Abstract: A clutch device includes a slipper cam mechanism which releases a back torque by moving a clutch center in an axial direction, and a plunger mechanism provided to the clutch center. The plunger mechanism engages with a movement restricting portion until a rotational speed of the clutch center reaches a threshold value thus restricting the movement of the clutch center in the clutch axial direction, and the plunger mechanism is operated by a centrifugal force when the rotational speed of the clutch center exceeds the threshold value such that it disengages from the movement restricting portion.

Abstract: A clutch apparatus for a vehicle includes cancel mechanism having a weight member fitted for sliding movement in a clutch hub. The weight member is configured to slidably move in a radial direction of an output power shaft, and has an engaging portion at an inner end portion thereof along the radial direction. An elastic member biases the weight member toward the inner side along the radial direction of the output power shaft. A locking element is formed on the output power shaft or a locking member fixed to the output power shaft, and is configured to be engaged with the engaging portion from the opposite side to a pressure plate.

Abstract: A clutch device includes a slipper cam mechanism which releases a back torque by moving a clutch center in an axial direction, and a plunger mechanism provided to the clutch center. The plunger mechanism engages with a movement restricting portion until a rotational speed of the clutch center reaches a threshold value thus restricting the movement of the clutch center in the clutch axial direction, and the plunger mechanism is operated by a centrifugal force when the rotational speed of the clutch center exceeds the threshold value such that it disengages from the movement restricting portion.

Abstract: A clutch apparatus for a vehicle includes cancel mechanism having a weight member fitted for sliding movement in a clutch hub. The weight member is configured to slidably move in a radial direction of an output power shaft, and has an engaging portion at an inner end portion thereof along the radial direction. An elastic member biases the weight member toward the inner side along the radial direction of the output power shaft. A locking element is formed on the output power shaft or a locking member fixed to the output power shaft, and is configured to be engaged with the engaging portion from the opposite side to a pressure plate.

Abstract: A crankshaft mechanism for an engine wherein a crankshaft can be disposed close to the piston side while securing a moment of inertia. In the crankshaft mechanism for the engine including the piston, the crankshaft is provided with a crank pin and counterweight parts, and a connecting rod connecting the piston and the crank pin of the crankshaft to each other, the inner side of a circumferential end, on the opposite side of the crank pin, of each of the counterweight parts is cut out along a curve at equidistance R from the center Q of the crank pin, to obtain such a shape so as to avoid a projected part, projected in the direction of the piston, at the lower end of a small end part of the connecting rod when the piston reaches the bottom dead center.

Abstract: In a motorcycle, a cable linked with a clutch release lever is reduced in length and arranged without being bent so much. A release mechanism for a friction type clutch device is provided with a clutch release lever on a lateral surface of a crankcase that is linked with a cable connected to a clutch operational lever disposed on the left side of a steering handlebar that is turned to perform a clutch release operation. The clutch release lever includes an arm portion linked with the cable and a release rod turned together with the arm portion to press the push rod. The release rod is disposed on a left side portion of the crankcase and the arm portion is attached to project outwardly of the crankcase. The clutch release lever is turned clockwise as viewed from above a vehicle body to perform clutch release operation.

Abstract: A vehicle engine includes the crankcase for supporting thereon the crankshaft, the input shaft and the output shaft, with the crankcase being composed of a left case half and a right case half which are joined to each other at a plane orthogonal to the axis of the crankshaft. A starter motor together with a speed sensor, for detecting the vehicle speed from the rotation of a gear in a transmission, are mounted to an upper surface of the crankcase. The starter motor is arranged at a portion, just above the input shaft, of the upper surface of the crankcase, while the speed sensor for detecting the rotation of a gear on the output shaft is arranged at a portion, just above the output shaft, of the upper surface of the crankcase. The crankcase is formed with a raised wall for covering one side surface of the speed sensor.

Abstract: A vehicle having an internal combustion engine with a supercharger is provided for reducing the number of parts and for reducing the size of the engine in the transverse direction of the vehicle by effectively utilizing an outer space around the engine. A supercharger is fixed to a rear end of a crank shaft, the crank shaft extends to the rear from a crank case, and is disposed on one side-face side of a cylinder head with an intake port formed therein. An air cleaner for the supply of air to the supercharger is disposed on an upstream side of the supercharger at a position above the supercharger and behind an engine E.

Abstract: A 2-cycle engine 1 is provided with an ignition device 8; an exhaust control valve 24; and a controller 40 for controlling the ignition device 8 and the exhaust control valve 24. The controller 40 controls spark ignition combustion by activating the ignition device 8 in a high load range, and controls self-ignition combustion of a mixture in the combustion chamber 10 by adjusting pressure in a cylinder chamber 3a with adjustment of the opening of the exhaust port 21 in a low load range. In a low load and low rotational speed range, moreover, there is formed a stratified mixture field, in which the air and the fuel are much distributed in the central portion 10c of the combustion chamber 10 and in which burned gas remaining in the combustion chamber 10 is much distributed in the outer side 10b of the central portion of the combustion chamber 10, so that the self-ignition combustion of the mixture may be performed by forming the stratified mixture field in the low load and low rotational speed range.

Abstract: A vehicle engine includes the crankcase for supporting thereon the crankshaft, the input shaft and the output shaft, with the crankcase being composed of a left case half and a right case half which are joined to each other at a plane orthogonal to the axis of the crankshaft. A starter motor together with a speed sensor, for detecting the vehicle speed from the rotation of a gear in a transmission, are mounted to an upper surface of the crankcase. The starter motor is arranged at a portion, just above the input shaft, of the upper surface of the crankcase, while the speed sensor for detecting the rotation of a gear on the output shaft is arranged at a portion, just above the output shaft, of the upper surface of the crankcase. The crankcase is formed with a raised wall for covering one side surface of the speed sensor.

Abstract: A vehicle having an internal combustion engine with a supercharger is provided for reducing the number of parts and for reducing the size of the engine in the transverse direction of the vehicle by effectively utilizing an outer space around the engine. A supercharger is fixed to a rear end of a crank shaft, the crank shaft extends to the rear from a crank case, and is disposed on one side-face side of a cylinder head with an intake port formed therein. An air cleaner for the supply of air to the supercharger is disposed on an upstream side of the supercharger at a position above the supercharger and behind an engine E.

Abstract: In a motorcycle, a cable linked with a clutch release lever is reduced in length and arranged without being bent so much. A release mechanism for a friction type clutch device is provided with a clutch release lever on a lateral surface of a crankcase that is linked with a cable connected to a clutch operational lever disposed on the left side of a steering handlebar that is turned to perform a clutch release operation. The clutch release lever includes an arm portion linked with the cable and a release rod turned together with the arm portion to press the push rod. The release rod is disposed on a left side portion of the crankcase and the arm portion is attached to project outwardly of the crankcase. The clutch release lever is turned clockwise as viewed from above a vehicle body to perform clutch release operation.

Abstract: A crankshaft mechanism for an engine wherein a crankshaft can be disposed close to the piston side while securing a moment of inertia. In the crankshaft mechanism for the engine including the piston, the crankshaft is provided with a crank pin and counterweight parts, and a connecting rod connecting the piston and the crank pin of the crankshaft to each other, the inner side of a circumferential end, on the opposite side of the crank pin, of each of the counterweight parts is cut out along a curve at equidistance R from the center Q of the crank pin, to obtain such a shape so as to avoid a projected part, projected in the direction of the piston, at the lower end of a small end part of the connecting rod when the piston reaches the bottom dead center.

Abstract: A 2-cycle engine 1 is provided with an ignition device 8; an exhaust control valve 24; and a controller 40 for controlling the ignition device 8 and the exhaust control valve 24. The controller 40 controls spark ignition combustion by activating the ignition device 8 in a high load range, and controls self-ignition combustion of a mixture in the combustion chamber 10 by adjusting pressure in a cylinder chamber 3a with adjustment of the opening of the exhaust port 21 in a low load range. In a low load and low rotational speed range, moreover, there is formed a stratified mixture field, in which the air and the fuel are much distributed in the central portion 10c of the combustion chamber 10 and in which burned gas remaining in the combustion chamber 10 is much distributed in the outer side 10b of the central portion of the combustion chamber 10, so that the self-ignition combustion of the mixture may be performed by forming the stratified mixture field in the low load and low rotational speed range.