1978 (k)Z650 carburetta overflow problem

Discussion in 'UK Motorcycles' started by martinski, Dec 21, 2003.

  1. martinski

    martinski Guest

    My bike ran for the first time in a number of years today much to my relief.
    All sounded good but i had petrol pouring out of one of the four carburetta
    overflows. Can someone tell me why this is happening and what i should do to
    stop it?
    martinski, Dec 21, 2003
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  2. Sticking float in the offending carb.

    Certain means of stopping it: remove entire carburettor bank, upend,
    remove screws on float bowl, remove float bowl, jiggle sticking float
    and/or remove pivot pin, clear crud on it, replace everything.

    Short way (which often works): give offending carb float bowl, in situ,
    a sharp tap with a hammer knocking on the end of a piece of hardwood, to
    jog the sticking float free.
    The Older Gentleman, Dec 21, 2003
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  3. martinski

    PDannyD Guest

    'it it wiv an 'ammer.

    FZS600 - silver/black
    GS125 - black/rust
    '81 Bobtail - vaguely green (FOR SALE £800)
    CAAD7 - black
    LTS2 - blue, not black
    OE6 + Quotefix
    PDannyD, Dec 21, 2003
  4. martinski

    Stu Guest

    Add to that, remove the needle valve, and clean its seat with a cotton bud,
    and check the crown for dirt.


    YTC#11 OSOS#23
    pull my plonker when replying
    Stu, Dec 21, 2003
  5. martinski

    martinski Guest

    Cheers for the advice. I went for option A, the removal of the carb bank. I
    love the way the manual says 'loosen the four cross-head screws and lift the
    bank of carburettas away'. It took me the best part of two hours, stood out
    in the December drizzle, trying to find a big enough gap between the engine
    and air filter box to jiggle the carbs out. I must have looked pretty
    strange doing my lap of honour round the garden with carbs held aloft like
    the Olympic flame. It was worth the pain though because it offered me the
    first opportunity to really inspect the carbs from a worms eye view and
    reveal its dark secrets. It soon became apparent that if i'd have banged the
    float chamber from now until the new millenium it would not have fixed the
    problem. The needle jet in the offending carburetta was well and truly
    siezed, preventing the correct movement of the float. Abit of WD40 and a
    gentle twist with a pair of pliers soon got it loose again. I also took the
    chance to thoroughly clean the entire unit and give it a well overdue
    lubrication on all the obvious moving parts.
    In a bid to avoid a repeat of the previous two hours of misery I've decided
    to fit independent air filters (K&N stylee, but not your actual K&N's) and
    lose the air filter box completly. I've always thought they look cooler
    anyway. And who knows, at this rate of progress I might even have the
    machine running inside a month or so. Happy New Year fellas.
    martinski, Dec 27, 2003
  6. martinski

    Pip Guest


    That's nice for you, dear.

    Now, if you would like to have a look here:

    You will find, described succinctly, the posting conventions
    applicable here - and why everybody follows them.

    It's good that you have sorted your carburettORs, but be aware that if
    you junk the airbox and its filter then the chances are that you will
    effectively weaken the mixture due to making so much more air
    available. You may wish to look into a Dynojet kit or similar to
    avoid unpleasant results.
    Pip, Dec 27, 2003
  7. I wouldn't. If you do this, you will almost certainly need to remove the
    carbs again to revise the jetting.

    And whatever you do, if you do decide to go the K&N route, don't junk
    the old air filter box but keep it somewhere safe.
    The Older Gentleman, Dec 27, 2003
  8. AOL.

    Don't replace the standard airbox with K&N types. The Z650 carbs are
    designed to be mounted back and front. You will end up with knackered
    inlet rubbers after a while. The engine will make more power with the
    standard air filter box on anyway...

    SimonB - South Wales. BOF#32
    email [email protected]
    Triumph Sprint ST,
    ZXR750L2 Wazimbaki.
    Kawasaki Z1R For Sale
    eric the brave, Dec 27, 2003
  9. martinski

    martinski Guest

    You know, i wish id read these replies this morning. I'm now the proud owner
    of a set of clamp on independent air filters that i bid on through ebay and
    will be winging their way to me from the good ol' US of A any day now. Any
    suggestions how these apparently redundant beasts might be better utillised?
    Handlebar mounted ash trays perhaps? Natty wheel trims? Might start a whole
    new fashion. Ho hum, it looks like i have two hours of misery ahead of me
    after all then. Can someone suggest an easier way of getting the friggin
    carb bank attached without my having to resort to hari kari in the process?
    martinski, Dec 28, 2003
  10. Depending on what bike it is...

    If you have a frame tube running directly front to back above the carbs,
    you could easily fabricate a small clamp-on bracket which will take the
    weight of the carb bank.

    By the way, please put your replies at the bottom.



    GS 850 x2 / SE 6a
    FUB KotL OSOS#12? UKRMMA#19
    Grimly Curmudgeon, Dec 28, 2003
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