I've been doing a lot of testing, tweaking, and general messing with my tune the last couple weeks. One of my objectives was to get the decel pop as minimal as possible without losing power, at least perceived power as measured by the butt dyno. During my research travels I ran across a piece of advice that at first seemed a no-brainer but, in the end, turned out to be really insightful.

Make sure your throttle is completely closed. Yep, that simple. I found that during normal riding my hand position, or whatever, was holding the throttle slightly, really slightly, cracked. By simply concentrating on holding it fully closed as I come down through the gears I find my decel pop is pretty much non-existent.

That simple, for me anyway. Maybe the rest of you are already doing it right but if you have a bunch of popping, maybe try this a time or two.