Rivals Indian had long ago demonstrated the efficacy and performance potential of the sidevalve engine, and in 1929 Harley-Davidson at last adopted this technology on a twin-cylinder model, having had a 'flat head' single in the line-up since 1925. This new engine was cheaper to produce, enabling Harley to price the new 45ci (750cc) Model D at $290, and its relative affordability would prove to be an important factor during the Depression years of the early 1930s.
For the 1930 model year, Harley-Davidson extended its sidevalve technology to larger models. Harley's 1930 brochure described the new 74ci machine as 'standing head and shoulders above all comers, with such startling new features as a 20% more powerful motor with Ricardo removable heads, interchangeable wheels, bigger tires, drop-centre rims, lower riding position, greater road clearance, automatic increase of generator output, drop forged forks, 100% stronger frame, theft proof lock, dual front drive chain, improved clutch, and many other features making the 1930 Big Twin the greatest motorcycle value ever offered.' Its manufacturer's hyperbole notwithstanding, the sidevalve Model V was far from an instant success. More massively built and heavier than its predecessor, the V was no faster and lacked top-end power to such an extent that the first examples were recalled for an extensive engine redesign. A larger crankcase accommodating heavier flywheels did the trick and, its problems solved, the 74ci 'flat head' v-twin went on to win the hearts of Harley-Davidson enthusiasts everywhere. The high-compression VL version produced slightly more power than the Model V and both were available with either coil or magneto ignition.
In 1934 the Model VD, as it had become, benefited from improvements introduced across the twins range, which included a strengthened frame and forks, new oil pump, High-Flo upswept exhaust system, curvaceous new mudguards and a large Airflow tail light, while the '35 motors incorporated improved cylinders and pistons. Revised with the frame, tank and wheels of the 61ci overhead-valve 'Knucklehead', plus dry-sump lubrication, the Model V became the Model U in 1937. Production recommenced after WW2, the old sidevalve '74' finally disappearing from the range at the end of 1948.
This restored Harley-Davidson 'flat head' is offered with an Automotoclub Historico Italiano certificate.