The Evolution of Harley-Davidson Police Motorcycles During the 1930's

Early 1930's Flathead with front fender mounted siren and rear mounted fire extinguisher.
Harley-Davidson's history with police departments dates all the way back to 1908, when Detroit purchased the first Harley designated for police use.  Those first police motorcycles were little more than civilian motorcycles painted white or grey instead of the standard olive drab.  Additional equipment that is usually associated with police motorcycles, like sirens, lights and radios, did not come available until much later.  When they did become available, it was often up to the mounted officer to purchase and install these extras himself.  In the late 1920's Harley finally began to offer some special equipment for their police units, but it wasn't until the 1930's that they starting producing police machines the resemble today's modern police motorcycles.

1934 Flathead with rear mounted siren.

1936 flathead with rear mounted siren.

Late 1930's Knucklehead with radio and dual headlights.

Note the speaker mounted to the handlebar.  This was a one-way system.

Close-up of a rear mounted siren.  A wheel on the inside of the unit pressed against the tire which caused it to turn and operate the siren.  A foot pedal and cable was used to hold the unit against the tire.

This flyer from 1936 describes the features on an early police radio.

Mesh radio antennae on the back of a 1938 Knucklehead.

By 1941 the mesh antennae had been replace by the standard whip antennae.  This motorcycle also has multiple front lights and a rear mounted siren.