my expansion chamber pipe was getting pedal ground to the point it failed,the pedal hitting is actually the exhaust bracket misaligned and too far up on the header BTW.
so when the muffler shop seen the deal, they cut an indian header i had into the three inch long extended lead into the expansion chamber.
the korean guy who banged it up, made a dimple and put a small air hole in the dimple. 180 degrees from port. was a master i bet he did quite a few small cc two strokes before.
when he was done it looked like a techno hunterish shape and angle. he was into it, he lit up when the boss told him to set me up.
when its daylight out i can get better pics of it. it is off the bike. that pic was three years ago