OUTBOARD ENGINE TO RACE BIKE

The engines were developed into 350cc, 500cc, 680cc (90hp) and later 750cc versions to suit the hydroplane classes, with many of the larger engines later going into world championship winning sidecars. When fitted to an outboard, the Konig engines had the crankshaft vertical to drive the prop shaft, with the exhausts on one side and the carburettors on the other. The 55kg (with gearbox) ‘boxer’ type motor is fitted into the frame in a north-south direction, with two cylinders facing forward and the horizontally opposed pair facing rearward. Each side shares the same crankcase and each side (left- then right-hand side) fires at the same time (big bang style), with a 180º firing interval between the left and right pairs. One horizontally mounted double barrelled down-draught 38mm Solex (later 42mm Tillotson) carburettor feeds the single-disc valvecontrolled powerplant. The forged Mahle pistons have a hole in the bottom skirt to allow a third Mz-style inlet port to enhance fuel/air charge. An electronic Krober tachometer was installed to monitor revs while a West German Hoeckle single crankshaft was employed, with caged roller big end and needle roller small end bearings. Unusual for a four cylinder two-stroke, the Konig engine has only two exhaust pipes. A twointo-one ‘Y’ branch was used on the outboard engine. However, there was no space for four pipes on the bike so the ‘Y’ branch pipe system was adopted on the race machine. When one piston is up the opposing piston is down, so when one fires the opposite side is blocked off by the piston.