Abstract: A two-stroke engine having a crankcase (10) with a crankshaft (11), a cylinder (13) with a piston (14) movable therein, and at least one passage (18) for transferring an air/fuel mixture from the crankcase to the cylinder. The engine is provided with at least one balance wheel (20) driven by the crankshaft and adapted to counteract vibrations caused by the movable parts of the engine. The wheel is provided with an axial opening (24) and adapted to cooperate with a sealing surface (23) surrounding the opening of the passage into the crankcase in such way that said passage (18) is alternately opened and closed by the balance wheel during rotation of the engine.

Abstract: A rotary valve assembly is provided for use in a combination engine, wherein the valve assembly is adjustable for variable valve timing during engine operation. The rotary valve assembly comprises a rotary valve plate formed by a pair of valve leaves mounted coaxially in overlapping relation and defining an open arcuate valve port. The valve plate is rotatably mounted to extend across and thereby open and close an engine valve passage, such as an intake passage in a two-stroke combustion engine. An adjustment sleeve is provided to rotate the valve leaves during engine operation to rotate the valve leaves during engine operation in response to one or more selected engine operating conditions, to correspondingly and selectively adjust the engine valve timing.

Abstract: A motorcycle powered by a two cycle internal combustion engine having an improved induction system that has a vertically extending intake pipe so as to permit a wide latitude of leaning of the motorcycle without interference from the induction system. The induction system serves the crankcase of the engine through a rotary plate type valve that has a helical connection to the engine output shaft so that the timing of the opening and closing of the intake port can be adjusted. A servo motor adjusts the helical connection under the CPU so that the timing change mechanism need not be powered directly by the engine.

Abstract: The present invention relates to an internal combustion, reciprocating pin engine with a piston which, on its up-stroke, sucks air or a fuel-air mixture via a flap valve or a similar device into the space beneath its base and, during the down-stroke, sends the then compressed gas via another flap valve or a similar device and a connecting passage to the inlet control ports of said internal combustion, reciprocating piston engine. The pump space of the piston pump which is formed by piston, cylinder liner and annular slide comprises an inlet passage and an outlet passage, equipped with diaphragm valves, respectively.

Abstract: A two-cycle engine with an intake port extending perpendicularly to a crankshaft, wherein the intake port is directed substantially parallel with a tangential line a crank web defines at its top point on the side of a cylinder. A cylinder skirt portion fronting an end opening of the intake port at the cylinder side has a part thereof cut, while keeping its length in the axial direction of the cylinder. The two-cycle engine further includes a rotary valve mechanism having a rotary valve cover covering a rotary disc, the rotary valve cover being formed with an intake hole, and an intake tube connecting the intake hole to a carburetor, and the intake tube is integrally jointed to the intake hole.

Abstract: A high performance two-stroke internal combustion engine comprises at least one disc inlet valve driven from a shaft via bevel gears. The shaft is driven from a pinion secured to the engine crank-shaft via a variable drive. The variable drive includes a spring which biases a cross pin to one end of a spiral slot in the shaft to maintain pinion at a position relative to the shaft which provides maximum inlet valve advance during starting. As engine revs increase the pinion progressively leads the shaft thereby retarding inlet valve timing. When the valve timing is fully retarded a bobbin of the drive is latched by a magnet to hold the valve timing fully retarded until engine revs fall.

Abstract: A 2-stroke engine having a combustion chamber and a scavenge port which is open to the combustion chamber. When the engine is operating under a light load in which a large amount of unburned components, incompletely burned components and oxygen remains in the combustion chamber, fresh air is fed into the combustion chamber from the scavenge port at a low speed so that the fresh air does not disturb the residual gas in the combustion chamber. As a result of this, oxidation of the unburned components and the incompletely burned components continues without interruption during the expansion stroke and the compression stroke and causes self-ignition of the residual gas at the end of the compression stroke. The self-ignited residual gas causes ignition of the fuel injected into the combustion chamber from a fuel injector.

Abstract: A two-cycle engine is disclosed which conventionally includes a piston that reciprocates between a closed combustion chamber and crankcase. The piston reciprocates through a connecting rod that is eccentrically connected to the crank discs of a crankshaft. The crankcase is partially circular in configuration, and the crankdiscs conform in shape to the crankcase. Each crank disc has an annular recess or pocket extending around its periphery for approximately 180.degree. and in opposition to the eccentric point of connection of the connecting rod. The pockets cyclically communicate with a fuel inlet port and carburetor, both of which are positioned below the crankshaft rotational axis on the downstroke side of the crankcase. Fuel transfer passages between the crankcase and combustion chamber are positioned to receive the fuel charge from each recess as it is thrown tangentially upward with rotation of the crank discs.

Abstract: An internal combustion engine has at least three cylinders and induction conduits opening into the lower portion of the cylinders or into the crankcase. The induction conduits are intended at least for combustion air, comprising at least one rotary disc valve rotatably driven by the crankshaft of the engine. The valve has the form of a disc whose rotation axis crosses or intersects the crankshaft of the engine and is arranged in a valve housing through which the induction conduits extend, said valve being designed to alternately open and close the passages of the induction conduits through the valve housing. Said valve housing has at least three induction conduit inlets and is driven at an rpm which is lower than the crankshaft rpm and has a number of sets of recesses corresponding to the rpm reduction for control of the induction.

Abstract: A two cycle engine is disclosed wherein a pair of pistons reciprocate within a common cylinder to operate a pair of crankshafts mounted at opposite ends of said cylinder. Intake mixtures for the cylinder are crankcase-pumped, and both the intake and output ports of each crankcase are valved. This valving prevents combustion within the crankcase and limits the compression volume in order to assure the highest compression of intake gases possible. A piston ring is included at the lower end of the skirt of each piston in order to further reduce the compressed volume.