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Thread: Help with vintage '80s SuperTrapp Muffler

  1. #1
    dux Guest

    Default Help with vintage '80s SuperTrapp Muffler

    Hello, all.

    I inherited a 1980 Yamaha XS1100LG Midnight Special with a SuperTrapp 4>1 exhaust.

    My questions are:

    Can anyone identify my exhaust from the pictures below?

    How many discs would give me as close to stock back-pressure as possible? I am currently rebuilding the carburators and I would like to to adjust the discs to be as close-to-stock as possible, so I can get a good baseline prior to any re-jetting. The bike had been running with 10 discs, but had a pretty significant stumble at the low end which may have been indicative of a lean condition(?).

    What is the fewest number of discs I should use? (1100cc, 4cyl) The muffler is a little too loud for my taste. I'd like the bike to be reasonably quiet-ish.

    Is it possible to remove the core from this particular muffler and repack the fiberglass? There are two rivets (one on the back, one one the bottom). It appears that by drilling them out, I would be able to remove the core, but I don't want to hack it up and find out otherwise, as I don't have the budget to replace it...

    Thanks in advance.

    Please ignore the soot... the bike had clogged slow jets and would only run on full choke, hence the carb rebuild. Plus there's a lot of PB Blaster on there...

  2. #2
    bschultz Guest


    This early construction was a purely mechanical core, removable, however without muffler packing (NOT REPACKABLE).
    10-12 discs w/closed end cap sounds about right for the 1100cc. Reduce the number of discs by 2-3 and see how she runs. I would think your performance would start to suffer below 6 discs.

  3. #3
    dux Guest


    Thanks so much. You probably saved me a lot of time and heartache...

  4. #4
    dux Guest


    Is there a replacement muffler that will bolt up to my existing headers? Or a replacement core?

  5. #5
    Join Date
    Jul 2007


    No, you have a piece of history there!
    No parts available for that.

  6. #6
    dux Guest


    Quote Originally Posted by jwells View Post
    No, you have a piece of history there!
    No parts available for that.
    Haha. Thanks. :/

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