No, Harley-Davidson motorcycles do not have only one cylinder. While it is true that Harley-Davidson is well-known for its iconic V-twin engines, which typically have two cylinders arranged in a V-shape, they also produce motorcycles with other engine configurations.
Harley-Davidson offers various engine options across its model lineup. The most common and traditional engine configuration is the V-twin, which can be further classified into different types such as the Harley-Davidson Sportster's air-cooled Evolution V-twin engine or the larger Milwaukee-Eight V-twin engine used in many touring and cruiser models.
In addition to V-twin engines, Harley-Davidson has also experimented with other engine configurations in certain models. For example, the Harley-Davidson Street models feature a Revolution X engine, which is a liquid-cooled, 60-degree V-twin. The LiveWire, Harley-Davidson's electric motorcycle, is powered by an electric motor.
So, while the majority of Harley-Davidson motorcycles utilize V-twin engines, the brand offers a range of engine configurations to cater to different riding styles, preferences, and technological advancements.