Exhaust device in combustion engine, and motorcycle therewith

An exhaust device for adjusting an exhaust gas cross sectional area of an exhaust passage communicating with an exhaust port of a combustion engine, the exhaust device comprising:

• an exhaust pipe forming the exhaust passage;
• a valve body arranged in the exhaust passage;
• a valve shaft fixed or integrally formed to the valve body and arranged so as to extend across the exhaust passage, the valve shaft changing the opening of the valve body by rotating with the valve body about an axis of the valve shaft;
• a pair of bearing members for rotatably supporting the valve shaft at both ends thereof in an axial direction of the valve shaft, each of the bearing members having an end face facing in the axial direction of the valve shaft, and each end face being on a side of the bearing member closest to the exhaust passage;
• and
• a pair of stoppers arranged on the valve shaft so as to face the end faces of the bearing members, respectively, the stoppers being restricted in the axial direction by the end face of each of the bearing members so that the valve body and the valve shaft do not move in the axial direction,
• wherein at least one of the bearing members is composed of an aggregate and a flexible graphite member, the aggregate having a knitted mesh form of fine wires of stainless steel, and the flexible graphite member being filled into the aggregate at high pressure so as to surround the aggregate, and
• wherein the valve body and the valve shaft are installed in the exhaust pipe such that the stoppers contact the end faces of the bearing members, respectively, at a constant pressure.