Abstract: A piston cooling structure for an engine includes a first nozzle and a second nozzle for injecting a cooling liquid towards a back face of a piston that reciprocally move within a cylinder bore along a cylinder axis line. The first angle of inclination of an axis of the first nozzle relative to the cylinder axis line is set to be smaller than the second angle of inclination of an axis of the second nozzle relative to the cylinder axis line.

Abstract: A combustion engine includes a supercharger which pressurizes intake air to be supplied to an engine body. A lubrication system for the combustion engine includes a main lubrication passage through which lubricating oil flows to lubricate the engine body, a supercharger lubrication passage through which lubricating oil flows to lubricate the supercharger, and an oil pump which supplies a shared lubricating oil to both of the main and supercharger lubrication passages.

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 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 upwardly protruding cylinder block is formed in a front portion of a crankcase for supporting a crankshaft of an engine. A cylinder head is connected with an upper portion of the cylinder block, and a combustion chamber of an internal combustion engine is formed within the cylinder block and the cylinder head. A knocking sensor for detecting the occurrence of knocking in the engine is fitted to a left side end surface of the cylinder block.

Abstract: A rotary unit is rotatably accommodated within a supercharger casing of a supercharger for pressurizing an intake air of an engine. The rotary unit includes a supercharger rotary shaft, an impeller fixed to a tip end portion of the supercharger rotary shaft, a rotating component rotatable together with the supercharger rotary shaft independently of the impeller, and a nut member for pressing the impeller and the rotating component in a direction axially of the supercharger rotary shaft to thereby fix them to the supercharger rotary shaft. The nut member is formed with an adjustment portion for the rotational balance adjustment.

Abstract: A power transmission system includes an input shaft, a supercharger rotary shaft disposed coaxially with the input shaft, and a transmission mechanism interposed between the input shaft and the supercharger rotary shaft. A lubricating structure of the power transmission system is provided with an injection passage through which a portion of oil for lubricating bearings for supporting the supercharger rotary shaft is supplied, from a supercharger casing for supporting the bearings, towards the input shaft by means of a jetting spray across an interior space within the transmission mechanism.

Abstract: An air intake chamber for a motorcycle is disposed downstream of a supercharger, for pressurizing and supplying an intake air to an engine, and upstream of a throttle body, for controlling the amount of the intake air to be supplied to an air intake port of the engine. The air intake chamber serves to accumulate the high pressure intake air discharged from the supercharger. The air intake chamber is provided with an injector, which has a fuel injecting port positioned at a location displaced from an axis of an outlet of the air intake chamber.

Abstract: An air intake chamber is disposed at a location downstream of a supercharger and upstream of a throttle body. The air intake chamber serves to accumulate an intake air pressurized by the supercharger. This air intake chamber includes a confronting portion, which has an outlet and overlaps the throttle body, and a connecting portion that connects between the confronting portion and a discharge port of the supercharger. The connecting portion has an outlet side opening set to be larger than an inlet side opening thereof.

Abstract: A motorcycle includes a supercharger to pressurize an intake air and supplying it to a combustion engine and an air intake chamber disposed downstream of the supercharger. The air intake chamber is made of a metallic material and has a capacity of an interior space thereof which is within the range of three to eight times the displacement of the combustion engine. The dimension from an upstream end portion on an inlet side of the interior space of the air intake chamber to a downstream end portion on an outlet side of the interior space of such air intake chamber is chosen to be three or more times the inner diameter of an outlet.

Abstract: Out of a plurality of speed change gears on one of an input shaft and an output shaft, for example, on the output shaft, two adjacent speed change gears disposed via an axial space therebetween are axially fixed and rotatably fitted around the output shaft. A dog ring for a dog clutch disposed between the speed change gears is fixed around the output shaft and axially slidably fitted thereto. The speed change gears on the output shaft and the dog ring are each provided with an engagement portion for the dog clutch engaged and disengaged by axial shift of the dog ring. The two speed change gears on the input shaft meshing with the two speed change gears on the output shaft are provided integrally with the input shaft.

Abstract: An engine (E) of a saddle-riding type vehicle has an engine case that is substantially L-shaped by a cylinder block (42) being protruded upward from an upper face of a front portion of a crank case (40). An air cleaner (55) is disposed rearwardly of the cylinder block (42) and above the crank case (40). An outlet (72) through which blow-by gas (G) in the engine (E) is discharged is formed in the rear portion of the cylinder block (42). A case body (84) of the air cleaner (55) has a blow-by gas introduction port (86) through which the blow-by gas (G) is introduced into the air cleaner (55). The outlet (72) of the cylinder block (42) and the blow-by gas introduction port (86) of the case body (84) are connected by a connecting pipe (90). The blow-by gas introduction port (86) is disposed close to the cylinder block (42).

Abstract: A motorcycle supercharger (42) pressurizes intake air (I) for a combustion engine (E). The supercharger (42) includes a centrifugal impeller (50) and an impeller casing (52) which covers the impeller (50). The impeller casing (52) includes an outer peripheral wall (84) located radially outward of the impeller (50) and a side wall (86) located axially outward of the impeller (50). Reinforcing first and second side wall ribs (94, 96) are provided at the side wall (86) of the impeller casing (52).

Abstract: A supercharging system for a combustion engine of a motorcycle includes a supercharger which pressurizes intake air and supplies the intake air to the combustion engine, an air intake chamber which is connected to downstream of the supercharger, a relief passage which relieves the high-pressure intake air within the air intake chamber, and a relief valve which is provided on the relief passage. The air intake chamber is disposed above the combustion engine, and the relief passage is disposed below an upper end of the air intake chamber. The relief passage is connected to a front surface of the air intake chamber.

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: A combustion engine includes a supercharger which pressurizes intake air to be supplied to an engine body. A lubrication system for the combustion engine includes a main lubrication passage through which lubricating oil flows to lubricate the engine body, a supercharger lubrication passage through which lubricating oil flows to lubricate the supercharger, and an oil pump which supplies a shared lubricating oil to both of the main and supercharger lubrication passages.

Abstract: An air intake duct of a motorcycle forms an air intake passage for supplying an intake air to a supercharger. The air intake duct forms a curve portion and is connected to the supercharger. The air intake passage has a transverse cross-section which is shaped such that a dimension in an orthogonal direction that is orthogonal to a radial direction of the curve portion is gradually reduced from the center of the curve portion toward an outer side, in the radial direction, of the curve portion.

Abstract: A combustion engine of a motorcycle has an engine rotary shaft extending in a vehicle widthwise direction. Incoming wind taken in from a front of a steering handle that is positioned in front of the combustion engine, is introduced through an air intake duct to the combustion engine. The air intake duct extends from the front of the steering handle to a rearward of a cylinder block so as to pass above a radiator and pass laterally of one side of the cylinder block.

Abstract: An oil filter and an oil cooler of a motorcycle combustion engine are disposed on an outer surface of an engine body side by side in a right-left direction. A first engine lubrication passage extending in the right-left direction is connected to an outflow passage for the oil cooler. A second engine lubrication passage is connected to the first engine lubrication passage, to extend frontward, and is disposed parallel to an inflow passage and an outflow passage for the oil filter. A third engine lubrication passage is connected to the second engine lubrication passage and extends upward from the second engine lubrication passage in front of the first engine lubrication passage.