1912 Harley-Davidson X8A

Though the Harley-Davison X9A's 4.3 horsepower doesn't sound like much, it represented a lot of muscle for 1912.

1912 Harley-Davidson X8A Pictures

While many companies had gone to a mechanical intake valve by this time, the 1912 Harley-Davidson X8A motorcycle stuck with an atmospheric intake valve.

1912 Harley-Davidson X8A

A tall lever on the left side of the tank activated the "Free Wheel Control," Harley's early clutch system.

1912 Harley-Davidson X8A

The atmospheric intake valve was located beneath the small dome at the top of the engine's right side.

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