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

possm said:

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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I thought it was a MK1 based on the above. It's a 2?

gpzkat said:

It would be cool to have a fuel tank airbrushed with the silhouette of the photographer on it as yours appears ha!

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That's me ha!

marshg246 said:

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.

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Ok, I remember now. Definitely not a combat. Thank you!

OK
A thorough shakedown and 50 or so pictures later I believe it may be a MK2 Fastback
- It has the early head steady - the flat plate type, not the boxed unit
- Center stand is mounted to the frame
- Roadster style kick up exhaust
- Early style Fastback oil tank - I don't have the left side cover. Is anyone holding and willing to sell?
- No marking on the cylinder head - RH etc.

And then, of course Marshg246's pages: My bike being 140114

34400

750

1969 or 70

Fastback, S Type, and Roadster

All

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

I woul dlike to beleive this bike is very, but not totally original. The previous owner's collection of information includes a registration tag from July of 1973. Also included are the title documents from the beginning, but it is unclear if he was the original owner. It is possible I am only the 2nd owner, or maybe the third. The previous owner may have bought this as a 2 or 3 year old bike. The mileage is consistent with the limited service notes showing just under 16,000 miles. Using my sleuthing abilities It is a very clean and well cared for bike that sat untouched, under cover in a dry garage for the last 37 years. The points plate and its parts look nearly new.

I am very enthusiastic to get this one back on the road.

Wow. There are so many 'opinions' here my head is spinning. 1) This was not a Combat from the factory. Combat engines were only built in 1972 and do not have 140XXX serial numbers. 2) This bike has a 1971 or later engine cradle and an oil filter found on 1972-up models. 3) Frame is a 1969-70. 4) I have only seen the chrome plated Atlas style headlight ears on 1970 model Fastback. 1968-69 were black and 1971-72 with late style frame had standard headlight and small gaiters found on 'S', Roadster, Interstate, etc.

I believe it was Brian Slark or Bruce Henderson that said Mk designations for 750 were not factory, but added later perhaps by authors such as Roy Bacon. The MkI, MkII, and MkIII designation for 850 were the only factory ones. Certainly the explanation in Bacon's book is very strange and difficult to follow.

(Fire suit on!!! )

Ron L said:

I believe it was Brian Slark or Bruce Henderson that said Mk designations for 750 were not factory, but added later perhaps by authors such as Roy Bacon.

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That cannot be true as 750 mark numbers not only appear in the factory records but also in dealer ads of the day.

Ron L said:

4) I have only seen the chrome plated Atlas style headlight ears on 1970 model Fastback. 1968-69 were black

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However, according to the parts book, chrome headlamp brackets were available from 1969 on Fastback and 'R' type.