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  1. #1
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    Default Parasitic drain?

    Hey dudes.

    First off, thanks for all the ideas and help. I've been reading and lurking for a while, and learning a lot from you talented folks, and even learning a little from you untalented fuckers. ; )

    I've got a 1987 Sportster. Used to be and 883, punched to 1200. When it runs, it hauls. But the battery will run down in a few days if I don't keep it on a tender every day, maybe ever other day. So I think I've got a trickle of current running through somewhere in the electrical system.

    Here's my question:

    Does anyone have a methodical approach for chasing down battery drain on a carbed Sportster? My wiring is pretty close to stock and I'm looking for what are the most common components to cause this problem.

    Also, can i see a couple of photos of how y'all have your circuit breakers mounted in custom applications? I'm looking for ideas there because right now, they are just mummified in electrical tape and hanging out under the seat, waiting to cause problems.

    thanks for your time.

    Bryan

  2. #2
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    Default

    check draw across the fuses to isolate the circuit and then start tracing that circuit.

  3. #3
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    Default

    Here are a couple places to start:

    One. Do you have a HD service manual for your year range bike, or at least a Chilton's manual for your bike? If not, the service manual has a real good troubleshooting section, as does the Chilton's. Get one.

    Two. Has this problem started small and gotten steadily worse, or did it happen from one day to the next?

    Three. Have you changed any electrical components, or fiddled with anything on the bike before this happened?

    Four. Do you know for sure how old the battery is? Have you pulled it and taken it someplace to be load tested( like Batteries Plus, or a bike mechanic)?

    Five. Have you inspected, cleaned, applied di electric grease to: POS/NEG terminals on battery, ground strap/ wire connect point on frame, voltage regulator connections, and your fuses?

    If you've addressed these all and still have this problem, the most likely components are a bad/ old battery that just won't hold a full charge any more; a bad/ old voltage regulator that is not recharging the battery properly anymore; or, less likely, a bad/ old alternator that is not providing a charge any more.

    I tried to list these in order of likely hood. Unless you were fiddling with the wiring (on purpose, or bumped it working on something else), then a parasitic draw from a shorting wire is pretty unlikely. If you did, or think you may have bumped/ jiggled a wire loose, then start there. Check for friction points that could cause worn insulation. Check connections to make sure they are still connected and tight. Get a volt meter and learn how to use it, if you don't already. Every once in a while, a wire can break or melt inside it's insulation, with no outward sign. That's where a volt meter comes in handy.

    The best advice I can give you is don't get frustrated and start buying replacement parts out of frustration( ask me why I say that...). My experience has been that electrical problems are usually something small and easily fixed, or cheaply replaced. I'm no expert but I have been in your shoes, they are uncomfortable. Good luck

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    Default

    first thing you need is to buy a manual. Check the battery for proper voltage. The manual will show you how to check the charging system. I have a 86 and a common problem is a magnet coming off not letting the stator work properly. If you've troubleshot everything else and it is your charging system the manual shows you how to remove your primary cover and get to your stator. if it does happen to be a magnet you will be able to see the real fast after removing the cover all the chunks of magnet inside.

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    Here's a dropbox link to the manual, if you don't have it allready.

    https://www.dropbox.com/s/3emk7sut6s...20Manual.pdf?m

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    Default

    Charging system?

  7. #7
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    Default

    Quote Originally Posted by Brendden View Post
    Charging system?
    Probably. Unplug the regulator and so if that stops the current draw.

    Bob

  8. #8
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    Default

    Thanks everybody, for the insight.

    Had the battery load tested and it shows up as serviceable but slightly weak so I'll be replacing that this week.

    I was getting 0.43 mA draw with the bike off. The factory manual states that anything above 1mA is a problem, but I wanted to try to see if i could get it lower anyway.

    I wirebushed and put dielectric grease on the ignition switch, battery terminals and all breakers, mounted the breakers more securely and checked again and now the draw is so low it doesn't register on a meter.

    So that's pretty cool. I believe my problems were probably some combination of the weak battery and a trickle of current through a terminal on a breaker rubbing on the frame or something.


    Thanks again. The manual download is really helpful. I get plenty of use out of my paper copy but having a digital one is also very useful.

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