Abstract: An air intake duct of a motorcycle extends rearwardly from a front portion of a motorcycle body so as to pass laterally of the left side of a motorcycle frame structure, and incoming wind is supplied as an intake air through the air intake duct to a combustion engine. The air intake duct is divided in a widthwise direction of the motorcycle. An upper dividing face of the air intake duct is disposed inward of an intermediate position, in a motorcycle widthwise direction, of the air intake duct.

Abstract: An impeller for pressurizing an intake air of an engine is provided on a left side end portion in a supercharger rotary shaft of the supercharger. The power from the engine is transmitted to a second sprocket, which is provided on a right side end portion of an input shaft of a speed increaser, through a chain to thereby allow the supercharger to drive. The second sprocket is removably fitted to the input shaft by means of a bolt. The supercharger rotary shaft, the input shaft, the second sprocket and the bolt are all accommodated in a supercharger casing. The supercharger casing has a right side end face formed with an access opening through which access can be made to the second sprocket and the bolt from an axial direction.

Abstract: A combustion engine (E) for a motorcycle includes a crankshaft (26) extending in a widthwise direction of the motorcycle and a supercharger (42) which pressurizes intake air (I). A clutch gear (72) to which a clutch is connected is provided at the right side of the crankshaft (26), and a supercharger gear (80) which drives the supercharger (42) is provided at the left side of the clutch gear (72). The supercharger gear (80) is formed on a crank web (75) disposed such that a journal (68) is located between the clutch gear (72) and the crank web (75).

Abstract: A combustion engine for a motorcycle includes a supercharger which pressurizes intake air. The supercharger is driven by power of the combustion engine. A first cushioning body which suppresses rotation fluctuation of power is provided on a power transmission path leading from the combustion engine to the supercharger. The first cushioning body has a damper structure to transmit power from an upstream side to a downstream side thereof through an elastic body.

Abstract: An air intake duct, of a saddle-riding type vehicle, in which a flow velocity of an intake air is less likely to be reduced to enable prevention of reduction of an efficiency of a supercharger, is provided. The air intake duct of a motorcycle serves to supply incoming wind as the intake air to the supercharger for a combustion engine. The air intake duct has a passage area that is gradually reduced from an air intake port at a front portion toward a downstream portion connected to the supercharger at a rear portion.

Abstract: A transmission lubricating structure which lubricates a transmission using a lubricating fluid, the transmission including a plurality of gear pairs each including a drive gear and a driven gear, includes a lubricating fluid feeding unit for feeding the lubricating fluid to the gears of the gear pairs; wherein the lubricating fluid feeding unit includes a plurality of injection nozzles, each of which directly injects the lubricating fluid to a tooth of the drive gear and a tooth of the driven gear, which teeth start to engage with each other.

Abstract: An engine supercharging device includes are a supercharger (38) for pressurizing air introduced in an engine (E), an air cleaner (36) for purifying an ambient air, a purified air supply passage (56) for supplying a purified air (CA) from the air cleaner (36) towards the supercharger (38), a supercharged air passage (62) for supplying the supercharged air (SA) from the supercharger (38) towards an air intake passage (60) of the engine (E), and a relief valve (68) for adjusting an air pressure within the supercharged air passage (62). The relief valve (68) has a discharge port portion (68b) which is accommodated within the air cleaner (36). The engine (E) has a plurality of engine cylinders, and a downstream portion of the supercharged air passage (62) is defined by an intake air chamber (54) for supplying the sucked air to respective air intake passages (60) of the plural engine cylinders.

Abstract: An engine supercharging device includes are a supercharger (38) for pressurizing air introduced in an engine (E), an air cleaner (36) for purifying an ambient air, a purified air supply passage (56) for supplying a purified air (CA) from the air cleaner (36) towards the supercharger (38), a supercharged air passage (62) for supplying the supercharged air (SA) from the supercharger (38) towards an air intake passage (60) of the engine (E), and a relief valve (68) for adjusting an air pressure within the supercharged air passage (62). The relief valve (68) has a discharge port portion (68b) which is accommodated within the air cleaner (36). The engine (E) has a plurality of engine cylinders, and a downstream portion of the supercharged air passage (62) is defined by an intake air chamber (54) for supplying the sucked air to respective air intake passages (60) of the plural engine cylinders.

Abstract: A supercharger drive device (1) for a combustion engine (E) includes a gear carrier shaft (6) operable to rotate in unison with a crankshaft (2) of the combustion engine (E), a high speed gear (8) and a low speed gear (10) provided in the gear carrier shaft (6), a drive shaft (14) of a supercharger (12) which is rotatable when coupled with either one of the high speed gear (8) and the low speed gear (10), a gear shifter (16) for selecting one of the high speed gear (8) and the low speed gear (10) for transmitting a motive force from the gear carrier shaft (6) to the drive shaft (14) through the selected one of the high and low speed gears (8) and (10), and a shifter drive unit (18) for actuating the gear shifter (16) in dependence on the rotational speed of the combustion engine (E).

Abstract: An exhaust system for a motorcycle provided with a multicylinder engine, includes an exhaust aggregating member for unifying a pair of exhaust passages, through which an exhaust gas exhausted from the engine is transported to a muffler, so as to form a single exhaust passage therein. The single exhaust passage is connected to the muffler without being merged with another exhaust passage. The exhaust system also includes an exhaust control valve incorporated into the exhaust aggregating member and capable of changing sectional area of the single exhaust passage formed in the exhaust aggregating member.

Abstract: A breather structure of an engine having a crank case and a cylinder fastened to an upper side of the crank case can improve the strength of a cylinder and can prevent an increase of weight of the engine. The breather structure is provided with a breather chamber integrally formed with the cylinder in an outer peripheral wall of the cylinder, and the breather chamber separates air including an oil mist within the crank case into an oil component and a gas component, returns the oil component into an oil reservoir of the engine, and discharges the gas component out of the crank case.

Abstract: A tubular case into which a drive shaft configured to transmit a driving force from a transmission T of an engine to a rear wheel of a motorcycle is accommodated, the case including a case body which has an opening portion extending in an axial direction of the drive shaft and is configured to accommodate the drive shaft therein through the opening portion, and a cover removably attached to the case body so as to close the opening portion.

Abstract: An engine including an oil passage through which oil output from an oil pump flows, an oil cooler mounted to the oil passage, and a branched oil passage for a hydraulically-powered device of the engine that is configured to branch in a location of the oil passage extending from the oil pump to the oil cooler to deliver the oil to the hydraulically-powered device.

Abstract: A tubular case 35 into which a drive shaft 32 configured to transmit a driving force from a transmission T of an engine E to a rear wheel 22 of a motorcycle 20 is accommodated, the case including a case body 33 which has an opening portion 57 extending in an axial direction of the drive shaft 32 and is configured to accommodate the drive shaft 32 therein through the opening portion 57, and a cover 34 removably attached to the case body 33 so as to close the opening portion 57.

Abstract: An engine including an oil passage through which oil output from an oil pump flows, an oil cooler mounted to the oil passage, and a branched oil passage for a hydraulically-powered device of the engine that is configured to branch in a location of the oil passage extending from the oil pump to the oil cooler to deliver the oil to the hydraulically-powered device.

Abstract: The invention provides a breather structure of an engine which can improve strength of a cylinder and can prevent an increase of weight of the engine. The engine has a crank case and a cylinder fastened to an upper side of the crank case. The breather structure is provided with a breather chamber integrally formed with the cylinder in an outer peripheral wall of the cylinder, and the breather chamber separates an air including an oil mist within the crank case into oil component and gas component, returns the oil component into an oil reservoir of the engine, and discharges the gas component out of the crank case.

Abstract: An exhaust system for a motorcycle provided with a multicylinder engine, includes an exhaust aggregating member for unifying a pair of exhaust passages, through which an exhaust gas exhausted from the engine is transported to a muffler, so as to form a single exhaust passage therein. The single exhaust passage is connected to the muffler without being merged with another exhaust passage. The exhaust system also includes an exhaust control valve incorporated into the exhaust aggregating member and capable of changing sectional area of the single exhaust passage formed in the exhaust aggregating member.