Schneurle porting

Schneurle porting is a system to improve efficiency on a two-stroke engine. The intake and exhaust ports are cut in the cylinder to make the most efficient exchange of intake and exhaust gases during running.

Non-Schneurle ported engines had a baffle on the top of the piston to make the intake charge move up and across the cylinder to help drive out the exhaust gases. Schneurle porting eliminates the baffle by using angled ports and creative timing to have the intake charge do a better job of getting rid of the spent exhaust gases, a process called "scavenging".

It is named after the late Anton Schneurle of Germany.