Ports Revisited

[PaulO]

Recently Ttriton has posted some questions on port types. Although I understand the basics of 2-stroke operation, I do not know what the port types are all about. Does anyone with this knowledge have the time to explain what each type of port is and what it does? Also, I am confused about changing port timing. My assumption is that this involves changing the placement/shape/size of various ports. In general, how is this done accurately and are you only able to enlarge ports?
Thanks,
PaulO

[us1]

The transfer ports are opposite each other; the charge comes in from both sides, hits in the middle and expands outward into the cylinder. The boost ports point up wards and push the charge up in a loop into the combustion chamber and down in front of the exhaust port, hence the name Looper. The exhaust port, well I sure you know what that is. Port timing is changed by raising or lowering a port, widening a port does not change the port timing.

[H2Onut]

GO HERE
Very good explanation with animated 2 cycle motor...

http://w3.one.net/~jschust/animations.html


OR


http://www.keveney.com/twostroke.html