I posted this as a response to a question in the classified section. It was a bunch of typing so I thought it might fit well here as a thread.
I made the pipe from some 1 5/8" tubing from the rems bin. Its flared a bit over an inch. Here's a quick explanation... If there is interest, I'll make another one, take pics, and do a tech thread.
First cut, to make the proper length, was made in the chop saw. Moving over to the bench, I chucked the tubing in the vise, and made a pie-cut with the plasma torch. Make sure not to cut across the whole tube, leave a few inches uncut at one end. Paper towel tubes are a good medium to practice your measuring/cuts. Be very careful if you try this with a grinder and cutting wheel, steel tubing has mucho kinetic energy and will spring open when you get to the end of your first cut.
Once I made the pie cut, I cleaned up the plasma slag and headed back to the vise. Here's where things get interesting... Now you can just squish the piece together in the vise and weld it back up, you will however end up with an out of round piece. I like to start at the closed end (the "point" of the pie cut) first, applying just enough pressure with the vise to be able to tack weld the seam closed. After you get a few welds holding the seam, you can play around with the shape.... The tubing will be out of round from the "twisting" motion of the steel and the removed material from the cuts, as you close the gap. Pay attention to the "roundness" of the tubing and adjust the piece in the vise to get the profile you're after. Take your time and don't apply too much pressure with the vise, cause wasting tubing and time sucks.
After you get a nice round cone shape, you get to fit the exhaust flange. This is where all the time spent shaping helps. I used the flange off an old Briggs muffler and welded it in the small end of the cone. This pipe will make your engine as loud as possible and even throw a little flame when you get off the throttle. If you like your neighbors, or just don't like the dealing with John Law, now would be a good time to fit a baffle.
As for the holes I just laid out a half inch spaced grid on the last two inches of the pipe, and started drilling for about seventeen years... There are 36 holes on mine, and they each got drilled twice. These holes serve no purpose other than looking neat and to let your friends know that you have way to much time on your hands.
I made the pipe from some 1 5/8" tubing from the rems bin. Its flared a bit over an inch. Here's a quick explanation... If there is interest, I'll make another one, take pics, and do a tech thread.
First cut, to make the proper length, was made in the chop saw. Moving over to the bench, I chucked the tubing in the vise, and made a pie-cut with the plasma torch. Make sure not to cut across the whole tube, leave a few inches uncut at one end. Paper towel tubes are a good medium to practice your measuring/cuts. Be very careful if you try this with a grinder and cutting wheel, steel tubing has mucho kinetic energy and will spring open when you get to the end of your first cut.
Once I made the pie cut, I cleaned up the plasma slag and headed back to the vise. Here's where things get interesting... Now you can just squish the piece together in the vise and weld it back up, you will however end up with an out of round piece. I like to start at the closed end (the "point" of the pie cut) first, applying just enough pressure with the vise to be able to tack weld the seam closed. After you get a few welds holding the seam, you can play around with the shape.... The tubing will be out of round from the "twisting" motion of the steel and the removed material from the cuts, as you close the gap. Pay attention to the "roundness" of the tubing and adjust the piece in the vise to get the profile you're after. Take your time and don't apply too much pressure with the vise, cause wasting tubing and time sucks.
After you get a nice round cone shape, you get to fit the exhaust flange. This is where all the time spent shaping helps. I used the flange off an old Briggs muffler and welded it in the small end of the cone. This pipe will make your engine as loud as possible and even throw a little flame when you get off the throttle. If you like your neighbors, or just don't like the dealing with John Law, now would be a good time to fit a baffle.
As for the holes I just laid out a half inch spaced grid on the last two inches of the pipe, and started drilling for about seventeen years... There are 36 holes on mine, and they each got drilled twice. These holes serve no purpose other than looking neat and to let your friends know that you have way to much time on your hands.
imp:
