Understanding the date range of serial numbers - What is the model year?

Denis J

Denis J

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Hi All!!
I am trying to understand the Norton serial number timeframe. I read the last few threads on this with the new search feature, but I didnt see any conversations specific to my concern.

Here is my question:
Are the Nortons like other motorcycles from England when it comes to its production date?
- Here is my example - My 1970 or maybe 1971 fastback does not have the vin plate on the steering head stamped with the month and year of production. The serial number is there, but no month and year.
According to the numbers and year list that any internet search will bring up, my Commando serial number fits right after the September of 1970 bike -mine is 140XXX
Now if this was a BSA or a Triumph, that would make it a 1971 Model year bike. Is the production window of August - through - July the case with the Commando's or if the list says 1970 then that is its model year?

Thanks for taking the time to read this.
 
Norton did not follow a strict timetable on model year changes in the same way as BSA and Triumph did. Hence the use of MK,s to show major change points instead of year but especially in the early years its fuzzy eg is there really a MK1 750.

There are 5 750 MK,s and 3 850 MK,s .

Details here

ILLF8ED

Thread 'Commando Mk series'

I see references to Mk series numbers for 750 and 850 Commando models. Just to clearify here is my understanding and would like to hear if there is agreement. I've see some mix on the 750 Mk series depending on if fastback or roadster style - ref Roy Bacon.

750Mk1 - 1968 original fastback
750Mk2 - 1969 some changes to fastback such as gas tank emblems, non sand cast primary
750Mk3 - 1971 models with revised oil tank, side covers, electricals up to VIN 152xxx
750Mk4 - 1972 with revised crankcase, side stand...others VIN 200xxx onward
750Mk5 - 1973 final form of 750 VIN 220xxx onward...
 
Last edited:
Denis J said:
Hi All!!
I am trying to understand the Norton serial number timeframe. I read the last few threads on this with the new search feature, but I didnt see any conversations specific to my concern.

Here is my question:
Are the Nortons like other motorcycles from England when it comes to its production date?
- Here is my example - My 1970 or maybe 1971 fastback does not have the vin plate on the steering head stamped with the month and year of production. The serial number is there, but no month and year.
According to the numbers and year list that any internet search will bring up, my Commando serial number fits right after the September of 1970 bike -mine is 140XXX
Now if this was a BSA or a Triumph, that would make it a 1971 Model year bike. Is the production window of August - through - July the case with the Commando's or if the list says 1970 then that is its model year?

Thanks for taking the time to read this.
Click to expand...
Norton had no "Model Year". The date, when present, on the Certification Label is not reliable to when the bike was started or finished being built but is close enough. As late as 1972, the month/year were not reliably on the label. Some only had a year and sometimes not in the correct area on the label and some were blank. The earliest Commandos didn't have that label, and the serial number was stamped directly in the frame.

Learn more here:

Norton Commando Model Identification and Change History - GME

Norton Commando Model Identification and Change History
gregmarsh.com
and here:

Survey of Existing Vintage Norton Commandos - GME

Ongoing Norton Commando Survey of Serial Numbers, Dates and Related Information
gregmarsh.com

They are my effort to make sense of it, but there is so much conflicting written, posted, and verbal info that there is no perfect info.

I would consider 140xxx to be considered "70" since most consider 141700 or 141717 to start "71". That also means it is a 750 MK I as 141700 or 141717 started MK II.

Most importantly, is the center stand on your frame or on your cradle? Do you have a cross-brace at the bottom front of the frame or bottom near the back of the engine? That's one of the differences in MK I and MK II.
 
Denis J said:
Now if this was a BSA or a Triumph, that would make it a 1971 Model year bike. Is the production window of August - through - July the case with the Commando's or if the list says 1970 then that is its model year?
Click to expand...

It often wasn't actually the case with Triumphs for instance 1977 Triumph model year began from GP (June 1976) and 1979 model year began at HA (July 1978) and continued until December 1979 and there are other years that didn't begin in August.

Triumph Serial Numbers - BritBike.com

Vintage British Motorcycle forum, the best of british motorcycles, includes bulletin boards and free classified ads.
www.britbike.com www.britbike.com
 
This is great information gents. Thank you so very much! I have a lot to read to understand.
marshg246 said:
Norton had no "Model Year". The date, when present, on the Certification Label is not reliable to when the bike was started or finished being built but is close enough. As late as 1972, the month/year were not reliably on the label. Some only had a year and sometimes not in the correct area on the label and some were blank. The earliest Commandos didn't have that label, and the serial number was stamped directly in the frame.

Learn more here:

Norton Commando Model Identification and Change History - GME

Norton Commando Model Identification and Change History
gregmarsh.com
and here:

Survey of Existing Vintage Norton Commandos - GME

Ongoing Norton Commando Survey of Serial Numbers, Dates and Related Information
gregmarsh.com

They are my effort to make sense of it, but there is so much conflicting written, posted, and verbal info that there is no perfect info.

I would consider 140xxx to be considered "70" since most consider 141700 or 141717 to start "71". That also means it is a 750 MK I as 141700 or 141717 started MK II.

Most importantly, is the center stand on your frame or on your cradle? Do you have a cross-brace at the bottom front of the frame or bottom near the back of the engine? That's one of the differences in MK I and MK II.
Click to expand...
This is super helpful
I am not familiar with a braces under then engine. I will attach a few pictures for viewing. I do see a cross brace right about where the center stand is.
The center stand appears to be attached to the frame.
I will gather all the information on the bike and email it to you if you like. I have a few more and so does my pops. If it's helpful for your investigation.
 
Last edited:
Please excuse the dust and dirt. This one has been sitting under cover since 1988. I just got it out to put back on the road.
Understanding the date range of serial numbers - What is the model year?

Understanding the date range of serial numbers - What is the model year?
Understanding the date range of serial numbers - What is the model year?
Understanding the date range of serial numbers - What is the model year?
 
L.A.B. said:
It often wasn't actually the case with Triumphs for instance 1977 Triumph model year began from GP (June 1976) and 1979 model year began at HA (July 1978) and continued until December 1979 and there are other years that didn't begin in August.

Triumph Serial Numbers - BritBike.com

Vintage British Motorcycle forum, the best of british motorcycles, includes bulletin boards and free classified ads.
www.britbike.com www.britbike.com
Click to expand...
This is good info LAB. Thank you.
 
Denis J said:
I am not familiar with a braces under then engine. I will attach a few pictures for viewing. I do see a cross brace right about where the center stand is.
The center stand appears to be attached to the frame.
Click to expand...

Yes, that's the early stand that attached to the frame used before 1971. Curiously the cradle appears to have what look like holes for the later stand.

Later frames have a diferent cross-member 06.7155 fitted further forward.
andover-norton.co.uk

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk
 
Yes, that's the early stand that attached to the frame used before 1971. Curiously the cradle appears to have what look like holes for the later stand.
Click to expand...

I have seen this before on late 1970 model year bikes i.e. I had a 1970 Roadster type where the frame had the mounts for the tyre pump, central oil tank halo etc but had the holes for the later centre stand.
 
Okay once again you guys are an incredible wealth of knowledge.
Looking at Marsh's pages and going off what you guys are saying here I'm going to assume this is a 1970 Mark 1 Fastback please correct me if I'm wrong
 
All Roadster introduced, S Type discontinued in June (Last=135088), Fastback MK II, Sept. 1970 (139571) to Jan. '71 (141717). According to Peter Henshaw, 135140 was the first Roadster and he says it happened in 1970 at 135140.

20M3 Fastback Black Barrels, other Silver Barrels Tires: 3.00x19 Front, 3.50x19 Rear

Looking at your headlight ears I suspect you have a fastback Mk2
 
possm said:
All Roadster introduced, S Type discontinued in June (Last=135088), Fastback MK II, Sept. 1970 (139571) to Jan. '71 (141717). According to Peter Henshaw, 135140 was the first Roadster and he says it happened in 1970 at 135140.

20M3 Fastback Black Barrels, other Silver Barrels Tires: 3.00x19 Front, 3.50x19 Rear

Looking at your headlight ears I suspect you have a fastback Mk2
Click to expand...
Understanding the date range of serial numbers - What is the model year?
 
Is there another way to identify with certainty that it's a combat? I'm looking at the fasteners for the cylinder head and for the cylinders and they definitely been turned on but I don't know if that means it's had Parts changed or serviced over the years. Knowing where this came from I think it's safe to say that nothing has happened in 37 years.
 
I copied and pasted Greg Marsh's earlier post, we are 55+ years down the way is it not likely the barrels have been off and been painted? Having owned Nortons continuously and been around them for 50+ years I have not come across a Combat built prior to the 72 model year [A friend has a '71 manufactured disc front brake Combat so therefor '72 model] maybe they were not exported in my direction!
 
"Is there another way to identify with certainty that it's a combat? I'm looking at the fasteners for the cylinder head and for the cylinders and they definitely been turned on but I don't know if that means it's had Parts changed or serviced over the years. Knowing where this came from I think it's safe to say that nothing has happened in 37 years."

Does it matter? the end of the day you have a bike hopefully you are happy with ! it's been around for 55 years why should it blow up now! Combats had 10-1 compression ratio and a SS cam, an easy way to put your mind as rest is to check the diameter of your inlet ports Combats were 32mm where as earlier heads were 28-29mm.
 
possm said:
"Is there another way to identify with certainty that it's a combat? I'm looking at the fasteners for the cylinder head and for the cylinders and they definitely been turned on but I don't know if that means it's had Parts changed or serviced over the years. Knowing where this came from I think it's safe to say that nothing has happened in 37 years."

Does it matter? the end of the day you have a bike hopefully you are happy with ! it's been around for 55 years why should it blow up now! Combats had 10-1 compression ratio and a SS cam, an easy way to put your mind as rest is to check the diameter of your inlet ports Combats were 32mm where as earlier heads were 28-29mm.
Click to expand...
I agree..I was hoping this was not a special bike as I intend to put it to work from here on out. I am happy owning this one, but I am no longer interested in being a steward of a rare machine.
 
Denis J said:
Is there another way to identify with certainty that it's a combat? I'm looking at the fasteners for the cylinder head and for the cylinders and they definitely been turned on but I don't know if that means it's had Parts changed or serviced over the years. Knowing where this came from I think it's safe to say that nothing has happened in 37 years.
Click to expand...
A Combat will have a "C" stamped on top of the head. A combat will have a 2S profile cam. Unless someone added those, it is not a Combat.

I have an engine with a 70 bottom end, 71 or 72 frame (71 serial), 850 style cylinders, and a RH6S (73) head. So, is it a 70, 71, 73? It is titled as a 72.
 
It is a rare fastback according to an article I read in "Classic Bike" there was not many Mk2 Fastbacks built.
 

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