A valve includes a flap, a tubular valve body defining a passageway, and a guiding device to guide the flap relative to the valve body for pivoting the flap relative to the valve body about a pivot axis between a closed position and an open position of the passageway. The guiding device comprises a pin traversed by the pivot axis and comprising a body with a base and, opposite the base, a free end resting against the valve body. The pin also comprises two lugs each protruding from the base in a direction opposite to the free end, the two lugs defining between them a slot, wherein an edge of the flap is received. The valve further comprises at least one member, connected to the flap, and which presses one of the lugs of the pin against the flap.