Old CBR600 Electrical

Discussion in 'Motorbike Technical Discussion' started by Puddin' Man, Aug 28, 2008.

  1. Puddin' Man

    Puddin' Man Guest

    '87 CBR600, 20k mi. Had to replace the pulse generator in the 90's. No
    electrical problems in many years since.

    Failed to start yesterday. Starter motor functions fine. No combustion
    (pop, splutter, etc) whatsoever. Fails spark test.

    All fuses are OK. Got too hot in the garage to proceed.

    The spark units on these things go bad? Anybody know how to test?

    Other possibilities?


    "I Ain't Blind, I Just Don't Wanna See"
    - the title of a tune by Little Joe Blue, maybe 1966
    Puddin' Man, Aug 28, 2008
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  2. Puddin' Man

    . Guest

    How about the 30-amp fuse hidden on top of the starter solenoid?
    Check for 12 volts at the ignition coil, and 12 volts to the ignition
    control unit and a good chassis ground.

    If you are getting 12 volts from the ignition coils to the controller,
    you should get ONE spark on the 1 and 4 or 2 and 3 spark plugs every
    time you turn the ignition switch on and off.

    Transistor ignition units basically replaced the older ignition points
    with a transistor, and every time the transistor gets a pulse from the
    pulser coil, it switches off momentarily.

    You can test the coils themselves by applying 12 volts to the plus
    side and using a wire from the minus side to chassis ground to
    simulate a set of ignition points

    It's possible to simulate the pulse by applying 1.5 volts from a
    flashlight battery to the pulser inputs on the control unit, but if
    you get the polarity wrong, you can blow out a transistor. :-(

    Your local Honda $tealer$hip probably has an ignition unit tester.
    ., Aug 28, 2008
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  3. With an electronic tach, this is pretty easy.

    If it's a problem in the trigger circuit, my tach stays flat while
    cranking but shows a blip when I turn the key off and the trigger
    circuit is grounded.

    If it's a problem in the coil rather than the trigger, the electronic
    tach will
    show some small RPMs while it cranks, indicating that it's triggering.

    If you don't have an onboard tach, an engine analyzer also shows
    RPMs when hooked to ignition coil negative. RPMs indicate
    that the trigger unit is making and breaking a ground.
    Rob Kleinschmidt, Aug 28, 2008
  4. Puddin' Man

    Puddin' Man Guest

    What I got is the original tach for '87 CBR600. I don't see
    a cable, so I assume it is electronic. The needle does
    nothing whatsoever when I test per above.

    Is the result above from a '87 CBR600? Some later year?

    Note: I am at best a novice mechanic. I've got a $10 analog and
    a $10 ($30 not-on-sale) dig. multimeter. Understand the bare-
    bones-basics of resistance, but don't know how to interpret
    some of the ohmmage readings I get on these flogging things.

    Further tests:

    Spark test fails on #1 (on coil 1) and #2 (on coil 2) cyl. plugs.

    Battery was somewhat run down from testing, but measured 12v at source
    and 10.6v to spark unit 6-pin connector. Battery is now on

    There are 2 tests for the 4-pin connector at the spark unit (pulse
    generator circuit):

    Ohms (each leg) - One leg consistent at ~ 1 ohm. Other leg erratic:
    all over the dial. Both should be ~ 500 ohms.

    Ground fault (each leg) - Tested OK, no fault.

    I think I smell another damnable pulse-generator failure, but I'm
    not sure.

    Would love a definitive test. Fear I'm out of my element.


    "I Ain't Blind, I Just Don't Wanna See"
    - the title of a tune by Little Joe Blue, maybe 1966
    Puddin' Man, Aug 29, 2008
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