A two-stroke internal combustion engine is disclosed having opposed cylinders, each cylinder having a pair of opposed pistons, with all the pistons connected to a common central crankshaft. The inboard pistons of each cylinder are connected to the crankshaft with pushrods and the outboard pistons are connected to the crankshaft with pullrods. Each opposed cylinder further comprises an integrated scavenge pump for providing positive intake pressure. This configuration results in a compact engine with a very low profile, in which the free mass forces can be substantially balanced. The engine configuration also allows for asymmetrical timing of the intake and exhaust ports through angular positioning of the journals on the crankshaft. |