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homemade Baffles for Short Pipes

Discussion in 'The Garage' started by DogBunny, Apr 18, 2013.

  1. DogBunny

    DogBunny Motorcychologist Top Contributor

    Here is a baffle I made for a friend's XS650 that uses a slash-cut stock double-wall header pipe for the exhaust.

    The baffle is constructed of 3/4" trade size EMT (Electrical Metallic Tubing), also know as "thinwall." Three slots were cut into each end allowing me to bend out three wings on each end. You can cut two or four slots if you want to make two or four wings. Three 1/4" nuts and bolts have been put in each baffle for anti-reversion and to provide "back pressure." The nuts and screw-heads have been ground down a little for clearance.
    All wings are over-spread, and the baffle is forced and hammered into the pipe. Friction keeps the baffle in place. There is no need to screw or bolt it in.

    The baffle was made as long as possible, based on the straight length of the header that existed. On longer pipes, I have made baffles up to 14" long.
    The bike runs excellent, and was easy to tune. I am not an engineer, and I am not an expert on reversion or pipe design, but I know that baffles like mine lower the power band, and make a bike with short pipes a lot more enjoyable to ride in town. This bike runs great in all riding situations.
    This bike is still plenty loud. If you want to quiet it down, you can wrap fiberglass or Chore-Boy around the baffle before you insert it.
    I have made plenty of these home-made baffles for long pipes, but this was my first for short pipes. For long pipes you may only need a single screw and nut.

    EDIT: I rode this bike recently, and I know think that the 3 bolts in the baffle are too much. I'm trying to get the owner to pull the baffles and just use the last bolt.

    EDIT: The owner finally removed 2 of the bolts, just leaving the one closest to the end in, and bike runs even better than before. One thing, he has had problems with is the baffles blowing out. This has only been happening on bikes just running headers, so if that's what you are doing, then run a self-tapping screw through the baffle and pipe.
    Last edited: Aug 15, 2013
  2. willyguzzi53

    willyguzzi53 XS650 Addict

    Good tip. Back in the day we would use the baffles with the beer can cuts in them and would keep straightening out the cuts until we got the sound we wanted.
  3. DogBunny

    DogBunny Motorcychologist Top Contributor

    Here is a complete system. I have already tack-welded and slotted the pipe adapter, part 548520 to the head pipe. For more info on the adapter and how it works, scroll down to PamcoPete's post #19 in the following thread:
    The other parts in the pic are a piece of straight pipe, a clamp, a 13" homemade baffle with a single bolt in it, and a trim piece.
    The clamp is a Stainless Steel Bolt Hose Clamp from McMaster-Carr, found here:
    I use part # 5443K22, check clamp for the size of the pipe you use.
    The trim piece covers the tack welds on the pipe adapter. There are a couple different Stainless Steel items in the plumbing isle at Lowe's that will work. I'll get the numbers next time I'm there.

    Here's the complete system installed.

    And here's the bike. Bike runs great and sounds great at all speeds and RPMs. The headers came with the bike, and all of the pipe was free, so all I bought was the adapters and the clamps, and some silver hi-temp spray paint, for a total of less than $20.
  4. I am Carbon

    I am Carbon shade tree mechanic

    i'm digging the baffles
    back pressure is a good thing.
  5. DogBunny

    DogBunny Motorcychologist Top Contributor

    Okay, here, as promised, is what I use as a trim piece to cover where the 548520 adapter is tack-welded to the head pipe. It is this:
    You throw away the rubber piece. It is Stainless steel, it comes with two riveted-on stainless worm clamps, and it is only $3.48. It is not strong enough to act as a pipe clamp, you still need the clamp on the left from McMaster-Carr.

    PamcoPete has suggested the above thin chromed steel item for a trim piece. You cut it to size and slot it, and slip it over the tack-welds, with the slot hidden in the back, then secure it with stainless worm clamps. It is chrome, which I don't like as much as stainless, and you still need to buy a pair of worm clamps and do all of the cutting, so I like the first suggestion better.

    BTW, I added an edit to the bottom of my original post in this thread.
  6. Could you use copper tubing instead of EMT for the baffle? I know it's more expensive. I have some 3/4 I.D kicking around.
  7. To answer my own question the answer is no. The copper is too soft and will break when you go to bend the flaps. I was wondering if it would hold up to the heat as well.
  8. DogBunny

    DogBunny Motorcychologist Top Contributor

    I think copper would work with a couple of changes. Not sure if it would break when the wings are bent, but to be safe, you could just cut more wings, like 5 or 6 instead of 3 or 4.
    I think the real problem is that the copper is too soft to grab the inside of the exhaust pipe, it would eventually get spit out, so you'd need to secure it with a self-tapping screw through the copper and the exhaust pipe. That's not a bad idea anyway -- I've never had problems with my long pipes, but a couple of customers with short pipes have had their baffles come out. Probably because their short pipes aren't anchored and vibrate too much.
    Anyways, you could always whip up a couple of temporary copper baffles to see the benefits.
  9. I didn't really read this thoroughly and just dove in and made a set from EMT. You said that 3 screws is too much for short pipes? I just have headers with about a foot cut off each one.
  10. DogBunny

    DogBunny Motorcychologist Top Contributor

    If they are shorter than the pipes in the first pic of the first post in this thread, then 2 or 3 bolts might be okay. It also depends on how long you made yours. Try 1, 2 and 3 bolts and see what works best. That's what's nice about these, they are easy to alter and experiment with.
  11. Made mine 5 inches long so i should be good with 3 bolts. Like you said you can experiment with them. Just got to get it running first. Ha, ha.

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