You have answered your own commentary:

"Yup. If you’ve just got to eliminate that popping, you’ll have to accept the fact that your motor is going to be forced to run rich to do it, and that isn’t necessarily a good thing."

The >engine< is running lean... the exhaust has unspent gases that are lagging behind due to the decceleration. When the now too lean gases that are hot enter the exhaust pipes they ignite the left over unspent gases. Under acceleration or normal throttle position the new gases are not lean and the rate of flow remains constant or increases.

C#

 

Once again thanks for all the info.
I can live with and sounds like I will have to live with the back fire.
Actually getting use to it and starting to like the pop every now and then.
Just wanted to make sure I'm not doing any damage to the motor.
Still going to get it Dyno ed when I get the funds.
But more to make sure the auto tuner is set right.
If it pops after that I'll live with it.

 

I dont mind the pop its not going to hurt the motor, I find that my motor is burning cleaner also with the pop, no more carbon on my pipes.... I'll take a tuned motor over de-tuned any day.

 

Before you go changing the mix,try running a tank with Redline cleaner,it might be a build up in the in injectors.it cured mine,for $6 its worth a try and will clear out any build ups,ALSO CHECK YOUR PIPES FLANGES TO MAKE SURE THERE ARE TIGHT

 

What kind of tuner are you running? I've got the same pipe as you can see, with a V&H FuelPak. This is from the V&H support FAQ:
Q. My pipe “pops” when coming to a stop, what can I do to eliminate that?


A. The Fuelpak has a function which shuts off the fuel when decelerating. No fuel=no pop. Obviously the Fuelpak has to turn the fuel back on at some point or the engine would die. Not all popping can be eliminated, but this feature does lessen it. Mode 23 controls the rpm where the fuel is turned back on. Try lowering this by one number and see if it helps you. If you have done this and have gotten to 14 or your bike is stalling when coming to a stop, that is all you can do and you will not be able to lessen the popping without changing the pipes or installing quieter baffles. The popping is not harmful, just annoying.

 

Ive been battling this issue ever since i put on V&H true duals and fuel pak on my heritage. While i was at my other place in Colorado I had no issues at all I know i run a little rich up there cause lack of air. I actually called V&H fuelpak tech yesterday to see if he could give me new values to richen up my mixture down here at sea level. He did, before i was going to reprogram I decided to throw a new set of plugs in since the ones I ran in Colorado were a little more black than normal and also had a Pink tint on one side of the porcelin. (FUel additive I think). Anyway I was running stock plugs, went down to the stealer and talked to my pal Mick about my situation, he recommended trying the screamin eagle plugs . I put them without changing my fuelpak , first thing i noticed is how fast the bike fired up, It actually scared the **** out of me. My bike always cranked a time or 2 before firing up. I took an 80 mile ride lots of stop and go and im actually still in denial here but not even ONE pop on decel between shifts or anywhere. I have always been an advocate of using plain ole stock plugs in all my vehicles. As of now im not going to reprogram just ride and see what happens.

 

On my carbed EVO with drag pipes and K&N air cleaner, I had to go up one size on the jets. That eliminated the popping on decel, and also made the bike run much better. I was getting 50 mpg before the change, and now I still get 50 mpg. So from what I am reading, carbs are different than FI, because I did not detune at all. Mine increased performance by going richer and got rid of the popping in the process.

 

Are these the $16 spark plugs? They are as proud of those as the government is of their $16 muffins!

 

Thats right, excess fuel, too much on the rich side. Gas not burned inside muffler on decel eventually explodes with any spark or hot etc and that conditions makes the pop.

 

I'd bet after 4 years, they've figured it out. Hopefully.