1918 Harley-Davidson 61ci Model 18F
Engine no. 18F5986
1909 marked the appearance of Harley-Davidson's first v-twin, though it was not until the adoption of mechanically operated inlet valves in 1911 (replacing the 'atmospheric' type inherited from the single) that production really took off. Known by the sobriquet 'pocket valve', this 'F-head' (inlet-over-exhaust) engine - built in 61ci and 74ci capacities (1,000cc and 1,200cc respectively) - would remain in production for the next 20 years. The Harley single's transmission arrangements - direct drive by means of a leather belt - were continued at first on the twin, but the need to make better use of the engine's power characteristics, particularly for sidecar pulling, prompted the introduction of a two-speed rear hub for 1914, by which time chain drive and a proper clutch had been adopted. Later that same year a conventional, three-speed, sliding-gear transmission with 'step starter' was introduced on the top-of-the-range version of the twin which, with full electrical equipment, was listed from now on as the Model J. Periodically revised and updated, the 'pocket-valve' Harley had gained a front brake, stronger fork and pumped lubrication by the time production ceased in 1929. Equipped with a Lucas 'King's Own' acetylene headlamp, the Harley-Davidson v-twin offered here is an example of the three-speed, magneto-ignition Model 18F, which when new was priced approximately $30 less than the Model J. One of the first machines acquired for the Collection, it was purchased in Barcelona in a dismantled state and restored by the vendor's father-in-law, Vicente Sevilla.