Harley-Davidson motorcycles are known for their distinctive rumbling sound and vibration, which is often referred to as "Harley shake" or "Harley wobble." This phenomenon can be attributed to a combination of design choices, engine configuration, and engineering philosophy unique to Harley-Davidson motorcycles. Here are a few factors that contribute to the shaking sensation at idle speeds:
Engine Design: Harley-Davidson motorcycles traditionally use air-cooled V-twin engines with a 45-degree angle between the two cylinders. This configuration, along with the use of large pistons and a long-stroke design, creates a significant amount of engine vibration.
Engine Mounting: Harley-Davidson engines are typically rigidly mounted to the frame, meaning they are bolted directly without rubber or other damping materials to isolate vibrations. This design choice enhances the feeling of engine power and character but also allows more vibration to be transferred to the rider.
Heavy Flywheel: Harley-Davidson engines have a heavier flywheel compared to some other motorcycle engines. The heavy flywheel helps provide low-end torque and contributes to the unique riding experience but can also result in more noticeable engine vibrations.
Exhaust System: The design and configuration of the exhaust system, particularly the use of a true dual exhaust system, can contribute to the shaking sensation. The pulses from each cylinder's exhaust create a rhythmic shaking effect.
It's important to note that the perception of engine vibration can vary between riders, and what some may consider excessive shaking, others may appreciate as part of the authentic Harley-Davidson experience. Harley-Davidson has made efforts over the years to refine their engines and reduce vibration, introducing features like counterbalancers in certain models to mitigate excessive shaking while maintaining the characteristic Harley feel.
It's always recommended to experience riding a Harley-Davidson motorcycle firsthand to fully understand and appreciate the unique characteristics and sensations it offers.