VIN and Production numbers.

Information on the identification and numbering of frame, motor belly, transmission and other parts
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VIN and Production numbers.


Post by Cotten » Tue Jan 25, 2011 12:04 am


The rule of thumb is that '48 and later production numbers on the belly of the cases carry a number before the year: 1 for FL series, and 2 for EL series.
The rear motormount boss would have a 6 for an El, or a 7 for an FL.

I have a '49 on the bench with a perfect, un-flawed, FL VIN, with 7s stamped upon the rear motormount boss to indicate an FL, but with 249- production numbers.

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Re: VIN and Production numbers.


Post by Panacea » Tue Jan 25, 2011 6:17 am

I have the belly numbers that start out 350, With no idea what the 3 stands for.The cases also have the 7 on the rear motor mount..Mike

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Re: VIN and Production numbers.


Post by Speeding Big Twin » Wed Jan 26, 2011 1:21 am

Cotten, I have photos showing code numbers 1 and 2 apparently on the wrong size Panhead engines for 1948, 49, 51 and 52 but I don't have a real explanation for it.

The 2 also appears on some lightweight models but in slightly different formats and with the sequential characters in a larger size than the code number and year, for example: 2-51- 37++. And my two photos of the Model S 125cc for 1949 show the year preceding the code number: for example, 49-2- 36++.

I've seen code number 3 at the start of Panhead belly numbers for 1950 and 58 but I can't explain why it's there. Number 3 often indicates 45ci SV (1948 or later G-series and W-series) but I've also seen number 3 on a 1950 Model S 125cc although the format and character sizes follow the pattern of the abovementioned 1951 lightweight.

Code number 4 is said to indicate 74ci SV (1948) and it does, but I've also seen 4 on 1949 45ci SV engines instead of the expected 3. Code number 5 is said to indicate K-series engines and it does, but I also have a photo of the 5 on a 1950 Model G and a 1950 WL.

Palmer's 1937-64 book only mentions code numbers 1, 2, 3 and 4 and I found nothing in it about any apparent oddities but in his 1932-52 military book he states: "The 1949 code is an enigma, with the extra first digit, but the code is not clear." However, it seems there are more years to be investigated than just 1949 and Bruce may have uncovered more about this since the military book was published. Eric

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