I just replaced the Screamin Eagle slip ons with Vance & Hines, and am curious if anyone else had this happen to theirs, or might know what might have caused the pipe to crack like this. I had 93K plus on my 2005 FLHRS when I replaced the pipes. Thanks

 

My guess would be thousands of heat/cool cycles combined with thousands of miles of vibration.

 

The muffler was loose enough to be worn thin from the vibration/rubbing, we see it all the time here at the shop. Make sure your new mufflers are tight and if they do not tighten down enough. In a pinch we have used cut up beer cans as shims to help get everything tightened down enough to not wear thin...

 

Bingo ... We have a winner. If the rest of the muffler is in serviceable condition a local muffler shop can "rebuild" the inlet ... FWIW ... although it might require a different clamp to tighten it.

 

Makes sense. I removed them when I did a cam tensioner upgrade, and might not have wrenched it down enough. Lesson learned.