Britbike forum

BSA Engine Number

Posted By: MotoMike

BSA Engine Number - 02/05/12 8:45 pm

Have a engine I was wondering about....the number reads as follows...A65TA 1900XD...I guess it is a 1967 but what is with the XD?
Posted By: LarryLebel

Re: BSA Engine Number - 02/06/12 12:51 am

XD = Dec. 1969
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/06/12 1:21 am

I don't think the XD is anything to do with the later coding system introduced during the 1969 season.

The Month/Year codes were always as a prefix.. from what we have been seeing so far it is only the 'Y' and 'X' bikes that had a suffix code.

I am pretty sure this is going to be a 1967 model engine.
It will be an interesting photo. As I see it at the moment all three portions of the S/N are contradictory.
A photo should be able to date the engine in itself, without reference to any markings.

This is going to be an interesting one.
The serial number itself would normally be considered too low in the model year to have earned a suffix.

Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/07/12 4:12 am

Another possibility is that it is a 1970 Thunderbolt engine and someone has modified the Y suffix to read XD.

That would make a lot of sense and remove some of the possible confusion the number would have otherwise generated.



If this is the engine then I doubt the factory would have been involved in the stamping... the 'Y' engines had been in production for many months by December (about 6 months).

As Larry has suggested, the XD could be taken as Dec 1969 for a 1970 engine and at least then you would be buying the correct parts for it.

All 1970 model A65 engines, apart from the 'Y' models, had five digit serial numbers.
Posted By: MotoMike

Re: BSA Engine Number - 02/08/12 2:29 pm

here is a picture....

[Linked Image]
Posted By: Ola

Re: BSA Engine Number - 02/08/12 3:45 pm

Oh no...
Posted By: MotoMike

Re: BSA Engine Number - 02/08/12 4:44 pm

yeah I was kinda thinking the same thing...
Posted By: Two Alpha

Re: BSA Engine Number - 02/08/12 4:51 pm

Oh yes! Great picture of a very interesting serial number.

Definitely not 1967.
Any chance you have the frame with a matching number?

Kevin had a picture of an engine with a similar case style, A65TA 12215Y.
The bike with your engine coming off the line in December of 1969 as a 1970 model does make sense based on the case style.
The 1900 number is odd, at that point in time it would normally be represented as 01900.
Seems like the guy doing the stampings may have gotten momentarily confused as to whether this one was to be a 1970, or a 1970 with a number that made it look like it was a 1967.
I'm looking forward to reading Kevin's take on this one.
Posted By: Rickman

Re: BSA Engine Number - 02/08/12 5:19 pm

Here is a thought:

Perhaps, JUST perhaps, these may be a set of replacement cases???

They are certainly later cases with that boss and BSA imprints, but the numbering sure looks to be '67...
Posted By: Two Alpha

Re: BSA Engine Number - 02/08/12 5:25 pm

That's possible, but a little unlikely. This style of case was only produced for a very short time, maybe only weeks, before it was replaced with an improved version.
Posted By: gavin eisler

Re: BSA Engine Number - 02/08/12 6:57 pm

Looks like 1970 barrels to me, thick flange. Does the clutch cable enter vertically or horizontally? What front brake is fitted, SLS or TLS.
after looking hard at the number and looking at the Bacon book.
A65 TA is weird, the T should represent the Thunderbolt model and the A suggest 67 , I think the A is a mistake or some other designation like a forces model or something, the XD is December 1970 by my reckoning, that fits with the embossed number area and the 1970 thick barrels. I hate to see red hermish3te on the joints, its hard to get off, paint stripper we call Nitromors in the UK I think you call it Naval jelly, will shift it, you know the stuff, it stinks and burns your skin.
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/08/12 8:24 pm

[Linked Image]



****EDIT****
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.



Posted By: MotoMike

Re: BSA Engine Number - 02/09/12 12:28 am

Amazing the amount of good info this forum has....I wish I could help more...I do not have a frame with the engine, got it with a pile of parts....now the question, what do do with it!
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/09/12 2:05 am

Quote
....now the question, what do do with it!


I know it is a good engine and deserves to be in a bike, but,-
.....

You can see how excited we have been to have seen it. I think a few of the guys here own 1970 bikes with a strange numbering sequence.
You may have read a few threads here already.

The thing is that until the last few years we just lived with the confusion, generated in part by websites such as the BSAOC UK and even indeed the dating info on our own site here.
Now, in the past year or so the guys have ganged up and yelled ENOUGH.
Let's get this sorted out.
In November Gary E helped us get a conclusion to the 1967 Dash Y issue many of us had been wondering about.

In the process we also made huge advances in obtaining a clearer picture on the Y bikes of 1970.
We now accept that the Y bikes of 1970 were made and we have a fair idea of the numbers. My guess is that possibly 10% of the 1970 A65 twins were stamped in a similar style to yours.

But all the others are stamped in a purely 1967 style sequence.... nothing about the number would lead the un-initiated to think they were anything but 1967.

Now we have one.... your engine !
One that is literally a missing link.

I believe it is a stamping error but to me everything falls into place.
We knew the date when that strange number casting was used. The sample pool was large enough plus we had a dating certificate I believe. Anyway it was only ever used on XD, a few AD and a number of A65TA*****Y and A65LA*****Y bikes.
Xmas/New Year of the 1970 model run.

Hahahha, I am wondering if this was a 'morning after' stamping job.
I would not be at all surprised.
The guy that did it may still be about 42 years after the event. He should remember doing it, I think he would have had to explain himself and would have been party to the discussion as to what they were going to do with the engine.

There may be another possibility also. Hard to envisage one though, perhaps along the lines of a Special Order for some customer.
What it has done is draw attention to the fact that the 1967 style A65TA code has been linked to the 1970 styled XD date system. It is all there to see and on just the one engine.

Until we crack the rest of the puzzle this remains unique and very much like a museum piece.
I am guessing someone like John or Bruce will be tempted to make you an offer for it.

[Linked Image]

Here is a pic of what a 'normal' twin would look like made that month.
Some points of interest. The XD is the prefix and the 4 digit number has the zero incorporated. You will note the distinctive casting also....it literally just seemed to have appeared for a few weeks production before it was revised.
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/09/12 8:54 am

[Linked Image]

Sorry about the quality but this is a Y bike of the same era.
Posted By: Two Alpha

Re: BSA Engine Number - 02/09/12 4:42 pm

That one is A65 TA 12215 Y.

Here's one more with the same style case, according to the seller it is AD 04670 A65L.

[Linked Image]

Posted By: Alex

Re: BSA Engine Number - 02/09/12 4:57 pm

As I understand it, at some point in 1970, BSA started putting the model designation (A65L, A65T) on the engine as the suffix while maintaining it as the prefix on the frame. The date code, however, stayed in front of the serial number.
Posted By: Two Alpha

Re: BSA Engine Number - 02/09/12 7:20 pm

The lowest number I've got, with the model designation as the suffix, is ND 02489 A65L. That bike would have come off the end of the line in October of 1969, more than a full month before MotoMikes.

A fair portion of the then current method was out the window when it came to MotoMike's engine. The usual method would be for the number portion to be stamped on the engine as it was completed, model and date to follow when the engine was mated with a chassis. You would also expect that they would have added the A65L, A65T, A65F, or A50 at the time the engine was completed.

All of the numbers at that point in time should have been five digits, only four digits on the MotoMike engine must have just added to the confusion.

Perhaps the guy doing the stamping started off with adding the "A" to fit the 1967 style (A65TA) then maybe realized that the number didn't match (all the 1970 Y bikes have five digit numbers), and capped it off with the date code (XD) at the end as the final coupe de grace/repair of a botched job.

edit: I had forgotten here that there were a few four digit 1970 "Y" bikes, in the 7000 range, that they must have missed when doing the 1969 "Y" bikes.
Posted By: LeonGustus

Re: BSA Engine Number - 02/09/12 7:56 pm

Would an A50R fit in this conversation? Two Alpha - my engine is stamped ND 02116 A50R all in a row on the background stamped boss. The frame# boss is stamped ND 02116 A50R with the A50R below but still on the boss.
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/09/12 7:57 pm

Quote
(all the 1970 Y bikes have five digit numbers),


I don't think that is the case.
All the normal 1970 serial numbers have the 5 digits for the 1970 season. This was achieved by placing a zero at the start of the number if required.

I have a couple of 4 digit Y bikes listed here.
I will see if I can dig up the numbers.
7879 is one, 7031 another. (Edited.. added 7867)
I am guessing it was because they were either picking up numbers, - or spare numbers.. from the 1967 despatch books.

The 1900 number is really unusual as you suggest though John.
It is very low if they were using the 1967 books as a guide.

I thought you may have been tempted to add the engine to your collection.
Posted By: Ola

Re: BSA Engine Number - 02/09/12 9:35 pm

[Linked Image]
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/09/12 9:57 pm

Hi Ola, yes that is a normal 1970 bike.
The Y bikes of 1970 used a completely different number sequence. Actually almost random in nature but it did have an affinity to big numbers, 11000 to 15000 or so.

The normal 1970 bikes were recorded in the 1970 shipping books.

On the other hand, the 1970 Y bikes had all their details recorded in the 1967 books (I know, don't ask us why)...
Because they were literally squeezed into the 1967 records we are still unsure whether they used vacant numbers, numbers of bikes that never existed, - or if there was a chance of a duplicated number. ie a Dash Y bike of 1967 sharing the same number as a Y bike of 1970.

The first Dash Y bikes started around 3000 in the 1967 year. Until now I am not so sure we had seen a number lower than that in the 1970 Y bike sequence. I think the two 7000 ones were the best I could come up with.

If you look at the dating lists for 1970 (normal) bikes it will say they started at 101. That is impossible as they were all 5 digits.

But you are correct, Mike's engine number is unique in more ways than one. Very unusual.

Because BSA were using two sets of books for the 1970 twin production it must have produced a few dilemmas along the way.

Which book did they record Mike's engine in for example ?

It would stand out like the proverbial if they recorded it in the 1967 records... likewise it would draw attention if it was entered in the 1970 books.

I actually doubt it was recorded anywhere. The numbers really are that damning.

Sorry Ola, I have just realised you may have been helping Leon, Alex and John out with their query.
I think Leon's number is typical. Alex has a good point about the change in style... I had been ignoring or overlooking that.
Posted By: Two Alpha

Re: BSA Engine Number - 02/09/12 10:16 pm

Originally Posted by LeonGustus
Would an A50R fit in this conversation? Two Alpha - my engine is stamped ND 02116 A50R all in a row on the background stamped boss. The frame# boss is stamped ND 02116 A50R with the A50R below but still on the boss.


Sure does, yours would have also came off the line in October, 2009.

Any chance of posting a photo of the engine serial number? Of course other photos of the bike would be a treat as well.
Posted By: Two Alpha

Re: BSA Engine Number - 02/09/12 10:33 pm

Originally Posted by Kevin (NZ).
Quote
(all the 1970 Y bikes have five digit numbers),


I don't think that is the case.
All the normal 1970 serial numbers have the 5 digits for the 1970 season. This was achieved by placing a zero at the start of the number if required.

I have a couple of 4 digit Y bikes listed here.
I will see if I can dig up the numbers.
7879 is one,7031 another.


I've got a few 1969's listed with only 4 digits, all of the 1970's are 5 digits starting with 0 or 1.

Originally Posted by Kevin (NZ).

I thought you may have been tempted to add the engine to your collection.


Well, you must know that it wouldn't take much of a hint to get me at least thinking about it. I'm a long way from Illinois so the freight costs alone would take some serious consideration. It is a very interesting serial number though!
Posted By: Two Alpha

Re: BSA Engine Number - 02/09/12 10:36 pm

Nice one Ola, that's the earliest number I've seen with the model designation as the suffix. Off the line in August, 1969.
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/09/12 10:48 pm

Hi John,

Just a quick clarification.

Quote
I've got a few 1969's listed with only 4 digits, all of the 1970's are 5 digits starting with 0 or 1.


I assume you are talking Y bikes here. I really don't know if I have seen one starting with a zero. I would have thought they would look out of place in the 1967 despatch logs as well.

Is it possible we are talking cross-purposes.
I have been saying all the normal 1970 numbers are 5 digits, to the extent that a zero is used at the start if necessary.

I am not sure about the Y bikes. The only two I have pics of are 4 digits without the zero... which then makes Mike's engine acceptable. Albeit 1900 is a very low number for a Y bike.
Posted By: Two Alpha

Re: BSA Engine Number - 02/09/12 11:50 pm

Hi Kevin,

Yes, it gets muddy quickly, starts in my brain and sometimes leaks out onto the keyboard.
I can see that, where you have quoted me, I have morphed from referring to "Y" bikes in the first half, to referring to "all" of the 1970's in the second half, all in one sentence!

Since I've been "collecting" these unit twin serial numbers, I hadn't come across a 4 digit 1970 "Y" and had assumed that they were all 5 digits, as are the normal 1970 numbers.
You've obviously got two examples with only 4 digits, proof enough for me.



Posted By: Semper Gumby

Re: BSA Engine Number - 02/09/12 11:51 pm

I'm guessing but I think that is a set of restamp cases bought from a dealer. This is one of the four (five?) variations of BSA A65 cases...

I wonder who made these? My first impression of this type of case is that they don't have the same casting flaws that are on my Thunderbolt and Firebird. I would love to compare a set of these case with mine close at hand.

Once again its a mystery I would love to know the story behind...

I bet it runs like this: Motor came off the line in 1967. It blew up and destroyed the original LH case somewhere between 1967 and 1970. A new case was procured and stamped by a dealer (who understood BSA numbering system) in December 1970 when the bike was put back on the road. Cool story eh wot?

People need to chronicle their bikes better so we don't have to guess so much.
Posted By: LeonGustus

Re: BSA Engine Number - 02/10/12 12:39 am

No need for a picture of my A50R as it looks exactly like Ola's - even the bosses are the same - his is way earlier than mine.
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/10/12 12:46 am

Hi Semper, are you thinking Mike's cases could be replacements ?

I am a little lost there but if that is your thinking I am sure they are not.

There are many differences between a 1967 engine and a 1970 model, the one in Mike's photo is all 1970. Indeed without even looking at the numbers we can see it is one that was cast up just before Jan 1970.
The casting numbers internally changed over time also and this one will be all period correct.

The XD is Dec 1969 (calendar) which coincidently is exactly when this particular set of cases should have been assembled and stamped.
Indeed 90% of the cases made that month would have had the XD stamping.
I am only assuming how the Y bikes were made but it appears a small percentage each month were for whatever reason stamped with the A65TA****Y sequence.
I remember Gary saying many were despatched in Jan to April 1970. I think we were talking approx 800 to 1000 bikes total.(Y bikes).

Regards Mike's engine, the stampings are all picture perfect and are exactly what we see on 1970 models,- both normal and Y models. I have no doubts at all they were stamped in the factory.

I have not seen many sets of replacement cases but the last two that I paid any attention to were certainly different. They were a combination of later castings but with earlier machining... they stood out as being unusual.

If we are to have theories then mine would be that the chap was sitting there with his set of stamps.... he only needs an A, L, R, T, F, Y, X and a D for this particular month. Not a full alphabet anyway.
I think he was stamping a set of Y cases up and was going well until he picked up the X instead of the Y.
Whether he then realised and stamped the D anyway or did them both first may not matter. Once the X was on they were committed anyway. I think he did the XD subconsciously.
That would be my take on it anyway. Ooooops..

I really think it would be interesting to hear what happened next. If it was a mistake such as this then the chap will still remember.
Is it a coincidence that this likely happened during the festive season also smile pint


[Linked Image]
A 4 digit Y bike of 1970.
Posted By: Two Alpha

Re: BSA Engine Number - 02/10/12 2:20 am

Hi Kevin, you're very good at spotting the differences between different years, what is it about this one (A65LA 7879 Y) that makes it a 1970 and not a 1969?
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/10/12 2:55 am

I was reluctant to show the pic for a few reasons.
One is that the embossed logos are either missing or very faint.
Against that I had in my mind that BSA was trying to portray these as older 1967 models anyway so did it really matter.

Ok I think it is a 1970 because of the larger 12 point barrel nuts, the thicker flange on the barrel, the lack of visible clutch cable (he says clutching at straws) and I am thinking the vertical casting line in front of the number pad may come into play.

I could easily be swayed if you think it is a 1969 Y bike.
The fellow doing the stamping was a little unsure of himself, perhaps he was doing a number sequence which was a little out of the ordinary for him.

If I am correct with the total number of Y bikes made then they may have only been stamping a small number each day. Possibly in the order of 5 to 10.



I have just done a search for the other 4 digit Y bike. While I don't have a pic of the engine number I can see that I have filed A65LA7230Y under 1969.

It has the earlier clutch entry and I think the smaller barrel nuts.

Did you find a pic of a 4 digit 1969 Y bike also ?
Posted By: Two Alpha

Re: BSA Engine Number - 02/10/12 4:53 am

Here are the "Y" bikes that I have listed as 1969 models.

-A65LA 7041 Y Frame only, listed as 69' based on number.

-A65LA 7652 Y Engine only, listed as 69' based on number. Looks like earlier clutch entry.

-A65LA 7752 Y Dating Certificate, New Jersey, August 18 1969. 6 point barrel nuts, earlier clutch entry.

-A65LA 7879 Y Listed as 69' based on number. (I have quite a few pictures of this engine, it has some 1970 features)

-A50RA 9922 Y Dating Certificate, New Jersey, June 1969. 6 point barrel nuts, earlier clutch entry.

-A50RA 10144 Y 6 point barrel nuts, earlier clutch entry.

-A65LA 10481 Y 6 point barrel nuts, earlier clutch entry.

I have engine pictures for all of the above except A65LA 7041 Y (picture of frame only).

I don't have anything for A65LA 7230 Y.
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/10/12 5:44 am

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

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.

Those two Service Bulletins, (2-70 and 5-70), referred to them as 1970 models. As far as the warranty was concerned all the earlier machines were no longer eligible because they should have been sold before March 1970.

I think much of this will be resolved when we get the truth and everything is exposed.

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.
I wish you would hurry up and solve this one. I am getting impatient.

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.


Posted By: Two Alpha

Re: BSA Engine Number - 02/10/12 7:33 am

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.
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/10/12 9:18 am

Quote
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.


The 1969 'normal' bike numbering started at 10,000 and the 1970 bikes all had a zero or one followed by 4 digits.(ie the numbering started at 01000 or similar). Neither at 101 like the dating lists say.
Neither scheme has provision for a four digit number.

All those Y bike numbers must have been chosen from the 1967 despatch books.
I am not convinced they were picked in any particular order also. I think there is every chance that 7879 number was from about March of 1970. wink
I really have no idea. The numbers just seem all over the show.

We would need to see the 1967 and 1970 books to have a fighting chance of working that stuff out.
Posted By: Ola

Re: BSA Engine Number - 02/10/12 10:17 am

Another detail:
The early 70 bikes (like mine august 69), had only 6 fasteners in the outer timing cover. Sometimes around x-mas the cover got the seventh screw right beneath the gear spindle.

[Linked Image]

[Linked Image]

Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/10/12 10:26 am

Excellent Ola. Thanks for that. I honestly did not realise and I am sure it is going to be real helpful.

That will put the cat among the pigeons here now. crazy

It will be interesting to see where those 7000 series engines lie with that little gem.
Posted By: KingKat

Re: BSA Engine Number - 02/10/12 4:03 pm

Please forgive my ignorance,but what is the significance of a Y bike? Thank You
Posted By: Two Alpha

Re: BSA Engine Number - 02/10/12 5:12 pm

Hi KingKat,

Funny you should ask as the topic does crop up from time to time around here. smile

Follow these links to a couple of the more recent discussions, they will bring you up to speed. Note that the actual answer is still a bit of a work in progress.

EBay A65 Dating question

Calling all Dash Y and Y bike owners
Posted By: Two Alpha

Re: BSA Engine Number - 02/10/12 6:16 pm

Originally Posted by Kevin (NZ).

All those Y bike numbers must have been chosen from the 1967 despatch books.
I am not convinced they were picked in any particular order also.

Given some of the info GaryE has provided, it appears that all of these "Y" bikes were replacing previous bikes that had been withdrawn from the market, for whatever reason. They must have been working off of a master list of these defunct 1967 bikes.
They probably continued to add numbers to this list as production went on, that would help explain the 4 digit numbers like MotoMikes showing up as late as December 1969.

The stamping guys on the engine assembly line would have been right up to speed as they would need to add in the low numbers under 10,000, and then work in the LA, TA, and RA "Y" numbers at the same time as they were producing the 1970 engines. I doubt very much that they were duplicating normal 1970 numbers, say A65LA12222Y and XD12222A65L, the engine stamper was probably stamping the A65LA, A65TA, A65RA on as well.

MotoMikes number suggests that the "Y" was left for the stamper on the final assembly line, that person would have needed the "Y" stamp for the frame anyway.
So, as you suggested, the guy probably used the "X" when he intended to use the "Y", then just added the "D" as that is the exact combination he would be using to date the very next bike down the line.

Originally Posted by Kevin (NZ).
The numbers just seem all over the show.
We would need to see the 1967 and 1970 books to have a fighting chance of working that stuff out.

Yes, it would be a great help to have full on access to the 1967 through 1970 books. Some of these numbers hit three of the four years, with only slight variations!
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/12/12 12:23 am

Originally Posted by Two Alpha
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.


I have to agree with the secrecy aspect.
We are not just talking Y bikes here either.
From our discussions here we can now categorise the various 'Y' suffix bikes into 3 groups.

We have the 1969/70 Y bikes that were obviously made during those years but assigned 1967 style numbers and recorded in the 1967 shipping books.

But we also have the other two..
The Dash Y twins of 1967 that we know are very common and Gary has shown us a BSA document stating it was the introduction of the 3 pipe oil manifold.
The last group is the Hybrid Spitfires that appear to have been made at the start of the 1968 season and yet assigned 1967 style numbers also.

We have three groups. Let's put numbers to them
800- 1000 Y bikes. (Edited.... 1970 styled LA, TA and RA bikes)
800 Hybrid Spitfires. (Edited.. actually 478 MkIV styled bikes with A65SA*****Y numbers)
6000-7000 Dash Y twins of 1967. (Edited... actually approx 12,000 bikes, mainly A65SA, HA, TA, LA and RA models)

Of all these bikes we don't have any mention in a Parts Book.
Not a squeak from Bacon or any BSA historical writer.

What do we have.
Two Bulletins from BSA USA. SB (Gen) 2-70 and 5-70. (About the introduction of the 180 day warranty for 1970 bikes).
We also had the publication Gary discovered a few months back. (Oil Pipe).

There is nothing sinister about the 3 pipe manifold of 1967.
Why did it take Gary E some time to discover that in writing.
Forty Four years..

And just think of all the crap stories that we have been fed during that time. I personally had ten years of believing it was to do with the electrics.

Was it the Hybrid Spitfire deal that people, and BSA, wanted to keep quiet and not draw attention to ?

Well, - as for the 1970 Y bike scenario...
hmmmm,- I just see DODGY written all over that one.

Apart from this forum where have we actually seen any mention of the Y suffix ?
The BSAOC website does (in a fashion)...
Have we noticed how keen they are to talk about it ?
WHAT IS THE REASON FOR ALL THIS SECRECY ?




Posted By: Gary E

Re: BSA Engine Number - 02/12/12 2:31 am

Originally Posted by Kevin (NZ).
...We have three groups. Let's put numbers to them
800- 1000 Y bikes.
800 Hybrid Spitfires.
6000-7000 Dash Y twins of 1967...


Not sure where those numbers come from. Did I supply the Hybrid and -Y numbers?

My notes indicate:
478 Hybrid Spitfires
aprox. 12,000 "-Y" '67's
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/12/12 7:54 am

Thanks Gary.
It was a lazy guess on my part, - based in part on a hazy memory.

I thought the 7000 Dash Y bikes would be a conservative figure.

12,000 is a massive figure in the scheme of things. We have all been lead to believe that our bikes were reworked and shipped again later.

I apologise for the number of Hybrid Spitfires, it was just a figure I had in mind.
478 is still a fair proportion of the years production.

Did we decide if they were entered in the 1967 or 1968 books ?
I thought it was 1967..

I was a little concerned when you did not offer some comments here.
What is your take on the numbers stamped on Mike's 1970 engine ?
Posted By: Gary E

Re: BSA Engine Number - 02/12/12 5:11 pm

Originally Posted by Kevin (NZ).
...Did we decide if they were entered in the 1967 or 1968 books? I thought it was 1967...

You are correct; they are in the '67 books, is a section all to themselves after some blank pages.

Originally Posted by Kevin (NZ).
...What is your take on the numbers stamped on Mike's 1970 engine ?


For me, the jury is still out on his case numbers. The numbers are too big if a 0 is added after them to make it 19000, but a 1 in front to make it 11900 is possible; an it fits in with other TA numbers I have in my ever expanding data base.

I speculate that it is a replacement case or a stamping blunder on the production line. A unique one, none the less. Worth saving. It is definitely "outside the box" as it doesn't fit into any logical scenario. It's got aspects of several possibilities, but none that are convincing in all.
Posted By: MotoMike

Re: BSA Engine Number - 02/12/12 11:24 pm

Well now what...I'm not a collector really...hate to just sell this to some yahoo who doesn't give a sh*t what it is...if anyone has a interest shoot me a [email protected]
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/12/12 11:58 pm

Please don't put it on Ebay or similar.

Some here will remember when Troy Engineering advertised a 'Y' engine a few months ago. He was changing the listing every second day as he and potential purchasers spun into a mire of confusion.

The same with yours. I can guarantee 95% of the queries you get will be telling you it is a 1967 model. They will even quote a website and tell you a fantastic story about a shipping strike and adverse exchange rates. Another 4% will have you believe it is out of a Kawasaki or similar.

I really do think a couple of members here would like it. The shipping being the main concern obviously.
It could find itself in a container on the way to the BSA Rally in Sweden.... that is not so far away.
http://www.bsaoc.org/int2012/

Morgan, he who runs this Forum, has a Brit Bike museum (in Sweden)and may be interested.
I am sure the guys stamping engine and frame numbers made numerous errors. This one is unique in that at the moment the dating lists would have us believe it is a 1967 model.
We can see it was produced in December 1969 and the stamping of the XD has to be the classic blunder.

Besides, John and Bruce have both advised me that this is the year that the 1970 Y bike mystery is going to be solved.
All is about to be revealed !!!

The engine may be even rarer than we can imagine....
Posted By: Graham Ross

Re: BSA Engine Number - 02/17/12 6:34 am

Very interesting discussion.

So I had to go out and take a look at my 1970 Royal Star.

[Linked Image]

and the number is very close to the one that Kevin showed earlier.

Graham
Posted By: Kevin (NZ).

Re: BSA Engine Number - 02/17/12 7:39 am

G'day Graham, welcome to the BSA side of the forum. Your Royal Star looks to be a nice clean example.

If you were paying attention here you may have worked out approximately when your bike came off the line.

For just a couple of months production we are seeing enough examples of that unique pad.
Thanks for posting and adding to the collection.
Posted By: Graham Ross

Re: BSA Engine Number - 02/17/12 11:58 pm

Thanks Kevin, the Royal Star is one of my best second only to the '68 441VS.

I didn't realize how different the number pad was until last night when reading this thread.

The whole Y, dash Y issue makes for great reading. I can hardly wait until the real story comes out.

Thank you for the perseverance in helping to track it down. In my opinion it is very important to the owners of these bikes.

Graham
© 2019 Britbike forum