The BA was one of several single-cylinder models that had disappeared by the mid-1930s.

1927 Harley-Davidson BA Pictures

The 1927 Harley-Davidson BA motorcycle featured a 21-cubic-inch single-cylinder engine. The resulting lack of power negated the need for front brakes.

There was a lot of working room around the little 21-cubic-inch flathead single, which was a selling point in the late 1920s.

"Big bike" features included leading-link front forks and three-speed transmission.

Electric headlights had largely replaced acetylene systems by 1927.

The BA's external-band rear brake was sufficient for the bike's modest speed potential.

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