Photo being reposted to show exactly the situation.
Woweee, what an amazing photograph..
Brilliant. Thanks for posting.
We have never seen anything like this before and it really does make a lot of sense.
We can tell by looking at the engine and the casting boss that it is a 1970 model engine and identical to those we have seen produced or stamped over that Xmas period of 1969.
I think we managed to deduce that from the normal and 'Y' bikes that we have seen. John gave an example of a 'Y' bike of this era. As he mentioned also, - the unusual shaped engine number pad was only cast like that for a few weeks.
Is there a frame that matches this engine ?
From what I am seeing it is a Y bike of Dec 1970 season that the guy stamping the engine has got confused with.
We can see from the castings, the engine itself, from the font and from the backstamping that the engine is all 1970.
It only has the four digits which makes it unusual.
We have never seen a Y bike leading the S/N sequence with a zero. Many of the normal sequence did which was an identifier for the 1970 year, ie they all had 5 digits so started with a 0 or a 1.
I am pretty sure we have seen a Y bike with 4 digits before though.
Wow, if ever we needed a missing link to tie the Y bike A65TA sequence to 1970 then this would be it.
The poor guy stamping the engines was used to doing one of two styles.... with this one he must have just lost himself. What other explanation could there be for it ?
Rather than picking up the 'Y' stamp he picked up the X and D stamps that he had been using all day.
That is certainly one out of the box... it would be interesting to see how they recorded that one in the despatch books.
I am 100% sure it was made, and stamped, within weeks of Xmas 1969 as a 1970 model machine.