I have a flstn 2008 and installed V&H big shots + screaming eagle airfilter, also purchased a screaming eagle super tuner pro. My dealer installed the pipes and filter and as he said he tuned my ECU using the tuner for high air flow. I have a lot of backfiring on decceleration and the engine goes very hot

Did my dealer lie about tuning my ECU properly??
Hi Lebowski
A download from a fueler for a specific set of running conditions is not always spot-on.
A motorcycle's injection system responds according to ambient temperature, air pressure etc etc...
Therefore if the bike is run from the UK (colder ambient) to lets say Cyprus (hotter ambient) you would expect to "fine tune" the fueler for the specific set of running conditions.
The ECU and fueler cannot tolerate 100% these climate changes.
So H-D or any other fueler would load the maps on the web/fueler systems on an average set of values.
Thats why our friends correctly advice dyno test runs for fine tuning.
You should not believe that your dealer fooled or lied to you as they have been professionally set for many years and have done this sort of mods with no problems whatsoever and believe me i know.
The small market does not tolerate the dealer to fool or lie to you as word to mouth spreads lightning fast and would cause problems.
The specific dealer is also dealing with Ducati and Polaris ATV and has dealt with numerous mods and alterations.
Unfortunately the dealer is not equipped with a Dyno since the market is small to compensate the investment but they have partners that deal exclusively with Dynos.
However, the SST pro is capable of decreasing/increasing various values to fine tune the system and this is done through professional Harley-Davidson University (HDU) training.
Why don't you visit the dealer to do so and in case this is not fixed they would arrange a dyno to see which values are sensitive to cause backfires.
Thanks for your attention