I have been In touch with Yamaha to confirm in writing the year of manufacture for my 1974 ty250. 

They said that they can not supply the date of manufacture only the model year! 

Will this be enough for the dvla or will I need something else? 

Here is there reply. 

Hi , did you have any luck registering your bike, I’ve had the same reply off Yamaha Uk today for my 1985 TY250R, regards Brett

I haven't heard back from them yet 

I said it's that I would still like the letter as i think more will be better to send to dvla 

I'm going to get one from a club too I think?

 

have you filled out the v555 yet? 

I’ve been told to get a dating letter off the’ vintage Japanese motorcycle club’ , looking into it tomorrow, fingers crossed

As the TY 250 did not sell in the numbers expected many hung around in the dealers or were stockpiled at Mitsui the Yamaha Importers at Oakcroft Lane Chessington. So a 1974 bike might not have been sold until 75, 76 and even then it may not have been registered. Again some bikes may have been stripped when new to provide the necessary parts for a Majesty leaving a perfectly good but standard frame to be disposed of, also a second hand unregistered bike may have suffered the same fate. Declared new at 1974 should be printed on the registration document, the day, month of the year are not that important apart from decal colours not much changed. Try the yamahaty web site for exact model year, this is also evidence for DVLA. The web site yamahaty has good info on dating your TY and Trials and Trail UK also have some research showing which could help. ??

Edited June 12, 20188 yr by section swept
Added content

I got my dating cert from vintage Japanese motorcycle club (very helpful) after a similar reply from Yamaha, the dvla had not issues using it for registration.

I've also got one from vjmc very helpful people. Just in process of rebuild now