Spotting Fake Vintage Triumph, BSA, & Norton Engine Numbers

Spotting Fake Vintage Triumph, BSA, & Norton Engine Numbers

Spotting Fake Engine Numbers

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With vintage British motorcycles increasing in value and popularity everyday, the rise of bogus engine numbers are starting to appear more frequently. Why "bogus" engine numbers? Well, some are trying to capitalize on rare models engine and frame numbers to increase a motorcycles value. For example, if you have a Triumph T120 engine case stamped "T120 DUXXXX" and you stamp "TT" after the "T120", you have now made a fraudulent Triumph T120TT. Some do it to get titles, the list goes on and on. Altering engine and frame numbers is a felony here in the states and is probably all over the world if proven guilty. The reality is YES, some slick people out there do this. When something is rare or unattainable like a Rolex watch, there will always be "knock-offs" or "fakes".


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Fraud comes in all shapes and forms. Be on the lookout


You would be surprised by going on eBay right now and seeing fakes listed for sale. The popular "fakes" that are usually replicated are the valuable models such as the 1959 Triumph T120 Bonneville, T120C, T120TT, T120RT, Hurricanes, and many other models. With this information, I hope that I can give buyers and sellers an insight of what to look for when buying or selling a vintage Triumph, BSA, or vintage Norton motorcycle. I am by no means trying to stir controversy, all I would like to do is make those aware the next time you purchase a vintage British motorcycle. Be on the lookout.



1959 Triumph T120 Bonneville

Fake 1959 Triumph T120 Bonneville? You be the judge...


Spotting a fake can be difficult as some British motorcycles did have some engine numbers that almost appeared to be fraudulent but where correct What I mean by that is by the stamping styles. Above is a classic example and probably the most popular vintage Triumph replicated. The 1959 Triumph T120 Bonneville. First year of the Bonneville. Although I do not have 100% proof that this is a fake, the engine number style and font raise questions of it's legitimacy. You can clearly see traces of the case being sanded or ground down by the dark shadow around the engine numbers.    



BSA A10 Engine Numbers

BSA unit twin construction stamped BSA DA10R. This one screams fraudulent...

This particular number "DA10R" is known as the later BSA A10 models. This case is clearly not an A10 but a later A50 / A65 case, probably a 1969. The case it's self and the raised oval shape boss was only used on models 1969 & later. I find this one funny, as someone stamped engine numbers that where used on a BSA Pre-Unit but instead on an A50 / A65 case. But why? Was this engine apart of a stolen motorcycle? Was someone trying to have fun? This engine case was for sale via eBay.

BSA A65 Engine Numbers

BSA A65 Hornet? Nope, a it's a BSA A65 "5A"

Another BSA example. Here is what appears to be a 1966-1967 BSA A65 engine case. This was also listed for sale on eBay. Engine numbers read "A655A". Looking through all literature, BSA never produced a model under a prefix "A65 5A". Now there was the BSA Hornet model with the prefix "A65 HA" but this is clearly much different. Font, numbers and sequence are all incorrect. This engine numbers raise a red flag.  


  • Andrew Molton

    If anyone out there has engine T120 030000 it was stolen from me by a motorcycle restoration co in Scotland. I have the matching frame but they took my engine and gave me a junk engine with the number filed off.

  • Matt Popio

    Does the title go to the frame or motor

  • Rob Marriott

    I inherited a (according to the vehicle registration document) Triumph 350cc HW from my grandfather. The VIN/chassis number is 25612 and engine number is 35612. I am a bit confused though as it records date of manufacture as 1937 but date of registration 08/06/1949. I also have the original license disc that licenses it as a bicycle, license to expire 31 Dec 1949. Can someone please let me know the actual age of the bike, is it possible it was unregistered through the war years?

  • Garry

    I have just purchased a triumph twr 500, I am trying to find out what year it is, can anyone help, engine number TWR 28585 NA frame number 6297N thanks garry

  • Aaron

    I’m buying a 1960 -1963_ ridged tale frame I was told a 120 go’s in it does it matter to me whate number it is as long as it’s a 120

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