Patent ID: 8033357
Filing Date: 2011-10-11
Classification: F01N

Abstract:
1. An exhaust system for a motorcycle having a frame, front and rear wheels operatively supported on the frame, a vehicle body operatively supported on the frame, and an engine operatively supported on the frame and arranged between said front and rear wheels, the engine having exhaust ports formed therein and connected to respective exhaust pipes extending respectively therefrom for emitting exhaust gas outside the engine via a silencer operatively connected to the exhaust pipes, said exhaust system comprising: a first muffler chamber situated between the engine and the rear wheel at a position below the engine, wherein said exhaust pipes extending from the exhaust ports of the engine converge in the first muffler chamber; and the exhaust gas from the engine flows into the first muffler chamber via said exhaust pipes; a second muffler chamber arranged substantially parallel to the first muffler chamber in a vehicle width direction at a position below the engine, including a partition plate that divides the second muffler chamber into a front chamber and a rear chamber, and a communication pipe that pierces the partition plate to allow for airflow communication between the front and rear chamber; a joining pipe extending from a rear portion of the first muffler chamber to the rear chamber of the second muffler chamber; and the silencer situated in rear chamber of the second muffler chamber and extending in a longitudinal direction of a vehicle body with a front end thereof piercing the partition plate and extending into the front chamber of the second muffler chamber, wherein the exhaust gas from the second muffler chamber flows into the silencer, and the exhaust gas is emitted outside the engine via the silencer wherein: the exhaust gas from the first muffler chamber flows through the joining pipe into the second muffler chamber in the vehicle width direction; the second muffler chamber is configured and arranged such that the exhaust gas received in the second muffler chamber flows in a forward direction therein substantially along the longitudinal direction of the vehicle body, is then turned back in the longitudinal direction of the second muffler chamber at a front inside portion thereof, and then flows rearwardly in the longitudinal direction of the vehicle body; the silencer is configured and arranged such that the exhaust gas which flows rearwardly in second muffler chamber is received by said silencer in the longitudinal direction at a front portion thereof; and the exhaust gas is emitted outside the exhaust system from a rear portion of the silencer; and a front end of the second muffler is disposed forward of a front end of the first muffler and a rear end of the second muffler is disposed rearward of a rear end of the first muffler.