Originally Posted by Kevin (NZ).

I found another.. A65LA7867Y, - it appears to be a 1970 but I can only go by the clutch entry.

Bruces bike, A65LA7752Y despatched on August 18th 1969, has the earlier clutch entry. It's a 1969 through and through but the despatch date is more suited to the new 1970 bikes. Ola posted a picture of 1970 model JD01287A65T (August, 1969) which surely has the newer clutch entry. There must have been some overlap here with 7867, 7879, etc. ending up with the newer timing side/clutch entry even though they were, I think, the last of the 1969 models. Of course the 1969 "normal" numbers went at least as high as 22610 so it's another mystery as to why these 7000 numbers were still around at the very end of the season.

Originally Posted by Kevin (NZ).
I don't know if it matters so much whether they are 1969 or 1970... we now know that the Y bikes exist and a little more about the shipping etc.

Originally Posted by Kevin (NZ).
I am sure we will not be surprised if the decision to make a batch of A65LA****Y bikes was made mid-1969 calendar year and away they went... making them for as long as they could, - or possibly needed to.

Sounds about right, seems the earliest despatch date we have for one of these is June, 1969. At least so far, perhaps someone will pop up with an earlier one.
Originally Posted by Kevin (NZ).
I wish you would hurry up and solve this one. I am getting impatient.

Ha! At least we're closer than we were a year ago. There are enough twists and turns with the numbers themselves to keep us interested, the real mystery though is why the reason for the "Y" bikes is such a huge secret that no one who is in the know has spilled the beans for over 40 years now? What passes for the official story is fairly shredded at this point.

Originally Posted by Kevin (NZ).
That vertical casting line I spoke of in front of the number pad seems to have run for a little over a year from Jan 1970.
I don't know of any 1969 model bikes that have it. My thinking was that it was the next stage after the XD and AD boss we have been talking about.
I should add that not all twins made during the 1970 model year had that line.
I would expect the majority of BD and DD bikes to have it at least. That could possibly date any Y bikes that look like they were cast during those months.

Absolutely. Those lines appear to have been left over after the XD/AD casing/mold was upgraded.