Split-single engine

As a consequence, a split-single engine can deliver better economy, and may run better at small throttle openings.

Early engines using a "side-by-side" layout (with the carburetor in the "normal" place behind the cylinder) had similar lubrication and pollution problems to conventional two-stroke engines of the era, however the revised designs after World War II addressed these problems.

[6] The "fore-and-aft" layout of the cylinders means that the V-shaped connecting rod has to flex slightly with each revolution.

Italian engineer Giovanni Marcellino arrived at the main factory of Puch with the instruction to wind up operations.

Instead of liquidating the factory, he settled in the town and designed and began production of a new split-single engine which debuted in the 1923 Puch LM racing motorcycle.

[13] In 1935, the Monaco-Trossi Grand Prix car was built with a 16-cylinder radial engine using a split-cylinder design.

[15] The 1953-1969 Puch 250 SGS (sold in the United States by Sears as the "Allstate 250" or "Twingle") used with an improved system of one connecting rod hinged on the back of the other.

[16] Increasingly, these models were fitted with an oil mixing pump, fed from a reservoir incorporated in the petrol tank.

[20] The Italian manufacturer began producing a 236 cc (14 cu in) split-single engine in 1952 for their Iso Moto motorcycle.

[21] Triumph-Werke Nürnberg (TWN) in Germany continued production of a split-single engines for their motorcycles in 1946, but not with asymmetric port timing as the pre-war BD 250.

[1] The bulbous shape of the exhaust of the Cornet and Boss is an anti-noise two-stroke TWN feature.