Have a 2010 Fat Boy Special with Stage 1, i.e. the engines is mapped for the louder more open exhaust I currently use.

I wish to revert the stock exhaust, however, well aware that this will affect engine performance but do I need to worry about engine damage?

 

Damage, no. Your bike will just run a bit rich...

 

Well , if your gonna reinstall catalytic converters extra fuel may foul them. That's what clogs a lot of cats. A bad plug can cause cats to plug/foul quickly

 

It will run fine if it runs fine now. My 04 had open duel Pythons on it. The Harley ECM was mapped to adjust since it is closed loop with no oxygen sensors. I put a brand new takeoffs from a 96 CI Night train. It runs fine. You cannot even really tell any difference in the plugs. The Harley set is from the open exhaust. Both set have 10 K on them. The rusted ones are from a freak ice storm I got caught in down South and they thru salt and sand all over everything. Bottom end is way better since the Pythons did not have a cross over and engine braking sucked. I never run top end and all that noise sucked.

 

Just go back where you had it tuned in the first place and have them make the adjustments. If you have no other modifications, you'll want the stock map, and then the VE's readjusted. They should be able to take care of you.

 

Thanks blackscootersociaty! Dont't know where it was done and didn't get the tuner kit when buying second hand from a dealer unfortunately. He said previous owner didn't provide it...

 

Thanks RIPSAW! Yes - the bike's doing great, a bit less power but hardly noticeable. I've been doing some 5.000 km with the stock pipes and may never return to the loud ones - had enough of the noice. Someone told me engine may not like it in the long run.

 

Mine has not complained for 30,000 miles. Runs like it always has. Now at close to 50K. People say all kinds of BS. I never WOT mine, so I have never noticed any power difference.

 

Kind of at a loss somewhat because it seems uncommon to go back to the stock(ish) tune. If you were only running pipes, it may not even be tuned at all really. I'm not saying it isn't, just that sometimes guys throw slip ons on and don't get a tune. Even if it was, it is just richened up a little bit all across the fuel maps, which isn't really going to hurt anything. It might soot up your pipes a little tiny bit. That's about it. Put some miles on with the stock pipes and check your fuel mileage and it will tell you if your in the ballpark of where you should be.

 

If your bike has a dealer-installed stage 1 tune another dealer should be able to undo it. There is probably no added tuning device.