Henderson 1931 “ KJ” 1305 cc IOE four cylinder combination engine # KJ 35770
Founded by Tom and William Henderson in Detroit in 1912, Henderson built nothing but four-cylinder motorcycles in its 19-year existence. Numerous detail improvements were made throughout the 1920s to ensure that the Henderson remained ‘the finest motorcycle in the world’. Nevertheless, by the decade’s end it had become obvious some thorough design changes would be needed to stay ahead of the pack. The result was the ‘KJ’, designed by ex-Harley-Davidson engineer Arthur Constantine. The new model was announced to the public early in 1929 and it was dubbed “the streamline Henderson” because of the graceful lines of its mudguards and petrol tank. The cast-aluminium tank halves took away the view of the frame top tube and had the looks of a saddle tank. The smooth-running KJ had a five-bearing crankshaft to replace the old three-bearing one, new design cylinders with heavier finning, new unit valve cage design with overhead inlet valves and a down-draught carburation system, to name some new features. On top of the tank a graceful instrument cluster was placed, consisting of oil pressure and amp gauges, speedometer and light switch. The brochure announced no less than 57 major improvements, and of course blew the new model’s trumpet: “The new Henderson offers you the last word in attractiveness and beauty of outline plus the ultimate in performance. The gracefully rounded curves, the long sweeping streamlines, the low saddle position, the balance and symmetry all combine to make an irresistible appeal to the eye.”
Producing 40bhp at 4,000rpm the Streamline Henderson proved exceptionally smooth and tractable, being capable of accelerating from 10mph to over 100mph in top gear. Sales were encouraging but with the Depression biting, Ignaz Schwinn decided to quit while he was ahead, ending production of all Henderson and Excelsior motorcycles in 1931 while the order book was still filled and concentrate on the cycle side of the business. KJs are highly sought-after by discerning enthusiasts and the combination we present here has been restored with care and is running well. The engine is fitted with a practical external oil filter and accessories include a comfortable passenger’s seat, a rear view mirror and an Edelmann spotlight.