Factory 1972 NON Combat spec?

Craig said:

My '72 Combat's head stock plate says April '72 it has the disk front brake , and all numbers match, but I have never been able to find any sign of a "C" marking on the head. The carb ports are 32 mm though ... I've always wondered what happened to my "C" marking ... all other aspects of bike say Combat #207384 ... is it really
Craig

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Look under the head steady plate. If not there don't worry, some of the combat heads reportedly didn't get a "C" stamp. The best way to tell is the close spacing between the bottom fin of the head and top fin of the cylinder due to the 40 thou shaved.

illf8ed said:

The factory was not necessarily stockpiling as the factory records show shipments out of the factory of '72 models prior to Jan '72. If any stockpiling it was at the distrubutors such as Berliner here in the US. The factory records only show date shipped and to which distributor. They don't show when the machine was sold to a customer.

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The reason I mentioned stockpiling (of Combat models) is that Jan 1972 announcement that is oft quoted.
We can assume the factory kept rolling out 1972 models from Sept 71 - without delving into if the unions were cooperating.
We have seen, and you mentioned too, numbers above 150,000

What some of us would like to see/know though is if Combat models were shipped out of the factory right from Sept 71,
or if that Jan 72 announcement is indeed true.
I don't think this distinction has actually appeared in print, yet ?

Bit like the 850 models were announced into early 1973,
but some were clearly made, and stamped onto the vin plate, in the months preceding this.
And stockpilied, for shipping after the announcement date ??
Or were they shipped on the date stamped on the vin.
Bit of a divergence, but a parallel example of Norton Factory practice...

In early '72 I wanted the disk brake but no Combat engine in a Roadster. I was told that if I wanted the disk brake I MUST have the Combat. So that's what I got. Bought from Comerfords in Thames-Ditton England. S/N 202093 Jan 72 date. Picked it up in June of '72 and put about 1000 miles on it in England before we returned to the states with "used" bikes.

Disk brakes were described in the ads as an option for 1972. Not available in 1971. Hi Riders did have the drum brake and the stock engine in 1972 and had silver barrels. Just my memory of it all and there are probably exceptions.

Thanks, thats exactly the sort of details from owners that is needed to clarify the discussion here.
Its going to be interesting to see if anyone bought a Combat before that Jan 72 date.

I've seen a couple of 72 Commandos, non-combat, that had a disk.
Owners claimed they came like that - but didn't buy them new.
I've also seen a 71 for sale with a disk.
Owner claimed it came like that - but again didn't buy it new.
The 72 brochure says a disk was an option for a Roadster or Interstate.
So were disks available at all, prior to that optional disk announcement ??
If Dealers didn't have any in stock, did they simply say they weren't available...

Wonder if the factory records show if a disk was fitted ?
David, that 71 for 72 sheet you have ??

Rohan said:

MikeM said:

Perhaps its interesting information for some of us new members.

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So ask away.
But its all in previous posts, if you care to search.

But hobot, on the other hand, has been through this, at least 10 times before.
And perhaps what some folks don't know here is that he cross posts all this to other lists.
Multiple times !!! The same ole linguine, again and again and again...

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I feel I need to beat the dead horse here. I am in another Ahem forum for an American brand who has a moderator that very often deletes "duplicate" posts. Sometimes posts that actually have value. I dont always have the time to search and go back and read those older posts and there is sometimes new members who post additional information.
All Im saying, is that its new to me, and seems to keep things going, and sometimes new informaton will surface. JMHO Thanks for listening.

Did any Combat heads come with 30mm ports?
I have another 72 that came from Germany with klm Speedo and have 32 carbs but the head has 30 mm ports?
Curious! It came with black barrels and disk brake. I never knew the previous owner. The headstock registration tag was also black and not the standard red plate.
Thanks,
Cheers,
Thomas
CNN

I bought a brand new combat in Canada in the summer of 72. As I recall the shop had about 10 Nortons all lined up. At one end were basic bikes at $1795.00 and at the other end of the line were combat roadsters and interstates at $1995.00, (only about 3 or 4 machines combined out of the 10). There was just the 3 types of styles and the 2 different prices. Only combat roadsters and the interstates had the disc brakes. I chose a black with gold combat roadster because I wanted the disc brake and the 10:1 compression, ss cam, bigger carbs and intakes etc. (the hopped up version). I think it was around may or june but I don't remember the exact date.

Germany had black id plates but I've never heard of a combat head with 30 mm intakes.

I believe there is a lot of misunderstanding and misinformation concerning production dates and model years. As with automobiles, new models were produced and sometimes found in the showrooms prior to January of the model year. Serial numbers will provide model years, i.e. 20XXXX are 1972 (MkIV 750) and 22XXXX are 1973 (MkV 750), but production for both of these obviously began prior to the model year. I have two '73 MkV's with November, '72 build dates.

More to Hobot's question, in 40 years of owning and building Commando's I have only run across one non-Combat '72 750. It had silver barrels, drum brake, and 30 mm carbs. I can't tell you what the build date was as it was 20 odd years ago. It also was not a showroom example. It did, however, have a 20XXXX serial number. I don't remember if it had a camshaft timed breather or rear crankcase breather.

I'm curious about Canuk's '72 with 32 mm carbs and 30 mm head. Are the ports actually 30 mm or 28.5 mm at the head? What intake manifolds does it use? There were no 32 to 30 mm manifolds supplied until the '74 850. Could someone simply have bolted on a set of 32's from a Combat and mismatched the ports?

Ron L said:

I'm curious about Canuk's '72 with 32 mm carbs and 30 mm head. Are the ports actually 30 mm or 28.5 mm at the head? What intake manifolds does it use? There were no 32 to 30 mm manifolds supplied until the '74 850. Could someone simply have bolted on a set of 32's from a Combat and mismatched the ports?

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Ron,

Ron L,
I just went into the cave and re-measured the intake ports on the head and these ports measure 28.5mm. The bike came with 32mm carbs. The gap between the head to barrel indicates that the head is shaved ala Combat. I think the original manifolds were 32-32 both ends. Again this was a bike I bought for 1000 bucks in the 80's. Originally I wanted it for a parts bike but I'm into the restoration mode, getting all my Norton’s on the road.
I just got to find the time.
Cheers,
Thomas
CNN

Ron L said:

I believe there is a lot of misunderstanding and misinformation concerning production dates and model years.

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It has, many times here, been noted that Nortons production year began in Sept.
So 1972 models would have been manufactured from Sept 1971.

However, it has also been noted, in a number of sources, that Combats commenced in Jan of 1972.
Whether this is true, or a complete myth, is what is being discussed here.
And how that came about, if it is indeed true....

What we need is someone who actually bought a Combat prior to that aforementioned Jan 1972 announcement ?

And, as a parallel to these Combats, we also have the new 850 models that were announced in early 1973.
This was very widely publicized in the press - but manufacture (and shipping ?) was clearly underway before this date,
because they were available out of the showroom right from the announcement.

Apart from the obvious there are other subtle differences between the combat and standard engines. These photos are from my 750 workshop manual. It was bought in 73 but I think it was printed in 72 as there is no reference to 850's in it. It is part #063419.

Of interest is the nominal inlet port diameter which shows the combat as the same as the standard (actually .002mm larger than standard) OR the larger known diameter of 31.75 so it looks like there may have been a period where combats were issued with the smaller inlet ports. Also the ex port nominal dia. is written as 31.76mm and 31.75mm on the combat. I've always considered this ex.port dia. as a typo as it differs by only .01mm.



The next two diagrams follow in the Technical Data and are all straight forward although the insulating washers were removed from the combat at some point to accommodate the higher valve lift and fitted length of springs:

Rohan said:

Wonder if the factory records show if a disk was fitted ?
David, that 71 for 72 sheet you have ??

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Not that much information as you would expect on the factory record sheet. How many words is a picture worth?
Here's the 151xxx page.

illf8ed said:

Not that much information as you would expect on the factory record sheet. How many words is a picture worth?
Here's the 151xxx page.

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Thanks. It was worth a try.
Those pages do show what colour they were though...

Lets try a different tack then.
Have you enquired of the NOC when your Oct 71 Combat was dispatched from the factory ?
(And if they were recorded as Combats or not ?).

It must be commented that we have previously noted that those manuals were none too accurate in the mm conversions, its evident the inches were the primary measurements and the mm were done later - there are a few terrible mm clangers.

Speaking of errors, has anyone noted that the Combat cam material has an error too !?
EN 32 B should be quoted for the combat material too (??)

Obviously a typo ...

Are the valve springs for a Combat stronger ?

RennieK said:

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I think the springs are all the same. The diagram is confusing because the free length (unassembled) is given in the top line of text to the left and only the fitted length appears in the comparison chart on the right. This chart shows where to shim the springs to in the valve closed position so they are just before coil bind in the fully open position.

Ah ha just as I thot non Combat spec '72's were rather late in the year produced, not a planed model at all and in rather low numbers. Trixie Combat Bomb had the taboo Al gasket with the taboo over slotted pistons cause sever damage while just about coasting at 50 mph.

>>>
Regarding models, this was a period of plenty, the Fastback with several exhaust systems still had a year to run, the Roadster having taken over from the 'S' Type was to last through to 1977 as an 850 while the clamour from the European market to get away from the high rise bars and peanut sized tanks gave us the Interstate, also with a new lower exhaust system. Low gear ratios fitted mainly for the American market were raised; these had allowed too much over revving, which didn't do much for the already overstrained Combat unit. As all these Combat modifications were well under way there was short term retuning, with the earlier cam and a lower 8.9:1 compression ratio. By 1973, Superblends and 32mm carburettors were standard, but the compression ratio was kept down to 8.9:1. The latter was achieved by a short term expedient of using a thicker head gasket, unfortunately the material chosen was aluminium instead of copper, it is said because the stamping machine couldn't cope with thick copper. True or not, aluminium is possibly the worst material ever used for this purpose, it just oozes out the more the bolts are tightened and oil seepage is ever present. Back to the drawing board, copper or flame ringed halite gaskets ended up being the only satisfactory ones. More here
http://lansdowne2.dh.bytemark.co.uk/Plo ... y/commando

I have a very late 72, Aug build date, 211xxx vin number. It was definitely not a Combat. Has a non-stamped head but judging by the fin to surface spacing was lower compression. It also has 32 mm carbs. I don't think the cases had been split and it had superblend bearings. It also had the standard cam not the Combat cam. Barrels were black but may have been repainted along the line. Disc brake, no turn signals. Must have been one of the last 72's built.
Interestingly it was titled as a 73 even though it clearly has a 72 vin. My guess was that it was a hold over until the next spring and titled as a new bike. I tried to get the Texas DMV to retitle it as a 72 and even when I showed them the records from the Norton Owners club showing it to be a 72 they wouldn't do it.

Ok htown that helps explain some my confusion d/t actual production year not matching official records that you'd have to use for court. Wonder what these non Combat '72's could do in the 1/8th mile or 1000 ft drags to see if gives up much to matter til up near the ton. Still if its a '72 then its part of the Cream of the Commando Crop year to me. I am ambivalent on black or ally shiny barrela, one looks bad nasty dull while the other a proud gleaming profile. Ok my reason to ask is now satisfied, so must strain extra to be accurate by having to type out "a Combat" or " a non Combat" instead of just '72's. Wonder if there's a range of numbers that covers the non Combat interim models, as article implies that Combats continued a while longer after non Combats stop gap, with the endurance upgrades installed.

I wonder if the 1st September has something to do with the recognised year of production of motor vehicle in Britain. Could this explain why a bike manufactured after that date may be referred to as being " next years model". This has sometimes been used to advertise vehicles in NZ I think.
I remember being told that people will wait till 1st Sept before buying a new vehicle in Britain just to get the next years reg. plate, and be considered in that age group for age of vehicle. Car dealers advertise the vehicle reg character rather than the actual age of vehicle etc.

Dereck

kerinorton said:

I remember being told that people will wait till 1st Sept before buying a new vehicle in Britain just to get the next years reg. plate, and be considered in that age group for age of vehicle. Car dealers advertise the vehicle reg character rather than the actual age of vehicle etc.

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The new UK registration plate 'year' actually started on the 1st. of August at that time.
http://en.wikipedia.org/wiki/Vehicle_re ... erritories
"1960s to 1982"