That is a fair question Shawn and I do not have a complete answer for you, other than the metering leaver seems to change with the different props I'm using.

When I first started the DL50 it was burbling a lot, and also had a lot of misfires, could not tune them out, so I did the adjustment of the metering leaver and got most of the burbling and misfires out. Depending on the weather it still burbled a little on some days. The metering adjustment was done with a 23x8 Xoar Sword and still in the break in phase.

A couple of weeks ago I had a bad landing I stalled it on approach and the Pitts fell out of the sky. I spread the gear on my Pitts and had a prop strike and cracked the Xoar 23x8 prop. So I reverted back to my break in prop a Xoar 22x8 Sword, to my surprise the engine is burbling again in the mid range, although not as bad as it stared out, believe it or not it was worse at the beginning. I have not yet friged again with the metering leaver, it was a pain in the butt the first time.

I have attempted to tune the needles on several occasions, but cannot get the burbling out with the 22x8, you can hear it burbling, gurgling and farting in this short clip of my Pitts in knife-edge at a 1/4 to 1/3 throttle with the 22x8 Xoar. Also in the video my exhaust pipe had fallen off the muffler, so it may also have something to do with all the burbling.

The power is great and it has never flamed out, but like you, I think it would be nice to have our cake and eat too.

http://www.youtube.com/watch?v=QLWrG0ZPCjo

Geppino