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Thread: Gsf 250 charging problems

  1. #1
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    3rd May 2018 - 22:07
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    Gsf 250 charging problems

    So I've had my gsf250 for a month and a half or so. When I got it the battery seemed pretty buggered (not starting, having to crash start etc), so I replaced it with a new one from the local motorcycle shop. Everything since has been fine except the same problems are starting to occur that caused me to replace my last battery.

    I charged the battery, left it overnight, and check the voltage in the morning. Voltage was 12.8V, I then started the bike and the voltage was around 13.3V. Rode the bike to work (about 10km) checked the voltage again while the bike was off and the battery voltage was about 12.3V. Started the bike again and the voltage was again around 13.3V. I then revved the bike and the voltage immediately dropped to around 12.9V-13.0V.

    This seems strange to me that the voltage would drop so sharply when revving the bike. I'm thinking problems with the charging coils (not sure what they are called on a bike, most of my mechanical/electrical experience is on cars).

    Any ideas on what this could be?

  2. #2
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    28th October 2012 - 13:59
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    Sounds like its charging ok, the slight voltage drop when you rev it is probably the regulator coming into play.
    I would be looking for a parasitic draw on the battery when the key is off, pre computer so imagine
    there should be no draw from battery with key off if everything is functioning correctly.
    Political Correctness, the chief weapon of whiney arse bastards

  3. #3
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    Quote Originally Posted by buggerit View Post
    Sounds like its charging ok, the slight voltage drop when you rev it is probably the regulator coming into play.
    I would be looking for a parasitic draw on the battery when the key is off, pre computer so imagine
    there should be no draw from battery with key off if everything is functioning correctly.
    Ill chuck a multimeter on it and see if there is any current draw.
    The only thing that I can think of that would cause that sort of draw is the aftermarket horn one of the previous owners installed, so i'm not sure

  4. #4
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    Quote Originally Posted by buggerit View Post
    Sounds like its charging ok, the slight voltage drop when you rev it is probably the regulator coming into play.
    I would be looking for a parasitic draw on the battery when the key is off, pre computer so imagine
    there should be no draw from battery with key off if everything is functioning correctly.
    I chucked a multimeter on the bike and was reading a parasitic draw of 0.42A when the key is turned off.
    I isolated the horn wiring and still found the parasitic draw of the same current.

    It doesn't seem like much, but I suppose that fact it doesn't have any computers, and its a reasonably small battery.
    I'll have to get around to diagnosing that, or install a battery isolator switch. One of the two.

  5. #5
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    Quote Originally Posted by geemannz View Post
    Ill chuck a multimeter on it and see if there is any current draw.
    The only thing that I can think of that would cause that sort of draw is the aftermarket horn one of the previous owners installed, so i'm not sure
    I would pop the negative lead off and then see if you can get a spark between the terminal and the lead by lightly
    brushing them togeather, if a good spark it could smoke your multimeter if you hook it up
    in series to get an amps draw figure but if faint probably safe to do so.
    one of the places you get a current loss is through your regulator/rectifier when diodes etc begin to fail.
    Political Correctness, the chief weapon of whiney arse bastards

  6. #6
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    Quote Originally Posted by buggerit View Post
    I would pop the negative lead off and then see if you can get a spark between the terminal and the lead by lightly
    brushing them togeather, if a good spark it could smoke your multimeter if you hook it up
    in series to get an amps draw figure but if faint probably safe to do so.
    one of the places you get a current loss is through your regulator/rectifier when diodes etc begin to fail.
    Bit late for that I guess lol. Thanks for the tip about the reg/rect. Ill have to check that out before I do anything.

  7. #7
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    Quote Originally Posted by geemannz View Post
    Bit late for that I guess lol. Thanks for the tip about the reg/rect. Ill have to check that out before I do anything.
    half an amp is a fair bit over 24hrs, soon flatten a battery.
    Political Correctness, the chief weapon of whiney arse bastards

  8. #8
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    Quote Originally Posted by buggerit View Post
    half an amp is a fair bit over 24hrs, soon flatten a battery.
    Looks like ill have something to do over the next couple of days. Cheers for your help

  9. #9
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    Geez that's huge loss. Erm, try unplug the regulator and dash and anything else you can think of until it stops.

    I'd be expecting to see 14v or thereabouts so you sound like a touch low. Maybe connected.
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  10. #10
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    Quote Originally Posted by buggerit View Post
    one of the places you get a current loss is through your regulator/rectifier when diodes etc begin to fail.
    or one of the phases of your alternator has failed, as revs increase the load does so the alternator isn't able to keep up and manifests as a voltage drop.
    suzukis are renowned for poor charger systems in the older days

  11. #11
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    Quote Originally Posted by jellywrestler View Post
    or one of the phases of your alternator has failed, as revs increase the load does so the alternator isn't able to keep up and manifests as a voltage drop.
    suzukis are renowned for poor charger systems in the older days
    I should be able to check that my checking continuity between the outputs yes? Assuming I can find the wires.

  12. #12
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    3 same coloured wires come out of stator through a connector (check contacts and plug melting) heading for the Rectifier-regulator. Unplugged you should get say 50vAC or at least the same as each other. Check ideally when warm but cold might give you a bad fault ie. Sometimes the insulation breaks down and wires touch only when hot for example.
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  13. #13
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    Hook up the meter with the bike off and start pulling fuses. When the 0.42amp draw goes away that’s your problem circuit. Ride to work. Unplug fuse. Plug back in to ride home.

  14. #14
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    Or perhaps, you know, fix it. Might be important like
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  15. #15
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    Quote Originally Posted by F5 Dave View Post
    Or perhaps, you know, fix it. Might be important like
    Eh who want to actually fix problems, if a bodge fix breaks, bodge it again right?

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