I just installed a pair of Cycle Shack slip-ons with my stage 1.

They sound great, but I noticed that after about 10 minutes of riding (once they get good and hot), the sound of the exhaust changes a bit. I start to get a bit of a echo or hollow sound coming from the area close to where the crossover tube meets the rear pipe (I have asportster 1200). Has anyone else noticed this with the Cycle Shack pipes? I'm wondering if having re-used the gasket at the crossover pipe caused a leak, and that is what I'm hearing (but why only when they heat up?).

 

did you ever find out what was causing the sound? I have exact same problem