Originally Posted by hardheaded
what he said! 1 inch x 16 inch paddle bit takes a little while to do and you get it all out, no problem. just do breath any of the dust. oh yea, hold on to the drill tight.
In my opinion, what you guys are doing is merely drilling a hole in the cat material. Having cut a panel out of my cat, I dont see any way at all that you have all the material out, not even close. With my panel removed, I had to chip, tear, scrap and grind ALL of the material out so that when I had the panel welded back up the surface was devoid of any little strips of the metal catalyctic material. I could imagin that leaving so much material that you would be leaving "could" possibly cause metal on metal tinny sounds as the exhaust pulses through the chamber.
Just my 2 pennies worth. Do as you want to your bikes.