Hey guys, I know this is an old thread, but I've read the whole thing and I'm superb excited to get going with my project. Thanks to everyone who has contributed, and laid down the ground work for those of us who wish to try to push the little Ryobi even farther.
What I have is a new style head (with 2 transfer ports), new style piston (with 2 rings), and new style I-beam rod. I will do the modifications that this thread has proven to be real performers: remove base gasket (I've also notched and bevelled my piston for piston clearance and to keep port timings stock which is good on the transfer port side), port exhaust to 150 degress, bend reed cage to 1/8", 11.1mm carb, after market box type exhaust with two big stingers (I think it's made by Bennet, but dont remember for sure), stuff the crank, and add electronic ignition. I will start here and run a gallon of fuel through it, then fine tune the carb. This will be my base line starting test. I live at over 5000 feet asl, so my numbers may not seem that impressive. I will use an apc prop and find which one keeps me at 7500 ish rpm's.
My goal will be to see what the biggest apc prop I can get this Ryobi to spin at 7500 rpm's. The next set of mods I want to throw at the Ryobi are: gas/glow fuel (even though it will still be ignited by ei), Boyesen two stage carbon fiber reed, and a tuned pipe. I will do these mods one at a time then test and post the results.
A few other things worth mentioning, the engine is practically brand new. I bought it new as a weed eater and got a dozen uses out of it before the plastic pull starter teeth stripped, had it fixed, then about half dozen uses later.... Yep plastic teeth stripped again. that's when I decided this was now going to be my next airplane engine. Also, the aircraft being graced by the Ryobi is a 30cc Gee Bee R3.
Thanks again to all the previous posters, i hope I can do this thread justice and take this Ryobi to the next level.