The engine of the EL earned the nickname "Knucklehead," which was inspired by the shape of its rocker-cover caps.

1936 Harley-Davidson EL Pictures

The 1936 Harley-Davidson EL motorcycle introduced changes that would influence the future of motorcycle design. Among them were changes to the rocker-shaft covers and air intake.

The tank-mounted instrument panel, still a Harley styling element, included amp and oil- pressure readouts.

Introduced in 1936, the Harley-Davidson EL went on to become one of Harley's most-popular motorcycles.

The 1936 Harley-Davidson EL offered this

Shift lever well forward indicates this Harley EL

The "fishtail" muffler was another period styling

A real piece of Americana: a 1936 Harley-Davidson

The EL proudly wears its California Highway Patrol badge.

Black and white was a traditional police color; many departments also mounted additional lights.

Evidence, ammunition, or just lunch, saddle bags

Cops appreciated Harley's rugged build, though presence of a rear suspension would have made long hours on the road more comfortable.

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