Abstract: A decompressor for use in an internal combustion engine is disclosed The decompressor is at least partially located within the venting passageway in response to pressure in the combustion chamber for selectively opening the venting passageway such that combustion gas located within the chamber is vented to the induction passageway. The decompressor opens the venting passageway when the engine is off and during an engine start up operation. The decompressor includes an expansible cavity operatively connected to the combustion chamber.

Abstract: A continuously variable transmission (“CVT”) is disclosed. The CVT includes a drive pulley adapted to connect to a crankshaft of an engine. The drive pulley has inner and outer halves with belt engagement surfaces to engage the sides of the belt. The drive pulley of the CVT also includes a slide sleeve disposed on the shaft adapted to engage an inner side of a belt. The inner and outer halves of the drive pulley are biased apart from one another by a spring. The slide sleeve engages the belt when the belt is stationary or traveling at low speeds. The driven pulley includes inner and outer halves with belt engagement surfaces. The two halves are biased into contact with one another. A connector connects the inner half to the outer half. In addition, a pneumatically-actuated driven pulley is described together with a CVT incorporating same.

Abstract: A vehicle includes an engine that powers a wheel through a drive train. The drive train includes a continuously variable transmission (CVT) and toothed gearing disposed between the CVT and the wheel. A release clutch is also disposed between the CVT and the wheel. A controller controls the release clutch so as to disengage the clutch when the engine is not running and engage the clutch when the engine is running. The controller includes a hydraulic cylinder that fluidly connects to the engine's oil system so that engine-generated oil pressure engages the release clutch. Disengagement of the release clutch makes it easier to push the vehicle when the engine is not running, for example, when the engine breaks down.

Abstract: A watercraft includes a shell, a ride plate, an internal combustion engine, and a jet pump. The shell defines a tunnel that extends forwardly from the transom and is defined laterally by the shell. The tunnel is open at its bottom The ride plate mounts to the shell under the tunnel. The engine and jet pump are supported by the ride plate and disposed in the tunnel. The engine drives the jet pump. The engine is cooled by water that continuously flows past the ride plate. The engine, jet pump, and ride plate are installed from below or the behind the shell.

Abstract: A power unit is described that combines an internal combustion engine and a lubrication system. The internal combustion engine includes a crankcase suction chamber and a transmission case suction chamber. At least one partition separates the crankcase suction chamber from the transmission case suction chamber. The lubrication system supplies lubricant to the internal combustion engine. The lubrication system includes a lubrication tank and a supply line for supplying lubricant to the internal combustion engine. At least one crankcase drainage line extends from the crankcase to drain a fluid from the crankcase suction chamber and transfer the fluid to the transmission case suction chamber. At least one pump operatively connects to one of either the crankcase chamber or the transmission case chamber. By the operation of the at least one pump, a negative pressure within at least one of the crankcase chamber and the transmission case chamber is created.

Abstract: A decompressor for use in an internal combustion engine is disclosed The decompressor is at least partially located within the venting passageway in response to pressure in the combustion chamber for selectively opening the venting passageway such that combustion gas located within the chamber is vented to the induction passageway. The decompressor opens the venting passageway when the engine is off and during an engine start up operation. The decompressor includes an expansible cavity operatively connected to the combustion chamber.

Abstract: An apparatus is described to separate oil from a gas in an internal combustion engine. The apparatus includes a rotatable member adapted to be rotatably driven by the internal combustion engine and a housing affixed to the rotatable member. At least one inlet hole is disposed through one of either the rotatable member or the housing, permitting oil-containing gas to pass therethrough. At least one outlet hole is disposed through one of either the housing or the rotatable member, permitting the gas to exit therefrom. At least one labrynthine passage extends between the at least one inlet and the at least one outlet so that, as the rotatable member and housing rotate, the oil-containing gas within the labrynthine passage is subjected to centrifugal forces. The forces cause at least some of the oil to be removed from the gas as the gas flows from the at least one inlet hole to the at least one outlet hole. A decompressor is also described.

Abstract: A gear selector mechanism for performing a gear shifting operation at reduced forces is disclosed. The gear selector mechanism includes a selector pawl pivotally mounted about a shaft. The gear selector mechanism also includes a rotatable gear shift plate having a plurality of radially extending teeth extending around a periphery thereof. Each of the plurality of teeth has an outer tip and an inner base portion. The selector pawl engages one of the plurality of teeth in an area adjacent the outer tip at a beginning of the gear shifting operation. The selector pawl further engages one of the plurality of teeth in an area adjacent the inner base portion at the end of the gear shift operation.

Abstract: An air intake system for an internal combustion engine has at least one air box and a short duct for each cylinder. Each duct can be extended to provide higher torque at low speed. At high speed, the shorter duct length can be selectively provided for enhanced engine performance.

Abstract: A straddle-type vehicle includes a frame supporting front and rear wheels, a seat supported above the frame, and an engine having an output shaft. The engine is supported by the frame below the seat. A transmission is coupled to the output shaft. The transmission includes gears. A shift assembly is operatively connected to the engine and is displaceable over a predetermined distance upon application of a predetermined amount of force by a vehicle operator. The selective displacement of the shift assembly shifts the gears. A parking gear assembly is selectively displaceable along with the shift assembly to selectively engage one of the gears to prevent movement of the output shaft.

Abstract: A system reduces the amount of work exerted by an ATV operator to change transmission gears. The system includes a foot lever assembly with a mechanical portion, such as a mechanical linkage, attached to an automated portion, such as an electrical switch. When the ATV operator applies a predetermined amount of force to the foot lever assembly, a clutch assembly and a gear box are actuated in a single motion, assisted by the automated portion of the foot lever assembly. Thus, the operator is able to exert less work in order to change the gears.

Abstract: A supercharged four stroke internal combustion engine. The engine includes a power take off housing located on one end of the crankcase. A supercharger for boosting air intake to an air intake manifold is mounted to the power take off and operatively connected to the crank shaft within the power take off housing. A personal watercraft having a supercharged engine is also disclosed.

Abstract: A four stroke internal combustion engine having a flexible arrangement is disclosed such that the engine can be easily configured for supercharged or normally aspirated operation. The engine includes a cooling system that includes both closed loop and open loop cooling systems for improved cooling efficiency. A power take off housing located on one end of the crankcase. Various engine components are operatively coupled to the crankshaft within the power take off housing including a cam shaft for a valve actuation assembly, a generator, an engine starting mechanism, a balance shaft, and a supercharger. The engine contemplated in accordance with the present invention also includes a dry sump lubrication system having lubricant separator for separating lubricant from blow-by gas within the engine.

Abstract: A system reduces the amount of work exerted by an ATV operator to change transmission gears. The system includes a foot lever assembly with a mechanical portion, such as a mechanical linkage, attached to an automated portion, such as an electrical switch. When the ATV operator applies a predetermined amount of force to the foot lever assembly, a clutch assembly and a gear box are actuated in a single motion, assisted by the automated portion of the foot lever assembly. Thus, the operator is able to exert less work in order to change the gears.

Abstract: A four stroke internal combustion engine includes a cylinder head having a valve train having reduced profile that permits access to a spark plug assembly located therein.

Abstract: An arrangement of an internal combustion engine is disclosed that balances the various inertia forces acting on the engine during operation. A plurality of counterweight assemblies are provided that counterbalance the forces generated during engine operation. A first counterweight assembly rotates about the crankshaft axis. Second and third counterweight assemblies are provided that are spaced from the crankshaft axis and the first counterweight assembly. The first, second and third counterweight assemblies combine to counteract and balance the inertia forces generated during operation of the engine.

Abstract: An all terrain vehicle (“ATV”) is disclosed having a frame with front, rear, right, and left sides. The frame defines a frame centerline extending longitudinally between the front and the rear sides. The ATV includes an engine with at least one cylinder having an axis that defines an engine centerline. The all terrain vehicle also includes an output shaft defining an output shaft centerline. A continuously variable transmission (“CVT”) operatively connects the engine to the output shaft and defines a CVT centerline. The engine centerline, output shaft centerline, and CVT centerline are positioned with respect to one another and the frame centerline. In one embodiment, the engine centerline is disposed between the output shaft centerline and the CVT centerline. In this embodiment, the engine centerline also may lie between the frame centerline and the CVT centerline.

Abstract: A continuously variable transmission (“CVT”) is disclosed. The CVT includes a drive pulley adapted to connect to a crankshaft of an engine. The drive pulley has inner and outer halves with belt engagement surfaces to engage the sides of the belt. The drive pulley of the CVT also includes a slide sleeve disposed on the shaft adapted to engage an inner side of a belt. The inner and outer halves of the drive pulley are biased apart from one another by a spring. The slide sleeve engages the belt when the belt is stationary or traveling at low speeds. The driven pulley includes inner and outer halves with belt engagement surfaces. The two halves are biased into contact with one another. A connector connects the inner half to the outer half. In addition, a pneumatically-actuated driven pulley is described together with a CVT incorporating same.

Abstract: An apparatus is described to separate oil from a gas in an internal combustion engine. The apparatus includes a rotatable member adapted to be rotatably driven by the internal combustion engine and a housing affixed to the rotatable member. At least one inlet hole is disposed through one of either the rotatable member or the housing, permitting oil-containing gas to pass therethrough. At least one outlet hole is disposed through one of either the housing or the rotatable member, permitting the gas to exit therefrom. At least one labrynthine passage extends between the at least one inlet and the at least one outlet so that, as the rotatable member and housing rotate, the oil-containing gas within the labrynthine passage is subjected to centrifugal forces. The forces cause at least some of the oil to be removed from the gas as the gas flows from the at least one inlet hole to the at least one outlet hole. A decompressor is also described.

Abstract: A supercharged four stroke internal combustion engine. The engine includes a power take off housing located on one end of the crankcase. A supercharger for boosting air intake to an air intake manifold is mounted to the power take off and operatively connected to the crank shaft within the power take off housing. A personal watercraft having a supercharged engine is also disclosed.