Understand the Motor & Frame serial numbers

Redrider736 · Oct 13, 2020

Looking to understand the different numbers on my Frame Head Stock, Left Side of my Motor and on the Forward portion of the Swing Arm.

Redrider736 · Oct 13, 2020

-Front Frame Head Stock plate:
JUL 71
144283

-Left Side of Motor
20M3S / 140461

-Forward Portion of Swing Arm
134708 N

Derek Wilson · Oct 13, 2020

Redrider736 said:
-Front Frame Head Stock plate:
JUL 71
144283

-Left Side of Motor
20M3S / 140461

-Forward Portion of Swing Arm
134708 N

By forward portion of the swing arm, do you mean the top of the transmission?

If so - ideally - all of these numbers should match.

From what you describe, you have a 'bitsa' - a bike that has been pieced together out of parts, or has had both catastrophic engine and transmission issues, necessitating the full replacement of each.

The engine is a late 1970, and the transmission is a 1969.

Hope this helps.

Redrider736 · Oct 13, 2020

Derek Wilson said:
By forward portion of the swing arm, do you mean the top of the transmission?

If so - ideally - all of these numbers should match.

From what you describe, you have a 'bitsa' - a bike that has been pieced together out of parts, or has had both catastrophic engine and transmission issues, necessitating the full replacement of each.

The engine is a late 1970, and the transmission is a 1969.

Hope this helps.

And my Frame is a 1971 ?

Appreciate the above information

Ron L · Oct 13, 2020

Redrider736 said:
And my Frame is a 1971 ?

Appreciate the above information

If the frame tag is the correct one for your frame, yes. The 1971 and later frame will have the centerstand mounted to the engine cradle, while the pre-'71 has the crossmember further rearward with the centerstand lugs mounted to it.

Does the title match the number on the frame?

Derek Wilson · Oct 13, 2020

Redrider736 said:
And my Frame is a 1971 ?

Appreciate the above information

Yes, assuming the tag is original to the frame, the frame would be a 1971. Like Ron said, the center stand should mount to the transmission cradle and not to the frame.

marshg246 · Oct 13, 2020

Redrider736 said:
Looking to understand the different numbers on my Frame Head Stock, Left Side of my Motor and on the Forward portion of the Swing Arm.

To better understand, look here: https://www.gregmarsh.com/MC/Norton/CommandoID.aspx and here: https://www.gregmarsh.com/MC/Norton/CommandoSurvey.aspx

Redrider736 · Oct 17, 2020

Trying to post up some pictures, But not sure how too... LoL

RickM123 · Nov 27, 2021

Date Jul 71 is interesting for 144283. Mine is 3000 units later later and verified as a 3 June 1971 build in factory dispatch records - frame plate is stamped MAY 1971. From Greg Marsh's list it looks like most frame plates were stamped the month before the build/completion date - I'd never noticed that before?

B+Bogus · Nov 29, 2021

Interesting that the build date is 3 June? Is it possible that this is the dispatch date and not the build date, given that it's from the dispatch record?

I've seen dates vary significantly within VIN ranges. I've wondered whether the date was stamped around the time of dispatch, or QA inspection pass?
It seems to me that the VIN and Date were stamped at different times on ones I've seen; Like the VIN was stamped prior to fitment of the plate and the date afterwards. The numbers are always neat, whereas the dates are sometimes quite out of kilter one way or another, and occasionally not present at all, hence my 'hypothesis'...

texasSlick · Nov 29, 2021

RickM123 said:
Date Jul 71 is interesting for 144283. Mine is 3000 units later later and verified as a 3 June 1971 build in factory dispatch records - frame plate is stamped MAY 1971. From Greg Marsh's list it looks like most frame plates were stamped the month before the build/completion date - I'd never noticed that before?

I don't know if Commandos are same as Featherbeds, but the frame date on Featherbeds is stamped on the lug or tab for the head steady. This number, ex: 02 62 is the month - year code when Reynold made the frame, and would normally be a month or two before the completion date of the bike.

My bike frame stamped 02 62 was dispatched from the factory May 1962..

Slick

RickM123 · Dec 6, 2021

B+Bogus said:
Interesting that the build date is 3 June? Is it possible that this is the dispatch date and not the build date, given that it's from the dispatch record?

I've seen dates vary significantly within VIN ranges. I've wondered whether the date was stamped around the time of dispatch, or QA inspection pass?
It seems to me that the VIN and Date were stamped at different times on ones I've seen; Like the VIN was stamped prior to fitment of the plate and the date afterwards. The numbers are always neat, whereas the dates are sometimes quite out of kilter one way or another, and occasionally not present at all, hence my 'hypothesis'...

Good point - there are two dates in the AN dispatch records - the dispatch date was the latter of the two, and for my Commando, 9 July 71. Look at Gregg Marsh's register - most if not all of the registration plates are dated a month earlier the the earliest of the two dates.

B+Bogus · Dec 7, 2021

texasSlick said:
I don't know if Commandos are same as Featherbeds, but the frame date on Featherbeds is stamped on the lug or tab for the head steady. This number, ex: 02 62 is the month - year code when Reynold made the frame, and would normally be a month or two before the completion date of the bike.

My bike frame stamped 02 62 was dispatched from the factory May 1962..

Slick

Some frames certainly have month/year stamped on the LH frame gusset behind the rear iso mount, but I haven't seen it on '60s frames

Understand the Motor & Frame serial numbers

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