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No baffles?????

Discussion in 'Motorcycle Tech Talk' started by nebassin, Dec 17, 2009.

  1. nebassin

    nebassin New Member

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    i have just gotten a 1997 XL1200, for my lady. i did a stage I on the carb.
    my question is would there be any advantage to knocking the baffles out of the SE slip-ons that are on the bike. thanks guys
    nebassin, Dec 17, 2009
    #1
  3. cowboy

    cowboy Moderator Staff Member

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    You need to leave some type of baffle in there for back pressure , so it will run right & keep the power through out the power band , you can open them up some & if they unbolt you pull them out & cut no more then half of them off , sounds better & keeps the back pressure
    cowboy, Dec 17, 2009
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  4. nebassin

    nebassin New Member

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    has anyone run a dnyo, with baffles and without, on the SE slip-ons?
    nebassin, Dec 17, 2009
    #3
  5. FLHTbiker

    FLHTbiker Moderator Staff Member

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    Without any baffles your pipes are then like straight pipes and have no back pressure. Back pressure gives more gains in HP and Torque. Many who have gone to headers with no cross over can loose some HP and Torque. I've seen the Dyno charts for the same set up doing both and the less back pressure the less power (HP and Torque). Stock pipes can be blocked to much so they can meet EPA regs. and putting a set of SE pipes or other aftermarket opens them up to flow better but not without some back pressure.
    FLHTbiker, Dec 17, 2009
    #4
  6. Art_NJr

    Art_NJr New Member

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    Short answer - NO.

    Assuming you've got the same SE slip-ons I do, which have a steel baffle held in by a small bolt on the side facing the bike, the baffle will come out. But you'll lose a ton of power on the low end & the bike will be as loud as with straight drag pipes. You might like the loud (I don't), but you definitely won't like the loss of power.

    When I bought the '95 bike, it had the older SE I slip-ons installed, but the baffles had been removed & you couldn't get 'em anymore. The bike was so weak on the low end that I put the stock mufflers back on until I finally found a set of SE baffles to put back in. Night & day difference & it's a proven fact that the best exhaust you can put on a street/road Sportster is stock pipes WITH crossover & the older SE I slip-ons's or equivalent, like Cycle Shack.

    And if you have the SE II slip-ons, the baffles are welded in. You can cut 'em out, but you'll tear 'em up in the process & you won't be able to put 'em back in again - which you'll want to do right away, believe me.

    The baffles aren't there to create backpressure as is commonly thought, they're there to break up "reversion" in the exhaust - the pressure waves that go back up the pipes & make tuning a nightmare. If more top-end performance is what you're after, you can remove SE I (or Cycle Shack) baffles & do my friend Crim's "top secret baffle mod", then put the baffles back in again:

    http://www.sportster.org/tech/exhaust-gc/baffle.gif

    Might want to read his article on Sportster exhaust too:

    The Sportster Home Page

    FWIW, Crim used the baffle mod on his '98 1200S to break 140 mph on a street-legal Sportster & we stuck my 1650 Soortster-based engine in another bike of his, which set 3 Land-Speed-Records @ Bonneville & won the East Coast Timing Assn. Championship (best run = 180.025 mph). We've been playing with Sportsters long enough to know what works, what doesn't & why ;)
    Art_NJr, Dec 17, 2009
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  7. FLHTbiker

    FLHTbiker Moderator Staff Member

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    Back pressure is like a generic term.
    Here is a site with some good info on what your wanting to do, should help you out.

    Exhaust Systems
    FLHTbiker, Dec 17, 2009
    #6
  8. nebassin

    nebassin New Member

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    thanks guys. that pretty much anwsers my question. happy trails and have a cool yule.
    nebassin, Dec 17, 2009
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