Deciphering Harley's VIN Numbers 1936 - 1964

The VIN number stamped on the engine case of a vintage Harley-Davidson contains a lot of useful information about the engine and in some cases the bike itself.   The model year, model and production number are all listed in a simple arrangement of numbers and letters which is clearly stamped at the top of the left engine case, right below the "V" formed by the two cylinders.

It's important to note that these numbers can be changed.  This could be to hide a stolen bike, to increase the value of a bike by making it appear to be a rare model, etc.  You can find people online who are experts in the fonts used to stamp the VIN number as these changed over time.  If you find an old bike with an engine number that looks a little too new, it certainly would be worth checking it out before making your purchase.

The basic format of the VIN number is as follows.  The first two digits indicate the model year followed by one to three letters which denote the model.  After the model designation, the final numbers indicate the production number of the engine.

Below I've listed the OHV models produced from 1936 - 1964, along with their distinguishing features.

1936

EL  61 OHV Special Sport Solo
E    61 OHV Solo, Medium Compression
ES  61 OHV Sidecar Gearing, Medium Compression
EM 61 OHV Specialty Model for Midget Car Racing

Note:
The "S" in the ES model is not stamped onto the engine case.

1937, 1938, 1939, 1940

EL  61 OHV Special Sport Solo
E    61 OHV Solo, Medium Compression
ES  61 OHV Sidecar Gearing, Medium Compression

Notes:
The E model was only built in 1937.
The "S" in the ES model is not stamped onto the engine case.

1941, 1942, 1944 (no civilian models built in 1943)

EL  61 OHV Special Sport Solo
E    61 OHV Solo, Medium Compression
FL  74 OHV Special Sport Solo
F    74 OHV Solo, Medium Compression

1945, 1946, 1947

EL  61 OHV Special Sport Solo
E    61 OHV Solo, Medium Compression
ES  61 OHV Sidecar Gearing, Medium Compression
FL  74 OHV Special Sport Solo
F    74 OHV Solo, Medium Compression
FS  74 OHV Sidecar Gearing, Medium Compression

Note:
The "S" in the ES and FS models is not stamped onto the engine case.

1948

EL  61 OHV Special Sport Solo
E    61 OHV Solo, Medium Compression
ES  61 OHV Sidecar Gearing, Medium Compression
FL  74 OHV Special Sport Solo
F    74 OHV Solo, Medium Compression
FS  74 OHV Sidecar Gearing, Medium Compression

Note:
The "S" in the ES and FS models is not stamped onto the engine case.

1949

EL   61 OHV Sport Solo
E     61 OHV Solo, Medium Compression
ES   61 OHV Sidecar Gearing, Medium Compression
EP   61 OHV Solo, Medium Compression, Springer Fork
ELP 61 OHV Sport Solo, Springer Fork
FL   74 OHV Sport Solo
F     74 OHV Solo, Medium Compression
FS   74 OHV Sidecar Gearing, Medium Compression
FP   74 OHV Solo, Medium Compression, Springer Fork
FLP 74 OHV Sport Solo, Springer Fork

Notes:
The "S" in the ES and FS models is not stamped onto the engine case.
The "P" in the EP, ELP, FP and FLP models is stamped on the engine case in an unorthodox manner.

1950

EL  61 OHV Sport Solo
E    61 OHV Solo, Medium Compression
ES  61 OHV Sidecar Gearing, Medium Compression
FL  74 OHV Sport Solo
F    74 OHV Solo, Medium Compression
FS  74 OHV Sidecar Gearing, Medium Compression

1951

EL   61 OHV Sport Solo
ELS 61 OHV Sport Solo, Sidecar Gearing
FL   74 OHV Sport Solo
FLS 74 OHV Sport Solo, Sidecar Gearing

Note:
The "S" in the ELS and FLS models is not stamped onto the engine case.

1952

EL   61 OHV Sport Solo
ELF 61 OHV Sport Solo, Foot Shift
ELS 61 OHV Sport Solo, Sidecar Gearing
FL   74 OHV Sport Solo
FLF 74 OHV Sport Solo, Foot Shift
FLS 74 OHV Sport Solo, Sidecar Gearing

Notes:
The "S" in the ELS and FLS models is not stamped onto the engine case.
The last "F" in the ELF and FLF models is not stamped onto the engine case.
The ELS and FLS models have high compression engines.

1953, 1954

FL     74 OHV Sport Solo
FLF   74 OHV Sport Solo, Foot Shift
FLE   74 OHV Handshift with Traffic Combination
FLEF 74 OHV Foot Shift with Traffic Combination

Notes:
The last "F" in the FLF and FLEF models is not stamped onto the engine case.
The FLF and FL models have high compression engines.
The "Traffic Combination" models have a special cam and carburetor.

1955, 1956

FLHF 74 OHV Super Sport Solo, Foot Shift
FLH   74 OHV Super Sport Solo, Hand Shift
FL      74 OHV Sport Solo, Hand Shift
FLF    74 OHV Sport Solo, Foot Shift
FLE    74 OHV Handshift with Traffic Combination
FLEF  74 OHV Foot Shift with Traffic Combination

Notes:
The last "F" in the FLF, FLHF and FLEF models is not stamped onto the engine case. 
The "Traffic Combination" models have a special cam and carburetor.

1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964

FLHF 74 OHV Super Sport Solo, Foot Shift
FLH   74 OHV Super Sport Solo, Hand Shift
FL     74 OHV Sport Solo, Hand Shift
FLF   74 OHV Sport Solo, Foot Shift

Note:
The last "F" in the FLF and FLHF models is not stamped onto the engine case.