You mean gas ported. It's in the piston, not the cylinder.. All engines now produced by YS have the feature, which I introduced them to several years ago. Not my idea, but the first time it was applied to a production model engine.


I have no idea what the problem is with your engine, why not call Richard at service and discuss it with him since they are last to work on it?

My guess is too lean with too much prop, but what do I know?