Are you talking BACKFIRE, or popping here and there on hard deceleration? Here’s what Brian at Fuel Moto told me when I called with same symptoms, stronger smell of fuel, and popping even after auto tuning their custom map for my application. Bike runs strong. He said “the smell is noticeable because the bike isn’t running lean anymore. You’re used to not smelling anything, and now that the bike is running richer, you’ll smell fuel”. So after that, I started looking, and to the man, bikes which have aftermarket tuners smell like they run rich compared to stock setups. Walk behind a bike that smells like it runs rich, and ask the owner if he’s got a tuner. Brian also told me the popping is there, just not as noticeable with stock set-up. There are ways to decrease it from happening, but you’re not going to eliminate it completely. It seems more noticeable when you change pipes because the aftermarket pipes aren’t as baffled. I guess it depends on how bad yours is popping, and just how rich it’s running. If you have actual backfiring, then like you said, you need to take another look. What tuner are you running?