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: This supercharger for a motorcycle is driven by power of a crankshaft of a combustion engine, and compresses intake air to be supplied to the combustion engine. The supercharger has an impeller of a centrifugal type, and an intake air control valve is disposed on the upstream side of the impeller of the supercharger with respect to a flow direction of the intake air. The intake air control valve is disposed so as to face a suction port of the supercharger in the flow direction of the intake air. The intake air control valve adjusts the amount of the intake air flowing into the impeller, and in addition, provides a preswirl to the intake air flowing into the impeller.

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 includes a supercharger rotary shaft, an impeller fitted to the supercharger rotary shaft and operable to pressurize a fluid medium sucked from one end portion side of the supercharger rotary shaft, and a fastening member to fix the impeller to the supercharger rotary shaft while pressing the impeller in a direction axially of the supercharger rotary shaft. The fastening member includes an internal thread portion defined in an interior thereof and engageable with an external thread portion of the supercharger rotary shaft. An outer surface of a tip end portion of the fastening member is so formed as to represent a diametrically constricted shape in which it is continuously smoothly tapered in a direction away from the impeller.

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: 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: 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: 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 reference angle detecting device includes a control shaft connected to a controlled object, an electric motor causing the control shaft to rotate via a worm gear mechanism, a stopper disposed on a motion track of a worm wheel, an angle sensor that can detect a rotation angle of the control shaft, and a controller. The stopper includes a spring member which is elastically deformable in an operation direction of the worm wheel. The controller drives the electric motor to operate so that the worm wheel may face the stopper, and stores the rotation angle at a time point when a change rate ? of the rotation angle ? detected by the angle sensor changes to a value less than a predetermined threshold ?1 as a reference angle ?0. Therefore, the reference angle can be detected with high accuracy for control of an angle of the control shaft.

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: 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: 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 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 valve gear operates an intake valve for a plurality of cylinders. The valve gear includes a driving cam shaft that rotates with an engine crankshaft, a driven member operated by a driving cam of the driving cam shaft, a pivot member which pivots in association with movement of the driven member causing the intake valve to reciprocate, and a valve gear case accommodating the cam shaft, the driven member, the pivot member, and a control shaft. The valve gear case mounts to an intake-side part of a cylinder head, and includes end wall portions at both ends in a longitudinal direction, an inter-cylinder wall portion, and connection wall portions connecting the end wall portions and the inter-cylinder wall portion.

Abstract: A valve gear operates an intake valve for a plurality of cylinders. The valve gear includes a driving cam shaft that rotates with an engine crankshaft, a driven member operated by a driving cam of the driving cam shaft, a pivot member which pivots in association with movement of the driven member causing the intake valve to reciprocate, and a valve gear case accommodating the cam shaft, the driven member, the pivot member, and a control shaft. The valve gear case mounts to an intake-side part of a cylinder head, and includes end wall portions at both ends in a longitudinal direction, an inter-cylinder wall portion, and connection wall portions connecting the end wall portions and the inter-cylinder wall portion.

Abstract: Provided are a drive cam having an improved wear resistant sliding surface that gives the drive cam enhanced durability and a valve operating system in an engine with such a drive cam. The drive cam of the present invention, made of a nitriding steel, has on its sliding surface, a hardened surface formed by nitrocarburizing wherein the hardened layer lies on top of the sliding surface. It is preferred that the driven mechanism used in combination with the drive cam has, in its sliding surface against which the drive cam slides, a chrome-plated layer and thereon a diamond-like carbon coating.

Abstract: A reference angle detecting device includes a control shaft connected to a controlled object, an electric motor causing the control shaft to rotate via a worm gear mechanism, a stopper disposed on a motion track of a worm wheel, an angle sensor that can detect a rotation angle of the control shaft, and a controller. The stopper includes a spring member which is elastically deformable in an operation direction of the worm wheel. The controller drives the electric motor to operate so that the worm wheel may face the stopper, and stores the rotation angle at a time point when a change rate ? of the rotation angle ? detected by the angle sensor changes to a value less than a predetermined threshold ?1 as a reference angle ?0. Therefore, the reference angle can be detected with high accuracy for control of an angle of the control shaft.

Abstract: Disclosed is an exhaust purification device in which an entire length of an outer cylinder of a catalyst can be used effectively for exhaust purification and it is possible to prevent heat in fixing of the catalyst to an exhaust pipe from affecting a connection portion between the outer cylinder and catalyst main bodies. A catalyst includes an outer cylinder and a plurality of catalyst main bodies provided in the outer cylinder in a state of being spaced each other in a direction of an axial center of the outer cylinder. An outer face of the outer cylinder positioned between the catalyst main bodies is a fixed face to be fixed to an inside of the exhaust pipe.

Abstract: Disclosed is an exhaust purification device in which an entire length of an outer cylinder of a catalyst can be used effectively for exhaust purification and it is possible to prevent heat in fixing of the catalyst to an exhaust pipe from affecting a connection portion between the outer cylinder and catalyst main bodies. A catalyst includes an outer cylinder and a plurality of catalyst main bodies provided in the outer cylinder in a state of being spaced each other in a direction of an axial center of the outer cylinder. An outer face of the outer cylinder positioned between the catalyst main bodies is a fixed face to be fixed to an inside of the exhaust pipe.