All Harleys made before 1970 have engine numbers only.   Located on the engine boss above the timing plug on the left engine case.   The first two numbers indicate year of manufacture.   The next two alphabetical letters indicate engine type and or cubic inch displacement.

W-WL-WLD ..........45 cubic inch side valve Flathead
K-KRM..........45 cubic inch side valve Flathead 1952-1953
G-GA.........45 cubic inch side vale Flathead 3 wheel servi-car
KH-KHK-KHRM..........55 cubic inch side valve Flathead 1954-1956
Xl-XLH-XLCH..........55 cubic inch overhead valve Sportster
E-EL..........61 cubic inch overhead valve Knucklehead/Panhead
U-UL.........74 cubic inch side valve Flathead
UH-UHL..........80 cubic inch side valve Flathead
F-FL..........74 cubic inch overhead valve Knucklehead/Panhead/Shovelhead
FLH..........74 cubic inch overhead valve Panhead/Shovelhead



The last four digits are the engine production numbers.   In 1962 Harley started coding these  numbers.   The first digit in the production number was even for even number years and odd for odd years.   The next to the last digits indicates the manufacture (H) for Harley-Davidson.   Some of the smaller bikes were built by an Italian manufacture.   The last digit indicates year 0 for 1970, 1 for 1971, 2 for 1972 and so on.

1A = FLP-FLPF 6A = Sprint SS
2A =FLH-FLHF 7A = MLS-125
3A = XLH 8A = M-165
4A = XLCH 7B = ERS
5A = GE 8B = MSR



Starting in 1970 with the cone Shovel, Harley made the frame number the same as the engine number.   The first two digits indicate the production number.   All models started with 10000.




Crankcase numbers are on the bottom outside edge of both halves of the cases.   They consist of three digits, a dash followed by four more digits.   The first digit is a code number.   The next two digits are the year the case was produced.   Most likely earlier then the boss number.   The following four digits are the case production numbers.

Crankcase codes

CODE 1 = 61 cubic inch E-EL and 74 cubic inch FL-FLH
CODE 2 = 125cc S and 165cc ST-STU
CODE 3 = 45 cubic inch W-WL-WLD-G-GA
CODE 4 = 74 and 80 cubic inch V-UL-VH-VLH
CODE 5 = 45 and 55 cubic inch K-KRM-KH-KHRM-KH-KHK-KHRM
CODE 6 = 125cc B model
CODE 7 = 55 cubic inch Sportster XL-XLH-XLC-XLCH



In 1962 Harley started stamping numbers on Frame, forks and transmissions of their two cylinder bikes.   Unfortunately there are alot of exceptions to this list.   List is for FL and XL models.   An alphabetical letter code followed by three or four digits.
CODE A-B = 1962-1963
CODE B-C-D = 1964
CODE C-D =1965
CODE D-E-F-G = 1966-1967
CODE J-K-L = 1969
CODE K-L = 1970



Well...........NOT VERY!!!   One thing I've learned about Harley numbers in the last 35 years is that you never know...........   One will come out of left field, and surprise the hell out of you!   For example, no records exist for 1958 and earlier, they were destroyed.  Most likely kept someone out of jail, who knows?   I was told once by a DMV employee in California that they had come up with seven bikes made in the sixties with the same numbers?   And they believed they came from the factory that way.......   A tax dodge, when Harley was broke, again, who knows?   But, it sure throws a monkey wrench into the numbers game!   If that's not bad enough, Harley sold a shit load of replacement cases and engines, all with numbers.   What numbers, nobody knows!   When AMF took over Harley in 1970, they put a stop to that.   But, of course, there back into it, now that AMF is gone.   As far as EVO's are concerned, I have no idea?   Try Harley, but my guess is, they don't have a clue, or won't release that info.   My suggestion, pick up a set of S&S cases and call it a day..........Ride free forever........RR