Just keep your Ryobi under 8000RPM on the ground and you should be fine for many many years of service. I don't know if anyone is running them at 8000RPM+ over the long haul, but I know they will run forever at 7500RPM.

Bump the compression, add a better set of rings to it, increase the exhaust duration, replace the stock muffler, bend the reed stop out and add a bigger carb-- and you'll need more prop. These engines respond very well to "tuning".

Just be aware, they don't hold up long when you push them past 8800RPM. Did that last summer. It was spectacular. Ran like a scalded cat for about 2hrs run time. Then it pretty much exploded. [sm=lol.gif] It was hilarious. Most fun I've ever had in the hobby. I don't know why, but myself and a friend have a sick enough sense of humor that we blew one up last summer and it was good for at least 15 minutes worth of gut laughing. They are cheap engines. They run good in stock configuration. They start running GREAT when you get one of them around some carbide bits, polishing wheels and a lathe. Modifying and runnning one of them to the point of failure was quite an education, as well as hours of enjoyment. I'm no engine guru, but I do love tinkering with engines. I actually had no idea one of these would run as good as it did when we finished cutting and grinding on it. It was quite a surprise.