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Thread: R1100S custom exhaust concept:

  1. #1
    BUBBAZANETTI
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    R1100S custom exhaust concept:

    so,

    i think i'm going to be in "major decision" time about my bike at the end of the summer.

    do i sell it, while it's still in fairly decent condition, and get ok money for it

    or do i keep it and in making it unpalatable to would-be thieves in the city, turn it into a TOTAL rat bike

    no-holds-barred, complete with truck bed spray liner paint and a new exhaust "idea" i've been considering

    hacking the pipes completely off just above where the exhaust pipe proceeds from the cat to the mufflers:


    (above and to the right of the riders boot)

    and installing one of these



    and totally removing the muflers, maybe i could install some sort of little luggage compartment under there!

  2. #2
    Blocking the slow lane
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    Uh, no.
    Jon Diaz
    BMW K75/K12GT
    BMWMOA Ambassador

  3. #3
    univers zero tessler's Avatar
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    Quote Originally Posted by jdiaz View Post
    Uh, no.

  4. #4
    Braz J Brase's Avatar
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    Bubba,

    If those are, indeed, the only two choices.....
    SELL IT!!!

    John

  5. #5
    Registered User
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    RoyB....
    2007 BMW K1200R Sport (abs),2007 Suzuki dl650 V Strom (abs),2004 Honda VFR (abs),1972 Honda Trail 90,
    2001 Moto Guzzi V-11 Rosso Mandello

  6. #6
    Nickname: Droid
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    I'm in process on making my own "diffused reverse flow" muffler for my 94 R1100RS from a scrapped stock muffler I got from my dealer.

    I made a center divider/crossover plate, a mid-point diffuser (it clears the inside of the canister by 3/8", and an oversize outlet pipe, all from stainless steel. Now I just nee to get it TIG-welded and see how it sounds.

    Worst part is that I lost no weight in the process. But it should be better breathing (like a Flowmaster muffler for a car) and better sounding without being loud. I plan to run this with a slightly higher output fuel regulator for a bit better performance.

    In the orignal muffler, the stub tube coming out of the CAT is the only one that ran to the outlet at the back of the canister. The hole below it had a long perforated diffuser tube sticking out of it (not welded in), which just emptied into the canister, and I'm guessing the canister back-flowed into the hole just above my new center divider. A strange design for sure and one I can't quite figure out.

    I first thought about a Y-tube connecting the two outlets to the rear outlet in a straight through design, perhaps with perforations on the Y-tube. But that was too much fab work for my simple abilities. After I studied the design of Flowmaster mufflers I came up with this setup.
    Attached Images Attached Images

  7. #7
    Registered User jgr451's Avatar
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    Smile Hard choices..

    Uh Bubba,you been to California again,where the tokin is easy?
    Sometimes,nothing is a real cool hand.

  8. #8
    Danger: Keep Back 500 Ft FredRydr's Avatar
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    Ratty S

    Bubba,

    If you want the rest of these images, drop me a line.

    Fear not; you are not alone in these urges.

    Fred
    Last edited by FredRydr; 05-25-2010 at 09:27 PM.

  9. #9
    BUBBAZANETTI
    Guest
    Quote Originally Posted by FredRydr View Post
    Bubba,

    If you want the rest of these images, drop me a line.

    Fear not; you are not alone in these urges.

    Fred
    ohhh,

    slick, i one time rode aroudn with my faring off, and i liked it!

    question though, where do you relocate all the electronics off the front rails????

  10. #10
    Danger: Keep Back 500 Ft FredRydr's Avatar
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    Your Mentor is in London


  11. #11
    Not available in stores.. PAGoldsby's Avatar
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    Quote Originally Posted by FredRydr View Post
    Bubba,

    If you want the rest of these images, drop me a line.

    Fear not; you are not alone in these urges.

    Fred
    < Hubert Farnsworth > Oh, my, yes! < /Hubert Farnsworth >
    Last edited by PAGoldsby; 08-02-2007 at 02:47 PM. Reason: Exorcise HTML demons.
    I can't believe how incredulous I am.

  12. #12
    BUBBAZANETTI
    Guest
    This has always been a fun, inspirational site:

    http://www.ratbike.org/


    i think it's the whole concept of "i'm gonna purposely make this bike look like i rode it through a house that was on fire" concept that seems so strongly juxtaposed to todays chopper and custom fads that really appeals to me.

  13. #13
    CustomSarge
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    Talking Bear in mind...

    increasing air/fuel flow through with stock injector mapping & rail pressures will lean it out. The system can compensate only so much. Be prepared to get a "chip" or some other method of addressing what the computer can't deal with. You Should have access to an Exhaust Gas Analyzer.

    Also, balance/match any flow changes on both intake & exhaust.

    My R11HR has NO muffler or cat. (avatar & Oilhead pix #36) Only a resonator & a fixed resistor network to sub as the cat. Intake is a pair of little conical K&Ns right at the injector venturis.

    Result: high 17-21:1 fuel:air. BAD

    Answer: change fuel rail regulator & push rail pressure from ~36 to 48 psi.
    As verified on an EGA: back to ~ low 15:1.

    Mileage? MUCH Worse, but that's what toys are for.

    Fun Factor? 10"-12" torque wheelies & flat leaving all but stage 3 built H-Ds.

    It all returns to: just what you want out of this bike?
    .............disappearing like a cartoon, with a cheshire grin....<<<)))

    P.S..... CAREFUL: pushing rail pressures that far has consequences on stock fittings.

  14. #14
    Nickname: Droid
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    SUCCESS! See my earlier post on this thread for the muffler design I came up with for my "stock" exhaust system. Just installed it this morning and took a ride. Nice deep tone kind of like a Staintune or Akrapovic (in my opinion).

    In town tone is manageable with reasonable throttle use.

    Highway tone is good, not excessive at all. Throttle response above 3500 rpm is good, maybe better than stock. Power above 4500 rpm is definitely better. I do sense a touch of lean condition around 3000 rpm, that I may address with the fuel regulator (tweakage). It does pop on decel, but again that may be addressed with a bit richer mixture.

    Anybody know some easy tweaks to get a "bit" more fuel delivery?

    In combo with this exahust, my bike has GS intake tubes, a K&N air filter (stock air box), blended/modified TB intake manifolds, and Autolite 3923 plugs. No surging problems. I may make my own cold air intake to get fresh cool air from the front of the bike.

  15. #15
    waehrik
    Guest
    So at the risk of bringing this waay back from the dead... assuming you've kept your bike, I'm running a very similar system on my R1100RS though I got rid of the cat and am running a 2" car exhaust pipe bent as a midpipe with a Holeshot slip on on the end. It's essentially a straight through pipe, though the slip on has stainless packing inside. I had to add a baffle to the end of it because the exhaust note was REALLY loud. With the silencer fitted it's much more muted but still a nice throaty sound.

    Of course I was running lean after that so in order to compensate I raised the TPS to 0.395v at idle (move it without touching the throttle plate stops) and added a 20k ohm resistor inline with the air intake temp sensor. That tricks the engine into thinking it's getting colder and denser air, so it supplies more fuel.

    I'm getting about 40-45 mpg which I'm happy with.

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