Abstract: In an air cleaner, an air cleaner case having an upper opening which opens upward is formed. The air cleaner case is formed of a front wall, a rear fender, and right and left side covers. The upper opening is closed by a seat. A sound absorbing member is bonded to a bottom plate of the seat and housed in an air cleaner space. The intake noise in the air cleaner is absorbed by the sound absorbing member.

Abstract: In an air cleaner, an air cleaner case having an upper opening which opens upward is formed. The air cleaner case is formed of a front wall, a rear fender, and right and left side covers. The upper opening is closed by a seat. A sound absorbing member is bonded to a bottom plate of the seat and housed in an air cleaner space. The intake noise in the air cleaner is absorbed by the sound absorbing member.

Abstract: A muffler of a motorcycle having an outside diameter greater than the outside diameter d1 of a rectilinear portion of a branch pipe is disposed at a transverse portion of an exhaust pipe. Since the muffler is formed to be roughly elliptic in sectional shape, the outside diameter of the muffler is represented by a major diameter da as the length in the direction of a major axis and a major diameter db as the length in the direction of a minor axis. When the muffler is disposed between a swing arm and a seat to be along the transverse portion of the exhaust pipe, the muffler can be disposed on the more vehicle front side while securing the capacity thereof. Therefore, protrusion of the muffler toward the rear of the vehicle is suppressed, and the external appearance of a vehicle rear portion is enhanced.

Abstract: An exhaust system for an engine includes an exhaust pipe connected to an exhaust port of an engine and a muffler attached to the exhaust pipe and configured to reduce exhaust noise. The muffler includes an inner cylinder part connected to the downstream end of the exhaust pipe, an outer cylinder part configured to cover an outside of the inner cylinder part and noise absorbing materials disposed between the inner cylinder part and the outer cylinder part. A plurality of first communication holes providing communication between an inside and an outside of the inner cylinder part is formed in an upstream portion of the inner cylinder part. A plurality of second communication holes providing communication between the inside and the outside of the inner cylinder part is formed in a downstream portion of the inner cylinder part. Guide walls extend toward the inside of the inner cylinder part.

Abstract: A muffler of a motorcycle having an outside diameter greater than the outside diameter d1 of a rectilinear portion of a branch pipe is disposed at a transverse portion of an exhaust pipe. Since the muffler is formed to be roughly elliptic in sectional shape, the outside diameter of the muffler is represented by a major diameter da as the length in the direction of a major axis and a major diameter db as the length in the direction of a minor axis. When the muffler is disposed between a swing arm and a seat to be along the transverse portion of the exhaust pipe, the muffler can be disposed on the more vehicle front side while securing the capacity thereof. Therefore, protrusion of the muffler toward the rear of the vehicle is suppressed, and the external appearance of a vehicle rear portion is enhanced.