power commander tuning

[ultra05]

I have a 05 ultra, 95 inch motor, tw26 gear drive. My power commander is not quite right. I have had too 2 tuners but still doing same thing. spark plugs are running even front to rear and color is good. Bike will accelerate and run down the road ok but on deceleration while down shifting will back fire quite a bit. is this something i can fine tune myself or not. I am not sure if problem is fuel or timing. any information would be appreciated. thank you in advance

[hdtuner23]

0% column, 2000 Thur 6000rpm add 10 to values, also adding 1-3 pts. ign. will help if that doesn't work.

[FLTRI]

0% column, 2000 Thur 6000rpm add 10 to values, also adding 1-3 pts. ign. will help if that doesn't work.

Sometimes as little as 5% will do the trick. Also the type of exhaust system plays an effective part in the decel backfire issue.
The most challenging system, for whatever reason(s) is the original "Y" pipe with SE-type mufflers.