Engine/ Frame Numbers (2005)

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Jun 3, 2005

My Commando MK2A 1975 has on the registration document frame# 112958 and engine# 318577, the engine number was found on the aluminium plate and matches the registration document.

Where do I find the frame number as I'm checking to make sure they match.



The frame number is steel stenciled onto the steering head tube on the right-hand side. It’s often difficult to see without looking closely with a bright light. Notably, this number will not match the engine number.

Jason Curtiss said:
Notably, this number will not match the engine number.
My own 850 Mk3 certainly does have matching numbers on the headstock plate, frame and gearbox! The engine would have been the same as well but the cases have been replaced with new items.

You must have one of those rare MK IIIs :wink: !

All of the ’75 Commandos I’ve seen stateside have a frame number that is different than the engine/transmission number. My ’75 is actually titled with the frame number, not the engine number. I think this identification number mismatch between engine and frame is unique to the ’75 model and to Commandos exported to the US. Perhaps Ron can expound on this subject.

As I have read and also been informed by a more knowledgeable person than myself that a lot of 850's had Italian built frames, (these are supposedly identified by the stamped headstock 'F' prefix, and the first number digit changed to '1') the British (Reynolds Tubing) manufactured frames more likely to have the matching numbers possibly?
engine/frame numbers

Hi Jason,

It gets a little confusing when talking about frame numbers on 850s. As you said all of the 850s I've seen have a number stamped on the head tube preceded with "F" that's different than the number on the engine. The aluminum plate number sometimes matches the engine number and sometimes matches the frame number. My understanding is the same as L.A.B. that the "F" are the Italian made frames.

No such issue with 750 Commandos. All ID plate and engine numbers matched from production and no stamped numbers on the frame tubes.

Another point of identification for 850 frames is the part number stamped on the left gas tank mount facing forward.
064140 is 1973
065404 is 1974
Don't get excited if your '74 has a 064140. Norton probably had left over frames while producing the '74 model. My '74 JPN was like this.
Well, I got home from work and checked the number stenciled into the steering tube. The prefix is 850F..., so it must have been made in Italy.

Thanks L.A.B. and illf8ed for the interesting info on Norton frames!

Checked out my frame number that was stamped into the headstock on the right hand side of the bike. The number is 850 F132272, I take it the bike has an Italian made frame?

What is the difference if any? Are they good or bad as this one looks alright.

The aluminium plate on the other side of the headstock has the number 318577 which matches the engine number.


What is the difference if any?

From what has been written about this apparently the Norton factory test riders could tell the difference in a blind test whether the bike they were riding had an Italian or British frame!

Many of the Italian frames were sent to Reynolds to be inspected and to have faults corrected after various Italian framed bikes were found to have handling problems. A lot of frames were found to be out of alignment, other faults included tubes that were found to be the wrong gauge and also tubes made of the wrong grade of steel!
Thanks for the information L.A.B.

A further question: When checking the registration certificate the engine number matches with the one on the aluminium plate. The VIN/Chassis/Frame No. on the document is 112958 and doesn't match the one stampted into the headstock which is F132272.

Does this matter?

Thanks again,

Does this matter?


I am guessing you are in the UK?

If so then you may have some problems at MoT time now the test has become computerised, the frame and engine number details are supposed to match those on the registration document and these now have to be entered on to the MoT database. I think the test can go ahead but the DVLA will contact you about any discrepancy.

Of course if you do not live in the UK then disregard what I have just said!
The 850 MkIII frames are supposed to have started from F125001, so F132272 would seem to be from the MkIII series? Is there a number on the front of the L/H frame tank mounting bracket? A MkIII frame should be stamped 06-5632.
I have a Dec 73 build, 74 model year 850 with the "850F.." frame stamp, but unfortunately no aluminium plate (not uncommon). On other makes (BSA etc) with matching numbers, the frames would have to have been made in the same place as the motor, or all the numbers put on at the last minute when the bikes were built up. On these other makes, the frame number is often painted over, so may have been stamped prior to painting. Seems like a pain for factory logistics, keeping things together.

Norton, however, had the frames made in factories separate from the engine, both in UK and Italy, so they only met the motor at the end. So they devised the aluminium plate, which they fixed to the frame when the bike was assembled, and stamped it with the engine number. Hence "matching" numbers and build date, and original factory frame-engine(and gearbox) sets.

There is some evidence that the "850F.." frame stamping is actually a batch number and not unique, as there are rumours that some people in places where the title contains the "850F.." number have been mistakenly pinged for having someone else's bike, as they had the same frame number!

And if you think about it, the "850F.." frame number shouldn't resemble at all the engine number, particulary if the frame is being made in Italy and the engine in the UK. Can't imagine Norton sorting through loads of imported frames, to find the right number for any given engine. I don't imagine they would have bothered!!

L.A.B. said:
The 850 MkIII frames are supposed to have started from F125001, so F132272 would seem to be from the MkIII series? Is there a number on the front of the L/H frame tank mounting bracket? A MkIII frame should be stamped 06-5632.

Checked out the left hand tank mounting bracket and sure enough - found underneath the layers of paint the number 06-5632 which I assume is a MK3 frame. I am a UK resident.

How the wrong frame number is on the document I don't know. The bike was supposidly bought brand new from a shop in Nottingham, UK and then sold to the second owner in Grantham, Lincolnshire 6 years ago. I am the third owner from new.

I am becoming suspicious as the man re-building the engine has found many things. His main finding was a copied racing camshaft that was fitted, that is a pattern and various other things. As to date, I have had to replace the camshaft, cam followers, pistons, valves, big end shells but things like the bores were ok - just needed honing.

The person building the bike assures me when the engine is finished it will be near perfect. I only hope he is right as it has certainly cost some money.

Thanks again for your replies,

Neil, my 850 MK2A is registered the same way even though like yours it has the aluminium plate with a number matching the eng number. I am in the UK too , one of these days I will get a DVLC bod to comeout and correct it but first need to get a dating cert from NOC to prove I am correct.
Damn Snow !!!!!!!!!!

Curiousity got the best of me, so today i went out to check s/n #'s

The bike is a 75 / 850 Roadster . The manufacture stamp is dated 7 - 75

All serial numbers match and would appear to be original

Are you saying that your frame number, engine number and transimission number match? If so, it's the first '75 Commando I've heard of where all three numbers match.


Have you forgotten my posting on Dec 27 already? Or your reply?

Well I guess in all the excitement about discussing Norton serial numbers, I did forget that you, too, had a Norton with all three numbers matching! (And possibly too many Boddingtons may have contributed to this oversight.) So, that makes two ’75 Commandos with three matching numbers! Sorry for the gross oversight there L.A.B..

It was your post that prompted me to check. Numbers don't make it run any better so i never worried much about them. Engine / tranny , frame and name plate all have the same numbers .I had a good look at the frame to see if the stamping was original and there are the little Norton circles before and after the number so i can only assume that the frame is correct.

I sold a Mark III about a year ago. The frame tag, engine and trans all matched. The frame had another number stamped in the neck that was different.
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