I have a 2008 Fat Bob with Standard UK silencer pipes. I want to fit silencers that give a more traditional throaty sound but have been told the bike would need retuning as it is a petrol injection. Is retuning required and what is the downside if any, if this is not done. Thanks. Roy

 

Generally speaking, you don't have to retune if you've only replaced the pipes. I got a bit of surging when I installed my Cycle Shacks, but I'm put on a pair of O2 IEDs and am pretty happy with them.

 

Roy,if you are just changing pipes a lot of forum members are running ied/xied wires & report no problems,with just a pipe-a/c change.Hope this helps,i'm not an expert,I have Xied's on my bike,which is standard, & I think they work great.
Graham