RE: 4 stroke Ryobi
I have most of the four-strokes available and the Ryobi is at the bottom of MY list as it is bulky and heavy for its displacement and the power is low. A buddy told me of a guy who made new cams and that helped the power, but that is a lot of work. The Ryobis can be had for cheap though! ( I got mine for $5, never run)
J