1915 Cyclone Boardtrack Racer -
Right side of engine

[yellow 1915 Cyclone Motorcycle]
    The hallmark feature of the 61 (60.86) cubic inch V-twin Cyclone engine is its shaft and bevel-gear-driven overhead-cam and valve arrangement, but there are other important features that presage modern high-performance engine technology.

    A near-hemispherical combustion chamber, the extensive use of caged roller and self-aligning ball bearings, and a precise recessed fit of the crankcase, cylinders, and heads, all contribute to the engine's exceptional performance.

    Even with its modest compression ratio of 5.5 to 1, it is estimated that the Cyclone engine produces 45 horsepower at 5500 RPM.

Installed:  April 12, 1997
Revised:  June 28, 2003