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The Twingle Split Single Engine


The twingle engine or split-single engine is a twin cylinder (or more) two-stroke engine more precisely, it has one or more U-tube cylinders that each use a pair of pistons, one in each arm of the U.

source.image: Repairman22

However, both pistons in each pair are used for power and the underside of both supplies fuel air mixture, if crankcase scavenging is used, and they only differ in that one piston works the transfer port to provide the fuel air mixture for use in both cylinders and the other piston works the exhaust port, so that the burnt mixture is exhausted via that cylinder.

In this video we analyze the split single engine also known as Twingle. We will see how it works, why it was invented and why it fell into disuse. Also because it was used by many motorcycle brands.


Unlike the Scuderi both cylinders are connected to the combustion chamber. As neither piston works as a displacer piston at all, this engine has nothing whatsoever to do with the split cycle engine apart from a purely coincidental similarity of the names.