1919 (?) motor

[Tommo]

Steve,
Using that reasoning we should see letters after M as the production figures as published in "The Legend Begins" and covering the years we are talking about get as high as 27,040 in 1920.
1918 - 26,708
1919 - 23,279
1920 - 27,040
1921 - 11,400
1922 - 10,780
1923 - 17,046
1924 - 17,648
So using that reasoning we should see Z for 1918, X for 1919 and maybe Z for 1920 as the production figures have rolled into the 27 thousands and the alphabet is finished.
As I've said previously I'm prepared to learn but at this stage I can't find a belly number with a prefix letter after M.
Can anybody help us here, has anybody got evidence of factory stamped crankcases with a prefix letter that falls somewhere between N and Z?

[MikeW]

Intrigued by this discussion I went out to the shed on this beautiful early autumn Southern Hemisphere afternoon and checked the numbers on a couple of crankcases. The numbers on a pair of 21J cases are particularly interesting in the context of the discussion on this thread.

P1030824 (2).JPG
P1030825 (2).JPG

The combination of engine and belly numbers is puzzling.. Assuming they are factory numbers (and they look correct to me), using Steve's explanation the belly numbers indicate that these were the 24,882nd crankcases machined in 1920 (or in 1919 and 1920 for 1920 machines?). They were then fitted to an early production 1921 J model.

But if the total production of 1920 models was over 27,000 (Tommo's numbers), why were these cases surplus to 1920 requirements? I assume (a) that Tommo's numbers are for total production - V-twins, singles and Sport Models and that (b) the belly number sequence explained by Steve applies only to V-twins, and that singles and the new Sport Models had their own stamping system. That might explain why this crankcase, nearly the 25th thousandth made for 1920 V-twins, was "surplus to requirements" for that year and fitted to an early 1921J in the fall of 1920 as the 1921 models were being assembled in the factory for shipment to dealers.

That's the only reasonable explanation I can come up with but I would be interested to hear the views of those a lot more knowledgeable about such matters.

Mike

[MikeW]

When I put away the 21F crankcases after taking the photos and posting the message above, I happened to look at a broken crankcase half which was also on the shelf. This was for a 1920 electric model and shows the same pattern of belly and engine numbers as on the 21J.

P1030830 (2).JPG

P1030828 (3).JPG
A high number crankcase machined in 1919 fitted to a 1920 model motorcycle. As I said above, I'd be interested to hear the comments of the experts and, in particular, whether this year difference was common. As I have only four crankcases, and two of them show this pattern of the crankcase belly number with an earlier year than the engine number (as well as the high production number "X"), I assume that it is not uncommon?

Mike

[Jerry Wieland]

When I put away the 21F crankcases after taking the photos and posting the message above, I happened to look at a broken crankcase half which was also on the shelf. This was for a 1920 electric model and shows the same pattern of belly and engine numbers as on the 21J.

P1030830 (2).JPG

P1030828 (3).JPG
A high number crankcase machined in 1919 fitted to a 1920 model motorcycle. As I said above, I'd be interested to hear the comments of the experts and, in particular, whether this year difference was common. As I have only four crankcases, and two of them show this pattern of the crankcase belly number with an earlier year than the engine number (as well as the high production number "X"), I assume that it is not uncommon?

Mike

I cannot speak about JD's but in Knuckles and Big Twin flatheads it is not uncommon that low numbered engines will have a previous years matching number underneath. Jerry

[Tommo]

This post by Mike certainly backs up what Steve has been saying all along so this old chap has certainly learnt something here.
I hope I've not upset anybody with my posts on this subject and if I have I apologize for that.
Mike lives nearby to me and I rang him in my quest to find N to Z letters and as it turned out he had two crankcases with a X prefix belly number.
We talked and I told him to post them so we could all learn and this gets us to where I say Sorry I was Wrong.

[joe fxs fxr]

Yes, if I would have read Steve's first post before responding I would have known things were done differently prior to 1925. I was right when I said I didn't know anything about 100 year old bikes.

[MikeW]

Steve's explanation of the belly numbers certainly seems correct and fits the evidence of the numbers themselves. The only matter which I'm not entirely convinced about is whether we should expect belly numbers and engine numbers always to be within "spitting distance" of each other. Yes, as crankcases were machined, stamped and stacked on trolleys (or whatever means the factory used for shifting parts from one production area to another) before moving to the motor assembly shop, we might expect belly and engine numbers to be in a rough relationship with each other. But I'm sure that stocks of cases would build up occasionally and wouldn't always be used in a strict sequence by the engine builders.

For example, my 21F restoration has a belly number B1 xxx and an engine number in the high 5000s. I understand that this means the engine and belly numbers are near enough to 4000 apart. Is that unusual?

Mike

[Speeding Big Twin]

Most of my BN photos are 1925-later. I have a few for 1924-earlier although I haven’t concentrated much on sorting them out but this thread is changing that.
In this BN format the highest letter I have at the start is Y. The SN for these cases is 19A22+++.







The letter I was used. SN for this case is 22JD12++.








When I finish sorting my other examples I’ll post the results.
Eric

[MikeW]

This post by Mike certainly backs up what Steve has been saying all along so this old chap has certainly learnt something here.
I hope I've not upset anybody with my posts on this subject and if I have I apologize for that.
Mike lives nearby to me and I rang him in my quest to find N to Z letters and as it turned out he had two crankcases with a X prefix belly number.
We talked and I told him to post them so we could all learn and this gets us to where I say Sorry I was Wrong.

Gracious as always Peter. I have two comments. First, irrespective of this matter, you've probably forgotten more than most of us have learnt about mid-1920s Harley-Davidsons. And second, as you are the same age as me, you couldn't possibly be described as an "old chap". How about "almost middle-aged"?!

My interpretation is that Eric's second example above is another one where a high belly number for one year (1921 9000s) is used on a low engine number for the following year.1922 12xx.

Mike

[Steve Slocombe]

Dear All, we only put forward this hypothesis of pre-1925 belly numbers after reviewing numerous Dutch and Canadian crankcase numbers supplied by AMCA contributors to the JD Book, so thanks to them for this new information. You can see from the 1938 factory tour brochure that Harley kept large intermediate stocks, and the belly numbers must have been applied before the engine numbers. For my period of the 1930s, I have a low number 1936 with late 1935 belly numbers, and have also had two early 1934 engine numbers with late 1933 cases. The most extreme example I know is a 46WR with 1942 cases, presumably matched and belly numbers added early in the 1942 season before Pearl Harbor, then left on the shelf for four years. In the 1930s the engine numbers are usually within a few hundred of the belly numbers, the exception being 1930. Here the first 2000 VL bikes were recalled and had engine cases replaced, with the same engine numbers but belly numbers around 2000 higher. For 1918/19 the factory must have been running flat out and with big stocks, so I'm guessing engine and belly numbers could easily have been further apart. Thanks for posting the X and Y belly numbers which I have not seen before. Isn't it great to find fresh knowledge on 100 year old motorcycles thanks to AMCA members across the world getting together!

[MikeW]

Nicely put Steve. Feel free to use any of the engine/belly number photos I have posted in this thread in future editions of your book

Mike

[maxglass]

IMG_2653.jpg this is L19A159XX the belly number reads Q9 746
Max

[Speeding Big Twin]

Here's what I have for 1917 and 1919–24 including the two I mentioned above.

D7 4++ for 17 T 23++
G7 9++ for L 17 T 56++
I7 9++ for 17 T 11+++

P9 4++ for L 19 A 15+++ A
W9 9++ for L 19 A 22+++
Y9 8++ for 19 A 22+++

A0 1++ for 20 W 23++

J0 6++ for L 20 T 86++

I1 3++ for 22 JD 12++

C2 5++ for 22 J 64++
E2 9++ for 22 JD 7+++

A3 2++ for 23 JD 51++
I3 1++ for 23 J 84++

P3 5++ M for 24 JE 15++
P3 6++ M for 24 JD 20++
Q3 8++ M for 24 FDCA 25++

D4 +++ for 24 JDCA 40++
E4 1++ for 24 JE 49++
E4 5++ for 24 FDCA 56++
L4 5++ for 24 JE 10+++
M4 8++ for 24 JD 13+++
O4 8++ for 24 FE 17+++

Why do three BNs have M at the end? I do not know. Anybody?


AFAIK BNs were introduced as of 1909 models and from then thru 1916 there appear to have been at least three different BN formats. For example 1234, 1234A and A1234. In twelve of the thirteen examples I have of the first two of those formats the BN is an exact and complete match for the SN and apparently this was done on purpose.
Letter at the end of the BN may have been introduced during the 1911 model year? Like it was with SNs?
When did a letter first appear at the front of the BN? Maybe 1915?
Eric

[MMasa]

Well, M is the factory letter code for 1924 and it seems that it’s only on the very high 1923 BN examples you’ve given.
Starting in 1924 ALL cases were large base (74” AND 61”)
The M is likely there to prevent one of these late cases from being stamped with a 1923 61” VIN.
Mark Masa

[Tommo]

If you're playing around with J's of this period you will find a wealth of information in this book.
I don't know if it's still available or not but it was put out by Antique Cycle Supply may years back and answers a lot of questions that appear on this forum.
Maybe the AMCA library has a copy you can download.
I've also included a couple of pages that are relevant to this thread to give you some idea of the sort of info that is in this publication.