Mods and How-to's

Inconspicuous Drag Pipes

Submitted by Jobiesaurus

Don’t like the idea of spending $300+ on new pipes? Do you like the stock exhaust look, but want the sound of straight drags? If your saying “Yes,” then this mod is for you. First I have to thank Streetrod750 for the baffle removal instructions, which got me rollin’. I’ll apologize for not having build pictures, but my camera is out of commission, so I’ll write it up as best I can.

• First of all, the exhaust needs to come off… On the bench I laid out rags, and wrapped the front pipes in some more rags for protection.
• Now, drill out the spot welds on the front and rear muffler chrome covers. There should be four welds on the front and two on the rear. I used a ½” flat bottom drill. Carefully remove the covers.
• Grind off the welds on the tabs of the big chrome cover with a cutoff wheel and slip the over off.
• Next, I put the exhaust in a vise (Clamped on the rear bracket). Time to cut off the end cover of the muffler case. I used a portable band saw and cut off the back as close to the end as possible. You can ditch the cutoff piece; you’ll make a new one later.
• Look at the muffler case, there should be nine spot welds in the case. The welds are in three rows of three. Drill them out; again, I used a ½” flat bottom drill.
• Now, with either a portable band saw or a cutoff wheel, cut around the front of the case, AFTER THE WELD. The cut needs to be just through the case, not through any of the innards. Make sure you mark across where you make your cut so you can line it up again later.
• After your cut is made, find a metal bar or some thing you can use to smash the muffler innards out with. From the back, slam your weapon of choice in to the inside of the muffler until the cut you made up front separates about 1”.
• Get a friend to hold the front pipes as you take your cutoff wheel or band saw and cut through the two inner pipes. Make the cut so that it leaves about 1” of pipe stub sticking out past the case you cut earlier.
• Next, smash out all the baffles and innards of the muffler so you have a hollow case.
• You can now weld up the nine spot welds in the case you drilled out. Weld them up and grind them relatively smooth. Give ‘em a shot of black paint to stop any rust.
• Get yourself a length of 1 ½” O.D. exhaust pipe (8’) from your local farm and fleet or auto store. Cut two 30” pieces.
• Slip a piece of pipe onto one of the stubs left from the last cut you made on the old exhaust. The new pipe will not slip on all the way due to interference with the outer case, you must notch out the pipe to clear the case. A notch about ½” wide and one inch long in the pipe is about good, it may vary from pipe to pipe, and so eye-balling it is just fine. Both pipes will need to be notched.
• Once you get them notched, check the fit. You should be able to get them to butt up against the front of the muffler case.

*** TOTALLY OPTIONAL STEP ***

Adding a balance pipe

• About 3” from the notched end we’re going to “fishmouth” each pipe, on the opposite side of the notch.
• You can do this by using a 1 ½” hole saw without the pilot drill. Put the hole saw in a mill or drill press. Put the center of the hole saw on the edge of the pipe and cut it through. Repeat for the other pipe.
• Now, take the left over exhaust pipe you bought and hole saw it on one end. Then, move down the pipe and hole saw it again; the minor length should be ¾” or so. You’ll need to do some measuring for yourself.
• Test fit the pipes back onto the stubs and slide the small piece you just cut in between the pipes, so it aligns with the “fishmouths” in the long pipes. If it looks good, tack weld your balance pipe in place.
• Remove the pipes from the stubs and finish welding the balance pipe in.

*** BACK TO THE STUFF YOU NEED TO DO ***

• With the pipes butted up against the muffler case wall, you can weld them in. It is possible to weld them in fully, it takes a little skill. I used a MIG welder.
• Slip the hollow muffler case back on and weld it onto the front piece, all the way around.
• Take some sheet metal about the same gauge as the muffler case and center punch two marks in it, 2 ¼” apart. Drill each punch mark with a 1 ½” hole saw.
• Now, take the sheet metal and slide it over the pipes sticking out of the rear of the muffler case. Trace around the case to mark the sheet metal.
• Band saw cut the sheet metal on your mark and slide it back onto the pipes. Weld it around the case and around each pipe.
• Slip the main chrome cover back into place and then the rear end chrome cover.
• Take a straight edge and lay it against the end of the end cover and across the pipes. Now mark the angle on the pipes with a marker.
• Remove your chrome again and cut off the pipes, on your marks, with a cutoff wheel.

*** TOTALLY OPTIONAL STEP ***

Adding slip in baffles

• Buy some slip in drag baffles for 1 ½” O.D. exhaust pipe from JC Whitney.
• Take a die grinder and knock down the seam weld on the inside of your new pipes.o Slip the baffles in and mark the bolt holes. I put the bolt holes facing the inside of the bike.
• Drill the holes.

*** BACK TO THE STUFF YOU NEED TO DO ***

• Give all the bare metal a shot of black paint.
• Stick the chrome back on in reverse order that you took it off, welding each piece one at a time.
• Re-install the exhaust on the bike with new crush gaskets from your Honda dealer.
• Fire it up and annoy your neighbors, just kidding…

~ Jobiesaurus