backfires on deceleration

[biscuit]

My 07 FXST only has SEII slipons and has been retuned by the dealer but crackles and pops on decel constantly. Never had this problem before with any other HD I've owned. My 03 Ultra had a stage 1 upgrade and never a problem.

Don't know where to go from here. These new engines have all sorts of sensors and valves everywhere. I'm thinking of installing V&H bigshots to get my traditional HD sound back.

Chips,my brother has a 2008 Fatboy and he put Rush slip-ons on it.From that point on the bike popped and banged and in general sounded like a machine gun on ANY deceleration.Im talking just backed off to slam-that-throttle-shut type of off.The QLD dealer said and i quote"They all do that".What a crock;the bike wasn't worth a pinch.
We put a Thundermax with autotune on it and INSTANT transformation.It idled,started,ran so much better.A TFI (available from motohansa in Sydney1300 557 889)might well do that also,but at this stage i have no experience of them.

Like a different bike.He loves it!His fuel economy has suffered a bit,but he rides it harder because it runs so much better.

 

[larryb]

The commonality I see here is NOT having a fuel/air management system in place on the EFI's. If you change the amount of air in/air out, you need a system. If you're going with a V&H setup then I would suggest a fuel pak that is adjustable to remove a decel pop. Thunder Max is highly touted but it cost a bit more. I'm running a Super SERT on my SERG, keeps all HD. several others on the market, Power Commander.
If you have 02 sensors and Cat Conv, then you are in a closed loop from 2k-4k and you cannot adjust beyond factory specs but over and under not a healthy situation for your bike without a tuning system.
I removed my stock baffles and replaced with Fullsac 2" ones, drilled out the Cat Conv and added the race Tuner. No pop, only butter. more HP and TQ than I need.

 

[sssmdg]

I had pipes, intake and mapper put on my 08 train and they dynoed it as well, about 100 miles down the road the same things was happening to me. I took her back and they found that the intake gasket was well not correct. They did something and no more issues.