Enduronut is far more of an expert on numbers than I, but I was under the understanding that the early model numbers were in worldwide use - only going to country specific numbering in later years?

I have never seen a number with RT2 at the beginning. The stars *COULD* be something added by a dealer to denote a replacement case, but if so, it is still not a good prefix. I would also agree that the font used on the stamp looks to be incorrect.

My guess is a replacement case, and someone stamped it not understanding the proper designation for the motor should have started with RT1 . . . I agree knowing the frame number may be helpful.

Thanks all for your opinions and help. Unfortunately I tend to agree with all of you. I am quite 'green' about these '70 classic 2 strokes Yamaha but I know very well the 4 strokes like XT and TT 500 from late '70 early '80 and I know too well that the VIN number of an original bike HAS to be in the VIN number list no matter from which country the bikes comes from.
This one doesn't appear to be in the list and I strongly suspect that someone stamped it after replacing the engine or part of it.
I will add the picture of the frame number asap.

I have an UK DT125 and it's stamped AT2 with the the stars either side ...... My dad was the second owner and we lived next door to the guy who bought it new so I'd say it's a euro vin ...... None of my 4 dt1s have been stamped with precision and look like the guy was having a bad day so don't read too much into how accurate they align ...... If the frame matches then it's likely to be factory stamped...
Cheers
T1

Thanks for your input T1! That's partially reassuring.
I've spent the last two days studying the Yamaha VIN numbers through the years to see how they can differ in time and from one country to the other. The problem is that in the past they were much simpler and less detailed than now.

At present Yamaha motorcycles have a 17 digit VIN and it's easy to find out from which factory the bike comes from and all.
If I could find somewhere an other 360cc bike with VIN starting with RT2 I'd be a happy man....

Later TY250 monos have the stars either side of the frame number.





The typeface used for the number 3 looks wrong to me - my 1972 DT2 has a 3 in the vin number buts its a different typeface. Rounded top and bottom rather than the flat top on the 3 on yours.





But who knows haw many different sets of stamps they had in the factory so it could be fine - My RT2 has matching numbers but typeface on the engine is different to the one on the frame.


Maybe we should start a thread showing typefaces for different models / years.

Right........maybe I solved the mistery.

I found a very very interesting article (written by someone with the same problem as me) who did a very accurate research for his Yamaha motorcycle with 9 digit VIN number like ours.
I quote here the most important part of all the article:
"Before we get down to deciphering a VIN number, let's take a brief step back in time, and recognize that prior to 1981, there was no real set standard for how VIN numbers had to be assigned.....in other words, the VIN Numbers used (by any vehicle manufacturer) prior to 1981 was more-or-less an internal-use number, and could be conjured up in whatever way struck a manufacturer's fancy and served their internal needs.

Starting in the late 1970's, with the proliferation of manufacturers, vehicle production volumes, and international sales, a solution to the "VIN dilemma" was suggested by the International Standards Organization (outlined in ISO Standard #3779, for the ultra-curious), and this standard was adopted and required to be used by all manufacturers that sold vehicles into the USA by the National Highway Traffic Saftey Administration (NHTSA) as of 1981. This is when the familiar, still-used-today 17-position VIN number came into use, and similar structured VIN formats were also adopted by Canada, the European countries, and many other countries around the world.

This alsomeans that VIN numbers for Yamaha bikes before 1981 could have been slightly different for each country and not standardized.

For whom is interested in reading the whole article (is actually a post inside a forum) this is the link:

viragotechforum.com/viewtopic.php?f=75&t=35708

Don't get your hopes up......many of us here have been dealing vintage Yamaha's for along time
and those numbers were NOT stamped by Yamaha at the factory regardless of what country it was shipped to.

Since there is a little debate if its real or not. I am going to put my vote. (As Mentioned by Enduronut, DEET and others) The engine case has been alternated. Yamaha never used the prefix RT2. Even outside the U.S.A.

I had come across some white elephants and sent those parts to Enduronut for him to look at,they were all well made fakes,one bike had a very robust exhaust bracket,it is nothing but a very well made copy. on bikes this old,strange things happen!

My research is still ongoing.....still I'm not convinced 100% that my RT2 VIN number is fake.

For example, this one below is the picture of a engine VIN number of a 1973 RT 360 Baja brown from UK. Look at the position and shape of the numbers in this photo and the one above posted by tytim: they are completely different and the distance between RT1 and the numbers in tytim bike's VIN is very wide....you'd say that either one of the two is not factory stamped....but they are both from original bikes.