The Emergence of the 2-Cam Engine Design

In consort with the other manufacturers,  Harley-Davidson withdrew from factory-supported racing in 1917 and 1918,  but the Milwaukee company did not stop work in their engineering department.  During the war,  Bill Ottaway began development of a new race motor.  Based on the smaller (1914 and earlier) H-D crankcase,  the new design employed the use of two separate cam shafts to operate the valves.  The new setup allowed the use of shorter cam followers than were possible in the standard, single cam-shaft design.

The goal of this change was to reduce the reciprocating weight of the valve train in order to increase power by increasing maximum rpm.  The shape of the timing chest that contained this new cam and lifter configuration resembled a "banjo" and the motor was referred to as a "banjo, 2-cam."  Both 8-valve overhead and standard pocket-valve versions of the new race motor were produced.  The banjo, 2-cam, however, would not make its full-fledged debut until the 1920 racing season.

Copyright ©1996 Daniel K. Statnekov

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