cams, other than the original ess ess cam, were designed by Peter Williams and his father. They were employed by Norton for the design work.
I'll guess that Peter Williams wasn't employed by Norton when he designed the PW3 profile.
The original ess ess cam was designed by Doug Hele.
BTW, great idea to call it the "ess-ess cam" as it should help to reduce confusion.

Glen

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The trouble with this stuff, is that changing only one thing often does not give the best possible result. From experience we become aware of the interactions between the variables, but every change is still based upon supposition. I am always surprised when I achieve an improvement in performance. If you fit a different cam, it usually interacts with the exhaust system differently. Advancing a Commando 850 cam can give an increase in torque depending on the exhaust system configuration, however the performance of the bike might not improve until the overall gearing is raised.
With a road bike, there is probably no reason to bother doing any of this idiocy.

When I was a young lad and just after building my hot 850 light weight Commando/Featherbed back in 82, a good friend of mine Brian who lived in the same street as me had a Z1 and he always put sh it on me about my Norton, the usual crap, Bristish bikes leak and aren't reliable etc etc, well in 83 we were on a mate's memorial run up to Landsborough and up the range to Mapton at the other end of the range but from Landsborough at the bottom of the range was a long climb up the range to the top the climb was about 5kms and very steep, well on the way back to Landsborough as we started the climb down my mate on the Z1 and myself were beside each other and it started we both opened the throttles, it was a very high speed run and both bikes were flat out, well both bikes were neck to neck he couldn't get away from me and I couldn't get away from him before we got to the bottom of the range and had to slow down real fast.
Well after that day my mate never put sh it on my Norton ever again and we both had respect for each other after that high speed run, we both were still young and silly, both light weights for our 5'8 size, the Z1 a heavy bike the Norton a lot lighter than when it's was in Commando form and a bit of work done to the motor and open exhaust system, we are still mates and run into each other from time to time, I still own the Norton but his Z1 has long gone, he rides a restored Honda 750 4 and lives out at Esk now and we still have respect for each other, we both remember that day but we don't talk about it, just a friendly grin lol.
I have never had to prove anything with my Norton, but that day was a fun day and the fastest I have ever been on any bike of the times.

Ashley

ashman said:

When I was a young lad and just after building my hot 850 light weight Commando/Featherbed back in 82, a good friend of mine Brian who lived in the same street as me had a Z1 and he always put sh it on me about my Norton, the usual crap, Bristish bikes leak and aren't reliable etc etc, well in 83 we were on a mate's memorial run up to Landsborough and up the range to Mapton at the other end of the range but from Landsborough at the bottom of the range was a long climb up the range to the top the climb was about 5kms and very steep, well on the way back to Landsborough as we started the climb down my mate on the Z1 and myself were beside each other and it started we both opened the throttles, it was a very high speed run and both bikes were flat out, well both bikes were neck to neck he couldn't get away from me and I couldn't get away from him before we got to the bottom of the range and had to slow down real fast.
Well after that day my mate never put sh it on my Norton ever again and we both had respect for each other after that high speed run, we both were still young and silly, both light weights for our 5'8 size, the Z1 a heavy bike the Norton a lot lighter than when it's was in Commando form and a bit of work done to the motor and open exhaust system, we are still mates and run into each other from time to time, I still own the Norton but his Z1 has long gone, he rides a restored Honda 750 4 and lives out at Esk now and we still have respect for each other, we both remember that day but we don't talk about it, just a friendly grin lol.
I have never had to prove anything with my Norton, but that day was a fun day and the fastest I have ever been on any bike of the times.

Ashley

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I had a race with a mate on his Kawasaki z1000j
This was a very late zed and supposedly the one that handled better
I was on my t140e
We had left the pub and were heading back to another mates house
The road was really twisty,I took the lead and he was right behind me
Trying to put a bit of distance I ran wide on one corner and clipped the kerb in the other side of the road
This carried on until the road straitened out into a dual carriageway when he got past me
But as we came to a gentle right hand bend his bike started to weave
He backed off and I went through and put enough distance to get to my mates house before him
You've never heard so many excuses in your life before
He wasn't trying
The bike wasn't running right etc etc
If the road had been straight he'd have beaten me hands down

acotrel said:

With a road bike, there is probably no reason to bother doing any of this idiocy.

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Thanks for stating the realities of so called performance enhancing modifications. Although new to Norton ownership, I spent a lifetime owning, working on, and tweaking just about anything that burnt gasoline. Except for that maybe 5 per cent of the top tuners, the vast majority of the rest of guys making mods, me included, are working off of here say of those top 5 per cent as to what "may" improve performance, and to me, anyway, for most owners it's about name dropping of the mods that have been done at what old guys, like me, used to call "bench racing" sessions. No offense to anybody who does have the knowledge and have actually made improvements, but like many other pursuits, the majority of us/me are playing follow the leader. On a road bike, as acotrel eluded to, is it really going to make any difference, other than self satisfaction?

kommando said:

The Norton Twin was designed from the start as a road bike, the Manx was a dedicated race bike but what parts from the Manx made it to the twins other than the notable exception of the featherbed frame. And when presented with the Featherbed frame what manufacturer would not introduce it to the road bikes, the clue is in the nickname Featherbed.

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Until I actually rode a Manx, I did not know the reason they were so good. With most bikes of that era, if you rode them fast, you had to be 100% on top of them. When a Manx gets off line in a corner, if you gas it while cranked over, it actually helps you. The motor is well-foward, so the front end does not go light, and the bike self-steers in the correct direction without taking on more lean. The Seeley frames were better than featherbeds - they are lighter and the self-steering effect is more pronounced. You would not use a Seeley frame for a road bike, there would be no point to doing that. Nobody rides a motorcycle on public roads in the way they are ridden on race tracks. When you watch a road race, what you see is not what you get. To me, when I watch road races, they always look slow. But from the inside, they never are.
With featherbed frames, I always seem to be bashing myself. The Seeley is slimmer. The Seeley 7R AJS was the best ever British 350cc racing motorcycle.