KTM 640 - engine randomly dies

Discussion in 'Thumpers' started by Queen of Spades, Dec 4, 2012.

  1. Queen of Spades

    Queen of Spades tall drink of water

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    Did that - ohmmeter confirmed a bad switch. Got the new one in a few days ago, installed it and my back brake light works now.

    Tomorrow I plan to get the turn signals put back on & will go through the wiring once more to make sure I'm not overlooking any frays or bare spots. I'd love to get the thing back together and see how she runs with the new CDI.
  2. Queen of Spades

    Queen of Spades tall drink of water

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    Quick update - got the turn signals wired in with new replacement connectors (with rubber covers, like stock) and also replaced the stock glass 194's with LEDs.

    On a final check before zipping the back fender/taillight back together, I noticed that the brake bulb is not being activated. Pulled all that apart, confirmed that I have continuity and ~14 volts on the taillight wire and when either brake is applied, the brake light wire as well.

    The fault is in the brake light socket. I've replaced the bulb with several known good ones to make sure it wasn't a worn bulb contact point.

    Plan to venture out to Autozone to see if they have a replacement push & twist socket that will work with my LC4. If I roll snake eyes there, I'll just order a replacement stock part and wait another week or so to put the back end together.
  3. Droptarotter

    Droptarotter Long timer

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    Somewhere there is a whole thread on a fix for the tail light.
    I tried a search for you , but no luck.

    Cheers
  4. Queen of Spades

    Queen of Spades tall drink of water

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    Before leaving for the auto store I removed the socket/harness and removed the connectors so I had bare wire. All three circuits (ground, tail, brake) now showed continuity. Cleaned up the contacts in the socket, replaced the old bullet connectors with new parts and tried again on the bike. This time it worked. I just had a faulty connection somewhere.

    Cross-referencing the tail light thread you referred to:
    http://www.advrider.com/forums/showthread.php?t=665240

    Next steps are to button up the tail end, then while I have this thing torn down, check valve lash. Have the motion pro feeler gauge and some new gaskets on hand.
  5. Queen of Spades

    Queen of Spades tall drink of water

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    Got the tailight section put together and it looks and works great. Everything is LED except the turn signals (which I prefer stock after trying the LED version).

    [​IMG]


    Update on the purpose of this thread in next post... :cry

  6. Queen of Spades

    Queen of Spades tall drink of water

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    After getting the lights working, I decided it was time to press the Red Button. Performed a cursory check of all connections and fittings, and put the tank back on thinking I'd be riding down the street in a few minutes. Rolled bike outside and hit the starter. No spark. Confirmed with timing light on plug wire (made sure timing light worked by testing on my car). No spark, no joy.. :cry:cry:cry

    So I've rewired half the bike, replaced a $$$ CDI, and am back where I started. I'm convinced the old CDI was bad or going bad because it was buzzing when I turned the key on. The new one is silent.

    If anyone is reading this in the Atlanta area who is A) an electrical whiz and B) eager to make a few bucks and C) more eager to help a fellow inmate.. please PM me.
  7. bmwktmbill

    bmwktmbill Traveler

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    Sweet Jesus!!!

    Check the ground for the CDI box...or you have lost power.
    bill
  8. Queen of Spades

    Queen of Spades tall drink of water

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    I hadn't checked this yet as I was sure the CDI was culprit. I'm going to slip out in the shop before work this morning for a quick visual inspection.
  9. Queen of Spades

    Queen of Spades tall drink of water

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    Will do. Everything looked tight there but I didn't actually put my fingers on the green wire.
  10. Queen of Spades

    Queen of Spades tall drink of water

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    Bill: coil screws were snug.

    On to the next step:

    [​IMG]

    Ignition cover.
    [​IMG]

    Cover removed. Gasket broke, so added one to my cart:
    [​IMG]



    Pulser coil and wires appeared to be in good shape externally.
    [​IMG]



    Stator & wires looked OK as well.

    [​IMG]


    I pulled the pulser coil from the case and noticed two small cracks - probably from bending the wires during removal. KTM Parts Warehouse sells replacement pulsers for $45, so that's on order as well.

    [​IMG]
  11. Kawidad

    Kawidad Long timer

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  12. Queen of Spades

    Queen of Spades tall drink of water

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    Thanks for your contribution. :zilla
  13. Droptarotter

    Droptarotter Long timer

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    C'mon.......you gotta have good popcorn when you are reading these threads:lol3

    I hope the cracked wires sort the problem!

    Cheers
  14. bmwktmbill

    bmwktmbill Traveler

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    Somebody shake Luke loose from where ever he is and let's get him to help.

    LUKE..LUKE???

    bill
  15. Queen of Spades

    Queen of Spades tall drink of water

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    With the bike leaning to the left, is it safe to remove the two oil hose flanges on the right side of the engine without losing oil? I have to disconnect these two to replace the pulsar coil.
  16. gunnerbuck

    gunnerbuck Island Hopper

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    Yes, you can remove those lines, very little oil will flow out from there as it needs the oil pump working to bring it up from the sump...
  17. mountaincadre

    mountaincadre Been here awhile

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    Those wires dont look good, whether its those two that are the culprits remains to be seen, but i would replace it anyway as those are bound to go leaving you stranded.
  18. Queen of Spades

    Queen of Spades tall drink of water

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    Well, it finally runs. :wings

    Damage list:
    New CDI (old one made buzzing noise)
    New pulse coil (old one had a couple cracks in wiring)
    New ignition coil (old one may have been OK, got a new one just in case/spare)
    New plug cap
    New plug
    New internal oil filter
    New rear brake switch (old one bad)
    New molex connectors in rats nest behind headlight
    New bullet connectors throughout

    Additions:
    Water resistant USB charger
    Hyperlight brake lights with custom mounting brackets

    To do:
    Valve adjustment
    Oil change with new external oil filter
    New fork seals
    Foldable mirrors
    Squadron LED headlight with dimmer switch
    New front tire


    LIke I mentioned earlier, I've never worked with electrical issues other than changing bulbs. This was frustrating and tried my patience. But it's finally running and hopefully I won't have to worry about electrical issues again!

    Thanks to everyone who chimed in to help.

    :freaky
  19. dolphins13

    dolphins13 orange rules

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    Thats cool it runs. How's it run? Does the carb need to be cleaned, and or rejetted? I believe you have the same bike as mine? 99 lc4e. No snorkel, 157.5 main jet, and open exhaust, and it really runs good. Oh ya and moved the needle 1 notch up. kenda 270's are ok all around tire?
  20. bmwktmbill

    bmwktmbill Traveler

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    Happy for you.
    b