Mark,
If the engine is still running reliably, then it should be fine. Especially if it has had the RE conversion. I have not had an engine like this one, not even a single cyl Saito until I got this and the FG40. They certainly are a little different to get tuned in and running properly. But they sing nicely when they get going well.
If yours is doing what mine is doing, and what
757jonp is saying, then I believe that you and I are too LEAN on the top end specifically. Normal gasser 2-strokes are simpler on the high end. Tune to max rpm, then lean it out a 8th of turn and you will be as close to good as you can get. With these, it needs to be richer on the high end, or so it would seem. It makes sense given that when I had the Walbro carb on, I tuned it the same way I would a 2-stroke and it was running perfectly on the ground....getting 6500rpm and singing nicely.... then, on take off, as it gained momentum, the prop unloaded to about 7200rpm and as it lifted off, it leaned out and died.....plane was trashed, and the only thing I lost was the Keleo...so they need more fuel when they unload...