Well, you have a choice: you can put one plug into the air hose on the right side of the engine, or two plugs in your ears.
There is an air induction hose on the top / right of the engine that draws air into the exhaust and that is what is causing the decel popping. Some folks pull the hose out of the frame (nothing retains or fastens it in there), plug it with something and reinsert it. If you do that though, be careful that the plug cannot work loose from the hose because it will end up inside the frame and will probably end up being sucked down one of the throttle bodies.
Brian
Before the site crash, I seem to remember a thread saying to plug or remove something to correct this. Could someone please refresh my memory? Thank You in advance.