Abstract: A water jet propulsion watercraft includes, a main engine body, a rotor chamber provided at a rear portion of the main engine body, a crankshaft arranged such that a rear end portion of the crankshaft is disposed in the rotor chamber, the rear end portion having a first connection portion, an output shaft having a second connection portion at a front end of the output shaft, the second connection portion arranged to be connected to the first connection portion of the crankshaft such that the output shaft rotates together with the crankshaft about a rotational center axis of the crankshaft, a rotor unit housed in the rotor chamber and fixed to the output shaft, a fastening member arranged to fasten the first connection portion and the second connection portion, a drive shaft connected to a rear end portion of the output shaft.

Abstract: A water jet propulsion watercraft includes, a main engine body, a rotor chamber provided at a rear portion of the main engine body, a crankshaft arranged such that a rear end portion of the crankshaft is disposed in the rotor chamber, the rear end portion having a first connection portion, an output shaft having a second connection portion at a front end of the output shaft, the second connection portion arranged to be connected to the first connection portion of the crankshaft such that the output shaft rotates together with the crankshaft about a rotational center axis of the crankshaft, a rotor unit housed in the rotor chamber and fixed to the output shaft, a fastening member arranged to fasten the first connection portion and the second connection portion, a drive shaft connected to a rear end portion of the output shaft and arranged to be rotated together with the output shaft, and a jet propulsion unit, having an impeller that is coupled to the drive shaft and arranged to suck in and jet out water.

Abstract: A small watercraft with an emergency shut-off system is provided. The emergency shut-off system is configured to shut off the engine of the small watercraft when the small watercraft is overturned. The emergency shut-off system comprises an electronic control unit that is operatively coupled to an overturn sensor and the engine. The electronic control unit is configured to sense a signal generated by the overturn switch. The electronic control unit is also configured to determine if the signal generated by the overturn switch continues for a period longer than a preset amount of time and to shut off the engine if the signal generated by the overturn switch continues beyond the preset amount of time.

Abstract: A small watercraft with an emergency shut-off system is provided. The emergency shut-off system is configured to shut off the engine of the small watercraft when the small watercraft is overturned. The emergency shut-off system comprises an electronic control unit that is operatively coupled to an overturn sensor and the engine. The electronic control unit is configured to sense a signal generated by the overturn switch. The electronic control unit is also configured to determine if the signal generated by the overturn switch continues for a period longer than a preset amount of time and to shut off the engine if the signal generated by the overturn switch continues beyond the preset amount of time. The electronic control unit can also be configured to activate a bilge pump when a level of water within the watercraft exceeds a predetermined level.

Abstract: A watercraft includes an improved engine control system that enhances the responsiveness of the watercraft and eases watercraft operation. The watercraft includes a propulsion device, such as a jet propulsion unit, and an engine that powers the propulsion device. The engine control system is configured to maintain or increase engine speed under certain operating conditions.

Abstract: A small watercraft with an emergency shut-off system is provided. The emergency shut-off system is configured to shut off the engine of the small watercraft when the small watercraft is overturned. The emergency shut-off system comprises an electronic control unit that is operatively coupled to an overturn sensor and the engine. The electronic control unit is configured to sense a signal generated by the overturn switch. The electronic control unit is also configured to determine if the signal generated by the overturn switch continues for a period longer than a preset amount of time and to shut off the engine if the signal generated by the overturn switch continues beyond the preset amount of time.

Abstract: A watercraft includes an improved engine control system that enhances the responsiveness of the watercraft and eases watercraft operation. The watercraft includes a propulsion device, such as a jet propulsion unit, and an engine that powers the propulsion device. The engine control system is configured to maintain or increase engine speed under certain operating conditions.

Abstract: An induction system for a 4-cycle engine of a small watercraft includes an improved construction which can accommodate a large plenum chamber notwithstanding being placed in an engine compartment limited in size. The induction system includes improved filtration, and accessibility characteristics. The air induction system can include a plenum chamber member defining the plenum chamber. The air induction system can also include one or more throttle bodies within the plenum chamber to allow the construction of a large plenum chamber. The plenum chamber member is can comprise at least three parts with at least one part being disposed substantially above the spark plugs and being removable. The air induction system can also include an air filter having a water repellent element and an oil-resistant element arranged such that a flow of air entering the combustion chambers passes through both the water repellent and oil-resistant elements.

Abstract: A small watercraft with an emergency shut-off system is provided. The emergency shut-off system is configured to shut off the engine of the small watercraft when the small watercraft is overturned. The emergency shut-off system comprises an electronic control unit that is operatively coupled to an overturn sensor and the engine. The electronic control unit is configured to sense a signal generated by the overturn switch. The electronic control unit is also configured to determine if the signal generated by the overturn switch continues for a period longer than a preset amount of time and to shut off the engine if the signal generated by the overturn switch continues beyond the preset amount of time. The electronic control unit can also be configured to activate a bilge pump when a level of water within the watercraft exceeds a predetermined level.

Abstract: A motorcycle having an improved fuel tank arrangement with an opening in an upper side wall of the fuel tank that is closed by a combined fuel pump, closure plate and return port arrangement. The fuel is supplied to a fuel injection system through an arrangement including a filter and pressure regulator with the filter pressure regulator and opening all being positioned on the same side of the motorcycle and at relatively the same vertical height. The assembly may be removed from the opening without draining fuel due to its high placement in the opening.

Abstract: A lubrication system for an internal combustion engine includes an oil pump assembly driven by the crankshaft. The oil pump can be mounted in various positions for maintaining a low center of gravity of the engine. Optionally, or in addition, the engine can include a bearing disposed between a valvetrain drive gear and an output drive gear.

Abstract: A small watercraft with an emergency shut-off system is provided. The emergency shut-off system is configured to shut off the engine of the small watercraft when the small watercraft is overturned. The emergency shut-off system comprises an electronic control unit that is operatively coupled to an overturn sensor and the engine. The electronic control unit is configured to sense a signal generated by the overturn switch. The electronic control unit is also configured to determine if the signal generated by the overturn switch continues for a period longer than a preset amount of time and to shut off the engine if the signal generated by the overturn switch continues beyond the preset amount of time.

Abstract: An internal combustion engine, which can be disposed in a water vehicle, includes an exhaust system having features improving the performance, ease of manufacturing, and/or the water preclusive effects thereof. The exhaust system can include an exhaust manifold defining a plurality of exhaust runners and being made from at least two parts. The exhaust system can also include a plurality of individual exhaust passages extending from exhaust ports of the engine to a forward end of the engine. The exhaust system can also include an exhaust passage which extends from the exhaust ports to varying elevations relative to the exhaust ports, as well as other features.

Abstract: A small watercraft with an emergency shut-off system is provided. The emergency shut-off system is configured to shut off the engine of the small watercraft when the small watercraft is overturned. The emergency shut-off system comprises an electronic control unit that is operatively coupled to an overturn sensor and the engine. The electronic control unit is configured to sense a signal generated by the overturn switch. The electronic control unit is also configured to determine if the signal generated by the overturn switch continues for a period longer than a preset amount of time and to shut off the engine if the signal generated by the overturn switch continues beyond the preset amount of time.

Abstract: A watercraft includes a lubrication system having a lubrication reservoir and a lubricant pump assembly. The lubricant reservoir can be constructed from an upper portion connected to a separate lower portion. The pump assembly can be co-axially aligned with and driven by the crankshaft of the engine.

Abstract: An induction system for an internal combustion engine of a small watercraft includes an improved construction that directs water away from the induction system. The air induction system includes an air intake box defining a plenum chamber. An upper surface of the air intake box includes at least one surface feature such as a channel, groove, depression, humps, protrusion and/or ramp. The surface features promote drainage of water disposed on top of the air box.

Abstract: A push rod operated multi-valve V-type engine particularly adapted for use in motorcycles or like vehicles and which engine is air cooled. The engine employs a very simplified construction and overhead valve actuating mechanism utilizing push rods. The push rods are contained within push rod tubes formed at one side of the engine that provide a neat appearance and ease of servicing without adversely affecting the air cooling. A composite cylinder head construction is employed, as well as an improved lubricating system for the pair of driven camshafts. Furthermore, a decompression system is incorporated in the valve actuating mechanism to lower the compression ratio so as to facilitate starting.

Abstract: A watercraft includes an improved engine control system that enhances the responsiveness of the watercraft and eases watercraft operation. The watercraft includes a propulsion device, such as a jet propulsion unit, and an engine that powers the propulsion device. The engine control system is configured to maintain or increase engine speed under certain operating conditions.

Abstract: An induction system for a 4-cycle engine of a small watercraft includes an improved construction which can accommodate a large plenum chamber notwithstanding being placed in an engine compartment limited in size. The induction system includes improved filtration, and accessibility characteristics. The air induction system can include a plenum chamber member defining the plenum chamber. The air induction system can also include one or more throttle bodies within the plenum chamber to allow the construction of a large plenum chamber. The plenum chamber member is can comprise at least three parts with at least one part being disposed substantially above the spark plugs and being removable. The air induction system can also include an air filter having a water repellent element and an oil-resistant element arranged such that a flow of air entering the combustion chambers passes through both the water repellent and oil-resistant elements.

Abstract: A lubrication system for an internal combustion engine includes an oil pump assembly driven by the crankshaft. The oil pump can be mounted in various positions for maintaining a low center of gravity of the engine. Optionally, or in addition, the engine can include a bearing disposed between a valvetrain drive gear and an output drive gear.