Abstract: An improvement for use on a V-type two-cycle engine having two rows cylinders with air intake passages aligned generally symmetrically on either side of an engine crankshaft is disclosed wherein the attachment of the air intake passages to the engine crankcase is rigidified so as to suppress the vibrations generated by the air intake system. This structural interconnection can take the integrally forming the intake passages with the crankcase, securing the between the cylinder rows end a support member formed integral with the crankcase and/or supporting the intake passages to the crankcase at their upstream ends through an air intake box. In addition, the air intake passages may be integrally formed with bearing supports for the engine crankshaft to enable the crankcase to be formed from more than one piece which can be readily detached for inspection and maintenance purposes.