Abstract: A porting and scavenging system for a two-cycle internal combustion engine that permits a more compact arrangement. The engine employs scavenging passages that lie on opposite sides of a plane passing through the cylinder axis and the center of the exhaust ports. These scavenging passages are arcuate in cross-sections perpendicular to the cylinder axis and their centers lie on the plane but are offset from the cylinder axis to the side opposite the exhaust ports. In addition, the scavenge passages extend at an angle to the cylinder axis so that their outlets into the cylinders disposed further from the exhaust ports than their inlets from the crankcase. This arrangement not only improves compactness but significantly improves scavenging.