A fuel tank cap includes: a cap body which opens and closes a fuel supply port of a fuel tank; a ring member which is disposed around the fuel supply port and is shaped so as to surround the cap body; and a hinge member which is coupled to the ring member to support the cap body in a turnable manner between a closed position and an open position. A first peripheral part of the ring member, which is opposed to an outer periphery of the cap body, has a larger dimension in a circumferential direction than a dimension of a second peripheral part of the hinge member, which is opposed to the outer periphery of the cap body. The ring member and the hinge member are made of mutually different materials.

A fuel cap is constituted to close an upper portion of a tubular member constituting a filler opening of a fuel tank, and wherein the breather mechanism is constituted to discharge vaporized fuel separated by gas-liquid separation in a labyrinth path within the fuel cap through a breather drain hose supported at a side of the fuel tank, the fuel tank further comprising: a plate member fixed to a support member to support the fuel cap to the fuel tank; and a seal member to airtightly communicate an exit of the labyrinth path and an end portion of the breather drain hose when the fuel cap is closed. The breather drain hose connected to a lower side of the seal member is supported by the plate member.

A fuel filling aperture opening and closing device includes a closing member turned to an open position to open a fuel filling aperture by an introduction of a fuel filling nozzle. The closing member is provided with a flap member having a ring-shaped seal member, and an urging device urging the flap member to be positioned at a closed position. The seal member is provided with seal portions respectively inside and outside, and one of the inner and outer seal portions is a plate-shaped portion pressed by the urging against a projection piece bordering an opening edge portion of a pass-through opening of the fuel filling nozzle, and the other of the inner and outer seal portions is formed by an inside circumferential projecting portion and an outside circumferential projecting portion respectively pressed against the flap member.

A closure device for closing a through opening on a vehicle is provided. An interior space with a filling or connection opening being accessible via the through opening, wherein the filling or connection opening is configured and provided for consumable filling on the vehicle, and it being possible for the through opening to be closed by way of a cover element which can be adjusted on the vehicle in a manner which is actuated by external force between at least one closure position for closing the through opening and an open position for opening the through opening. A control electronics system for triggering an adjustment of the cover element being provided with at least one first and second sensor device.

A saddle-type vehicle includes a fuel tank, a tank cap that covers the refueling port provided in the fuel tank in an openable/closable manner, and an operation cable that performs an unlocking operation of the tank cap, wherein the fuel tank includes a first opening and a second opening that extend through the fuel tank, the path member is provided that passes through an interior of the fuel tank and connects the first opening and the second opening, the operation cable is arranged through an interior of the path member, and the operation cable protruding outward from the first opening is connected to the unlocking mechanism for unlocking the tank cap.