Harley Davidson motorcycles are known for their distinct engine design, often referred to as a "V-twin" or "Big Twin" engine. This engine configuration can contribute to a noticeable shaking or vibrations at idle. Here are a few reasons why Harleys may shake at idle:
Engine Design: Harley Davidson motorcycles typically use air-cooled V-twin engines, which have two cylinders arranged in a V-shape. The firing sequence of the cylinders and the nature of the V-twin design create inherent vibrations. The uneven firing intervals of the engine produce a pulsating power delivery, resulting in the characteristic shaking sensation.
Engine Mounting: Harley Davidson motorcycles often use rigid engine mounting systems, where the engine is bolted directly to the frame without much isolation or damping. This direct connection allows for better power transfer but also transmits more engine vibrations to the rider.
Large Displacement: Harley Davidson motorcycles are known for their larger displacement engines, which tend to produce more torque and power. The increased size and power output of the engine can contribute to more pronounced vibrations, especially at lower speeds and idle.
Heavy Flywheels: Harley Davidson engines typically feature heavy flywheels, which help to smooth out power delivery and provide low-end torque. However, the weight of the flywheels can enhance the perceptible vibrations at idle.
It's important to note that while some riders appreciate and associate the vibrations with the character and feel of a Harley Davidson motorcycle, others may find it less desirable. Manufacturers have made efforts to reduce vibrations in newer models by implementing counterbalancers, rubber engine mounts, and other techniques. If excessive or abnormal vibrations are experienced, it's advisable to have the motorcycle checked by a qualified technician to ensure there are no underlying issues with the engine or other components.