Hi

If I am right then that second port is a stratification system port...

its one of the methods use to make clean burn 2-strokes and it was used on the Zenoah engine as fitted to GEBE's in the past.

Im not exactly sure how the system works but I *think* the idea is to dilute the exhaust gases and also to form an air block so the mixture in the crankcase at that point cant vent to air either way - which maybe something to do with the reason why the little Zenoah kicked so far above its weight.

Its just a suspicion. It would help if you had a manufacturer for the motor so research could be done

Jemma xx

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