FORCES OF CREATION

The Harley-Davidson V-Twin has shaped American motorcycling

- KEVIN CAMERON

The defining engine of American motorcycling for more than 100 years? The Harley-Davidson V-twin. The form of this engine we know today is as expressed by the Milwaukee-Eight Big Twin—still a large-displacement 45-degree V-twin turning on rolling bearings and covered with the fins that define air cooling.

Despite these traditional features, which have been retained over many years to satisfy the preferences of those who own and ride them, these machines meet the same standards for noise, emissions, and in-service durability that apply equally to the most recent of designs.

They are the product of 84 years of adaptation of product to ever-changing conditions of use. When the beloved “Knucklehead,” or EL, of 1936 came into being as Harley’s first OHV design, effectively doubling available power, many miles of America’s highways were dirt, speeds were low, and journeys were short. In those conditions, cylinders and heads made of iron were adequate to handle the resulting modest heat of operation. Absolute was the need for ruggedness with comfort, dictating a sprung seat, large-section low-pressure tires, and simplicity of construction.