I have posted this a couple of ways in other forums but am not getting any responses. Maybe I'm not asking right or my question is stupid. Regardless I still have the question dumb or not.

I installed a set of S&S Power Tune Duals and kept my 2012 SE Street Performance Mufflers with stock baffles. Now I have a rough idle... a lot rougher than with the stock head pipes... and more vibration up to about 2100. I have checked everything I can think of including taking the pipes back off to make sure there wasn't something hitting the frame that I couldn't see. Nothing. I read on another forum about loosening all the mounting and flanges while very hot and then resetting them. No help.

Then I thought maybe these mufflers aren't the same flow on both sides and the added back pressure on one side is making it run rough at low speed. I haven't had any input on that from anyone. I tried to get Fullsac to help, thinking they made baffles for these but they said they don't do SE parts.

I just don't know where else to look or what I could have possible done to create this. Do duals run rougher than the stock set up with the rear Y pipe? The pipes I installed do have a small interconnection between the cylinders.

Anyone have any ideas?

 

do the new sportsters have o2 sensors on them...if they do they could be hooked up reversed....

 

Nope... no 02 sensors on this one

 

bump...

 

In the hopes that this might help someone else...

I finally found the source of my vibrations. In fact the engine was running no rougher than normal, I was simply feeling it more. Seems the headers or mufflers may be slightly malformed... or there is something out of alignment on my bike.

Whatever the cause the deal is that when I put the bolts in the rear muffler hangers, I had to lift up the muffler slightly... about an inch. I had the clamps loose when I did this, but still had to pull them up a bit.

That inch was enough to force all the vibes of the engine into the frame, even with good rubber bushings. The fix was that I picked up some 3/4 inch chrome spacers (local hardware store) and used 1 inch bolts to attach the mufflers. Bingo vibrations are gone! It's like the difference between a solid mount engine and a rubber mount. Huge!

So if you have changed anything on the exhaust and ended up with a new vibration, be sure to look at this area. It doesn't take much to make a huge difference.

 

Thank you for the info.

 

Is it fuel injected?

 

Yes, fuel injected 88