Abstract: A subsidiary fuel tank apparatus in a motorized two-wheeled vehicle of the type that a vehicle body frame having front and rear wheels is provided with an internal combustion engine in the middle, a fuel tank on the upper side, and a detachable driver's seat in the rear of the fuel tank. The vehicle body frame is provided at its rear portion with a pair of right and left back stays situated below the driver's seat and with a pair of front and rear cross members extending across the back stays so that a room space is formed between the cross members and below the driver's seat, and a subsidiary fuel tank is accommodated in the room space.

Abstract: A system for feeding a fuel to a carburetor on a motorcycle, comprising a frame on which an engine having a carburetor is mounted, a main fuel tank disposed at the front side of an upper portion of the frame for storing fuel such as alcohol therein, and an auxiliary fuel tank disposed at the rear side of the upper portion of the frame for storing fuel such as gasoline therein. The main and auxiliary fuel tanks are in communication with the carburetor through main and auxiliary fuel passages, respectively. A switch cock is provided in the main fuel passage for opening and closing thereof, and a measuring pump is interposed in the auxiliary fuel passage for supplying an auxiliary fuel at a predetermined flow rate from the auxiliary fuel tank to the carburetor. The switch cock and measuring pump are disposed at opposite sides of a lower surface of the main fuel tank. Accordingly, a driver on the motorcycle can easily reach and operate the switch cock and measuring pump in his sitting posture on the motorcycle.