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I have what reads on the side panels a 750 Bonnie but the numbers on the frame and motor are different. Frame # T100rxe06092 and a engine # t140v dh31628, what do i have? This is supposed to be a 73 . Help
 

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Here is the listing I've always used to ID a triumph. I'd say your engine is a 73 but I can't fit your frame number to my list.

T140DBA= T140=(750cc) (D=Bonneville) (B=Febuary) (A=1979)

## MODEL VERSION ##
A US MKT - ROAD (1960)
B US MKT - COMPETITION (1960)
R US MKT - ROAD (SOME YRS UK)
RT US MKT - ONLY 750 MADE (1970)
C US MKT - COMPETITION
V FIVE SPEED GEARBOX
E CONFORMS TO US ENVIRON. REGS.
ES ELECTRIC START
D BONNEVILLE SPECIAL (1979-1980)
TSS EIGHT VALVE ENGINE
TSX US STYLE CUSTOM
LE LIMITED EDITION ROYAL (1982)
AV ANTI VIBRATION (POLICE FRAME)

PREFIX LETTERS SUFFIX LETTERS
## MONTH ##
A JANUARY
B FEBUARY
C MARCH
D APRIL
E MAY
G JUNE
H JULY
J AUGUST
K SEPTEMBER
N OCTOBER
P NOVEMBER
X DECEMBER

## YEAR ##
C 1969
D 1970
E 1971
G 1972
H 1973
J 1974
K 1975
N 1976
P 1977
X 1978
A 1979
B 1980
KDA 1981
EDA 1982
BEA 1983
## MONTH YEAR SERIAL # VERSION
X A 123456 E
Meriden Bonneville
SERIAL NUMBERS
T120 650cc 1958 - 1972
T140 750cc 1973 - 1983
 

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Frame

T100 500cc Twin
R Roadster (Daytona Twin Carb)
X December
E 1971 (actually a 1972 model)
06092 Sequential Serial No
 

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This is strange,because a Bonneville engine won't fit in a T100R frame.You could do anything with a welder,but I doubt anyone would go to the trouble.
 

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Here's a site with the numbers for you:

http://www.britishonly.com/tech/joust/techtiptriumphmf.htm

I think you may have a 1969 500cc frame with a 73 motor.
This seems like pretty good info, thanks! I have a DU XXXX serial number, where do I find out what each individual number means? I bought the bike in 1975 already modified into a chopper, but I'd like to know what model it is, Tiger, TR6 or what. Thanks again for any info. The bike hasn't been on the road since the late '80s and even tho' it was completely trouble-free for the 13 years I rode it, I would like to do a total rebuild before putting it back on the street. Thanks for any help!

Eddie.
 

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I have a DU XXXX serial number, where do I find out what each individual number mean?
D 650cc
U Unit construction
XXXX Sequential Serial no

You will also have a set of letters/numbers beginning with T such as TR6R, T120R or similar, this gives the model.
 

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The amazing thing is that the "grandfather" of the Bonnie was the '37 Speed Twin which for all intents and purposes, is the SAME engine.
And people say the the Speed Twin engine is little more than two Val Page L2/1 single engines side by side. This would take you back to 1931.
If you go back further, the Schulte/Hathaway design of 1905 basically carried through to 1929. A short live interim design followed. It, in turn was superseded by the Val Page family of designs and so on to Edward Turner's Speed Twin.
Most of Triumph's production, from their first "in house" design of 1905 to the end of Meriden with just 4 engine designs (three if you ignore the very short lived design of 1930)
To add a further twist, Burt Hopwood, who worked for both Turner and Page, designed both the Norton Dominator and BSA A7/A10 engines which in turn gave rise to the Commando and A65 engines and all these engines were based on the Val Page 6/1 design rather than the Speed Twin.
 

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I only go back to the Speed Twin, because of the arrangement of the cam drive and shape of the timing chest. It's virtually identical to the last '62 pre-unit which then went unit through the '83 spec which was unmistakably it's descendent.

On that note, that's 25 years of pre-unit engines and 20+ years of unit engines each. "If it ain't broke, don't fix it" (although that line of thinking eventually sunk them)
 

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I only go back to the Speed Twin, because of the arrangement of the cam drive and shape of the timing chest. It's virtually identical to the last '62 pre-unit which then went unit through the '83 spec
You could also add the Terrier engine by Turner (53?) which gave rise to the Tiger Cub, the BSA C15 and its single cylinder descendents which went through to end of BSA, a span of 20yrs.

Also the Rocket 3/Trident engine which as a Turner twin and a half.

Just a few basic designs covered almost the first 80yrs of Triumph.
 

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T140V: the first engines were 724cc. Then, later in 1973, they changed to 747cc. Is there a way to find out which engine numbers were 724cc and from which numbers they were 747cc?
I have ordered a copy of John R Nelson's Bonnie book, I understand this is a good reference book for all things Bonnie.
 

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Good info everyone and thank you Epynt for the Val Page tidbits. Now I have something else to research. Always a good thing for me, like Johnny 5 said " Innnnput! "
 
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