'09 RIII tune out popping in exhaust over run

Into my second year of RIII ownership; love the bike and power delivery, but previous owner removed muffler baffles and bike pops and farts through the 'open' pipes on over run (throttle closed, slowing down) like a Banshee eating a hot curry after a Friday night out on Guinness.

Although I own numerous classic bikes over my 50+ year riding career, I don't do tech well. Now if the bike were carbureted, I'd diagnose fuel mix leanness or even a manifold leak, but all this talk on the forum of electrickery and black boxes playing different tunes has me swivel eyed with a total lack of comprehension.

Can someone explain how to correct this lean condition please. I've always done all my own work on all my bikes but have to admit changing tunes is well beyond me. Key questions are 1) What tune should I use to richen the low end mixture? and 2) Where do I take it to get this tune installed?

Please dumb down your answers to a level that might be understandable to this analog man in a digital world.
Cheers,
Dan Dare in PA

Appreciate the 'thumbs - up' but could someone re-read my post regarding tunes and offer sage words of wisdom.
Took her out for a ride in yesterday's sunshine - first of the year - and the popping and farting out of the exhaust on the overrun is frankly getting to be just too much and spoiling a great bike. No issues on acceleration.

So even if the rocket is tuned correctly it will do this.
A proper exhaust system is what you need. I swapped out for cobra pipes and put in a 5/8 baffle lower db and it is perfect.
Strait pipes are going to pop and fart like that.
Basic point is it's the exhaust not the tune

The bigger the pipe the more air it will suck in and the more fuel the louder the bang.

Once you install free flowing exhaust and intake, she will run lean. @HansO used to be the expert on Rocket 111 tunes. I haven't seen him on the forum for some time. He provided a tune for me with 5% more fuel added which eliminated the popping on my 2012 Roadster. I'd send it to you but it won't work on a pre-Roadster model. Do a search and you will find dozens of posts available fixing the problem. You will need to purchase a Lonelec cable or equivalent. https://www.lonelec.com/product/tune-ecu-kkl-interface-cable-lead You will also need to download (for a fee) Tune ECU for an Android device. Used to be free for Windows but not available now??? Go to the map section and choose a map for your model, year and exhaust config. Not the simplest thing to do if you aren't a bit tech savvy.

You could bring it to a dyno shop and have them fix the problem too.

Great responses everyone and thank you! Now I have something to work with to attempt a fix for the loud popping on the over run. I agree with the lean condition diagnosis. If I give her a whisper of throttle when going downhill where I'd normally have the throttle closed (I live on a hill) the popping significantly de-creases indication too much air in the mix.
I'll take a look at adding baffles in the 3 mufflers and see what that does. I notice there are allen bolts in the muffler end caps for their removal, so assume this is how the previous owner removed them. I'm putting the bike on the lift this week to replace 2 leaky fork seals, so will investigate the exhaust system while it's up there.
As for delving into the mysteries (to me at least) of changing computer tunes, I'm not that man! The suggestion of taking it to a dyno shop makes sense.

Actually you can just fatten the last 6% of throttle opening to get rid of the decel pop. If you go to TnueECU and download the correct tune for whatever exhaust you'll eventually be putting on the machine, you can fiddle the AFR tables to fatten the last bit of throttle and off throttle. I had an 05 Standard that had a nasty decel pop when I put on the TORs exhaust silencers and bought a Tuneboy to correct it. Tuneboy has been surpassed by TuneECU so that would be the way to go today. You'll need a chip enabled cable and an android device (I recommend a tablet since most tablets have a USB-C port and USB to USB-C adapters are fairly cheap). There are free tutorials on YouTube to use TuneECU you can check out to see what all TuneECU does (pretty nifty tool actually). You'll have to purchase a license (last I did it was $25.00) for up to 5 bikes. I use it on 4 of my bikes and my son-in-laws Speed Triple (his I must use my old Tuneboy cable attached to my Galaxy tablet). Good luck and enjoy your learning curve.