Hi Rcpilet
Did you open the engine up to confirm the ring all worn out or just lost compression? From what you describe, carbon and stuff can stick the ring and prevent the ring to expand to give a good seal, that is one of the failure of engine. Maybe between cheap oil and extra oil, after 550 hours will do it. BUT BUT BUT!!! The most important, you got 550 hours out of a Ryobi, a single ring cheap engine. I don't exactly call this bad at all. Thanks I hope more people can put in their experience.

BTW how are the ball bearings?

Thanks

I am curious how big a difference is pure synthetic oil compare to just any JASO FC or FD. I am using Echo Power Blend which is JASO FD. I am just playing it safe, not using the cheapest but cheap JASO FD. Echo is about as cheap as it get for the JASO FD.