About Combat engine numbers

The link below says that combat engine starts in 1972 with n. 200976 but with n. 204049 they come back to the standard cam.
The question is: all the other 1972 engines that are not included into those numbers cannot be combat?.
Ciao
Piero
http://www.motos-anglaises.com/motos/no ... histo.html

I think that link is wrong.

A change was made to the camshaft bush/scrolling at 204048-9 but that's all as far as I know.

Quote from Service Release N3/13:

Use scrolled journal camshafts prior to Engine Number 204048 with plain bushes NMT2036 6
NMT 2037
Use plain or scrolled journal camshafts subsequent to Engine Number 204049 with scrolled
bushes 062600.

Click to expand...

https://www.oldbritts.com/cam_bush.html

Hi Les,
it means that 206.... or 207.... could be Combat Endine?
Thanks.
Ciao
Piero

pierodn said:

it means that 206.... or 207.... could be Combat Endine?

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Yes, could be, because as far as we know, Combat production was supposed to have ended at 211110, although standard specification models were also produced during the 200976-211110 series.

It means that are Combat all the engines in this range of numbers with the C stamped on the head, 2S cam, 932 carbs, and compressed pistons?
Ciao
Piero

pierodn said:

It means that are Combat all the engine in this range of numbers with the C stamped on the head, 2S cam, 932 carbs, and compressed pistons?

Click to expand...

If the engine serial number falls within *200976* - 211110 and appears built to Combat specification then there is a reasonable chance that it would have been a Combat originally, however, after 40+ years nothing can be taken as certain unless the factory or other historical records prove it.

*(Some apparently Combat spec. machines have been reported with serial numbers lower than 200976).

Compressed pistons

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Combat pistons were the same compression ratio as standard pistons, as the skimmed Combat cylinder head was responsible for the increase in Combat compression ratio.
All 750 models were subsequently fitted with the stronger "Combat" pistons.

L.A.B. said:

pierodn said:

as the skimmed Combat cylinder head.

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Click to expand...

Les,
i have two C head, one is skimmed, the other not, is full.
Ciao
Piero

pierodn said:

i have two C head, one is skimmed, the other not, is full.

Click to expand...

That is unusual.

Are there any other stamp markings on the head that isn't skimmed?

Does it have 32mm inlet ports?

L.A.B. said:

pierodn said:

i have two C head, one is skimmed, the other not, is full.

Click to expand...

That is unusual.

Are there any other stamp markings on the head that isn't skimmed?

Does it have 32mm inlet ports?

Click to expand...

Only C stamped and has inlet 32 ports.

Combat engines were trouble. So dealers tended to detune the beasts when the engine blew up. There is a Service Information about what to do with a Combat engine to make it last, shamefacedly for "Racing Purposes" (see http://www.andover-norton.co.uk/SI%20Combat.htm) but in fact the cure for all of these unfortunate #200.000 on-crankcases.

The German importer Koerner rebuilt 400 engines in 1972 on warranty and made a point of de-tuning every single one of those. He also claims he found the "Superblend" solution to the main bearing question.

They fired the poor man as importer, not acknowledging he sold the "Combats" to American soldiers in the Frankfurt area, the region where one finds six-lane autobahns, at the time virtually empty and without speed limits. Guess what a 19-year-old American does with his Norton on that autobahn.... Most probably the same I did on Norton F1s 30 years later as a German importer, thus finding out the tank breather was calibrated too small- the petrol pump could not cope with vacuum developed by the fuel consumption riding flat-out on that autobahn for a while. Something that never occurred in England, not even at MIRA. So even thirty years later it was still possible to ride that autobahn flat-out at 130mph plus. No longer possible today in bright daylight, though!

Joe/Andover Norton