Harley-Davidson Model 7D

The Harley -Davidson Model 7D of 1911 was the second two-cylinder motorcycle in the U.S. American manufacturer Harley- Davidson and for the company a major step forward in motorcycle.

History and technology

The predecessor 5D was in every way a flop, technically behind, hard to start sniffer valves of the time and no buyers demand.

The motor dimensions of the previous model with bore ( 76 mm), stroke ( 89 mm ) and engine capacity 811 cc maintained one. The motor control was now with at camshaft for exhaust and intake valve according to the IOE system. Fitted with a Bosch magneto ignition and Schebler carburetor 45-degree V engine is expected to reach a power of 6.5 hp. This engine concept remained until the introduction of " Flathead engines " in 1929, unchanged from the program.

The automatic belt tensioner, patented by William S. Harley, prevented the slippage of the drive belt when wet. The wheelbase of the 28 -inch wheeled machine was 1435. The maximum speed was, according to author, 55 to 60 mph ( 89-97 km / h) and was the competition appropriately; was slowed by a band brake on the rear wheel. The machine was well constructed and quiet operating noise of the engine in conjunction with a silencer left the manufacturer with "The Silent Grey Fellow" praise. It is estimated about 3,500 copies built the model supplied only in " Renault - gray ", which was available for $ 300 at that time. On 21 October 2006, Harley -Davidson was 7D auctioned for 187,000 dollars.

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