hi bought a 2nd hand dyna fatbob and was hoping someone can answer a question the bike is a 2009 has vance and hine short shots thunder monster baffles hd heavy air breather and vance and hines fuel pak the bike runs good but a bit of popping on deceleration.I noticed the O2 sensors are in the pipes do most guys keep them connected or do they remove them when they put a fuel controller on?Looked at the plugs and look a little on the lean side to me.thanks for the help

 

Unless you use some type of mod that requires the o2 delete, then they "must" stay on the bike. The o2 sensors are not causing your problem. Most likely the tune is.

 

from OP: "... bought a 2nd hand dyna fatbob and the bike runs good but a bit of popping on deceleration."

You picked a great bike - congrats! One thing you might look at are the header pipe flange nuts. If they haven't been snugged up in a while there could be some leakage causing the popping you are hearing - only takes a minute to check and doesn't cost you anything. Hope you get it worked out.
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short shots are known for popping. I've never had a fuel pak so I don't know how it works with O2 sensors or not. You should give vance and hines a call to find out. Alternately FuelMotoUsa offers 100 to 150 cashback for trading in any fuel tuner. Best bet give them a call they will get you on with someone and you might even get your answer about the fuel pak from them.

 

There is a mode on the fuel pack that deals with fuel cut off. I cant recall what one though. I think its in the 20s. I want to say like 23. My old bike I had set to like 16 on the stock map and dropped it to 14 and took the pop out. Email V&H about it and they will tell you what to change. It's simply decel pop that can be fixed with a few settings.

 

If the plugs look on the lean side, you might consider a set of xieds from nightrider.com. You can see the mods done to my bike in my signature and I still get a little popping on decel. I kinda like a little popping on decel, it sounds cool

 

fuel pack is a v&h product too use on their pipes. they don't like to mixed with other pipes, some after market units are adjustable , try a you tube search, FOR top performance and tuneabillity you need some thing like a dyno jet that your maps can be tunned for indavigull bikes... Back fireing can be a bit removed by running a bit rich,, Most causes are air leaks at muffler joins/exhaust flange,, ads too character,