13 SG. Initially kept stock head pipes and went with Rush Big Louie with 3 in. Baffles. Enjoyed the sound and performance, did not like the heat, and wanted more performance and even better sound. Went with Rush True Duals, stage 1 with SE air, tuner and 2 in baffles in the Big Louie. Like the performance, sound is Ok but a little loud and a bit tinny. Don't really like it. Thinking of putting the stock mufflers back on with the Rush True Duals. Stupid idea? Will I need to retune or should I be Ok to install and ride?

 

Any time airflow through the motor is changed, your bike will benefit from proper tuning.

 

I had the Rush TD's for two seasons. Tried numerous mufflers, all 6 pairs were loud as hell and tinny. Went to a Fullsac DX pipe and with 1.75" baffles it is basically stock sounding, a little deeper perhaps. It's the True Duals shooting you in the foot.

 

You can have your stock pipes modifed by American Custom to accept adjustable baffles.
You can then easily change the sound from stock to loud per your preference.

 

no need to retune ride and enjoy,

 

look for some stepped duals with a core placement option.
These will offer the best performance for a dual set up and depending on the system will sound great.
I like hacker custom exhaust for these.
Lump

 

Doesn't the stock left muffler have some kind of restriction in it? I only ask because I seem to remember getting less exhaust flow from the left side while idling when I had stock exhaust. I have Jackpots now and I'm pretty sure the left side is restricted because the opening at the rear of the muffler is a fair amount smaller than the right.

Something to do with 2 into 1 into 2? Just curious.

 

I can't speak of anything other than my 04 rk. There is no left pipe restriction that I've found, and I've had the entire exhaust off and apart. The front cylinder goes to the right pipe. The rear cylinder splits between the left and right pipe. So, assuming perfect flow, 75% of the engine goes out the right pipe, and 25% out the left. It's not well balanced.

It's also worth looking inside the pipes, particularly where the rear cylinder joins into the right pipe. On mine, the joined pipe protruded almost an inch, really strangling flow from the front cylinder. I did some grinder work here, and elsewhere, eliminating the really bad flow restrictions.

 

The "Y" pipe may have something to do with back pressure to increase low rpm torque but I don't really know. I understand what you're saying about your 04 but he has a 2013 and there may be some difference, I don't know. I was just thinking that if the left pipe was restricted on his bike, it may cause problems if he installed the stock mufflers on true dual headers, then again, it may make no difference anyway.

If there is no restriction in the left muffler then I don't see why using the stock mufflers is a problem. OP could try it easily enough and make up his mind after riding for a while.

 

I have a '12 Road King with V&H Powers Duals and RCX-Haust slip ons along with an H-D SEST tuner and Ness Big Sucker air cleaner. Got home from a 3,000 mile trip and thought I needed a little more quiet, so I put the stock mufflers back on - what a waste of time. It sounded like it just left the showroom floor - very quiet. Put the RCX-Haust mufflers back on and wear ear plugs on long trips. However, to your question: do you need to retune? I would not. Seems like that tuner ought to have enough flexibility to adjust for another set of slip ons. May not run quite as good, but probably not worth a tune. Just my opinion.