2 stroke compression calculator

[hartwill]

Hey guys, I know a lot of you have been trying to figure out your compression ratio instead of static cranking compression. I found this website and it seems pretty simple. Maybe too simple, idk.. let me know If you guys think it's accurate. It says it's specifically for 2 strokes.
http://www.torqsoft.net/compression-ratio.html

[mx91a]

It is accurate but to make the calculation with only the cylinder head volume it will only be accurate for an engine with a flat top piston that is flush with the deck at TDC and is running no head gasket (o-rings). Really that field should be changed to "volume above piston at TDC" or include fields for deck height, head gasket thickness and piston dome volume as these three parameters in addition to head volume are needed to calculate the compression ratio on our engines.

[Skyman]

Ok mx, I was just taken to school. Thanks for the lesson.

[beerock]

and most R pistons I have seen have around 2-5mm to go before flat tot he deck