Electrical help 640 ADV

Discussion in 'Thumpers' started by CDG, Jan 11, 2007.

  1. CDG

    CDG Been here awhile

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    I have a gremlin or two in my bike it is a 98 640 ADV and was in need of some help or links or something.

    Ok when I picked it up the battery was flat, so I have since charged it but it only seems to get say, 15 or 20 starts before she's all over and all you get is this clicking noise.

    So what I did today was go to both the battery shop and an auto sparky to see what the go was.

    The battery shop put a meter on the battery and it had some 12.45v showing which looked good ( this was after me charging it ), so I then started it up and at idle it dropped down to 12.2 or something like that so the next thing I did was rev it to about 3500rpm and all that happened was the volts started to rise but very very slowly almost like counting 12.45, 12.46, 12.47, this seemed a bit slow.

    The guy seemed to think it was the regulator/ rectifyer which is what I was also thinking, so I went down to see the sparky and he told me the volts should go up quick as and pretty much told me to replace the regulator and it should be sweet.

    When I went to leave him it would not start again, so I got a jump and rode it home. Once home I checked the battery while not running and I got 12.4Volts :huh hit the button and nothing but the friggin clicking again and the slowest turning over ever.

    The regulator is one thing, and I will replace it but why would it not start with 12+ volts in the battery?

    I'm electricaly stupid so any help would be much great
    #1
  2. meat popsicle

    meat popsicle Ignostic

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    Hopefully your gremlins will sound familiar to some other unlucky soul and you will get your answer.

    I can offer a weak test: some folks who have had weak batteries have used the manual decompression lever to take some of the heat off the starter just for a wee bit o' time - don't hang on the bugger! But I tend to agree that 12+V should do something better than "clicking".

    You don't have access to another similar battery that you know is good? Hopefully someone will post how to test the regulatory rectifier for ya.

    An "electrical" link from the index:
    http://www.advrider.com/forums/showthread.php?t=107961
    (check out Happe's regulator tests :D)
    #2
  3. bmwktmbill

    bmwktmbill Traveler

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    CDG,
    A couple of things from a guy who is also having a battery issue with symptoms like yours except my regulator is putting out, maybe too much.
    Check your meter against another on to make sure it is accurate.
    If you are running a "sealed battery", break into it to make sure it has electrolyte.

    My battery would charge but not hold a charge(no electrolyte) and my meter was reading a volt high.
    I would charge the battery disconnected and let it sit for a couple of days to make sure it holds a charge and then hook it up in the bike and do the same. I messed with mine all summer.
    Thank goodness the bike kickstarts easily.
    Bill.
    #3
  4. CDG

    CDG Been here awhile

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    Thanks guy's this give's me a start for sure.

    It's all new to me atm as I've never done anything to do with electric's at all.

    Happe's regulator test should maybe sort out whether she's buggered or not.
    #4
  5. crazybrit

    crazybrit Long timer

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    You need to load test the battery. Any decent shop can do this. Hooking up just a volt meter won't prove much.

    According to the 98 LC4 repair manual, @5000rpm (on a battery which is 90+% charged] a voltmeter across the battery terminals should read betwen 14 and 15VDC.

    If this isn't the case you need to verify the stator output before you can be sure it's the R/R.

    There are plenty of good charging system troubleshooting guides around, Electrex/Electrosport used to have a good flowchart online.

    Tony
    #5
  6. CDG

    CDG Been here awhile

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    Just done a bit of mucking around with the multimeter and the strangest thing seems to happen.

    At idle (1700ish rpm) it stays around 12.7-12.8volts, at 2000rpm's it goes up to just over 13v, 13.09-13.12 but then any more revs and the volts go down constantly to around 12volts!

    Another question when the key is off volts are say 12.5-12.7, but with the ignition on it drops of hard and fast to say 10v real quick, I understand that the lights and whatnot require power but is this normal?
    #6
  7. bergdaddy

    bergdaddy tire guy

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    a good hot battery will test out at 13 plus volts.12.4 is not enough..also if the battery internally shorts out the ktm will not run learned this from experience in baja.i thought my electrical system was fried .replaced the battery bike started and ran great..i am a ktm dealer in las cruces new mexico and ride lc4s all the time..put the battery on a charger at two volts let it set for five hours.test it .if you dont have at least 13.2 volts replace it .a reg rec for that bike is over 100 dollars from ktm..start with the battery it is probably the cause ...tim
    #7
  8. ChrisC

    ChrisC Amal sex?

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    I'm thinkin' you mean 2A not 2V... no? :huh
    #8
  9. crazybrit

    crazybrit Long timer

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    I never use more than a 0.5A charger. KTM Manual recommends 0.8A.

    The manual states, just for completeness when measuring the voltage of the removed battery

    >12.7v - fully charged
    ~12.5v - 75% charge, charge for 4h @0.8A
    ~12.2v - 50% charge, charge for 7h @0.8A
    ~12.0v - 25% charge, charge for 11h @0.8A
    ~11.8v - 0% charge, charge for 14h @0.8A
    #9
  10. CDG

    CDG Been here awhile

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    Convinced it was thr R/R I went out and bought a new one only to come home and find out that the problem is still there.:cry

    An expensive lesson learnt.

    I posted on the Oz forum that I tried another battery on the bike and this didnt change anyehing which is why I bought the R/R, silly me.:huh
    #10
  11. crazybrit

    crazybrit Long timer

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    Like I said earlier, "If this isn't the case you need to verify the stator output before you can be sure it's the R/R". Perhaps you should have read more closely :D

    The R/R just regulates the incoming A/C. If that isn't correct, it can't perform magic. I'm not sure on the KTM but on other bikes you can just disconnect the R/R and measure the stator output, usually 3 wires in.

    Tony
    #11
  12. CDG

    CDG Been here awhile

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    Your right mate I should of read a bit more closely.

    I took a punt, and when I rang KTM just to price it should I need one, the guy told me the he was 99% sure thats what It would be.

    Bit of the old Blind leading the blind I reckon.
    #12
  13. gunnerbuck

    gunnerbuck Island Hopper

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    I would suggest to inspect your wiring for abrasions at any rub points , an intermittent short could be the cause of your troubles.
    #13
  14. CDG

    CDG Been here awhile

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    Probably wouldnt hurt as most of the bits I have played with are pretty ordinary looking to say the least.
    #14
  15. Dotbond

    Dotbond Africa, Africa

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    CDG.
    I am having the same problem as you are. Battery is reading about 12.4V after sitting for a week after a charge. But not enough to crank the motor over properly.
    #15