How is this engine set up? Is it bone stock?

The key to ryobi performane seems to be

1. As good of a ring to cylinder seal as you can get. How much ring gap do you have? one ring two rings? what is the cylinder condition. May i suggest building a leak down testor to test this. It is the only way you know for sure what you have for a seal.

2. get as much of a compression ratio as possible. This is acomplished by reducing cylinder base gasket thickness or removing it altogether. if you do this make sure you measure as some engines will hit piston to head is you take it out completley. mine would hit so i used a .010 thick gasket instead of the .030 thick gasket. Power gain from this isnt extreme but should yeild 80 - 100 rpm.

3. As free flowing muffler as possible. An expensive aftermarket muffler isnt neccasary although they look nice and are much lighter. many guys on here have had good luck gutting out a stock one and welding in a half inch emt tube for the outlet and this will be more than adequate.

4. A much larger than stock carburetor. the stock carb venturi is about 7.5 mm. you want one that is 11.1 to 12.7 mm.

These from the testing I have done seem to be THEmost important factors in getting this engine to run good. I have tried many of the other mods suggested and have no power gain yeild from them when done on a test bench.

Depending on what cylinder you have you may benifit from increasing the exhaust port timming to about 105 degrees. the cylinders that seem to benifit fron this mod is the newer style cylinder with two transfer ports per side.

Also how did you set up your ignition. Did you use a degree wheel? did you make sure you had tru tdc set on your degree wheel?