Real Question 03 640 Adv

Discussion in 'Thumpers' started by alpiv, Nov 25, 2007.

  1. alpiv

    alpiv Sr. nOOb

    Joined:
    Dec 1, 2004
    Oddometer:
    2,183
    Location:
    Indianapolis, IN
    I've now had the Adv going on two years and as you can tell, I'm enjoying it.

    Yet, and there is always one. I'm having an unusual problem.

    It doe snot matter is the bike is cold or hot.

    I turn the key and hit the magic button; the starter engages and turns the motor, yet no spark. I stop and wait a few moments and try again, same thing, eventually it starts and starts fine and runs till I turn it off, that could be hours on end. Yet, when I go to start it again, it will act up again.
    This is a hit and miss sort of thing.
    I’ve taken the tank off and verified that I’m not getting spark when this happens.
    This summer I replaced the plug wire and coil.
    I’m thinking its either the key switch, or starter button switch, yet if it was the starter switch it would not turn the motor over.
    <o:p> </o:p>
    I’m down to the key switch since it allows the starter switch to work, yet does it control spark as well?
    <o:p> </o:p>
    I’m at a loss.
    #1
  2. crazybrit

    crazybrit Long timer

    Joined:
    Mar 16, 2006
    Oddometer:
    8,786
    Location:
    Portland, OR
    If you think one of the switches is bad, why not debug it using a multimeter. If you probe around with the aid of the factory wiring diagram when it's acting up you should be able to confirm or refute your theory.
    #2
  3. paddythesmith

    paddythesmith Been here awhile

    Joined:
    Jan 11, 2006
    Oddometer:
    216
    Location:
    Wenatchee, WA
    Although I have an 02 640 adv, this comes from a 65' Land Rover I sold a year ago: I put a 'kill switch' to help thwart theft on the low tension lead going to the coil. Since the vehicle had a separate ignition switch and starter button, with my kill switch turned off, the key turned in the ignition would make all the dash lights come on, and the starter button would make the starter turn the engine, but no spark meant no starting the engine.

    I think it's food for thought. I'm no master of motorcycle electrics, but using the above example, you're obviously getting no spark (I think).
    #3
  4. gunnerbuck

    gunnerbuck Island Hopper

    Joined:
    Nov 19, 2005
    Oddometer:
    6,624
    Location:
    N.V.I, B.C.
    Why not pop off the fairing and take the bottom part off the key switch to inspect. Make sure all the wires are still solidly soldered to there posts....

    I just went thru an intermitten E -start problem and found it to be a worn thru wire [vibration] going to the relay. While I was going thru the wires I found and taped up a few others that were showing shielding wear.
    #4
  5. alpiv

    alpiv Sr. nOOb

    Joined:
    Dec 1, 2004
    Oddometer:
    2,183
    Location:
    Indianapolis, IN
    I did this inspection a year ago and one of them was bad and I repaired them then.

    I'm at the point of going threw the testing listed above by many of you again.
    This time if a post is bad, I'm replacing with new!
    #5
  6. OldnoGPS

    OldnoGPS Just a sightseer

    Joined:
    Sep 18, 2004
    Oddometer:
    1,596
    Location:
    Virginia
    Al,
    I remember that you repaired the ignition switch. That sure sounds like a likely culprit, especially since you've put a lot of hard miles on it since then.

    I've had batteries that woud crank the engine over fine but not have enough juice left to fire the unit. Usually more of a cold start problem than when hot, but - is the batt getting old? They can behave erratically if a plate is loose and it IS on a 640...
    #6
  7. alpiv

    alpiv Sr. nOOb

    Joined:
    Dec 1, 2004
    Oddometer:
    2,183
    Location:
    Indianapolis, IN
    I replace the battery this spring.
    thanks.
    My gut tells me it's the key switch.
    #7
  8. alpiv

    alpiv Sr. nOOb

    Joined:
    Dec 1, 2004
    Oddometer:
    2,183
    Location:
    Indianapolis, IN
    Ouch! $82.78 through Munn racing and that is with the 15% discount.
    It includes new key, key switch, bottom 1/2 of switch and wireing harness.
    #8
  9. halfcab

    halfcab Been here awhile

    Joined:
    Apr 6, 2007
    Oddometer:
    687
    Location:
    Dog Patch S.C.
    I would check the clutch safety switch (if you still have it) first. Then the kill switch on the bars.

    If everything comes ON (that should be ON) when the key is turned to On, chances are it not the key switch.
    You don't crank a bike by holding the key in start.

    I'm not there so it's only a guess.
    #9
  10. alpiv

    alpiv Sr. nOOb

    Joined:
    Dec 1, 2004
    Oddometer:
    2,183
    Location:
    Indianapolis, IN
    true, I need to look at the wiring diagram to ensure that it does not control something. Yet you making sence.
    #10
  11. OldnoGPS

    OldnoGPS Just a sightseer

    Joined:
    Sep 18, 2004
    Oddometer:
    1,596
    Location:
    Virginia
    Al,
    The fly in the ointment here is that the bike runs OK for as long as you ride it after it starts.
    If it was the insulation on the wires coming out of the ign switch failing again and allowing a short/no connection in that harness, I would expect that you would see intermittent cutting out while riding/turning the bars and stretching the wires.
    If it was the clutch switch it would either never let the bike start or you would see the same intermittent cutting out while riding.
    Neither of the above are likely to only cause a short/failure only when you're cranking the bike if it runs OK otherwise.
    Don't discount battery weirdness. Thumpers vibrate enough to loosen battery plates and cause strange activity. I know, the same arguments as above likely apply. However, it may be that there's a failure (loose plate/shorting) causing the batt to have enough juice to start and supply ignition at some times and not others. I just had a year old battery on my GS acting funky - tested ok on a load tester at the battery store but 80% of the time the voltage was low enough to cause ABS faults. Other times not and it was inconsistent. It even went so low once that it reset the clock, but would show fully charged on the battery tender. I bought a new gel battery and it fixed all the problems.
    Again, this is not real likely but keep it in the back of your head.
    At least you know the starter button works since it's consistent.
    Maybe check for a loose/bad wire at the ign trigger in the motor? Vibes from starting would cause it to shake, make and break. I've had the pickup wire in distributors on cars do just that. Wires are usually tiny and don't like vibration.
    #11
  12. OldnoGPS

    OldnoGPS Just a sightseer

    Joined:
    Sep 18, 2004
    Oddometer:
    1,596
    Location:
    Virginia
    I realized I didn't fully explain my battery concept above:

    I've had 3 cars that wouldn't fire while being cranked but would fire just after the starter was disengaged and the engine was still spinning. Sometimes they would start on those last couple of engine revolutions, often they wouldn't. The batteries had enough juice to spin the starter (and at enough speed to sound pretty normal) but not enough juice to supply the ignition with sufficient voltage, while cranking, to start.

    If the batt is acting like this it would explain why the bike runs OK after starting (it has sufficient juice to run the ignition circuit but not enough for both the starter and ignition) without intermittent cutting out that you might expect from some other sources.
    Again, it may be a long shot but it's a possibility.

    FYI - I sold Al the 640 so I'd like to help here (besides, I keep having visions of these problems happening to me if I had kept it!
    #12
  13. alpiv

    alpiv Sr. nOOb

    Joined:
    Dec 1, 2004
    Oddometer:
    2,183
    Location:
    Indianapolis, IN
    Hmm, I'm a thinkin.......... another $80 battery! Ya....
    I'm going to have it tested, thanks for the input.
    #13
  14. OldnoGPS

    OldnoGPS Just a sightseer

    Joined:
    Sep 18, 2004
    Oddometer:
    1,596
    Location:
    Virginia
    Al,
    Don't forget - the guy at the battery shop said my GS battery was fine. It wasn't.
    He was only guessing anyway, most load testers are for car batteries. If the innards have a bad plate you may get a "good" reading anyway depending on how you shook it on the way to the battery store.
    I'd try to find a known good battery from another bike and swap it. It's an easy check that way.
    Please post up when you get it figured out and good luck.
    #14
  15. Luke

    Luke GPoET&P

    Joined:
    Aug 25, 2004
    Oddometer:
    5,002
    Location:
    Beaverton, OR

    Just test it yourself. Hook a voltmeter up to the battery. With everything turned off it should read between 12 and 13 volts, depending on how well charged it is. When you turn the bike on and hit the starter, it should be at least 10V. It's easier than taking the battery out, and you are testing it with its real load.

    The older ('02 and earlier) Kokusan ignition required at least 5.5V on the 12V input (orange wire) to run, but I don't know what the new one needs.

    Looking at the '03 wiring diagram, the ignition wires you need to worry about are the orange and red/orange wires. The orange comes from the handlebar kill switch and provides power for the ignition. It should have 12V on it.
    The Red/Orange comes from one of the diodes and the sidestand switch. I don't know what the voltage should be.
    #15
  16. OldnoGPS

    OldnoGPS Just a sightseer

    Joined:
    Sep 18, 2004
    Oddometer:
    1,596
    Location:
    Virginia
    A better plan for testing the battery for sure! I've done that before but didn't even think about it. Duh.
    Al's bike only came with a centerstand. Sidestands, AFAIK, were only accessories with no switch. Wonder what the deal is with the sidestand switch in the wiring diagram?
    #16
  17. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
    Oddometer:
    14,552
    Location:
    Circumlocution Office of Little Dorrit
    Did you try kick starting it? If the kick starter fails to start it disconnect your headlight and try again; there are reports that the headlight draw can over-tax a drained battery and without it you can kick-start an LC4 with a low (or dead?) battery. Might be an easy way to troubleshoot a battery, and narrow the field of choices on the intermittent spark issue.
    #17
  18. bmwktmbill

    bmwktmbill Traveler

    Joined:
    Jul 16, 2005
    Oddometer:
    5,986
    Location:
    Traveler
    Check the main fuse, the 20 amp by the battery.
    Squeeze the clips tight in the rubber fuse holder.
    Mine went for a vacation and drove me a little crazy 'til I found it.
    Eventually the bike would not start at all.
    b.
    #18