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Thread: carby bakefire

  1. #1

    Default carby bakefire

    Hi I have a S&S super e carby on my81 fx I have tuned it in as per the guide but it pops and backfires at around 50 mph when backed of or under load .
    Has this something to do with the carby or has it to do with timming . It also find it doesnt respond very well.

  2. #2
    Join Date
    Mar 2008
    Location
    New Jersey
    Posts
    71

    Default

    I am not a big fan of S&S carbs. More info needed. Is this a recent addition? If so did it run ok before? Is it a stock engine? Is it backfiring through the carb or out the exhaust? It sounds as though it is backfiring through the carb which usually indicates a lean condition and it may need a jet change. But before that is tried, a bubble test should be done on the manifold and connections to determine if there is leakage there. If no leakage at the plumbing connections, at 50 MPH it should be operating on the low speed circuit and may need fattening up.

  3. #3
    Join Date
    Jun 2001
    Location
    Central Illinois, USA
    Posts
    4,080

    Default

    As Lyle said!

    http://virtualindian.org/11techleaktest.html

    O-ring assemblies should be tested while assembled to prevent over-tightening.

    Please remember the clamps do not secure the carburetor upon the machine;
    The carb support does.

    .....Cotten
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  4. #4

    Default

    Hydraulic or solid lifters? color of spark plugs? stroked/ cam change? new condition or was running OK before? drag pipes? High speed backfire through "carby" would indicates larger main jet needed, tuning per guide addresses needs for larger jets.

  5. #5

    Default

    This is a stoke ariginal engine .when I bought it it came with the S&S on it I have done a leak test on Manifold it was all okay both plugs are not oily or lean looking nice colour to them and it only backfires though the carby when under load or when just twisting the throttle .

  6. #6

    Default

    Check accelerator pump? Timing?

  7. #7
    Join Date
    Feb 2009
    Location
    Nashville,Tn.
    Posts
    3

    Default

    What kind of ignition are you running? Points or Electronic with or without a spark advance? TB

  8. #8

    Default

    Condenser? I have been hearing of them causing misfires.

  9. #9
    Join Date
    Jun 2019
    Posts
    8

    Default

    Probably chase your tail if you dont just pull carb....clean emulsion tube and all passages. Than change out both intake o-rings. Make sure carb has a support bracket. New plugs and go from there. Most super E s i have done this fixes them. Less time,headache and 99% of them need it anyway...Know that 91 and 93 octane gas in most states goes bad after only 3 weeks.....yep with as much ethanol thst they use it sucks up water like crazy.....should be using treatment in gas for stuff not used everday.

  10. #10
    Join Date
    Nov 2018
    Posts
    130

    Default

    I have always found the S&S Super E to be a good carby. If it is tuned as per the instructions, good o rings(or bands) and support fitted, they run well.

    One thing I have come across many times is the electronic module breaking down. I have replaced every one I have come across. They typically show some potting material leaking out of the enclosure. This will give you some strange effects.
    If you are still using the original springs in the advance and retard, they loose some tension after time. The spring anchors also seem to bend inwards sometimes.

    Even if the timing is in good condition, I like to change it out for a later electronic system. Can be set up as single fire if preffered with a new coil, and is very tunable. My personal favorite is the Crane HI4, before S&S brought them from Crane.

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