Harley-Davidson
Abbreviations Explained

Example: FLHTK

Harley-Davidson model codes are not random. They usually combine letters that describe the model family, chassis style, front end, touring equipment, trim level, or special package. Older Harley codes are not always perfectly consistent, but they are useful once you understand the pattern.

For example, FLHTK is commonly associated with the Electra Glide Ultra Limited / Ultra Limited family. The letters help place the bike in Harley’s Touring lineup.

Important Note

Harley-Davidson model letters changed over time, and some codes were reused, retired, or adjusted as platforms changed. Treat this as a practical model-code reference, not a factory parts manual. Always verify the exact year and VIN when ordering parts, fluids, or service information.

What The First Letter Of Your Harley Engine Series Means

The first letter in many Harley-Davidson model codes often identifies the motorcycle’s engine family or original platform type. While Harley naming changed over time, understanding the first letter gives riders a strong starting point for identifying what type of motorcycle they are looking at.

Letter	Meaning
G	Servi-Car three wheeler (1937–1972)
E	Overhead-valve 61 cubic inch “Big Twin” with separate engine and transmission
F	Overhead-valve Big Twin platform
K	Side-valve 45 and 55 cubic inch sport bike (1953–1957), predecessor to the Sportster
U	Side-valve Big Twin
V	Side-valve 74 cubic inch engine (1930–1936)
W	Side-valve 45 cubic inch platform (1937–1952)
X	Sports and Special Construction motorcycles
VR	Revolution liquid-cooled engine family (V-Rod)

For example, an FLHX Street Glide starts with F, meaning it belongs to Harley-Davidson’s overhead-valve Big Twin family. A VRSC V-Rod begins with VR, identifying the Revolution engine platform developed for higher-performance liquid-cooled applications.

The Importance Of The Second Letter: Front End Size Identification

The second letter in many Harley-Davidson model names often refers to the motorcycle’s front-end size and fork configuration. This distinction helps separate larger touring and cruiser bikes from narrower sport-oriented models.

Letter	Meaning
L	Wide front tire and Hydra-Glide style front forks
X	Narrow front tire and sport-style forks

This is why Touring motorcycles commonly begin with FL, while performance-oriented bikes such as Dynas and Sportsters often begin with FX or XL.

Understanding The Third Letter: Frame Style Designation

The third letter in a Harley-Davidson model name often identifies the motorcycle’s frame style or riding category. This makes it easier to tell the difference between Touring, Softail, Dyna, and other Harley families.

Letter	Meaning
H / T	Highway or Touring frame
ST	Softail frame
D	Dyna frame

Additional letters may be added to represent trim packages, suspension styles, touring equipment, fairings, CVO editions, police models, or engine displacement variations. Harley-Davidson sometimes reused letters across different generations, which is why model decoding can occasionally become confusing.

For example, FLTRX identifies a Road Glide platform, while FLHTK identifies an Ultra Limited Touring platform. Both belong to Harley’s Touring family, but their additional letters distinguish trim and configuration.

What Harley-Davidson Suffix Letters Mean

After the main model letters, Harley-Davidson often adds additional letters to identify trim level, fuel system, suspension setup, police use, touring equipment, or special editions. These suffixes became especially important during the Twin Cam era when Harley offered both carbureted and fuel-injected motorcycles.

Letter	Meaning
I	Fuel Injection
C	Classic
S	Sport / Special (depends on model family)
T	Touring designation
P	Police model
U	Ultra touring package
L	Low model / lowered configuration
R	Road / performance-oriented trim
SE	Screamin’ Eagle / CVO model
X	Special, Custom, or performance variation

For example, an FLHRCI breaks down into:

• FL = Big Twin / wide front-end platform
• HR = Road King family
• C = Classic
• I = Fuel Injected

On many older Harley-Davidson motorcycles, the I suffix matters because Harley sold both carbureted and fuel-injected versions of the same motorcycle. Later motorcycles stopped using the I designation because fuel injection became standard equipment.