I made the exhaust tip from 3" solid aluminum. Joe Bell bored the center of it to 1.5" for me and I machined the rest of it on the Smithy. I wanted it to look like a flash suppressor on a machine gun. The Cycle Shack 2 inch shotgun drag pipes are going to be modified to run down the side of the bike under the carb but above the nose cone as a straight pipe with the rear cylinder coming in as a 2-1 exhaust. The 1.5" I.D. of the tip will be the only baffle and I hope the reduced diameter will give me a little back pressure anyways. My intention is a lakes pipe look with this tip on the end mounted right above the rear axle on the frame.