Abstract: In a semiconductor device having at least a first semiconductor layer and a second semiconductor layer which are arranged so as to form a heterojunction, an edge of a conduction band of the first semiconductor layer being positioned lower in energy than an edge of a conduction band of the second semiconductor layer in the vicinity of the heterojunction, at least one pair of electrodes which are electronically connected with the first semiconductor layer, and means to control carriers induced in the vicinity of the heterojunction; a semiconductor device characterized in that a low impurity concentration region is comprised in at least the part of the first semiconductor layer between the pair of electrodes, that a region adjoining each of the pair of electrodes is a high impurity concentration region, and that at least one layer containing an impurity which has a conductivity type identical or opposite to that of an impurity contained in the aforementioned regions is comprised in the first semiconductor layer.

Abstract: A radiator circular or conical in shape for a motorcycle which may be advantageously located in a position adjacent the motorcycle in an arrangement similar to that of a muffler. The radiator includes a core of ring-shaped cross section with an inlet tank and an outlet tank. The inlet and outlet tanks may be positioned on either end of the radiator with radiator tubes extending generally longitudinally therebetween. Alternately, the tubes may be ring-shaped with the inlet and outlet tanks arranged generally along the longitudinal direction. A plurality of corrugated or plate fins may be used to enhance heat transfer. A plate may be positioned at one end of the radiator to insure radial air flow through the core thereof.

Abstract: A heat exchange device for mounting between the front fork and the engine of a motorcycle comprises two vertical coolant outflow tanks on either side of a core area, and a coolant inflow tank located midway between the outflow tanks and connected to the latter. The lower part of the device comprises a series of bent tubes having cooling fins therebetween, to form an inverted U-shaped space which straddles the top of the engine, so as to provide sufficient clearance to accommodate the expansion and contraction strokes of the front fork.

Abstract: A motorcycle is provided with an air cleaner mounted beneath the tank and between downwardly extending portions thereof, between the frame members. The air cleaner is provided with a window for viewing the element and is inspected by pivotting the tank upwardly.

Abstract: A fuel tank assembly for a motorcycle includes a main tank and an auxiliary tank joined by a fuel hose or pipe. A breather pipe having an inlet in an upper portion of the auxiliary tank extends to a position proximate the fuel inlet of the main tank to exhaust air from the auxiliary tank to increase its effective capacity. The breather may extend either separately from or within the fuel pipe and may be provided either internally or partially externally of the main tank; the auxiliary tank may be provided with a pump operable when a low fuel level is reached in the main tank, which increases the freedom of placement of the auxiliary tank relative to the carburetor.

Abstract: A rear wheel suspension device for a motorcycle has a support frame comprising side bars extending from a horizontal bearing cylinder and having a cross member fixed to the side bars to define an opening. An upright damper is pivoted to the main frame and extends through the opening and is pivotally connected to short arms of bell crank members. Long arms of the bell crank members are pivoted to the support frame. Tension rods are pivotally connected to the main frame and to the bell cranks. The long arms each comprise parallel spaced side plates, for weight reduction, and the rear wheel drive chain extends through one of the long arms between said side plates.