90 suzuki katana 600 not starting, won't fire at the plugs

Discussion in 'Motorbike Technical Discussion' started by jsbandit, Jan 11, 2007.

  1. jsbandit

    jsbandit Guest

    Ok, here's one for ya. My '90 katana 600 won't fire. I've checked the
    coils and I have the right ohm reading at the plugs and the electrical
    connections. When I turn the key on, both sides of the coil read +. I
    have switched out the coils and the ignitor box already with new ones.
    I checked the signal generator as well. My resistance reading is
    166ohms on the leads which according to the book is within specs.
    However, when I crank it over, none of the plugs fire. Is there
    something I'm missing or doing wrong? It also turns over very slow,
    even on different batteries. Don't know if that helps or not but it
    only seems to turn at 1/2 the normal start-up rpm. All the other wires
    seem to test out okay. I've gone through the electrical schematics
    with a fine tooth brush and it looks like everything is wired up
    properly. Are both ends of the coil (not the plug ends) suppose to be
    hot all the time except for when it fires? How does the signal
    generator work? Does it ground itself out to create the fire signal to
    the ignitor?
    Please help me!!! All I want to do is ride!!!
    jsbandit, Jan 11, 2007
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  2. If there's an electronic tach, that makes an easy test. The tach is
    likely driven by that same pulsed ground. If the ignitor box is being
    driven, the tach should show RPMs when you crank. If there's no
    trigger or the box is bad, the tach needle would stay flat. Not
    with this particular bike, but definitely look at the tach.
    If you pull the plugs and ground them, that'll get rid of most of the
    starter load and you ought to see a spark if there's one to be had.
    Make sure the plug bodies are grounded so you don't have high
    voltages looking for a path to ground.

    Bump starting is an OK test if you've got friends to help you. Alone,
    I wouldn't bother.

    You also checked the plug wires I assume.
    If it keeps on cranking, I wouldn't worry too much about the battery.

    I missed a ride last saturday because of a really dumb problem.
    After farting around with the ignition system for an hour or so,
    I finally noticed a broken throttle return spring that was keeping
    the throttle wide open when I rolled off at the twistgrip. I replaced
    the broken spring and it immediately started.

    DOH !!!
    Rob Kleinschmidt, Jan 13, 2007
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