I took a 1 3/4 in. metal cutting hole saw, cut the cup in two equal parts, dobber welded a piece of 1 3/4 in. tubing (left over fence post) about 18 in. long. Welded the cutting end to one end of tubing and mandrel end to the other end of the tubing, Smoothed the dobber welds a little and drilled away. I wrapped a cardboard strip around the hole saw, old welder trick,to mark for a true cut and used a pipe cutter on the tubing. It's not perfect but works pretty well. I started drilling with a cordless but ended up with a 1/2 in. electric drill. I took all the baffels out of the short Triumph off road pipes and they sound great. I have spotted some baffels at a bike shop which will fit as soon as I get a ticket for loud pipes.
Also you have to remove the glass from the pipes. One side of the pipes had already blown out most of the glass but the other was full and firm. ****? Cost me about 15 bucks, But I welded it myself, sort of!
