I had the same problem on my Glide. Check for leaks, and I had none. Installed the PCiii software in my laptop, and zeroed out the throttle, that helped a bit. Then I called Fuel Moto, and Keith suggested I add some fuel to the zero column (15). That fixed almost all of it except at 2000 RPM. I am tuning that out now.

 

+1 on adding more fuel at zero throttle setting. I bumped mine (PCV on 09 SG) up to 10 from 3,000 down to 1,000 RPM. Popping on decel is gone.

 

+1 on what Dawg said: checking for leaks. A loose muffler clamp or loose flange nuts are a sure way to get a case of decel pop. If mufflers have been on and off several times, it might be time for new muffler clamps.