1928 Harley-Davidson 350cc Model BA Engine no. 28BA3381
* Overhead-valve single-cylinder sports model * One of only 943 built in 1928 * An older restoration
Boyhood friends William S Harley and Arthur Davidson began experimenting with powered transport in the early 1900s, producing their first complete production motorcycle around 1903. Little more than a motorised bicycle, the first prototype Harley-Davidson had proved fragile, prompting a major redesign and the establishment of a reputation for ruggedness that endures to this day.
For the 1913 season the Harley-Davidson single was updated with the mechanically operated inlet valve developed on the twin, growing to 35ci (565cc) at the same time as well as boasting a balanced bottom-end, alloy piston and improved carburettor. Known popularly as the '5-35' (5 horsepower, 35ci capacity) this new Harley single was available in belt- and chain-driven versions while ease of use was considerably enhanced by the availability of the rear hub clutch first seen on the twin. As the twin's popularity grew so that of the single declined, accounting for only 4% of sales in 1917, and production of Harley-Davidson's '5-35' ceased in 1918.
Indian's launch of the single-cylinder 21ci (350cc) Prince in 1925 prompted Harley-Davidson to return to the roadster singles market in '26 with a brace of similar-sized machines: one sidevalve, the other with an overhead-valve engine. Model designations were 'A' (magneto-equipped) and 'B' (battery/coil) for the 'flat head' (sidevalve) versions and 'AA' and 'BA' for the overhead-valve equivalents respectively. Looking every inch a scaled-down v-twin, the single featured a similar frame, controls and 'floating' saddle but its engine adopted a detachable cylinder head, an advance not yet seen on the bigger Harley. A 30.5ci (500cc) 'flat head' - the Model C - joined the range for 1930, by which time a braked front wheel had become a welcome addition to the specification. The Harley singles were instantly successful, over 7,000 being sold in the first year of production, but sales trailed off steadily thereafter and in 1934, the final year of manufacture, only 954 were sold.
An older restoration, this overhead-valve Model BA is offered with an Automotoclub Historico Italiano certificate.