Two Stroke Evolution

In case you believe that spaghetti grows on trees, or that the Japanese invented the two stroke engine, here's a few facts to set the record straight.

The two cycle engine was developed by Sir Dugald Clark in 1878.  The first patented two-stroke engine was a vertical twin by Alfred Scoff in 1904. Scott also developed a rotary valve engine in 1912. The Schnuerle ported engine was patented in 1925 and featured two bypass ports (loop scavenging method). In 1957 Walter Kaaden (MZ, E, Germany) added a third transfer port opposite the exhaust port.

Erns Degner defected from East Germany to join Suzuki. In the 60's Suzuki and Yamaha won the World Championship using exotic porting and rotary valve developed by DKW and MZ.

Bill Wisniewsk (my countryman) applied the principle of three port, or Schnuerle porting, to a miniature engine and won the 1964 FAI world speed championship.

Yamaha added a pair of auxiliary transfer ports along side the main transfer ports. Dr. Hans added a pair of small auxiliary exhaust ports at the side of the main exhaust port.

In the 1980's the Society of Automotive Engineers began to publish the works of Dr. Gordon P. Blair on two cycle engine technology.

In 1991 the first computer aided two stroke engine design programs, perfected by Tom Turner of TSR. became available to the public.

In 1992 George J Grabowski, contributing editor to Personal Watercraft Illustrated, began publishing technical articles which brought watercraft from the dark ages and ended an era of secrecy surrounding two stroke engine modifications.

George Grabowski HPT Sports USA

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