Abstract: A leisure vehicle configured to be propelled by a friction between a drive wheel thereof and a ground surface with which the drive wheel is in contact, including a power unit configured to drive the drive wheel, a speed control device configured to control drive of the drive wheel, and a controller configured to control the speed control device to increase a rotational speed of the drive wheel while maintaining a state in which the drive wheel does not slip on the ground surface in a predetermined amount or more.

Abstract: A titanium alloy tappet that is slidable at a high speed is provided by covering shortcomings of lightweight and high-strength titanium alloy. A surface 1A of at least a slidable portion of the tappet 1 for use with a valve system is subjected to a carburizing process.

Abstract: A leisure vehicle equipped with an internal combustion engine as a power unit to drive the leisure vehicle, including a drive wheel, a slip sensor unit configured to detect a slip of the drive wheel, a throttle device mounted to the internal combustion engine, a throttle valve position changing device configured to change a position of a throttle valve of the throttle device, a throttle close operation sensor unit configured to detect that a rider has performed a throttle close operation to close a throttle of the throttle device, and a controller configured to control an operation of the throttle valve position changing device.

Abstract: A crankshaft equipped in an engine, including an oil passage through which oil is drawn from a crank journal to a crank pin. The oil passage has an inlet formed at a peripheral region of the crank journal. When a plane including a center axis of the crank journal and a center axis of the crank pin crosses a peripheral surface of the crank journal at two cross portions, the inlet is located to be spaced apart in an opposite direction to a rotational direction of the crank journal from a journal side cross portion located on an opposite side of the crank pin with respect to the center axis of the crank journal. The oil passage is configured to extend to be spaced apart from the center axis of the crank journal as seen from a direction of the center axis of the crankshaft.

Abstract: An engine for a leisure vehicle including a lubricating oil pump configured to feed a lubricating oil to engine components, and an actuator drive oil pump that is provided separately from the lubricating oil pump and is configured to drive an actuator operating with an oil pressure. The actuator drive oil pump is configured to feed an oil with a discharge pressure higher than a discharge pressure of the lubricating oil pump.

Abstract: A water-jet personal watercraft comprises a body including a hull and a deck covering the hull from above, the body being configured to form an engine room inside thereof in which an engine is mounted, and the deck being provided with a first opening configured to guide air from outside into the engine room, and a steering handle provided on an upper portion of the body, the steering handle including a steering shaft having a base portion where the steering shaft intersects an upper surface of the deck, wherein the first opening is provided on the upper surface of the deck at a position defined between the base portion of the steering shaft and a substantially center position between a front end portion of the body and the base portion of the steering shaft.

Abstract: A method and device for processing self-diagnostic information relating to an operating state of a jet-propulsion personal watercraft to display the self-diagnostic information on a display device equipped in the personal watercraft.

Abstract: A stand-up type personal watercraft comprises a body including a hull and a deck covering the hull from above, the body having a foot deck at a rear portion of the deck, on which an operator rides, a water jet pump configured to propel the watercraft, and a four-cycle multi-cylinder engine provided within the body and configured to drive the water jet pump, wherein the engine is disposed forward of the foot deck within the body and substantially at a center position in a longitudinal direction of the body.

Abstract: An oil cooler of an engine for small watercraft. The oil cooler typically includes a mounting portion configured to mount the oil cooler on an outer wall face of an engine of the small watercraft, an oil passage configured to allow oil to flow therethrough and lead to outside of the oil cooler at the mounting portion, and a coolant passage through which coolant for cooling the oil flows, wherein the oil cooler is capable of being disassembled such that an inside of at least the coolant passage is exposed.

Abstract: A water-jet propulsion personal watercraft is disclosed. The personal watercraft typically includes a body including a hull and a deck covering the deck from above, a water jet pump configured to propel the watercraft and including a pump shaft extending in a longitudinal direction of the body, a V-type four-cycle engine mounted within the body and configured to drive the water jet pump, wherein the engine includes a crankshaft, an output shaft extending in a direction substantially perpendicular to the crankshaft and connected to the pump shaft, the output shaft being configured to output rotation transmitted from the crankshaft to outside the engine, and a rotation transmission system configured to transmit the rotation of the crankshaft to the output shaft, wherein the engine is mounted within the body in such a manner that the crankshaft extends in a width direction of the body.

Abstract: A personal watercraft comprises an engine, a sensor configured to detect an operating state of the engine, a control device configured to control an operation of the engine based on a detection signal from the sensor, and a display device including a first display portion configured to output a state of the watercraft based on data output from the control device, wherein the display device includes a storage portion configured to store the data output from the control device.

Abstract: A small watercraft including an engine mounted in a body such that an axial direction of a crankshaft corresponds with a longitudinal direction of the body, an oil tank provided such that a longitudinal direction thereof corresponds with the axial direction of the crankshaft, a first communicating port and a second communicating port formed in the oil tank at least two positions spaced apart from each other in the longitudinal direction, a gas-release chamber having a third communicating port and a fourth communicating port provided at two positions spaced apart from each other, and at least one fifth communicating port located to communicate with an ambient side, the gas-release chamber having a bottom face located higher than a liquid level of oil inside the oil tank, wherein the first communicating port communicates with the third communicating port and the second communicating port communicates with the fourth communicating port.

Abstract: A multi-cylinder engine for driving a vehicle is provided. The multi-cylinder engine includes a plurality of cylinders. The engine also includes a multi-throttle valve device having a plurality of air-intake passages, each of which being configured to lead air to the respective cylinder, and a plurality of throttle valves, each of which being configured to open and close the respective air-intake passage. At least one of the throttle valves is configured to be opened and closed independently of at least one of the other throttle valves.

Abstract: An air-intake device of an engine for a leisure vehicle, in which at least two air-intake passages are arranged within an engine body of the engine, is disclosed, including an air-intake pipe through which fresh air is supplied to the at least two air-intake passages arranged within the engine body, and a throttle valve openably mounted within a passage of the air-intake pipe. Typically, the air-intake pipe is structured such that the passage has a cross-section of a non-perfect circle shape and an outer periphery of the air-intake pipe has a cross-section of a circle shape with a continuously varying positive curvature. Typically, the throttle valve has a valve disc of a non-perfect circle shape conforming to the shape of the cross-section of the passage of the air-intake pipe.

Abstract: An exhaust system for a small watercraft is disclosed, wherein the exhaust system includes an exhaust chamber having a predetermined volume, within which an exhaust gas discharged from an engine flows, the exhaust gas containing water supplied at a position of the exhaust system, and an exhaust pipe having an upstream end portion in a flow passage of the exhaust gas, which is connected to the exhaust chamber, the exhaust pipe being configured to discharge the exhaust gas from the exhaust chamber, wherein the upstream end portion of the exhaust pipe is configured to protrude into the exhaust chamber to a vicinity of a lower end of the exhaust chamber and has an upstream opening end face that opens substantially downward so as to be spaced apart a predetermined distance from an inner surface of the exhaust chamber, which is opposed to upstream opening end face.

Abstract: A personal watercraft typically comprises an engine having a plurality of fuel injectors arranged along a longitudinal direction of the watercraft, a fuel tank configured to store fuel and to have an outlet port from which the fuel outflows out and a return port through which the fuel is returned to the fuel tank, and a fuel distribution pipe provided between the outlet port and the return port of the fuel tank and configured to distribute the fuel outflowing from the fuel tank to a plurality of fuel injectors connected to the fuel distribution pipe at positions thereof and to return remaining fuel to the fuel tank, wherein the fuel distribution pipe is configured to extend such that an upstream portion is located lower than a downstream portion in a flow passage of the fuel flowing within the fuel distribution pipe.

Abstract: A personal watercraft and engine therefor are provided. The engine typically is mounted in a personal watercraft and configured to discharge an exhaust gas through a water muffler. The engine typically includes a cylinder head forming a combustion chamber, wherein the cylinder head is provided with an exhaust port configured to draw the exhaust gas from the combustion chamber to the water muffler, and an air passage configured to allow the exhaust port and an outside of the engine to communicate with each other, and the air passage is provided with a valve configured to restrict a flow of air within the air passage.

Abstract: Disclosed is a watercraft comprising a body; a hull constituting a lower portion of the body; a deck having deck floors formed on both sides of the body in a width direction and a raised portion at least extending from a center portion of the body to a rear end portion of the body in a longitudinal direction and being raised from center-side end portions of the deck floors on both sides in the width direction so as to form an engine room that contains the engine, the deck covering the hull from above and constituting an upper portion of the body; a straddle-type seat mounted over an upper end of the raised portion of the deck for a rider to straddle with feet put on the deck floors on both sides; and a rear cowling mounted behind the seat and extending rearwardly from a rear end of the seat.

Abstract: A personal watercraft comprising a water jet pump, an engine for driving the water jet pump, and a mechanically driven supercharger provided independently of the engine and configured to draw taken-in air to the engine.

Abstract: A small watercraft comprises an engine for propelling a body of the watercraft, an oil tank configured to reserve oil for lubricating the engine, an oil separator configured to separate the oil from a blow-by gas of the engine, and an oil return passage configured to return the separated oil to the oil tank, wherein a baffle member is provided in the vicinity of an opening portion at which the oil return passage opens in the oil tank so as to inhibit the oil from moving from a predetermined direction toward the opening portion of the oil return passage within the oil tank.