• Year of manufacture 
  • Motorcycle type 
  • Engine number 
  • Lot number 
  • Condition 
  • Colour  
  • Location


1928 Harley-Davidson 1,200cc Model JDH 'Two Cam'
Frame no. 28JDH4629
Engine no. 28JDH4629

* Rare 'Two Cam' model
* Top-of-the-range super-sports machine
* An older restoration

Following an abortive debut in 1909, the twin-cylinder Harley-Davidson returned for 1911 in redesigned form boasting mechanically operated inlet valves, replacing the 'atmospheric' type inherited from the single. Production really took off and this 'F-head' (inlet-over-exhaust) 'pocket valve' engine - built in 61ci and 74ci capacities (1,000cc and 1,200cc respectively) - would remain in production for the next 20 years. The Harley single's transmission arrangements - direct drive by means of a leather belt - were continued at first on the twin but the need to make better use of the engine's power characteristics, particularly for sidecar pulling, prompted the introduction of a two-speed rear hub for 1914, by which time chain drive and a proper clutch had been adopted. Later that same year a conventional, three-speed, sliding-gear transmission with 'step starter' was introduced on the top-of-the-range version of the twin which, with full electrical equipment, was listed from now on as the Model J. Periodically revised and up-dated, the Harley-Davidson F-head twin had gained a front brake, stronger fork and pumped lubrication by the time production ceased in 1929.

Before then, Harley-Davidson had introduced a new high-performance variant, known as the 'Two Cam', which was an addition to the range in 1928. This twin-cam arrangement had first been seen in 1916 on the works-only eight-valve racers and was adopted on the factory's F-Head racers in 1919. Thus equipped, the racing F-head twins were only slightly slower than their overhead-valve siblings but were considerably more reliable.

The roadsters' twin-cam F-head engines are easily distinguishable from their lesser cousins by distinctive peanut-shaped timing covers and side-by-side (as opposed to fore-and-aft) direct acting tappets. They were also fitted with Dow Metal magnesium alloy high-compression pistons. Other distinguishing features of these top-of-the-range models included a slimmer fuel tank, 18" diameter wheels and - most importantly considering the performance on offer - the provision of a front brake. Priced at $390, the 74ci JDH 'Two Cam' was the most expensive model in the range. For the Harley-Davidson devotee, these limited-production 'Two Cam' hotrods were the ultimate high-performance roadsters of their day and as such are among the most sought after of pre-war Harleys by today's collectors.

An older restoration, this Model JDH 'Two Cam' is offered with an Automotoclub Historico Italiano certificate.

Bonhams 1793
101 New Bond Street
United Kingdom
Contact Person Kontaktperson
First name 
Bonhams Collectors’ Car department