HARLEY RARELY RUSHED change, and it always knew the value of cubic inches. The history of the 45° F-head V-twin goes back to the original prototype twin of 1907, and by 1928 it was approaching its expiration date. In 1922 Harley created the JD model by increasing capacity from 61 to 74 cubic inches (1213cc).
The result was a high-performance machine capable of outrunning almost any other vehicle on the road in the 1920s. No wonder these models were popular with police departments. Harley dropped the big F-head twins and replaced them with side-valve machines in 1930.
| Model: | HARLEY-DAVIDSON JD28 |
| Capacity: | 74 cu. in. (1213 cc) |
| Power output: | 9.5 bhp (4500 rpm) |
| Weight: | 365 lb (166 kg) |
| Top speed: | 75 mph (121 km/h) |
| Country of origin: | US |