The biggest problem in trying to describe the De Luxe motor is deciding where to start! Beginning with the top end, we find a rather typical (for the period) American overhead-inlet valve, side exhaust layout. The cast-iron pistons have floating gudgeons, onto which the conrods are clamped. Not unheard-of in car engines, this is rather uncommon in motorcycles. The rods themselves are in the "master and slave" configuration, where the bearing for the front rod is carried on a boss on the rear.
Things start getting very weird at the bottom. The crank is built up from many pieces, with the crankpin fixed to a pair of small diameter, light-weight "flywheels", with the "real" flywheels sliding over the mainshafts to rest against them. The pulley (my machine is direct belt drive) slides over a parallel mainshaft on the drive-side, while the skew gear to drive the cam does the same on the timing side. Tightening nuts at either end clamps everything together, holding the flywheels in place and taking up endfloat. The camshaft runs fore-and-aft, with face cams on which bell cranks bear to drive tappets. End thrust on the cam is taken up by an elaborate system of adjustable ball races. The mechanism to lift the exhaust valves is just a tad more complicated than most! Inspecting one of these motors on the bench is a rare delight! Why oh why did they make it all so complicated? Note that the motor shown here is equipped with a Schebler single-lever carburettor, typical of its application to American machines. Period advertisements show the Australian-built De Luxe fitted with a double-lever carburettor, probably AMAC or B&B.
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