Abstract: A power transmitting device includes a first rotor and a second rotor rotatably disposed coaxially with a rotational central axis and in facing relation to each other. A first pressing protrusion projecting from the first rotor and a second pressing protrusion projecting from the second rotor are disposed in relative positions on superposed rotation trajectories. A soft rubber member elastically deformable to a large extent and has a small modulus of elasticity and a hard rubber member elastically deformable to a small extent and has a large modulus of elasticity are interposed between the first and second pressing protrusions. While no relative torque load is being applied to the first and second rotors, the soft rubber member is held in contact with both the first and second pressing protrusions, and the hard rubber member is interposed between the first pressing protrusion and the second pressing protrusion with gaps therebetween.

Abstract: A power transmitting device includes a first rotor and a second rotor rotatably disposed coaxially with a rotational central axis and in facing relation to each other, a single arc spring that is elastically deformable to a large extent and has a small modulus of elasticity, the arc spring being interposed between the first rotor and the second rotor for urging the first rotor and the second rotor to opposite sides in a ration direction, a first pressing protrusion projecting from the first rotor and a second pressing protrusion projecting from the second rotor, the first pressing protrusion and the second pressing protrusion being disposed in relative positions on superposed rotation trajectories, and a rubber member that is elastically deformable to a small extent and has a large modulus of elasticity, the rubber member being interposed between the first pressing protrusion and the second pressing protrusion with gaps therebetween.

Abstract: In a rotation speed detecting apparatus of an internal combustion engine having a rotor supported by an end part of the crankshaft, a pulser ring that has a detected body composed of recess-projection teeth and rotates integrally with the rotor, and a detector that detects the rotation speed of the crankshaft by detecting the detected body, the detected body has a detected surface opposed to the detector, and the detected surface is inclined in such a manner as to be located closer to the outside of the crankshaft in the axial direction of the crankshaft as getting more apart from an axis line of the crankshaft in the radial direction. In the detector, an axis line of the detector is inclined with respect to the axis line of the crankshaft in such a manner that the detector is opposed to the detected surface.

Abstract: In a rotation speed detecting apparatus of an internal combustion engine having a rotor supported by an end part of the crankshaft, a pulser ring that has a detected body composed of recess-projection teeth and rotates integrally with the rotor, and a detector that detects the rotation speed of the crankshaft by detecting the detected body, the detected body has a detected surface opposed to the detector, and the detected surface is inclined in such a manner as to be located closer to the outside of the crankshaft in the axial direction of the crankshaft as getting more apart from an axis line of the crankshaft in the radial direction. In the detector, an axis line of the detector is inclined with respect to the axis line of the crankshaft in such a manner that the detector is opposed to the detected surface.

Abstract: A power transmitting device includes a first rotor and a second rotor rotatably disposed coaxially with a rotational central axis and in facing relation to each other. A first pressing protrusion projecting from the first rotor and a second pressing protrusion projecting from the second rotor are disposed in relative positions on superposed rotation trajectories. A soft rubber member elastically deformable to a large extent and has a small modulus of elasticity and a hard rubber member elastically deformable to a small extent and has a large modulus of elasticity are interposed between the first and second pressing protrusions. While no relative torque load is being applied to the first and second rotors, the soft rubber member is held in contact with both the first and second pressing protrusions, and the hard rubber member is interposed between the first pressing protrusion and the second pressing protrusion with gaps therebetween.

Abstract: A power transmitting device includes a first rotor and a second rotor rotatably disposed coaxially with a rotational central axis be and in facing relation to each other, a single arc spring that is elastically deformable to a large extent and has a small modulus of elasticity, the arc spring being interposed between the first rotor and the second rotor for urging the first rotor and the second rotor to opposite sides in a ration direction, a first pressing protrusion projecting from the first rotor and a second pressing protrusion projecting from the second rotor, the first pressing protrusion and the second pressing protrusion being disposed in relative positions on superposed rotation trajectories, and a rubber member that is elastically deformable to a small extent and has a large modulus of elasticity, the rubber member being interposed between the first pressing protrusion and the second pressing protrusion with gaps therebetween.

Abstract: An internal combustion engine with a reduced size while securing a sufficient amount of lubricating oil for rocker shafts in the internal combustion engine. A cam holder formed in a cylinder head extends from a rear wall portion of the cylinder head toward the attachment hole, and an intake-side downstream rocker shaft oil supply passage formed in a cross shape by causing two linear portions to intersect each other is formed inside the cam holder. In the intake-side downstream rocker shaft oil supply passage, one of the linear portions communicates with a left intake-side support hole located on a left side and configured to support a left intake-side rocker shaft, while the other one of the linear portions communicates with a right intake-side support hole located on a right side and configured to support a right intake-side rocker shaft.

Abstract: An internal combustion engine with a reduced size while securing a sufficient amount of lubricating oil for rocker shafts in the internal combustion engine. A cam holder formed in a cylinder head extends from a rear wall portion of the cylinder head toward the attachment hole, and an intake-side downstream rocker shaft oil supply passage formed in a cross shape by causing two linear portions to intersect each other is formed inside the cam holder. In the intake-side downstream rocker shaft oil supply passage, one of the linear portions communicates with a left intake-side support hole located on a left side and configured to support a left intake-side rocker shaft, while the other one of the linear portions communicates with a right intake-side support hole located on a right side and configured to support a right intake-side rocker shaft.

Abstract: A variable valve gear for an internal combustion engine that is capable of being disposed in a small compact manner and also capable of reducing the generation of a knocking sound. In a variable valve gear, a camshaft is supported by supporting walls of a cylinder head, and camshaft holders formed separately from the supporting walls, two exhaust rocker arms are disposed adjacent to each other, and a connecting pin is movably inserted into pin holes provided in the exhaust rocker arms by an actuator through a pushrod to connect or disconnect the exhaust rocker arms to or from each other. In the variable valve gear, the pushrod is slidably supported in a rod insertion hole of the camshaft holder with the connecting pin being disposed between the pair of camshaft holders and has an axis that is offset toward the camshaft with respect to an axis of the pushrod.

Abstract: A motorcycle is provided that includes a connecting pipe, a throttle body, an intake pipe, and an air cleaner, which are intake system parts disposed forward of a cylinder of an engine and are connected to the front side of the cylinder. The motorcycle further includes an exhaust pipe and a muffler, which are exhaust system parts connected to the rear side of the cylinder. The cylinder is inclined rearward, and the exhaust pipe of an exhaust system part extends forward along one side of the motorcycle in a widthwise direction of the engine 50 and detours the front of the engine and then extends rearward along the other side of the motorcycle in a widthwise direction of the engine.

Abstract: A variable valve gear for an internal combustion engine that is capable of being disposed in a small compact manner and also capable of reducing the generation of a knocking sound. In a variable valve gear, a camshaft is supported by supporting walls of a cylinder head, and camshaft holders formed separately from the supporting walls, two exhaust rocker arms are disposed adjacent to each other, and a connecting pin is movably inserted into pin holes provided in the exhaust rocker arms by an actuator through a pushrod to connect or disconnect the exhaust rocker arms to or from each other. In the variable valve gear, the pushrod is slidably supported in a rod insertion hole of the camshaft holder with the connecting pin being disposed between the pair of camshaft holders and has an axis that is offset toward the camshaft with respect to an axis of the pushrod.

Abstract: A motorcycle is provided that includes intake system parts connected to a front side of a cylinder of an engine, and exhaust system parts connected to the rear side of the cylinder. The cylinder is inclined rearward, and the intake system parts are disposed forward and upward of the cylinder. A cylinder axial line C of the cylinder passes rearward of the motorcycle with respect to a lowermost portion of a seating face of a seat, as viewed in a side elevation of the motorcycle.

Abstract: An internal combustion engine including a valve system and a breather system. The valve system includes a camshaft having intake cams and exhaust cams. The intake cams open and close intake valves, and the exhaust cams open and close exhaust valves. The breather system includes an upstream-side breather chamber and a downstream-side breather chamber. Blow-by gas flows into the upstream-side breather chamber through a chain chamber. The down-stream side breather chamber is provided in the camshaft, and also formed of a through hole constituted of a plurality of hole portions. The hole portions have different sizes and are aligned in the axial direction. The through hole opens to the chain chamber at a first shaft end portion of the camshaft, and also opens to the down-stream side breather chamber at a second shaft end portion of the camshaft. The down-stream side breather chamber is formed of a cam holder.

Abstract: A motorcycle is provided that includes intake system parts connected to a front side of a cylinder of an engine, and exhaust system parts connected to the rear side of the cylinder. The cylinder is inclined rearward, and the intake system parts are disposed forward and upward of the cylinder. A cylinder axial line C of the cylinder passes rearward of the motorcycle with respect to a lowermost portion of a seating face of a seat, as viewed in a side elevation of the motorcycle.

Abstract: A motorcycle is provided that includes a connecting pipe, a throttle body, an intake pipe, and an air cleaner, which are intake system parts disposed forward of a cylinder of an engine and are connected to the front side of the cylinder. The motorcycle further includes an exhaust pipe and a muffler, which are exhaust system parts connected to the rear side of the cylinder. The cylinder is inclined rearward, and the exhaust pipe of an exhaust system part extends forward along one side of the motorcycle in a widthwise direction of the engine 50 and detours the front of the engine and then extends rearward along the other side of the motorcycle in a widthwise direction of the engine.

Abstract: In an internal combustion engine, a lubricated camshaft assembly is in a cam chamber formed between a cylinder head and a cylinder head cover. The cylinder head includes outer bolt-receiving holes in which selected head bolts are inserted, and which are outside of the cam chamber. An oil discharge passage in the cylinder head has an inlet opened into the cam chamber, and an outlet opened into an outer bolt-receiving hole. The inlet of the oil discharge passage is disposed on one lateral side of the cam chamber. An opening part of a timing chamber is on the other lateral side of the cam chamber. An endless loop timing chain or belt is disposed inside of the timing cover, for transmitting the power of a crankshaft to the camshaft. A vehicle, which may be a four-wheeled all-terrain vehicle, may incorporate the engine and cylinder head as described.

Abstract: To reduce the cost of an ignition plug tube by making it of a cylindrical member and to provide a simple structure having only a small number of parts for mounting the ignition plug tube. A mounting structure of an ignition plug tube that is made of a cylindrical member includes a sealing member made of a soft member fitted to a cylinder head cover. The sealing member is interposed between the cylinder head cover and the ignition plug tube. The ignition plug tube is fixed and supported between an ignition plug plughole formed in a cylinder head of an internal combustion engine and the cylinder head cover.

Abstract: An internal combustion engine including a valve system and a breather system. The valve system includes a camshaft having intake cams and exhaust cams. The intake cams open and close intake valves, and the exhaust cams open and close exhaust valves. The breather system includes an upstream-side breather chamber and a downstream-side breather chamber. Blow-by gas flows into the upstream-side breather chamber through a chain chamber. The down-stream side breather chamber is provided in the camshaft, and also formed of a through hole constituted of a plurality of hole portions. The hole portions have different sizes and are aligned in the axial direction. The through bole opens to the chain chamber at a first shaft end portion of the camshaft, and also opens to the down-stream side breather chamber at a second shaft end portion of the camshaft. The down-stream side breather chamber is formed of a cam holder.

Abstract: In an internal combustion engine, a lubricated camshaft assembly is in a cam chamber formed between a cylinder head and a cylinder head cover. The cylinder head includes outer bolt-receiving holes in which selected head bolts are inserted, and which are outside of the cam chamber. An oil discharge passage in the cylinder head has an inlet opened into the cam chamber, and an outlet opened into an outer bolt-receiving hole. The inlet of the oil discharge passage is disposed on one lateral side of the cam chamber. An opening part of a timing chamber is on the other lateral side of the cam chamber. An endless loop timing chain or belt is disposed inside of the timing cover, for transmitting the power of a crankshaft to the camshaft. A vehicle, which may be a four-wheeled all-terrain vehicle, may incorporate the engine and cylinder head as described.

Abstract: To reduce the cost of an ignition plug tube by making it of a cylindrical member and to provide a simple structure having only a small number of parts for mounting the ignition plug tube. A mounting structure of an ignition plug tube that is made of a cylindrical member includes a sealing member made of a soft member fitted to a cylinder head cover. The sealing member is interposed between the cylinder head cover and the ignition plug tube. The ignition plug tube is fixed and supported between an ignition plug plughole formed in a cylinder head of an internal combustion engine and the cylinder head cover.