KTM 640 - engine randomly dies

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

  1. tallbob

    tallbob Been here awhile

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    Mine's a 99 640E too. Picture isn't too clear but there are 2 yellow/red wires on one pin and 2 brown wires on the other pin of that connector.

    [​IMG]
    #21
  2. Queen of Spades

    Queen of Spades tall drink of water

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    That works - suspected they fell out of the connector. Not sure of the best way to get them back in it -- will soldering work here? It seems like it would need to be cleaned off prior to that, though. Any ideas?
    #22
  3. bmwktmbill

    bmwktmbill Traveler

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    Problems like this are difficult.

    You will have to release the connector from the plug with a pick, resolder and then reinsert.

    Sometimes that works. If it doesn't you will need new stuff to somehow recreate the connection.
    bill
    #23
  4. Queen of Spades

    Queen of Spades tall drink of water

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    Have you seen any youtubes or pictoral guides on how this is done (releasing fitting from connector with a pick)?
    #24
  5. bmwktmbill

    bmwktmbill Traveler

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    #25
  6. clintnz

    clintnz Trans-Global Chook Chaser

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    Go to an electronics, auto sparky or auto parts store & get some new spade terminals to go in the plugs, should only be a few cents. The connectors come in all different shapes & sizes but the actual terminals inside are fairly standard. Once you have the new bare terminals you'll see how they are retained.

    Cheers
    Clint
    #26
  7. Queen of Spades

    Queen of Spades tall drink of water

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    We don't have an Auto Sparky (though I wish we did - love the name!), but I will drop in at a Radio Shack and see if they still sell anything remotely close to what we are talking about.. Used to be a good place to get electronic parts, but now they are geared up as a phone dealer with a few odd audio/power cables.
    #27
  8. ChrisC

    ChrisC Amal sex?

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    Google "McMaster Carr" - they have all sorts of 12V connectors, including waterproof, so you could rewire and replace the faulty connector... :deal

    [​IMG]
    #28
  9. wrk2surf

    wrk2surf on the gas or brakes

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    radio shack does have molex connectors similar that come with the new pins and they sell the tool .. works in a pinch !
    #29
  10. Queen of Spades

    Queen of Spades tall drink of water

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    Good news/bad news.

    Good: made a tool to get the molex connector removed. It worked.

    [​IMG]

    [​IMG]

    I crimped the wires back to the clip and soldered the connection too. It is snug as a bug.

    [​IMG]

    More good news: it started up no problem. Warmed the engine up, then let it idle while I went over to talk with a neighbor.

    About 5 minutes later I heard the bike stall out of nowhere. The headlight stays on, it just won't start. I've jiggled the connections, taken them apart and put them together. Fuses ok.

    Exact same f'ing problem as before.

    I want to pull my hair out. What else would randomly cause it to die? Nothing else in the battery area is loose or worn/exposed.
    #30
  11. Queen of Spades

    Queen of Spades tall drink of water

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    Pulled the headlight shell and tank/shrouds off. I cannot find a single wire that has a bare spot on it. Nothing is loose.

    What on earth would be causing this problem? Please help?
    #31
  12. Aussie Steve

    Aussie Steve Long timer

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    Does sound like an electrical connection gone bad. They can be a real pain, for example my intermittant charging issue from a while ago was this:-

    [​IMG]

    Fuse looked fine from the outside and tested okay when tested normally, a voltage drop test when it was playing up found the problem and the fuse cover broke when trying to remove fuse.

    Sorry but you're going to have to trace the fault, start by confirming that you loose spark when it wont fire (it does crank doesnt it?). id it does from there check for power to ignition system, stator and pickup coil tests when its not working.
    #32
  13. Queen of Spades

    Queen of Spades tall drink of water

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    Yes it turns over - just no fire. I don't have the right size socket to get the plug out to test that. Thought it was 5/8.
    #33
  14. dolphins13

    dolphins13 orange rules

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    Of course you turned the gas back on? I've messed with myself a few times by forgetting to turn on gas. Especially after I have been dealing with an annoying problem or havnt ridden in a while. Did a fuse blow? I mean it was just purring away and died for no reason? Sounds like something quit, fuel or spark? Have you studied all the info on page 1 of the main 640 thread? To have it just die sounds like gas quit? Your connection held? Maybe you left the plug cap loose? I can't be the only one that has done all these dumb mistakes? I also have a 99 lc4e so I am feeling for you. My bike has been nothing but a dream. To have it not run would drive me nutz. good luck
    #34
  15. Queen of Spades

    Queen of Spades tall drink of water

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    Fuel is flowing from the petcock just fine. Bike runs crisp and STRONG when it runs. All 4 fuses are in tact. It seems electrical. Just can't find anything obvious, and I'm not very familiar with a multimeter. Wouldn't know where to begin (other than knowing that I would need to do *something* between component A and component B).
    #35
  16. Aussie Steve

    Aussie Steve Long timer

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    dont need to pull the plug out, pull the lead off, slide an appropriately sized screwdriver into the lead, holding it by the plastic end (you'll know if you dont) about 4mm off a good earth crank the bike. Does a spark jump across to the earth when its going well?

    if yes do the test again when its not running

    if no check its a good earth and screwdriver is inserted properly and repeat.

    when test is done when not running

    if there is spark forget electrical, check your plug and carb.

    if no spark its electrical, check as per previous post with service manual.

    Edit.

    after previous post if its electrical find a sparky or someone who knows a bit about auto elec (very basic knowledge is all)
    #36
  17. Queen of Spades

    Queen of Spades tall drink of water

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    #37
  18. bmwktmbill

    bmwktmbill Traveler

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    The plug itself can fail, it happens after they warm up. Aussies test works for the system but not the plug itself, put another one in. And you did tighten the plug cap to the lead?

    Have you tightened the main fuse?
    Not the circuit fuses, the main fuse. Should be back by the battery?

    Do you have any saftey switches still working?

    Start thinking about how you will test the ignition switch.

    On my '02 640a the engine would kick out for no good reason at speed, scared me, it was the ignition switch.

    Check the wires coming out of the ignition coil, sometimes they wear against each other.

    You say fuel isn't your problem. Next time it dies close the gas tap and open the drain screw on the bottom of the carb, gas will drain until the bowl is empty...hope you get half a tea cup.

    Very sorry for your problem.
    bill
    #38
  19. Queen of Spades

    Queen of Spades tall drink of water

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    Bill,
    The bike does not sputter or lose power when it cuts off. Running clean and strong one second, off the next. Not so much as a cough when turning over. After it died yesterday I tried a little starting fluid - still no much as a cough.

    I removed then replaced the main 20a fuse by the battery. It required a little effort to remove and replace - it fits snugly in the clips.

    The head/taillight, turn signals, horn, neutral indicator, and starter continue to work in this condition.

    I suppose the next step is to check that I have spark & rule out a possible faulty plug.

    The engine service manual I have is for a 98 LC4 Enduro, not sure what changed between 98 and 99 -- but it does list some detailed instructions for checking different components of the electrical system. Some of the tests have to be done with bike running so I doubt I will be able to do that (if it starts at all this morning).

    Still 39 degrees outside, too cold in the shop just yet. I'll dig in a bit later.
    #39
  20. mountaincadre

    mountaincadre Been here awhile

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    Sorry if it's been said before but you have checked it's not another dodgy side stand issue.
    #40