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Replacing AC generator

Discussion in 'XJ Technical Chat' started by Rockpanther, Sep 29, 2009.

  1. Rockpanther

    Rockpanther New Member

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    I turn my key and nothing happens...battery is draining no matter what my key position. Traced all circuits and continuity and isolated problem to my AC generator...I'm thinkin this unit is bad (83 XJ 750 Maxim w/ 30K miles). My question is about replacing. Is it difficult? My manual would suggest I need to remove motor...is that right? Am I barkin up the wrong tree? Some feedback please...
     
  2. MBrew

    MBrew Member

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    You'll get more feed back if you post this in the XJ chat section. This section is to buy and sell stuff.

    For the record, its very unlikely that your alternator is draining the battery while the bike is off.

    Mike
     
  3. SQLGuy

    SQLGuy Well-Known Member

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    I would expect that the rectfier/regulator would be the problem in this case, not the alternator.
     
  4. Rockpanther

    Rockpanther New Member

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    Well the battery is draining when hooked up. With schematic in hand and a meter, I checked the course through fuse box, stop switch which showed nothing. Working back the other way through the main fuse showed a short, so you may be right about the regulator...but it seems impossible that a short circuit would occur on that device...makes more sense to me is that a coil in the stator would be more likely...of course I am neither an electrician nor a trained mechanic, nor terribly experienced with motorcycles. Regulators are less reliable than stator coils?
     
  5. SQLGuy

    SQLGuy Well-Known Member

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    Anything short in the alternator would still be isolated from the electrical backbone by the regulator - specifically the rectifiers in the regulator. Also, the alternator windings are supposed to be only a couple of Ohms in resistance. So, regardless of whether the alternator was good or bad, a shorted rectifier is going to drain a lot of current back through the alternator.
     
  6. MiCarl

    MiCarl Active Member

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    Agreed.
     
  7. Rockpanther

    Rockpanther New Member

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    Even with the key off?
     
  8. SQLGuy

    SQLGuy Well-Known Member

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    Yes
     
  9. MiCarl

    MiCarl Active Member

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    Disconnect the regulator/rectifier.

    If the problem goes away:

    With key off voltage between the brown wire and ground. It should read 0 volts. If it doesn't you have a bad switch or wiring problem. If it reads 0 volts replace the regulator/rectifier.
     
  10. Rockpanther

    Rockpanther New Member

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    read what you wrote....LOL...which is it?
     
  11. Rockpanther

    Rockpanther New Member

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    LMAO...thanks for the help guys...turns out..it was the "new" battery...evidently faulty....no wonder we couldn't track the short down...LOL
     

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