The reply in audio here :  Your browser does not support the audio element. Harley-Davidson motorcycles, especially those with high-performance engines, often require premium gas to maximize performance and engine longevity. Here’s why: High Compression Engines: Harley engines, like the Milwaukee-Eight and Twin Cam, are designed with high compression ratios to generate more power. This high compression can lead to "knocking" if the fuel ignites too early. Premium gasoline, with...