View Full Version : Triumph Number help

10-19-2009, 6:38 PM
Are the frame and engine numbers the same on a 1970 Triumph. The guy says its a bonneville but when I went to take a look the frame numbers started with tr6 and the engine T120rDU****. It had dual carbs and he said it was a 650 with a 750 kit on it. Can anyone tell me what I'm looking at and what to be suspicious of. I looked everywhere and did some searches but I'm having trouble coming up with anything. Any help would be great this is the first triumph Ive considered buying he does have a title should that match the frame or motor numbers. thx

10-19-2009, 7:06 PM
TR6 is a Trophy that is what my 70 is and T120 is a bonnie so my question would be does the number start with D or J that will tell you if it is a 70 but regardless your motor isnt the same as your frame if everything is how you say it is ...Two different model bikes...

10-20-2009, 12:32 AM
Thats what I was suspicious of, the motor being different from the frame. the frame has a bolt on hard tail and like I said it has two carbs and a 750 kit. He does have a legit title though and he wants 1200 for what looks like a decent 70's style chop, GMA front brake, sportster 35mm frontend,
he said the motor has 12-15 miles on the rebuild but its leaking like a stuck pig out of the head gasket when running so it definitely has to be completely gone through because I'm sure the slug trap was not tended to and I understand thats a serious issue. Starts on second kick and the bike was cold, I never kicked a bike over so easy but Ive only owned harleys with kickers, and this was kinda like stepping on the kicker instead of jumping on it. thoughts?
number on motor does start with D and has the triumph stamps under the numbers?

10-20-2009, 2:42 AM
The letter "D" is the first letter? If so, that only designates it as being as a machine that was manufactured in April,...Its the second letter your wanting to decipher,....

10-20-2009, 6:54 AM
this link may help with TRIUMPH numbers:


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10-20-2009, 7:29 AM
if the head gasket is leaking I would say either head torque was lost or the head is warped either way not a issue ...My Triumph or any I have ahd doesnt kick hard if it does something is wrong ....I have seen Triumphs you could almost start with your hand .....Make sure the title matches the frame that's the big one ...atleast in ohio it is we register by the frame numbers here not the engine numbers....

10-20-2009, 11:22 AM
thanks for the help guys. I guess I have more research to do. The list on the link confuses me, under the 1970's it lists numbers for 350/500 unit and 500/650 pre-unit. I'm pretty thick on brit bikes but I would assume this would not fall under either of those and I thought all motors became unit in the late fifties? the frame numbers started with TR6 so I assume the matching numbers follow the letters on the motor and frame? Sorry I know its exhausting answering all this crap

10-20-2009, 1:17 PM
Here is the numbers you are worried about see 1962 they start unit ...and first letter is D all the way upto 69

1963 DU101 to DU5824
1964 DU5825 to DU13374
1965 DU13375 to DU24874
1966 DU24875 to DU44393
1967 DU44394 to DU66245
1968 DU66246 to DU85903
1969 DU85904 to DU90282

See then they start using H N J and actually follow the yr and month code but as you see if you follow the letter code from 63 to earlier 69 the code would suggest all these bikes were built the same time cause they carry the DU code ...This is Why I asked if your frame started with anything other than D and your engine too a fast way to know if your dealing with something from the 60's or 70's other than looks...Yours was obvious though at the instance of T120 and TR 6 being two different model bikes ...

1969 Mid '69 number change (then) NC00100 to HC24346
1970 JD24848 to ND60540

My bike is a 70 TR6 and it starts with JD

10-20-2009, 2:30 PM
Heres another link ..http://raskcycle.com/techtip/page145.html mabe it'll help?


10-20-2009, 11:29 PM
Is it just me, or is a leaky head gasket going to lower compression (a la easy kick)? Seems so, but I'm no expert...

Yeah, it's no harley to kick over, but she should have some bite when healthy.

The numbers stuff is right on. The little Triumphs all over the engine case boss is a good sign, at least those haven't been altered. You clear on the model difference between T120 Bonneville (dual carb) and TR6 Trophy/Tiger (single carb)? Check into your state registration laws, cause you may find a loophole that you can exploit. Note that these discrepancies should alter the price in your favor, due the amount of potential hassle it will bring you in sorting it out. Do not pay the asking price!

10-20-2009, 11:47 PM
I think I got it all sorted out now tr6 frame and bonny motor. Funny thing is the guy won't call me back now. HMMM. At least now I know what to look for and how to decipher the numbers. I'm pretty sure he would have taken 800 bucks which I feel would have been a reasonable price even with the head gasket problem. But now I'm suspicious. On to the next one I guess. I do appreciate the help and now we have a triumph number thread I guess.