Harley-Davidson 1947 model FL “ Knucklehead” 1207 cc OHV V-twin frame #
WEGTPSW52G16Z4093 engine # 47FL1705
During the Depression years of the early Thirties Harley started the development of a new line of motorcycles, an up-to-date OHV model with sophisticated dry-sump recirculation lubrication system and a constant mesh four-speed gearbox. The side-valve V series big flat-head twins that were the company’s main offering were very robust in design, but were modest in performance and still featured total loss lubrication. The frame of the new model was different of that of any other Harley: a duplex loop with twin down tubes. The new model was well-designed but hastily launched on to the market; it took the company several years to sort the resulting teething troubles. The first Model E “Knuckleheads” -named after the shape of the polished aluminum rocker shaft covers- were brought out with 989cc engines in 1936. In April 1937, Fred Ham, a Pasadena motorcycle police officer took his own, carefully-broken-in Model E to Muroc Dry Lake (now known as Edwards Air Force Base). He outlined a five-mile circle with flags and flare-pots for round-the-clock riding. Stopping only for fuel, oil, fruit juice and to change a broken rear chain in the 20th hour, Ham completed 1,825 miles, averaging 76.02mph. He set 43 new speed and distance records for himself and Harley-Davidson’s Model E, single-handedly founding the legend of the Knuckleheads. Fred Ham’s exploits were the best advertising Harley-Davidson could hope for and silenced the critics who were pooh-poohing the Harley EL knucklehead engine as unreliable. H-D sales improved and the company kept the knucklehead design as its engine, thanks, in part, to Fred’s exploits. Harley-Davidson later acquired the record-breaking engine and gave Fred a brand new one, which he proceeded to install into the same 1936 frame he used to set the endurance record, and Fred used the bike as his daily police motorcycle while he was a patrol cop in West Covina, California, until his death (aboard the bike) while on duty on December 10, 1940.
Year by year the Knuckle was developed further and from 1942 on the 1207cc Model F was available next to the E. 1947 would be the last year for the Knuckle, the 1948 models E and F got aluminium alloy cylinder heads and hydraulic tappets which required a new frame. Effectively, the 1948 models were completely new motorcycles which only had their front fork construction in common with the original 1936 model.
The machine we present here has been built up by a German enthusiast. The engine has been overhauled by dealer Toxic Twins in Lohmar; a Leineweber camshaft, W & W oil pump and Truet and Osborn crankshaft have been fitted. The steering head is equipped with tapered roller bearings. After being overhauled this Knuckle has been ridden for about 500 km. She has the Flight Red colour scheme; other options were Brilliant Black, Skyway Blue an Police Silver for the US market. Export models were finished in Olive Green.