Harley Davidson 1928 1217cc Two-Cam 3412

Harley Davidson 1928 1217 cc Special Two-Cam engine # 28JDH11137

The twin-cam arrangement had first been seen in 1916 on the works-only eight-valve racers that were developed by William Ottaway and was adopted on the factory’s F-Head racers and hill-climbers after World War 1. Twin-cam engines were used all through the twenties only to the factory team and some favoured dealers. But in November 1927, too late to be included in the 1928 catalogue, road going two cammers were made available to the eager private buyers. There was a 61 ci (989 cc) JD version and a 74 ci (1217 cc) JDH model. The timing gear case had a distinctive peanut shape, which made it easily recognizable as a Two-Cam. The single-lobe cam arrangement of the standard engine limited the possibilities of tuning the engine for high performance and the extra cam made it possible to enhance the power output, that amounted to about 29 hp, some 5 hp more than the standard JDH engine produced. The new Two-Cams were very fast and differed in a number of respects from standard models: fuels tanks were narrower, front forks were specially forged and there was the option to order a smaller wheel size to create a somewhat lower centre of gravity. By the end of 1929 production was stopped though due to the changing market conditions: the depression years were coming and the Two-Cam models were expensive machines. A standard JD was priced at $320, a Two-Cam cost $370; this was a considerable amount and consequently only a limited number of machines was sold.
The difference between 1000 and 1200 cc engines can be seen by checking the cooling fins: 1200 cc models have eleven fins of the same diameter, while the 1000cc model have its five bottom fins gradually tapering in diameter. This highly desirable and rarely offered sporting Harley model has been restored some time ago and comes with 100 mph Corbin speedometer.