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Hi all, after having to sell my 66 Bonnie, I am now starting another project and have this old engine case from a trade so wanted to ask if anyone could help me identify this model and year from the serial number. I think it is a 71 engine but from everything I read, I expected to see 2 letters at the beginning and this seems to have only one (E) with a strange slash in front of it. Can anyone who has seen more engines than me confirm what it is? Thanks
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Discussion Starter #4
Thanks Kadutz and HayMike, The X is stamped pretty weakly but thanks for identifying it for me.
 

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Hi Mike,

Regrettably, that webpage contains several errors and ambiguities:-

Each model year started in August and ran until July of the next year.
:LOL: (n)This is out-and-out cobblers. Some "model years" started in an August and some ended in a July. That every one always did is a hoary old chestnut possibly put about initially by Roy Bacon; repeated by any later author places a question mark over the rest of that later author's research. :( Also, the start and/or end of a model year could vary between ranges in the same model year and between Meriden and Small Heath (the BSA works, that built all triple and 250 - Triumph and BSA - engines).

TRIUMPH ALPHA NUMERIC SYSTEM STARTS 1969
In 1969 Triumph introduced a new system of numbering engines and frames. There are two letters, a five digit number, and a model designation. The first letter represents the month, the second the model year, and the number which began at 00100 for each model year.
To be clear:-

. At various times in the early months of the '69 model year; at different times in different ranges; e.g. Meriden introduced it during October 1968, for the 650 and 500/350 ranges that were the only engines built/numbered there.

. It was specifically the engines that were coded; a frame only received the same code when a given engine was installed in it. So a Triumph triple or 250 engine built at Small Heath would receive its code ("two letters, a five digit number, and a model designation") when completed at Small Heath. The code on the Triumph frame was a copy of the engine code when the engine was installed in the frame at Meriden.

. The model designation sometimes preceded the date code and five-digit number.

. The number did not always "begin at 00100 for each model year." Each range beginning at 101 every model year had been a Small Heath 'thing'; otoh, as that page shows for the 350/500 and 650 numbers before '69, Meriden carried on the same number sequence year after year; '69-on, it did in fits and starts - 00100 possibly in October 1968, sequence continued for '70, restarted at 00001 for '71, sequence continued for '72, restarted at 15101 for '73, restarted at 55101 for '74, etc., etc.

MONTH OF MANUFACTURE | YEAR OF MANUFACTURE
The first is correct, the second is nonsense; under "TRIUMPH ALPHA NUMERIC SYSTEM STARTS 1969" it even says, "The first letter represents the month, the second the model year," ... :rolleyes:

For example: PD32232 TR6R would be a 1971 TR6R manufactured in November of 1970, and KC16670 T120R would be a 1970 T120R manufactured in September of 1969.
... so this is complete twaddle:-

. "PD" translates as "the November [P] of the 1970 [D] model year" - i.e. the bike is a '70 model year made in calendar November 1969.

. Otoh, if "KC16670 T120R" really exists on a bike, it's something never stamped at Meriden ...:-

.. similar to the above, "KC" translates as "the September [K] of the 1969 [C] model year";

.. there are triples and 250's with KC date codes but not Triumph 350's, 500's or 650's ... because - as above - Meriden didn't start using the format 'til "the October [N] of the 1969 [C] model year";

.. and the first 1970-model-year T120R was JD24849 - i.e. "the August [J] of the 1970 [D] model year" - in this case calendar August 1969;

.. so, because US-market '69 650's (if not always T120R's) were built in batches between NC00100 and possibly HC24346 (source: Triumph In America), while there might be "C16670 T120R" (because the same number sequence was used for all 650's, 500's and 350's), the preceding month letter cannot be a "K".

Btw, if your head's whirling already, the 1970 model year is one that rubbishes pretty-much all of the 'certainties' on that webpage:-

. Afaict, the earliest '70 bike was HD23795, a TR6 (version unknown) built in calendar July 1969 and the latest was ND60540, another TR6, built in calendar October 1970 ... so there are HD-, JD-, KD- and ND-dated '70-model-year bikes built in both calendar July, August, September and October 1969 and the same months in calendar 1970, only the numbers will differ substantially.

. At the same time, '71-model-year 500's started in calendar September 1970 with KE00001.

. Reason in this case was the very late discovery that complete 650 engines couldn't be installed in the new OIF.

Given the recommendations I've read for Franz & Grubb, maybe they should stick to fixing Triumph engines ...? :)

Regards,
 

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Stuart

You have to much free time to do all that typing 😉.

You didn't mention how they were still making 1979 bikes in December of 79 when they started production of 1980 model in November of 1979.🥴

K
 

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Hi K,

You have to much free time to do all that typing 😉.
:cool: The snow is travelling pretty-much horizontally past the window and the wind-chill something in double figures below ...

You didn't mention how they were still making 1979 bikes in December of 79 when they started production of 1980 model in November of 1979.🥴
I didn't want want the poor guy to glaze over too soon before the end ... :LOL:

Regards,
 

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Hi K,


:cool: The snow is travelling pretty-much horizontally past the window and the wind-chill something in double figures below ...


I didn't want want the poor guy to glaze over too soon before the end ... :LOL:

Regards,

Well here it's a balmy 42 F (6 C) and overcast. We are supposed to get hit with a snow storm later I will believe it when it happens..

I wasn't real impressed with the F&G listing either. I prefer the one at www.vintagebikemagazine.com or British Only Tech Section. But for some reason the British Only Triumph numbers are coming up gone fishing while the BSA/Norton ones come up normally. I have some thoughts on the T65T questions and will post them later on that thread.


K
 

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Thanks Stuart. In both the charts, the column labelled year of manufacture should be considered to be model year instead? It's a moot point on the one I'm working on now, It's GC, so the same either way.
Mike.
 

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Hi Mike,

column labelled year of manufacture should be considered to be model year
The 'year' letters are always "model year"; as you say, sometimes the "year of manufacture" coincides, sometimes it doesn't. :)

There is one :rolleyes: infamous cock-up at Meriden. Having started using the 'C' year letter in calendar October 1968 for the '69 model year, whoever stamped the engine numbers changed to "D" at the beginning of calendar January 1969 ... :oops: Amazingly, no-one noticed for something like three weeks! :eek: So most of the January '69 production (all 500's) are stamped "AD" ... :LOL:

Possibly one reason Meriden didn't restart the number sequence for the '70 model year is, when they reached January 1970 and wanted to use "AD" again, the first figure would be "2" or "3", whereas January 1969 "AD", the first figure is zero. (y)

Hth,

Regards,
 

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Discussion Starter #13
So if I can navigate the various comments on this XE 07249 would be late 70 early 71 - do I have that right? Thanks
 

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What you have is an engine from a model year 1971 Bonneville T120R. That was manufactured sometime in December of 1970. It would have been an early Oil In Frame machine.

K
 
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