Firing order of a 74 Honda CB350F

Discussion in 'Motorbike Technical Discussion' started by Scott, Feb 27, 2012.

  1. Scott

    Scott Guest

    I am trying to get this bike put back together but I need to know how
    the cylinders are numbered. I am guessing 1 is all the way to the
    left then 2,3 and 4. Just needing to know so I can hook up my coils.
    Scott, Feb 27, 2012
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  2. That's the way yhe cylinders are numbered, yes. Not the same thing as
    the firing order, though, but the coils use a wasted spark system so as
    long as you've plugged them in correctly, it'll work.
    The Older Gentleman, Feb 27, 2012
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  3. Scott

    ` Guest

    The firing order of an I-4 has traditionally been 1, 3, 4, 2.

    The cylinders are numbered 1, 2, 3, 4, from left to right, from the
    viewpoint of the rider astride the motorcycle.

    The spark plug leads coming from the coils on the left must be
    connected to the the #1 and #4 spark plugs and the
    spark plug leads coming from the coils on the right must be connected
    to the #2 and #3 spark plugs.

    You can mix up the leads between #1 and #4 or between #2 and #3, and
    the engine will run just fine.
    `, Feb 27, 2012
  4. Scott

    Scott Guest

    Thanks for the replies they were just what I was looking for. The
    bike is very hard starting but once warmed up it sounds fine. I have
    plugs, points and condensers coming this week so I am hoping that will
    help with the starting. The bike had been sitting for a long time
    before I started taking it apart so I am sure it could use a tune up.
    Thanks again for the replies.

    Scott, Feb 27, 2012
  5. Scott

    ` Guest

    The basic problem with any of those old Kettering ignition systems
    (battery, points, condensor and coil) was low voltage caused by poor
    condition of the contact points.

    The ignition coils also had to be rather small so that inductive
    reactance wouldn't prevent the rapid breakdown of the magnetic field
    in the coils that produced a spark.

    So the systems were lucky to produce 9000 to 12000 volts.

    A spark that weak has a hard timing jumping a .0.028 inch spark plug
    gap, and a gap of 0.025 inch works better.

    Old time riders will also swear up and down that their engines
    wouldn't start until they fried the spark plugs with a blow torch.

    The real problem was that a lower voltage spark doesn't produce enough
    heat *power* (in joules) to light off a relatively weak mixture.

    The carburetor engineers were actually working against the ignition
    engineers as they attempted to get good fuel economy out of their

    Our solution back in the 1970's was to make the idle mixture a little
    richer by turning the idle air screws clockwise a half turn or so.

    We were also installing K-Mart ignition coils which produced 35,000

    They would make a bright white spark an inch long compared to the
    feeble 1/4 inch long spark coming from the stock coils.

    There was a penalty for using those big K-Mart coils, they burned up
    the ignition points rapidly.

    I had a transistorized switching box which was trigger by the ignition
    points. The box handled the heavy current, the points just controlled
    the switching transistors.

    You might want to check with to see if they sell a
    transistorized ignition system for your bike.

    Dyna and Dyna-S were two models of electronic ignition which are worth
    looking into.

    Unless you're a masochist and you are willing to put up with ignition
    points in the interest of "authenticity."
    `, Feb 28, 2012
  6. <snip>

    usual nonsense....
    The Older Gentleman, Feb 28, 2012
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