I just talked to the mechanic at the nearest HD shop, an old friend of mine, and he says just changing the pipes does not require re mapping unless you do an intake upgrade also. He recommends the remap but says it's not required for just a pipe change.

 

Hi to everyone! Another question in the same topic for you guys.....I do have a 2004 FXST EFI down here in Brazil with stock pipes (the exhausts) but I cutter the mufflers at the end taking all the inside parts of mufflers. Giving a big pipe role looking! I do have K&N air cleaner on, 10mm spark plugs cable (scream eagles), Platinum spark plugs (scream eagles) and the engine looks to run as was before. Reading the friend's question, I was wondering that I will have any problem to run the bike like this. Please, all comments will be welcome! Thanks.