Crankcase compression in 2 stroke engines.

[Kasey]

Does anyone know what the minimum compression ratio for crankcase compression is for a 2 stroke engine, to start/run adequately ? ie 1:1 or would 1:2 or even lower be adequate?

 

[lohring]

With tuned pipe engines, the pipe provides most of the pumping action. One of the best two strokes, the Aprilia 125, had a 1.2 crankcase compression ratio. Industrial engines like the Zenoah 260 run higher ratios closer to 1.4 or 1.5.

Lohring Miller