Cover structure for the transmission of a motorcycle

A cover structure (1) for a motorcycle transmission, arranged sideways to protect a transmission member transmitting a driving force from an engine to a rear wheel, comprising:

• a first cover member (2) configured to protect said transmission members, longitudinally extending along a direction which coincides with a direction of travel (F), from a receding front area (4), corresponding to an engine axis, to a rear area (13) corresponding to a driven axis of the rear wheel, and comprising an inlet hole (6) positioned at an inlet port of the transmission at said receding front area (4);
• a second cover member (3) partially overlapping said receding front area (4) to protect said inlet hole (6), forming, with the said first cover member (2), an air intake (19) at a portion of the receding front area left uncovered by said second cover member (3), extending from an upper edge to a lower edge of the first cover member (2) and defining an air inlet section facing said rear area (13), oriented in a direction opposite to the motorcycle direction of travel (F);
• a baffle (20), disposed between the first and the second cover members (2, 3) at said air intake (19), in such a way as to form a channel driving air upwardly to said inlet hole (6);
• and
• a base plate (5) arranged between the first and second cover members (2, 3), said base plate (5) having an opening corresponding to the inlet hole (6) and sealed to the first cover member (2),
• wherein the base plate (5) has a groove (33) contouring said inlet hole (6) and providing an airtight seat for an edge wall (23) perpendicularly projecting from an inner face of said second cover member (3) and partially contouring the inlet hole (6) having a closed curved profile, to form an annular space within a space between the base plate (5) and the second cover member (3).