Abstract: A motorcycle of such a type that a vehicle body frame is provided thereon with an internal combustion engine 4 in front and a transmission 5 in rear. An intermediate driving shaft 18 is interposed between a crankshaft 8 of the engine 4 and an input shaft 13 of the transmission 5. The driving shaft 18 is provided at its both end portions with an A.C. generator 19 and a control member 20 for an ignition circuit, for instance, a pulse generator or a contact breaker. According to this arrangement, even in the case where the engine is of a multiple cylinder type and the crankshaft is comparatively large in length, the motorcycle is prevented from becoming remarkably large in width locally at its crankshaft portion.

Abstract: Power unit apparatus for a motorcycle driven by an internal combustion engine has a split power unit case. The crankshaft and the driving shaft of a reduction gear mechanism are clamped between the upper and lower sections of the power unit case. The driven shaft is located on the lower section. A guide shaft for shifter forks and a shift drum controlling operation of the shifter forks are both located on the upper section above the driving and driven shafts.

Abstract: A power transmission system for vehicles comprising a driving member connected to an engine crankshaft, and a driven member connected to a driving wheel, the driving and driven members being connected with each other via a one-way clutch and a friction clutch which are disposed in parallel to each other. The one-way clutch is in a connected state when a forward load is applied to the engine, and in a disconnected state when a back load is applied to the engine. The friction clutch is operated to slip when it receives a torque greater than a predetermined value.

Abstract: A power transmission device of a motorcycle comprising a main transmission case formed integrally with an engine crank case and accommodating a main transmission, and a sub-transmission case provided at the rear side of the main mission case. The sub-transmission case accommodates a sub-transmission which is drivingly connected to the main transmission and also to a rear wheel of the motorcycle through a transmission mechanism. The transmission mechanism and the sub transmission are disposed at opposite sides of the rear wheel. The sub-transmission case is composed of a case body and a cover for covering an opening of the case body. The opening is formed at a lateral side of the gears of the sub-transmission so that the gears are accessible and replaceable by removing the cover from the opening.

Abstract: A transmission device in which a centrifugal starting clutch is in a casing mounted on a crank shaft of an engine. A multiple plate type speed change clutch is mounted on a speed change input shaft. The starting clutch has an output member operatively connected to its input member through a reduction gear train. The speed change clutch is interposed between the starting clutch and the reduction gear train. The starting clutch is immersed into lubricating oil in the casing, whereas the speed change clutch is totally positioned above the surface of lubricating oil.

Abstract: A power transmission for a two-wheeled vehicle includes a variable-diameter drive pulley mechanism (2) mounted on a drive shaft (1) connected to an engine (E), a variable-diameter driven pulley mechanism (22) mounted on a driven shaft (18) operatively coupled with a driven wheel (W), and a clutch (36) mounted coaxially on the driven shaft (18) and operatively connected to the driven pulley mechanism (22). The drive and driven pulley mechanisms (2,22) are interconnected by a V-belt (7). The drive and driven pulley mechanisms (2,22) have axially movable members (5,24) located on opposite sides of the V-belt (7) adjacent to the engine (E) and the clutch (36) to allow parallel displacement of the V-belt (7) during the changing of the diameters of the pulley mechanisms (2,22), to prevent belt twisting or distortion and to prevent the belt (7) and pulley mechanisms (2,22) from being loaded while the vehicle is moved around with the engine (E) turned off.

Abstract: A power transmission casing apparatus in a motorized two-wheeled vehicle which comprises a case main body extending from one lateral side of an internal combustion engine to one lateral side of a rear wheel in rear thereof and supporting rotatably a wheel axle of the rear wheel. The case main body is applied with a cover member for containing therein liquid-tightly a reduction gear means, and is applied with another cover member for containing therein a V-belt means.

Abstract: A motorcycle of such a type that a vehicle body frame is provided thereon with an internal combustion engine 4 in front and a transmission 5 in rear. An intermediate driving shaft 18 is interposed between a crankshaft 8 of the engine 4 and an input shaft 13 of the transmission 5. The driving shaft 18 is provided at its both end portions with an A.C. generator 19 and a control member 20 for an ignition circuit, for instance, a pulse generator or a contact breaker. According to this arrangement, even in the case where the engine is of a multiple cylinder type and the crankshaft is comparatively large in length, the motorcycle is prevented from becoming remarkably large in width locally at its crankshaft portion.

Abstract: A motor cycle which is suitable both for use as a trail machine and as road bike has an engine and gear box assembly which forms an integral part of the monocoque frame of the motor cycle. The gear box has an input shaft, an intermediate shaft and an output shaft and a chain driving sprocket mounted on the output shaft. The rear wheel of the motor cycle is mounted in a swing arm, the pivot axis of which is coincident with the axis of the gear box output shaft and the rear wheel is driven by a chain passing over the sprocket on the output shaft and a sprocket attached to the rear. Since the swing arm axis and output shaft axis are coincident, the swing arm and rear wheel are able to accommodate large suspension movements without affecting the chain tension because of these movements.