MS660 Magnum Muffler Mod

jeffesonm Posted By jeffesonm, Sep 19, 2013 at 12:49 PM

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  1. jeffesonm

    jeffesonm
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    May 29, 2012
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    My DTI TT-20K just arrived in the mail so I'd like to mod the muffler on the MS660. As I understand it you basically enlarge the hole (or create another one) so the total area is about 75-80% the exhaust port area. Then re-tune (2,500 rpm idle and 13,500 rpm WOT as per the manual).

    Does that sound right? Can I get rid of this little cage thingy inside the stock muffler?

    [​IMG]
     
    smokinj likes this.
  2. ironworker

    ironworker
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    Dec 3, 2011
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    What I did was drill two holes on the top of the baffle then cut the middle of the holes out with a Dremel making one long hole and then I opened up the ports,as I have a dual port muffler. I believe you can get a cover with a port in it for yours.
     
  3. clemsonfor

    clemsonfor
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    You can buy a cover with an additional port in it so its a dual port.
     
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  4. clemsonfor

    clemsonfor
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    I will do this to my 650 once I get it back together and running.
     
  5. clemsonfor

    clemsonfor
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    Its in no shape for a muffler mode now. Well I could do one, but not much point till I get the plastic in.
     

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  6. jeffesonm

    jeffesonm
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    May 29, 2012
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    Thanks for the info all.

    I ended up removing the entire baffle from the muffler. I used a dremel with a carbide bit to enlarge the stock hole until it was pretty much the entire area behind the stock deflector. Then I bet a piece of sheet metal and welded it on as a deflector extender. Finally I spray painted it with high temp grill paint and retuned with my fancy new tach. Cut some hickory today and it works well... throttle response seems better.

    [​IMG]

    Be easy on the welding... this is the 2nd thing ever I've welded and didn't feel like grinding much.
     
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  7. ironworker

    ironworker
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    Nice job, how do you like the way it sounds.
     
  8. clemsonfor

    clemsonfor
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    Who are you talking to?? That seemed random?
     
  9. JOHN BOY

    JOHN BOY
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    The saw will also run alot cooler as well . should help to produce more torque.
     
  10. webbie

    webbie
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    Heck if I know....that guy came and went. But, maybe a hint, he was pushing some agendas as if he was here before in force! Your guess is as good as mine. Sad and depressing, actually. You'd think adults would act like same.
     
  11. sclarke

    sclarke
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    Oct 21, 2011
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    you may not want to run it at such high rpm. anytime you modify a muffler you run the risk of burning up the cylinder if you do not richin up the carb.
    here is a very helpful link http://www.madsens1.com/mnu_main.htm
     
  12. Fifelaker

    Fifelaker
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    Tune by ear first, then check with a tach if you want a reference.
     
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