A motorcycle includes a frame, a front wheel, a rear wheel, an engine and a plenum.
The rotational axes of the front and rear wheels define a first plane that is perpendicular
to a second plane. The engine includes an air intake port and an exhaust port.
A first pipe transmits air from the plenum to the air intake port and has a first
longitudinal section. A second pipe receives exhaust from the exhaust port and
has a second longitudinal section. The first and second longitudinal sections have
substantially identical cross sectional configurations and are located on opposite
sides of the second plane such that they are, at corresponding longitudinal locations,
substantially equally spaced from the second plane. Also, the first and second
longitudinal sections are located such that they are, at corresponding longitudinal
locations, substantially equally spaced with respect to the first plane.