Hi Proud USAF Dad,Actually, the popping was always there, you just couldn't hear it with the stock pipes.
Classic is absolutely right. The stock pipes hid the sound underneath all the good baffling and Cat converter. The spark plug colour will be the quick way to answer your main question. If you are not planning to add PCIII (or similar) and modify the air intake to increase air flow then just the pipes on their own are fine. Some find their bikes are running very slightly lean in this situation. Ride safe.