1919 (?) motor

[DarrinM]

Hi everyone, this is my first post here but I’ve been a member for a little over a year.
I recently purchased my first JD project (1926 frame with a 28 motor)
The pile came with this extra motor that I’m told is a 1919.
The serial number is illegible but the belly numbers are M8 534. I’ve read that the belly number is typically a year before the actual assembly date?
It has small base cylinders.
The flywheels that were included have casting number 150-13 B.
So is it a 1919 motor?

[Steve Slocombe]

Dear Darrin, those are pre-1925 belly numbers with the 8 for 1918 and the M for the 13th thousand and 534 the sequence number. So say 18J/F13534 or thereabouts for an engine number. 1918 and 1919 were the most produced JD models as they had military contracts for WW1. 26,000 1918 pocket valve Big Twins were produced, so 13,000 would be half way through and I'd suggest the engine is more likely to be '18 than '19 from the crankcase belly numbers. Many machines of this period went to France and had USA stamped to the top left of the number plinth, which I don't see here. The 74s didn't come out until 1921 so all earlier bikes would be 61s with the small base cylinders. The spoked flywheels are pre-1920 so maybe all the bits came from the same motor. Nice find.

[exeric]

Your cylinders are pre 1920, and 5 fin for the 61" motor. H-D didn't offer a JD until 1921.

[DarrinM]

Thank you both for the verification!
Its going to make a nice piece of garage decor.

[exeric]

Your cylinders are the most valuable part of that motor. More valuable is the timing gear train, and by far the most expensive is the outer gear cover with it's oil pump assembly. For some crazy reason, the outer gear cover is a very rare item. If you have a knucklehead, or early panhead, their Alcoa gear covers are all over the place. . . . Go figure

[DarrinM]

Your cylinders are the most valuable part of that motor. More valuable is the timing gear train, and by far the most expensive is the outer gear cover with it's oil pump assembly. For some crazy reason, the outer gear cover is a very rare item. If you have a knucklehead, or early panhead, their Alcoa gear covers are all over the place. . . . Go figure

That’s great news, I suppose..
now I just have to figure out which stuff is for the 1918 motor and which is for the 1928 motor!
I can see differences in the parts but I really need to research.
I guess I should start off by getting a copy of Mr. Slocombes book!

Thanks again for the helpful replies

[exeric]

I used to have 2 different 1916 motors on display stands. Maybe you could do that with your motor, Darrin, and just throw parts at it when you find them. They're beautiful motors and look good as static displays.

[DarrinM]

That’s exactly what I have planned for it, Eric!
Either that or find someone local who wants to trade it for parts for my 26 project

[Tommo]

As a matter of interest I had a look at a set of 1919 cases I've got and as I was not aware that the belly numbers represented anything to do with the engine numbers I'm interested to hear thoughts on this combination of numbers DSCF4262.JPGDSCF4261.JPG

[Tommo]

The same goes for these 1920 cases DSCF4263.JPGDSCF4264.JPG

[joe fxs fxr]

Tommo, I think the first part of the belly numbers represent month and year of manufacture, so Oct 1919 and April 1920 would coincide with the serial number years. But I'm not an expert in 100 year old bikes.

[Tommo]

Joe that's my take on it too
A= January and we get to H for August with I being dropped because its too much like the numeral 1 (one) so J is for September through to M being December.
Steve's answer saying that M = 13 and that 13 has some connection to the engine number is new to me but I'm not too old to learn so I was hoping for an explanation.
It's late here at the moment but tomorrow I'm going to see if I can find any belly numbers that have the letters N to Z and that would blow my theory out of the water.
Good Night All it's past my bed time

[DarrinM]

Joe that's my take on it too
A= January and we get to H for August with I being dropped because its too much like the numeral 1 (one) so J is for September through to M being December.
Steve's answer saying that M = 13 and that 13 has some connection to the engine number is new to me but I'm not too old to learn so I was hoping for an explanation.
It's late here at the moment but tomorrow I'm going to see if I can find any belly numbers that have the letters N to Z and that would blow my theory out of the water.
Good Night All it's past my bed time

I’m curious about that as well. It sure would be interesting to see a prefix letter past M.
Your theory makes sense to me. But then, companies don’t always do things just to make collectors understand things 100 years later.

Im wondering if that’s why I was told it was a 1919 motor, since if the cases were made in December 1918,surely it wouldn’t have been assembled until 1919?

[Tommo]

I've had a look at my 1918 and the two 1920 bikes that I have along with a set of 1923 cases and I find no letters after M on any one of them but what I do find is that my all original mag model 1920 has a M9 prefix belly number and a very low engine number 20F 10--
As this number is on an original, unrestored bike I'm cautious about putting full numbers up here.
The 23 cases are E3 694 with an engine number 23F 6040
I'd be very interested to hear other peoples comments on this subject

[Steve Slocombe]

Dear Tommo and all, I don't think the belly number letters are months, but thousands of cases, so it would be possible for 1918/19 bikes to have letters such as M. Your 23 case makes sense this way, with a belly number in the fifth thousand (E) and serial 694 being 5694 and within spitting distance of the 6040 engine number. 20T2770 belly numbers also make sense this way as above, as do those for 19A10047.

If you need a copy of the 1915-29 pocket valve Harley book, buy it from Replicant Metals and then bring it to Oley for signing.