Patent ID: 7318405

Claim:
An engine for a motorcycle, comprising: a crank case; a cylinder head provided at an upper side of the crank case and having a front face which faces in the same direction as a forward direction of travel of the motorcycle, an exhaust passage outlet in the front face of the cylinder head; an oil pan formed independently of the crank case and attached to a lower surface of the crank case for reserving lubricating oil of the engine therein, the oil pan having a lateral dimension perpendicular to the forward direction of travel of the motorcycle, a shallow portion with a flat lower surface and a concave portion forming a main oil reservoir; the shallow portion having left and right lateral end portions and the concave portion being positioned adjacent to one of the left and right lateral end portions and extending from the one of the left and right lateral end portions to a lateral end portion of the crank case; an oil supply path communicating the oil pan with lubricated positions of the engine; an oil pump drawing the oil from the oil pan and pressure feeding the oil to the lubricated positions via the oil supply path so as to circulate the oil in the oil pan; and an oil filter interposed in the oil supply path and mounted to a front face of the concave portion of the oil pan; wherein a width of the concave portion in the left and right lateral direction is approximately equal to or less than about one half of the entire width of the oil pan in the left and right lateral direction; and wherein the concave portion includes a side surface, the side surface and the lower surface of the shallow portion forming a space for permitting an exhaust pipe to pass through.