Kz700 blows smoke when cold

Discussion in 'Motorbike Technical Discussion' started by Masospaghetti, Dec 21, 2005.

  1. Hey all - working on a 1984 KZ700 with 8700 miles. When starting in the
    morning, having sat for a day, the bike will blow a lot of smoke out the
    tailpipes, sometimes both pipes, sometimes one or the other. The smoke
    looks bluish. I asked a local mechanic and he said that it doesn't mean
    Am I staring at a mechanical nightmare in the near future? Valve stem
    seals? The motor runs and sounds great once it warms up.
    Masospaghetti, Dec 21, 2005
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  2. Masospaghetti

    CK Guest

    Correct. Keep the oil from carbonizing onto the intake valve stems by
    mixing Techron Concentrate with your gasoline to avoid burning the
    intake valves. Keep an eye on the valve clearances and listen for
    spitting back through the carburetors. When the compression drops off,
    do a valve job and, for that matter, re-ring the pistons.
    CK, Dec 22, 2005
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  3. Masospaghetti

    alan&alon Guest

    i would get the seals replaced asap or as soon as you can afford it the
    dealer should be able to do this without pulling the head then you can get a
    valve adjustment at the same time and save some money if you dont care much
    about the bike then just run it should last a few years anyway
    alan&alon, Dec 31, 2005
  4. Masospaghetti

    Wudsracer Guest

    Rules of thumb:
    It if is black smoke, you are burning a rich fuel/air mixture.
    White smoke, you are burning water.
    If it is blue smoke, you are burning a bit of oil.

    Blue smoke on start-up, which goes away after warm-up, is leaking
    valve guide seals. (oil is seeping past the seals after the previous
    Continuous blue smoke, which never goes away, is compression/oil
    leaking past your rings (both ways).

    Given your symptoms, I'd say leaking valve guide seals. It is not a
    real problem, and will be easy to fix during your next needed top end
    job. Any good quality top end gasket set for 4-strokes will have valve
    guide seals included.

    Jim Cook
    Smackover Racing
    Gas Gas DE300
    Team LAGNAF
    Wudsracer, Jan 3, 2006
  5. Be smart and check compression dry and wet. see if has valve seals or not
    for that bike. you can check them when you have the valves adjusted. the
    guides may be worn, leting oil in when shut off. go one step at a time. good
    luck, and ride safe.
    ROBERT MILLER, Jan 11, 2006
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