This may sound silly but I can't figure this out. I'm sure I have no exhaust leaks since I just replaced a cracked pipe. I now have some serious decel backfire and have been told the cooler damp weather and running too lean can cause this. Before the weather change I did not have this problem so running too lean seems strange. Any ideas?

 

My 2000 has the same FI system as yours. With slip-ons and the SE Stage I, it backfired on decel. Blue flames would shoot out. The plugs always looked good, not like it was too lean. I rode it for 54k miles like this, then swapped on True Duals. That was the end of my decel backfiring.

 

I have true duals, high flow AC and had the remaping done at the same time. Off and on I had backfiring problems but associated to exhaust leaks, when fixed no back fire. No real issues until resently. I all so have a cobra tuner but I'm not happy with it since I don't actually notice any difference when I adjust the settings (it may not be working properly) but the bike did not back fire until this past couple of weeks when the weather changed. I'll be taking off the tuner to see if that helps since it should be reset to original mapping.