Abstract: A power unit includes: a rotation plate 62 that is fixed to an end of a shift drum 50, includes a plurality of recessed portions 63, and rotates together with the shift drum 50; a shift lever 66 that engages with the rotation plate 62; a shift shaft 74 fixed to the shift lever 66; a support shaft 76 disposed substantially in parallel with the shift drum 50; a stopper lever 78 rotatably supported by the support shaft 76; and a stopper roller 88 that is provided in the stopper lever 78 and engages with the recessed portion 63 of the rotation plate 62. When viewed in an axial direction of the shift shaft 74, the stopper lever 78 is disposed to intersect a first line segment A that connects a center 74C of the shift shaft 74 and a center 62C of the rotation plate 62 to each other.

Abstract: A power unit includes: a crankcase 24 that houses a shift drum 50, a shift lever 66, at least a portion of a shift shaft 74, and a stopper lever 78; and an oil pan 28 disposed under a lower crankcase 26. The lower crankcase 26 includes a frame portion 26F which is located above the oil pan 28 and to which a cover 29 is attached when viewed in an axial direction of the shift shaft 74. The shift lever 66 is disposed so that when the shift shaft 74 is located at a second rotational position, a portion of a second arm 70 of the shift lever 66 is located lower than the frame portion 26F of the lower crankcase 26 and inside the oil pan 28 as viewed in the axial direction of the shift shaft 74.

Abstract: A power unit includes: a rotation plate 62 that is fixed to an end of a shift drum 50, includes a plurality of recessed portions 63, and rotates together with the shift drum 50; a shift lever 66 that engages with the rotation plate 62; a shift shaft 74 fixed to the shift lever 66; a support shaft 76 disposed substantially in parallel with the shift drum 50; a stopper lever 78 rotatably supported by the support shaft 76; and a stopper roller 88 that is provided in the stopper lever 78 and engages with the recessed portion 63 of the rotation plate 62. When viewed in an axial direction of the shift shaft 74, the stopper lever 78 is disposed to intersect a first line segment A that connects a center 74C of the shift shaft 74 and a center 62C of the rotation plate 62 to each other.

Abstract: A transmission includes an input shaft which rotates synchronously with a crankshaft, an output shaft, which rotates synchronously with a driving wheel, a shift drum of a rotary type which engages with a shift fork to drive at least one slide gear, and a rotary stopper mechanism including a friction spring frictionally engaged in a circumferential recessed groove provided in an outer periphery of the output shaft, a rocker arm biased by the friction spring toward the shift drum in accordance with rotation of the output shaft, and an engagement recessed portion provided in an outer periphery of the shift drum to restrict rotation of the shift drum through engagement with the rocker arm. Accordingly, cost is reduced as compared to a conventional transmission, and heat generation of the friction spring is minimized.

Abstract: A power unit includes: a crankcase 24 that houses a shift drum 50, a shift lever 66, at least a portion of a shift shaft 74, and a stopper lever 78; and an oil pan 28 disposed under a lower crankcase 26. The lower crankcase 26 includes a frame portion 26F which is located above the oil pan 28 and to which a cover 29 is attached when viewed in an axial direction of the shift shaft 74. The shift lever 66 is disposed so that when the shift shaft 74 is located at a second rotational position, a portion of a second arm 70 of the shift lever 66 is located lower than the frame portion 26F of the lower crankcase 26 and inside the oil pan 28 as viewed in the axial direction of the shift shaft 74.

Abstract: A transmission includes an input shaft which rotates synchronously with a crankshaft, an output shaft, which rotates synchronously with a driving wheel, a shift drum of a rotary type which engages with a shift fork to drive at least one slide gear, and a rotary stopper mechanism including a friction spring frictionally engaged in a circumferential recessed groove provided in an outer periphery of the output shaft, a rocker arm biased by the friction spring toward the shift drum in accordance with rotation of the output shaft, and an engagement recessed portion provided in an outer periphery of the shift drum to restrict rotation of the shift drum through engagement with the rocker arm. Accordingly, cost is reduced as compared to a conventional transmission, and heat generation of the friction spring is minimized.