Abstract: A drive transmission apparatus includes a dog clutch including a dog gear assembly and a dog ring, which are configured for rotation and relative axial adjustment between an engaged condition in which torque can be transmitted and a disengaged condition. The dog gear assembly includes a dog gear, a retractable dog assembly configured for movement relative to the dog gear between an extended position and a retracted position, and a control element that controls movement of the retractable dog assembly. The dog ring includes a plurality of first dogs and the dog gear assembly includes a plurality of second dogs that engage the first dogs in the engaged condition, and that are disengaged from the first dogs in the disengaged condition. The second dogs include a plurality of fixed dogs that are mounted on the dog gear and a plurality of retractable dogs of the retractable dog assembly.

Abstract: A drive transmission apparatus includes a dog clutch including a dog gear assembly and a dog ring, which are configured for rotation about a rotational axis and relative axial adjustment between an engaged condition in which torque can be transmitted between the dog gear assembly and the dog ring, and a disengaged condition in which torque cannot be transmitted. The dog gear assembly includes a dog gear, a retractable dog assembly configured for movement relative to the dog gear between an extended position and a retracted position, and a control element that controls movement of the retractable dog assembly. The dog ring includes a plurality of first dogs and the dog gear assembly includes a plurality of second dogs that engage the first dogs in the engaged condition, and that are disengaged from the first dogs in the disengaged condition. The second dogs include a plurality of fixed dogs that are mounted on the dog gear and a plurality of retractable dogs of the retractable dog assembly.

Abstract: The inside in an engine case is sucked to turn a pressure in the engine case into a negative pressure. A breather chamber is disposed above a vacuum pump. An intake port of a blow-by gas is disposed in an upper portion of the vacuum pump. A discharge port of the blow-by gas is disposed in a lower portion of the vacuum pump.

Abstract: The inside in an engine case is sucked to turn a pressure in the engine case into a negative pressure. A breather chamber is disposed above a vacuum pump. An intake port of a blow-by gas is disposed in an upper portion of the vacuum pump. A discharge port of the blow-by gas is disposed in a lower portion of the vacuum pump.

Abstract: An engine for a motorcycle includes an engine case, a crankshaft rotatably supported within the engine case and extending laterally, an intermediate shaft being substantially parallel to the crankshaft and being rotated by the crankshaft at the same speed via a primary drive gear and a primary driven gear, a transmission input shaft being substantially parallel to the intermediate shaft and being rotated by the intermediate shaft at reduced speed via a secondary drive gear and a secondary driven gear, a transmission output shaft being substantially parallel to the transmission input shaft and being rotated by the transmission input shaft at changed speed via any combination of a plurality of transmission drive gears and transmission driven gears, and a clutch unit disposed on the intermediate shaft and capable of transmitting and interrupting rotation of the intermediate shaft to the transmission input shaft.

Abstract: An engine for a motorcycle includes an engine case, a crankshaft rotatably supported within the engine case and extending laterally, an intermediate shaft being substantially parallel to the crankshaft and being rotated by the crankshaft at the same speed via a primary drive gear and a primary driven gear, a transmission input shaft being substantially parallel to the intermediate shaft and being rotated by the intermediate shaft at reduced speed via a secondary drive gear and a secondary driven gear, a transmission output shaft being substantially parallel to the transmission input shaft and being rotated by the transmission input shaft at changed speed via any combination of a plurality of transmission drive gears and transmission driven gears, and a clutch unit disposed on the intermediate shaft and capable of transmitting and interrupting rotation of the intermediate shaft to the transmission input shaft.