Patent attributes
An intake duct structure having an intake path extending forwardly from a cleaner box, penetrating through an area near a head pipe of a vehicle body frame, and opening at a front end portion of a front cowl. During low speed operation of the engine, an intake valve closes a main intake path MR from a front end intake port and opens a sub-intake path SR from a lower portion intake port. On the other hand, during high speed operation of the engine, the intake valve opens the main intake path MR and closes the sub-intake path SR. The lower portion intake port opens forward of a head pipe inside a front cowl and obliquely downwardly toward the rear. With this arrangement, entry of rainwater into the intake path can be minimized during low speed operation of the engine.