Parts Of A Harley

Parts of a Harley

Harley-Davidson. The name alone conjures images of freedom and the open road. America’s greatest motorcycle has been around since William Harley and the Davidson Brothers opened the Harley-Davidson Motor Company in 1903. The Motor Company‘s signature V-twin-powered motorcycles have become an American icon since then.

The Motor

Part for part, the motor is the heart and soul of a Harley-Davidson. Since the very beginning, Harley-Davidson has used an air-cooled 45-degree vertical twin cylinder motor. The signature motor design employs a shared crankpin to actuate both cylinders pushrods. Harley-Davidson engines have changed little, undergoing only seven revisions since the Company’s inception. Motor types included the Flathead, Knucklehead, Panhead, Shovelhead, Evolution and Twin Cam 88 motors. The seventh motor, called the Revolution, is a departure from Harley-Davidson’s original designs. The Revolution motor is a liquid-cooled, dual overhead cam, 60-degree V-twin engine that was developed by Harley-Davidson’s Powertrain Engineering team and Porsche Engineering for the VRSCA (V-Rod).

Ignition and Fuel Delivery

Over the years, Harley-Davidson has employed a variety of ignition systems to start its motorcycles. Earlier models used either a points and condenser or a magneto ignition type system, with electronic ignition module systems being equipped on all present models as far back as 1980. Fuel is delivered via electronic fuel injection on all Harley-Davidson models as of 2007; however, earlier models employed a butterfly-type carburetor that was replaced in 1989 by a Constant Velocity carburetor based on Mikuni CV carburetor designs. Exhaust gases are typically expelled via a two into two exhaust system.

The Frame

Supporting the torque producing Harley-Davidson V-twin motor requires a strong frame, which vary by model family. Although most frames are similar, each model has slight variations that separate them. For example: Although touring frames use twin coil-over air suspension in the rear, similar to the Dyna series, they are built to support the additional weight of saddlebags and can be distinguished by the location of the steering head, which is forward of the front fork assembly. Softail frames do not use coil-over suspension, instead relying on a hidden rear suspension system to maintain a rigid tail image while providing comfort and performance.


Harley-Davidson uses a system that specifies the type of suspension used by a model type by the motorcycle’s designation. The designation FL is a code for the Touring line, which uses a wider, large-diameter telescopic fork with FX denoting a model equipped with a smaller-diameter fork. For example, the Road King is known as the FLHR, while smaller forks are used on the Dyna Wide Glide (FXDWG) and Softail Deuce (FXSTD).


The aftermarket is filled with a variety of accessories, intended to either dress-up a motorcycle or to increase its performance. Fuel systems can be upgraded with the addition of the Screamin’ Eagle Race Fueler EFI system, air cleaners and exhaust systems. Handlebars are often changed for comfort or performance, either to a taller ape-hanger or a low drag style handlebar.