Requesting help in identifying 850 model

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Mike T

Mike T

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asking for a friend..

Hello guys

One of our club members has just bought a very promising basket case 1974 850 Commando and he would like to know what model it is.. i.e. MK2, MK2A or other?

The side panels look earlier as the LH side has the bracket for the dsuz fastener and not the MK2A recess in the bottom right corner. But the chainguard looks to be MK2A with the cutaway for the inspection grommet. But this could be just a selection of parts from various bikes.

The VIN number on the engine case and the frame plate match and are: 313764

Here's a little video of his project

Thanks for your help
Mike
 
Mike T said:
asking for a friend..

Hello guys

One of our club members has just bought a very promising basket case 1974 850 Commando and he would like to know what model it is.. i.e. MK2, MK2A or other?

The side panels look earlier as the LH side has the bracket for the dsuz fastener and not the MK2A recess in the bottom right corner. But the chainguard looks to be MK2A with the cutaway for the inspection grommet. But this could be just a selection of parts from various bikes.

The VIN number on the engine case and the frame plate match and are: 313764

Here's a little video of his project

Thanks for your help
Mike
Click to expand...

As the old bloke tells in his video there were some subtle changes going on before the MK3, hence the MK2A. Airbox, bean can mufflers, cut away on chain guard for brake inspection, recess in side cover, you have 2 swing arms in your video, the appropriate one would be the one with the reinforcement, plus it should have the welsh plugs on the swing arm pivot. Your frames do not have the extra brackets for the hinged seat either. My bike is # 31661#, June 74 and it is an MK2. MK2A had late year changes in anticipation for the 75 MK3. Chain guard cutaway, swing arm, air box, etc.. So what you have is a bunch of parts, but most are for the MK2, which is what you have. So just put it together using parts references for the MK2 except for the swing arm. Good Luck.
 
The bike came with extra parts, one of which is the '75 swingarm, we knew that. It also came with an extra frame which is earlier than a '74. My frame has an additional plate under the rear upper frame (rear brake light attaches to it) for strength to keep passenger's weight from bending rear upper frame but does not have the plate for holes for '75. Bike was pretty complete when taken apart 18 years ago. The seller is the person that took it apart so had first hand knowledge of what he did and why. So parts as far as we can tell are from the '74 year. Built in 03/74 so early model and might not have all the changes Norton did during the year closing in on the many changes for the '75 model. With VIN number and date of build I was hoping to get the correct model name/number from one of you knowledgeable Norton owners. Thanks for you input. My previous Norton was a '71 so no mystery on that year.
 
My April 74 mk2 314xxx has mk3 style swing arm and bushes, lengthwise battery tray and cut out chainguard.

Telltale for the 2a is transverse battery tray as that is needed for the plastic airbox, and that is not what is in your video.
 
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My Mk2a has a VIN of 311 and build date of December 1973 (Did L.A.B say Mk2 and Mk2a bikes were built at the same time)
It has everything except the grommet brake plate, chain guard cut out and that added plate at the shock absorber mount.
It does have the inner primary cover with cone at the sliding plate for the output shaft.
Only thing not original (That I know of ) was the front rim and S/S spokes (Got a NOS MC275 rim from the UK) and although not a factory part ? I picked up a NOS set of TEX Viewmaster mirrors.
I had in the beginning been under the impression that the Mk2a was after the Mk2 and the last right hand shift model but it was not the case.
It seems even the Mk2a was getting updates through the 1974 year until the Mk3 release.
 

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Mk 2 and MK2a's were built concurrently, MK2's for US and 2a for UK europe but some 2a's did get to US, best clue as to which version the bike was originally is the battery tray.
 
If it's of any interest, my M2A was built September '73, has the transverse battery (QED) but engine number 308xxx. Make of that what you will ...!
 
Time Warp said:
My Mk2a has a VIN of 311 and build date of December 1973 (Did L.A.B say Mk2 and Mk2a bikes were built at the same time)
It has everything except the grommet brake plate, chain guard cut out and that added plate at the shock absorber mount.
Click to expand...

According to the Mk2/2A parts supplement, the 065818 chainguard with the brake lining inspection slot wasn't fitted to both 2 & 2A until January '74.
A Dec. '73 build not having the triangular shock inner mount plate extension is unusual. The rear view mirror and stem are also listed in the supplement.


NortonMKIIA850 said:
If it's of any interest, my M2A was built September '73, has the transverse battery (QED) but engine number 308xxx. Make of that what you will ...!
Click to expand...

Sounds normal enough.

https://issuu.com/sealycycleservice/docs/norton-850mk2-2a_06-5988
"850 Mk2 & 2A After Engine Number 307311" (the drawings added to the supplement are from the '73 parts book. The actual Mk2/2A supplement having no illustrations).


300000 850 Mk1.
306591 850 Mk1A low noise emission model intended for 'Europe'.
307311 Mk2 and Mk2A (according to one source, the first Mk2A was 308360)
850 Mk2 = Upgrade of Mk1 (but with the higher 'A' 2nd. gear ratio).
850 Mk2A = Upgrade of low noise emission Mk1A also intended for Europe but some Mk2As were eventually sold in the USA, according to one source the first US Mk2A was 316170.

325001 (frame F125001) = 850 Mk3.
 
" The seller is the person that took it apart so had first hand knowledge of what he did and why."

If he took it apart 18 years ago and says he can remember what he did and why, he must have been placed in suspended animation the following day and awakened a couple of days ago! :)
 
Mine is a 312xxx serial and is a USA bike with the ham can so is a MkII. Feb 74 manufacture.
So look to see if the rear air filter plate is among your bits.
 
L.A.B. said:
307311 Mk2 and Mk2A (according to one source, the first Mk2A was 308360)
850 Mk2 = Upgrade of Mk1 (but with the higher 'A' 2nd. gear ratio).
850 Mk2A = Upgrade of low noise emission Mk1A also intended for Europe but some Mk2As were eventually sold in the USA, according to one source the first US Mk2A was 316170.
Click to expand...
Ooh, so if that source is correct my MK2A was around the 200th to be built – not terribly exciting, but the engine and gearbox numbers match, and now I'm wondering how many bikes were being turned out per week (month?) around that time ... Sorry, I expect that information's out there somewhere ...
[Edit:] From searching the forum, I see that discussing Commando production figures can be akin to debating how many angels fit on the head of a pin! Forget I mentioned it! :p
 
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My 1974 Norton Commando 850 Roadster MK2 [HASHTAG]#313641[/HASHTAG] (Date "3 74" on plate). Very close to yours. 1974 models are arguably the best year of Commandos!
 
Thanks Kim. I wonder what the differences are on the '74 MarkII (not A or B) are from the '72?? I know my frame has additional support plate just under passenger position and cut out on chain guard but do not know what else was different for that year in early production. My air box is standard wire mesh type as an example. I am owner of above 313764 bike we have been asking questions about. Thanks.
 
Mike T said:
asking for a friend..

Hello guys

One of our club members has just bought a very promising basket case 1974 850 Commando and he would like to know what model it is.. i.e. MK2, MK2A or other?

The side panels look earlier as the LH side has the bracket for the dsuz fastener and not the MK2A recess in the bottom right corner. But the chainguard looks to be MK2A with the cutaway for the inspection grommet. But this could be just a selection of parts from various bikes.

The VIN number on the engine case and the frame plate match and are: 313764

Here's a little video of his project

Thanks for your help
Mike
Click to expand...


Mine is 310311 and is MK2A for the most part, it was built in November 1973 (1974 Model Year). I think (not sure) around the time mine was built MK2 was transitioning to MK2A - I don't think it was an overnight switch. The one you have is a later 1974 model year so I'm confident it is 2A. I bet if you keep checking, you'll find MK3 similarities as well since yours was nearing the end of the MK2As.

My chain guard is a MK3 type and my air box is the MK3 plastic kind and both were definitely on the bike in 1976 when the second owner bought it.

So, it can be real hard to be sure. Although mine is stock now, here are the things it went through in it early life as told to me by the second owner - I have service records to prove parts of it:

Purchased in Scotland in Spring of 1974.
Imported to Pennsylvania in the Summer of 1974.
Converted to a Café Racer.
Converted back to stock.
Ridden to California in early 1975
Converted to a Café Racer.
Converted back to stock.
Ridden to Pennsylvania in 1976.
Sold to the second owner in the Fall of 1976.
 
marshg246 said:
Mine is 310311 and is MK2A for the most part, it was built in November 1973 (1974 Model Year). I think (not sure) around the time mine was built MK2 was transitioning to MK2A - I don't think it was an overnight switch.
Click to expand...

There was no "transition" from Mk2 to Mk2A.

The Mk2 was an upgrade of the Mk1.
The Mk2A was an upgrade of the Mk1A.

Mk2 and Mk2A variants were produced concurrently as they were intended for sale on different world markets so both Mk2 and Mk2A were produced until around the end of 1974.
The Mk1A and Mk2A were low noise emission models originally intended for the European market, the Mk2 continued to be sold in the USA although some Mk2As were eventually sold in the US they didn't entirely replace the Mk2.



marshg246 said:
So, it can be real hard to be sure. Although mine is stock now, here are the things it went through in it early life as told to me by the second owner - I have service records to prove parts of it:

Purchased in Scotland in Spring of 1974.
Imported to Pennsylvania in the Summer of 1974.
Click to expand...

As it was originally built in November '73 and purchased in Scotland then it probably was built as a Mk2A and why it wouldn't have had the cutout chainguard.
The "Mk3 chainguard" was part 064837 with holes for extension piece 064822, buttons and spring, introduced during '73 after 307091. The slotted brake lining inspection chainguard 065818 introduced on both the Mk2 and Mk2A from January '74.
 
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L.A.B. said:
There was no "transition" from Mk2 to Mk2A.

The Mk2 was an upgrade of the Mk1.
The Mk2A was an upgrade of the Mk1A.

Mk2 and Mk2A variants were produced concurrently as they were intended for sale on different world markets so both Mk2 and Mk2A were produced until around the end of 1974.
The Mk1A and Mk2A were low noise emission models originally intended for the European market, the Mk2 continued to be sold in the USA although some Mk2As were eventually sold in the US they didn't entirely replace the Mk2.


As it was originally built in November '73 and purchased in Scotland then it probably was built as a Mk2A and why it wouldn't have had the cutout chainguard.
The "Mk3 chainguard" was part 064837 with holes for extension piece 064822, buttons and spring, introduced during '73 after 307091. The slotted brake lining inspection chainguard 065818 introduced on both the Mk2 and Mk2A from January '74.
Click to expand...

Interesting, the MK1->MK2 and MK1A->MK2A is new info to me and I haven't seen that in print. I'm MUCH more knowledgeable about Triumph than Norton so I don't doubt you.

That probably explains why my bike has differences with the parts manuals. But it doesn't explain things like the plastic air box never being used before 1975 or the chain guard extension only being 1975, at least in the parts manuals I have and those online at AN.

I've seen a list of the changes by serial number but not through 1975. Is there a place where I can find documents to improve my Norton library?
 
marshg246 said:
That probably explains why my bike has differences with the parts manuals. But it doesn't explain things like the plastic air box never being used before 1975
Click to expand...




I'm not sure I understand what you mean as the plastic airbox was introduced on the Mk1A, then used on Mk2A and finally the Mk3, however, although the basic airbox moulding is the same, the assemblies are slightly different and thus have different part numbers.


"850Mk1A Carburettors, Air Box, Battery Tray"
https://andover-norton.co.uk/en/shop-drawing/185/850mk1a-carburettors-air-box-battery-tray

"850Mk2A Carburettors, Air Box, Battery Tray"
https://andover-norton.co.uk/en/shop-drawing/174/850mk2a-carburettors-air-box-battery-tray



marshg246 said:
or the chain guard extension only being 1975, at least in the parts manuals I have and those online at AN.
Click to expand...

Do you have a copy of the Mk2/2A supplement?

It wasn't all that long ago that AN had no 'A' model parts lists/drawings on their site except for the 'A' black cap exhaust system so their parts lists tended to jump from '73 straight to '75 as many of the specific 2/2A parts were, and still are, unavailable.

The 064837 chainguard obviously isn't in the '73 parts book as it was yet another of those 'mid-year' modifications but it is in the '74 Mk2/2A parts supplement and chainguards with the extension can be seen in the '74 brochure.

http://www.classicbike.biz/Norton/Brochures/1970/74NortonBrochure.pdf

Service Release N3/55 May, '73 also details the change.


SERVICE RELEASE
NO. N3/55 motorcycles
CATEGORY OF RELEASE: 5
NATURE OF RELEASE: Introduction of rear chainguard extension
MODELS AFFECTED: All Commando
DISTRIBUTION: Worldwide (General distribution)
EXPLANATION: A new rear chainguard has been introduced on
assembly subsequent to engine number 307091
which incorporates a detachable extensicn piece.
The new chainguard 064837 is similar to the
superseded part 061865 but incorporates two
additional pierced holes into which the
additional plastic extension piece locates.
ACTION: I. To replace existing chainguard 061865 use the
following ccmponents:-

1 064837 Chainguard
1 064822 Chainguard extension
2 064823 Chainguard extension button
1 064824 Chainguard extension spring

MAY 1973
Click to expand...



marshg246 said:
I've seen a list of the changes by serial number but not through 1975. Is there a place where I can find documents to improve my Norton library?
Click to expand...

There seems to be less information from '73 unfortunately.
 
L.A.B. said:
Do you have a copy of the Mk2/2A supplement?

It wasn't all that long ago that AN had no 'A' model parts lists/drawings on their site except for the 'A' black cap exhaust system so their parts lists tended to jump from '73 straight to '75 as many of the specific 2/2A parts were, and still are, unavailable.
Click to expand...

As LAB says, you have to be careful with the AN site. I have ordered a few parts off of the AN site prior to getting the 2A list, only to discover that they were wrong, despite my bike being a mk2 and not a 2A it had many of the parts on the 2A list that were common - like the slotted chain-guard and the mk3 swing-arm bushes.

It is essential to compare what you have with what you are ordering, I discovered...
 
L.A.B. said:
I'm not sure I understand what you mean as the plastic airbox was introduced on the Mk1A, then used on Mk2A and finally the Mk3, however, although the basic airbox moulding is the same, the assemblies are slightly different and thus have different part numbers.


"850Mk1A Carburettors, Air Box, Battery Tray"
https://andover-norton.co.uk/en/shop-drawing/185/850mk1a-carburettors-air-box-battery-tray

"850Mk2A Carburettors, Air Box, Battery Tray"
https://andover-norton.co.uk/en/shop-drawing/174/850mk2a-carburettors-air-box-battery-tray
Click to expand...

There's something wrong here. When you go thru the AN menu you do not get those pages, you get the pages that match what I'm saying.

MK1A: https://andover-norton.co.uk/en/shop-drawing/205/carburettor-mountings-air-filter-and-fuel-line
MK2A: https://andover-norton.co.uk/en/shop-drawing/205/carburettor-mountings-air-filter-and-fuel-line
MK3: https://andover-norton.co.uk/en/shop-drawing/135/carburettor-mountings-air-box-and-fuel-line

I have no idea how to get to the pages you provided. The links certainly work so I don't dispute them. I'll ask AN what's going on.
 
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