Tech Tips

Straight Facts About Harley's

I. D. Numbering and Coding Systems

     Only a person who has had his chopper ripped off can fully appreciate the sick, helpless, frustrated, empty feeling one gets when discovering his bike is gone.

     Having had mine ripped off, I speak from experience. After the first shock of discovering it had been stolen, you are hit again-right square in the balls- when the police tell you there is nothing they can do, that " it was probably dismantled before they reached their destination."

     Not only you have lost your bike, but you have nothing to cling to-no hope that it just might be picked up, nothing to make the pain easier-its gone, and you might as well forget about it. Bang. Its gone-and you’re sick.

     So what can we do? Well first off, make it as difficult as hell for your bike to be stolen. Then take the profit out of stealing by not knowingly buying hot parts.

     This article will tell you how to spot the altering of engine numbers. It will show you how to read them (including fartory coding), so that you can check a bike out before buying – especially from a private party. It might even be a good idea to check your own bike out to see if your numbers are in order.

      The vehicle identification number is on the left side of your Harley engine, slightly below the cylinders on a raised flat surface (engine boss).

     Up until the 1970 model, Harley was the only bike registered by engine number. Starting with the1970 model year, Harley started putting the same number on engine and frame.

How to read numbers

All Harleys produced prior to the 1970 model year have only an engine registration number. See chart for a visual breakdown of the following information

The first two numbers indicate model year of engine.

The next set of one or more alphabetical letters indicate type of engine and/or cubic displacement at the time engine was manufactured.

W-WL-WLD	45 cu.in side valve
K, KRM	45 cu.in side valve 1952-53
G, GA	45 cu.in side 3 wheel servi-car
KH, KHK, KHRM	55 cu.in side valve 1954-56
XL, XLH, XLCH	55 cu.in overhead valve, Sportster since 1957
E, EL	61 cu.in overhead valve
U, UL	74 cu.in side valve
F, FL	74 cu.in overhead valve since 1948
FLH	74 cu.in overhead valve since 1955
UH, ULH	80 cu.in side valve
S	125 cc single cylinder 1948-52
ST	165 cc single cylinder since 1953
B	125 cc single cylinder since 1955

The last four digits are the engine production number. (Note: factory coding started with 1962 model year; first digit of production number will be even for even number years, odd for odd number years.)

Numbers for 1970 forward

Commencing with 1970 model year, all Harleys have the same engine and frame numbers these numbers are different from earlier numbers: (see chart) The first two digits indicate the model. The next five digits are the production number. Numbering started on all models at number 1000. (Note factory coding: first two digits of production number are even for the even number years, and odd of the odd number years The next to last digit indicates manufacture (Harley)
The last digit indicates model year. Example, 0 is 1970, 1 is 1971. The following is what first two digits indicate:

DIGITS	MEANING
1A	FLP, FLPF
2A	FLH, FLHF
3A	XLH
4A	XLCH
5A	GE
6A	Sprint SS
7A	MLS-125
8A	M-65S
7B	ERS
8B	MSR

Crankcase numbers

In add to engine and frame numbers, there are also numbers on the bottom of both halves of the engine crankcase. They are located on the outside edge, near the front of each half. This is a good place to check; for even the burn artist luck out and does a passable job of changing engine numbers, odd are he’ll overlook these seldom-mentioned numbers (see chart)
The crankcase number consists of three digits, a dash, followed by four digits. The first digit is a code number:

CODE NUMBER	MEANING
1	61 cu.in E or EL model, and 74 cu.in FL and FLH models
2	125cc S model and 165cc ST and STU models
3	45 cu.in W, WL, WLD, G and GA models
4	74 cu.in and 80 cu.in V, UL, VH, and VLH models
5	74 cu.in and 80 cu.in V, UL, VH, and VLH models
6	125 B model
7	55 cu.in sportster XL, XLX, XLC, and XLCH models

The next two digits are the year the crankcase was produced. This number will usually be one year earlier than year stamped on the engine due to Harley’s pre-stamping cases in advance of anticipated needs. If all cases stamped are not used before the end of the year. They are used in the next year’s model! This screw-up applies only to crankcases.

The figures following the dash are the crankcase production number. This number will not correspond with engine production numbers. Be sure to keep these two discrepancies in mind, in case you are ever checked out by the local heat and they are not aware that model year and production number on the case will not match engine numbers.

Fork and transmission number

Additional identifying numbers have been assigned to all of Harley’s two cylinder bikes since their 1962 model year. These numbers are stamped on the frame, front forks and with the exception of the Sportster models, on the transmission.
These numbers consist of an alpha character followed by three or four digits. The following alpha prefixes will apply to the XL and FL series. Unfortunately there are deviations from this list-so the following must be used only as a guide.

Numbers starting with this alpha letter	Generally apply to these years on FL and XL series
A and B	1962-63
B, C, and D	1964
C and D	1965
D, E, F, and G	1966-67
J, K and L	1969
K and L	1970

Screwed-up Records

All Harley records prior to 1958 have been destroyed. Coupled with this, Harley sold replacement crankcases and engines until late 1969 needless to say, this really screws things up as far as having any hard and fast rules on any numbers prior to 1969.

Starting in late 1969, Harley will only replace engines or crankcases, if old cases or a portion of, containing the number are turned into them. Harley will then restamp the old number on the new case or engine, and the bike retains the original identity number.

Factory Coding

Harley started a coding system with the 1962 model year. The first digit of the production number will be even for the even number years and odd for the odd number years. Also, in production numbers containing five rather than four digits, the first two digits will be even for even numbered years, and odd for odd number years. Here are some examples:

63FLH7593
64FL8613
69FLH11891

If you have a 1965 bike, and your number is 65fhl2234 then you have problems.

INDICATIONS THAT ENGINE NUMBERS HAVE BEEN CHANGED

1. Any obvious removal of numbers by grinding or filing

2. Any over-stamping. Where it appears numbers have been superimposed. This is usually indicated by difficultly reading     numbers which are not clean cut

3. A surface that has been ground down, original numbers removed and substitute numbers stamped on it. Look for unevenly     stamped numbers

4. Watch closely: For grinding marks on protrusions surrounding a flat area (engine boss) where engine numbers are stamped,     such as ridge above the boss surrounding the engine bolt The e" dogs" on older engine which protrude out from engine boss
    The spoke like ridges extending from center of case to the outer edges The cooling fins on engine cylinders – incase grinding     was done while engine was assembled. The bottom portion of the boss that has a flat horizontal line instead of one which     follows contour and rounded surface of the case surrounding the flywheel.

5. The raised engine boss containing numbers is completely ground away, and then sandblasted for even textured surface, and     phony numbers added.

6. The entire engine boss is removed and then the surface is built up by heliarc welding. This is a popular method, for it makes     it impossible for police to restore original numbers by chemical process. Here is what to look for to see if the heliarc method     has been used: Weld marks on the side of the engine boss A merging or partial merging, of the boss with the upper     horizontal ridge (sportster engine only) (The standard production space between the boss and the ridge is one-eighth inch).     Look for pit holes on surface of boss, caused by air bubbles that may from at time of welding.

7. Any mistake in numbering. This article give you all the information you need in this area

8. A distinct difference in texture between surfaces where number is located and the immediate surrounding areas. The texture     should be the same for engine cases are cast in a mold. Many times, however, texture is uniform because the engine is     sandblasted by the rip-off artist after the numbers have been changed. With this article you should be able to spot a hot     bike-or at least one you should think twice about buying-because before you can say," but officer, I didn’t know those parts     were stolen!" He may have started to crease your gourd and cut off your circulation with chromed vise grips, as you see     your bike being hauled downtown