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Voltage/Rectifier WTF? - FIXED!! Pics!

Discussion in 'XJ Technical Chat' started by skippy344, Oct 12, 2009.

  1. skippy344

    skippy344 Member

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    OK, so in the process of my fuel flow issues with Rosie,

    I noticed that the Voltage/Rectifier is too hot to touch, and the wiring is so hot that it will soon melt the Molex connector.

    What is causing this?? When she's running, the voltage across the battery is 14.4v.

    Oh, and she still bucks while accelerating, like she is fuel starved.

    I stopped working on the fuel starvation thingy until I figure out what is going on with the too hot V/R and wires.

    Any ideas?
     
    skippy344, Oct 12, 2009
    #1
  2. lostboy

    lostboy Well-Known Member

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    Re: Voltage/Rectifier WTF?

    Check the connections in the Molex plug. A bad contact leads to resistance witch leads to heat.
     
    lostboy, Oct 12, 2009
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  3. skippy344

    skippy344 Member

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    Re: Voltage/Rectifier WTF?

    The plug is fine. I recently replaced it. I also used dielectric grease on the connector.

    The connector was melted on one of the alternator wires when I got the bike from the previous owner.

    Don't know why the alernator wire is heating up, or maybe it is coming from the V/R.

    It is a replacement that I got from the salvage yard. The original one has the melted connector.

    I took apart the alternator to see if the brushes were ok, and they looked fine.
     
    skippy344, Oct 12, 2009
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  4. MN-Maxims

    MN-Maxims St. Paul Minnesota

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    Re: Voltage/Rectifier WTF?

    Maybe the battery is not in that good of shape and the alternator is working too hard to keep the charge up thus overheating the wires and regulator. Have the battery load tested and see if its up to par.

    MN
     
    MN-Maxims, Oct 12, 2009
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  5. David3aces

    David3aces Member

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    Re: Voltage/Rectifier WTF?

    Clean all the ground connections; Battery to engine connection and harness to frame connection.
     
    David3aces, Oct 12, 2009
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  6. skippy344

    skippy344 Member

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    Re: Voltage/Rectifier WTF?

    Battery is brand new, 12.8v while off.

    I will check the grounds, but I recently replaced both cables with model correct cables.

    Thanks,
     
    skippy344, Oct 12, 2009
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  7. MN-Maxims

    MN-Maxims St. Paul Minnesota

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    Re: Voltage/Rectifier WTF?

    OK
    Also is the bike stock or do you have any thing on there that would increase the load on your electrical system, Lighting, radio or ?

    MN
     
    MN-Maxims, Oct 12, 2009
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  8. skippy344

    skippy344 Member

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    Re: Voltage/Rectifier WTF?

    Stock, except for the Dynatek coils.
     
    skippy344, Oct 12, 2009
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  9. Robert

    Robert Active Member

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    Re: Voltage/Rectifier WTF?

    Have you checked the alternator brushes for length (looks fine isn't good enought I'm afraid)???? They must be within operating length (12-8.5mm max/min)
    They WILL cause a multitude of problems including melting the connector (you ain't alone on that one). Bad idle, flaky electrical issues, the list goes on.
    Be sure to clean up and examine the brush ring on the rotor, use a pink pencil eraser/rubber to gently clean it off. Do a resistance check on the rotor and the stator windings.
    The other culprit for melted alternator connectors is corrosion on/in the supply/return wires!
    The resistance of the supply wires goes up as corrosion does it's dirty work. This occurs since the conductor of the wires are not insulated against moisture. We all wash our rides but this and rain are the reasons we are having problems this far down the road. The water wicks into the wire and the corrosive process begins. See a green connection? If you strip the wire back, you will still find the green corrosion due to this condition. Best fix is to replace the wire and seal the ends to prevent this problem from reoccurring.
     
    Robert, Oct 13, 2009
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  10. skippy344

    skippy344 Member

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    Re: Voltage/Rectifier WTF?

    Thanks for all the great advice. Here is my plan...

    I went to an auto junkyard today and clipped a couple of 8 position harness connectors.

    I am going to cut off my melted ends, pull the wires out from my water-tight connector I bought, solder my wires onto the pins and plugs on the new connector and see what happens.

    Pictures to follow...
     
    skippy344, Oct 13, 2009
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  11. zrttodd

    zrttodd Member

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    Re: Voltage/Rectifier WTF?

    I had the same problem with my 700 X. Fixed the melted wires.Replaced the key switch and that was the problem. Check this web site out www.geocities.com/motorcity/speedway/7795/ it is the xj electrical page.
     
    zrttodd, Oct 13, 2009
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  12. skippy344

    skippy344 Member

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    Re: Voltage/Rectifier WTF?

    Wow, Todd, that site is thorough! I have been studying for the last 2 hours!

    Reading, I have found I have more electrical problems. My headlight comes on as soon as I turn on the key. I see its not supposed to until the bke is running. Gotta go trace that problem too!

    So, possible new key switch, replace reg/rec connector, fix lighting circuit.

    I should be busy the rest of the week, thanks!

    Appreciate the help folks.
     
    skippy344, Oct 13, 2009
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  13. skippy344

    skippy344 Member

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    Re: Voltage/Rectifier WTF? - Fixed!

    Rosie lives again! I went an auto salvage yard and found an 8 position water-tight connector and installed it onto the rectifier/regulator harness.

    The wires do not get hot anymore!!!

    Here are some pics of the repair, enjoy...

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    [​IMG]

    You will notice that I have a head gasket leaking oil, but no compression loss. Or, could this oil be coming from somewhere else?
     
    skippy344, Oct 17, 2009
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  14. Kracket

    Kracket Member

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    Re: Voltage/Rectifier WTF?

    dang the website does not exsist anymore...

    Just bought a xj650
    the guy said it does not run and it might be something to do with the V/R...
     
    Kracket, Mar 6, 2011
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  15. adrian1

    adrian1 Active Member

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    adrian1, Mar 8, 2011
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  16. Shannonside

    Shannonside Member

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    Re: Voltage/Rectifier WTF?

    Hi,

    Is there a problem if I share that info with individuals who would like to have it ?

    I actually copied that material onto my hard drive a couple of years ago, and it really is fantastic information.

    Don't want to tread on anybodys toes, naturally.
     
    Shannonside, Mar 8, 2011
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  17. Alive

    Alive Active Member

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    Unless there was something stated in the info when it was posted to suggest it was copywrited or similar. I'd say go for it
     
    Alive, Mar 8, 2011
    #17
  18. amfmtxca

    amfmtxca Member

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    Looking forward to that posting, I am tackling lots of small problems, dont have a lot of time so I want to get everything working like new so I can enjoy what little time I do have to ride
     
    amfmtxca, Mar 10, 2011
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  19. Shannonside

    Shannonside Member

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    Hi folks,

    I rooted that article out, and when I Googled it's title - ''XJ-OWNERS Electrical System FAQ'' - I discover somebody has archived it already - on this forum !

    http://xjbikes.com/Forums/viewtopic/p=184440.html

    Hope it's useful to people, I've surely found it very valuable !
     
    Shannonside, Mar 10, 2011
    #19
  20. adrian1

    adrian1 Active Member

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    :lol: I posted that link in my post of March 8 :wink:
     
    adrian1, Mar 10, 2011
    #20
  21. RickCoMatic

    RickCoMatic Well-Known Member

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    If the information isn't protected by copyright, ...
    and, ...

    Is Valuable because it contains information which is helpful and correct, ... making it available to others is a nice gesture.

    If there's a problem with it that needs correcting or clarification; bringing it in for others to read may be doing more harm than good.
     
    RickCoMatic, Mar 10, 2011
    #21
  22. Shannonside

    Shannonside Member

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    :lol: I should have probably run the search in the forum's search facility, but Google gave me that other thread as the first hit. No harm done I suppose :wink:

    As far as RickCoMatic's point goes...

    The top of the document says clearly
    I'll leave it to wiser heads than my own.
     
    Shannonside, Mar 11, 2011
    #22

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