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Thread: Burning up the packing with old #027-7853

  1. #1
    Kevdog Guest

    Default Burning up the packing with old #027-7853

    I recently picked up a 1999 Ultra Classic with the MM EFI, it has the Big Sucker air kit and 510 cams with a Fullsac true dual kit on it.

    The slip-ons have the number #027-7853, they have the center bolt with the closed end and 12 discs on each side.

    When I pulled them apart the packing on the right side was half gone and burnt and the left side was completely gone.

    I picked up some packing from the local cycle shop (not Harley specific) and it sounded great! but within 4 months the same thing happened.

    The plugs look grayish black and look black at the top of the threads.

    My question is do I need to change the number of discs or do you think its a map issue or both?

    Also, I have read about some ceramic blanket used as packing so that it wont burn up as fast?

    I appreciate any suggestions?
    Last edited by Kevdog; 04-20-2014 at 09:18 PM.

  2. #2
    bschultz Guest


    Over time & mileage sound vibration and heat will deteriorate muffler packing. The length of repacking intervals can vary by the quality of muffler packing, mileage, the state of tune of the machine and the riders riding style.
    Spark plug color could indicate a lean running condition (light & ashy). Other indications of running lean is decel popping and lack of bottom end torque.
    I would consider experimenting with the number of discs, 2-3 at a time (removing/adding).
    More discs, more flow, more sound...leaner running
    Less discs, less flow, less sound...richer running

  3. #3
    Kevdog Guest


    Thanks for getting back to me!

    I will pick up some more discs and give it a go, is there a "not to exceed" number of discs with those old closed end pipes?

    Do you think the ceramic wool would be better than the fiberglass packing?

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