Abstract: A multi-cylinder reciprocating piston internal combustion engine, preferably operating on the two-stroke cycle, having a cylinder block 8 incorporating a bank of cylinders 10 each communicating with a crankcase 15. Each cylinder having inlet ports 20,21,22,29,30 located on each of the two opposite sides of the bank of cylinders 10, and a conduit 17 communicating at least one port on one side of the bank with at least one port on the opposite side of the bank. That conduit 17 extends through a crankshaft bearing support portion 14a of the cylinder block 8 located within said crankcase 15 below the level of the cylinders 10. There is preferably one bearing support portion 14a within the crankcase 15 and below the junction between each two adjacent cylinders 10, with a respective conduit 17 extending through said bearing support portion 14a.