Popping noise coming from exhaust and also..

Discussion in 'Engine, Fuel and Exhaust' started by The Rook, Nov 9, 2007.

  1. The Rook

    The Rook Member

    49
    16
    0
    I'm getting popping(backfiring I'm assuming) coming from my exhaust and also what can only really be described as a "shuffing" noise coming what sounds like straight out of the air cleaner. Any ideas?


    As always thanks in advance.


    P.S.: I looked over some of the 'self-help' section and didn't really find it. Unless I saw it and didn't realize it.


    UPDATE: I looked at my vacuum hoses under the tank and have a 'Y' shaped connector that only has two hoses attached. When I plug the missing one the engine runs much better. Anyone have an idea as to where I could find a diagram/schematic of the vacuum hoses on a Sportster '96?
     
    Last edited: Nov 9, 2007
  2. glider

    glider Veteran Member

    25,464
    108
    43
    The open vacuum linw will cause the popping you are experiencing.

    Try to follow the two lines and see where they terminate and post what you find. Quite possible the missing line is from the intake manifold or the carb . You may find the third line you are missing disconnected.
     
  3. The Rook

    The Rook Member

    49
    16
    0
    I looked at them again and one hose comes from above the carb another comes from a little circular thing(I'm researching it currently) and the third one is completely missing. I plugged the open port and took my motorcycle for a ride and that seems to have solved the problem with the popping noise. But I'm fearful that I still need that third vacuum hose hooked up to somewhere, and since I only have a Clymer manual I believe I'm totally screwed cause this Clymer manual is a total waste of money.
     
  4. glider

    glider Veteran Member

    25,464
    108
    43
    The circular thing is probably the VOES switch that changes your cruise ignition advance. It has a vacuum line on it that goes to the carb. You may have a vacuum operated fuel petcock also, not sure on that bike but look on the back of the fuel petcock and see if there is a vacuum line on it. The other would probably come from the carb. If you are unsure the dealer can show you a diagram that would clear it up for you.

    [​IMG]
     
  5. Not Very PC

    Not Very PC R.I.P

    528
    28
    1
    I've encountered this same-thing on 2 bikes over the years both had replaced the ignition with aftermarket ignitions and felled to remove the VOES system completely and just plugged off the line going to the VOES switch. after a few heat cycles and the constant vibes the plug falls off and the bike runs like crap because of the lean mixture created by the open vacuum line.
     
  6. The Rook

    The Rook Member

    49
    16
    0
    I will try to take photos later and see if I can post on here. Thank you for the replies.