1941 Harley-Davidson 1,200cc Model UL Engine no. 41UL4228
* Dating from the final year of peacetime production * High-compression model * An older restoration
For the 1930 model year, Harley-Davidson extended its sidevalve technology, previously confined to the singles, to its large-capacity twins. Announced in August 1929 as a replacement for Harley's long-running and much-loved F-head 'Big Twin', 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 Model V's detachable cylinder heads, interchangeable wheels (including that of the sidecar, when attached), larger brakes and tyres, lower seat and increased ground clearance all represented advances over the outgoing F-head twin. 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 VD became the Model U in 1937. Inside the engine there was virtually nothing left unchanged: the crank pin was enlarged, connecting rods strengthened and the flywheels grew in size, while in the interests of rationalising production, the bore size changed to that of the OHV '61' and stroke to that of the '80'.
This high-compression UL model has the 16" wheels standardised for 1941. By this time Harley-Davidson had become increasingly preoccupied with catering for the demands of the US military, so major changes from the preceding year's models were few. As far as the larger sidevalve twins were concerned, the big news for '41 was the adoption of a new clutch with greatly increased frictional area.
Dating from the final year of peacetime production, this restored Harley-Davidson UL is offered with an Automotoclub Historico Italiano certificate.