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Thread: 02 GS Alternator/Generator Lifespan

  1. #1
    ohbeemer
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    02 GS Alternator/Generator Lifespan

    I am planning for long distance riding and have never had any service on the electrical generating system. Any history of the lifespan on these? My bike has 90k miles.

  2. #2
    Registered User
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    95K on mine, no concerns to date. just be sure alt. belt is in good condition. should get changed out about every 35K (factory used to say 25K, but collected experience indicates the longer interval is reasonable).
    Ride Safe, Ride Lots

  3. #3
    Nickname: Droid
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    At about 120k on my 94 RS the alternator nose cage bearing would whine a bit. That winter I rebuilt the alternator with parts swapped from a salvage alternator with low miles on it.

    I also checked the brushes for wear. Even at 120,000 miles the brushes were not even half worn, so I'd assume them to last at least 200,000 miles.

    I have seen many Oilheads with well over 100k on the clock and no noise/issue from the alternator. I wouldn't worry about it unless you plan to do a bunch of long term maintenance on the bike anyway.

  4. #4
    Alps Adventurer GlobalRider's Avatar
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    Quote Originally Posted by pat View Post
    Any history of the lifespan on these?
    The brushes (part of the voltage regulator) and slip rings are a wear item. So are the bearings. That is just about it.

  5. #5
    Pepperfool GSAddict's Avatar
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    Alternator

    One of the more reliable components on oilheads.
    If you are really concerned, stop by a automotive electric repair shop. They can easily load test the alternator for you for a nominal fee.
    '
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    It's all about the details.

  6. #6
    Pepperfool GSAddict's Avatar
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    Quote Originally Posted by bikerfish1100 View Post
    95K on mine, no concerns to date. just be sure alt. belt is in good condition. should get changed out about every 35K (factory used to say 25K, but collected experience indicates the longer interval is reasonable).
    I have seen a couple belts start to fail when exceeding the interval. The big risk is when they start to shred, the thread gets wrapped around the lower pulley and destroys the hall sensor assembly. $312 and you are stranded.

    Penny wise and Pound foolish really applies here as a new aftermarket belt is less than $12 (a BMW OE at $28)
    '
    Ufda happens..........

    It's all about the details.

  7. #7
    ohbeemer
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    90 k Oilhead Worries?

    Thanks to all who have posted, sounds like it is not too big a worry. SO, what is on this bike at 90K? She laid down on a trip last yr....the old bugaboo, the rear end final drive bearings. I did a complete rebuild on that. Brakes/Tires are good, never have replaced clutch cable but a new cluth at 72k. Any suggestion, for a solo rider besides the great anonymous book. ?

  8. #8
    Rally Rat
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    If you plan to keep the bike I recommend you do a significant overhaul prior to your next big trip. I would replace the throttle cables and alternator belt first, especially if you haven't done them recently. The spec used to be 36K miles.

    Then, I would replace the brake lines, the fuel lines, the driveshaft and the rear pivot pins. I'd be interested in the status of the starter motor and the clutch slave cylinder. I'd consider buysing a used starter, slave cylinder and fuel pump to carry or have on standby to be overnighted.

  9. #9
    Alps Adventurer GlobalRider's Avatar
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    Quote Originally Posted by GSAddict View Post
    If you are really concerned, stop by a automotive electric repair shop. They can easily load test the alternator for you for a nominal fee.
    For about the same money, he can buy a 500A carbon pile load tester at Harbor Freight that can be used not only to test an alternator, but to load test a battery. They are about $50 when they are on sale.

    Also, a load test tells you what is happening now, not down the road. Even though it load tests fine, the brushes and/or slip rings may almost be at the end of their life.

  10. #10
    Pepperfool GSAddict's Avatar
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    Quote Originally Posted by GlobalRider View Post
    For about the same money, he can buy a 500A carbon pile load tester at Harbor Freight that can be used not only to test an alternator, but to load test a battery. They are about $50 when they are on sale.

    Also, a load test tells you what is happening now, not down the road. Even though it load tests fine, the brushes and/or slip rings may almost be at the end of their life.
    Not necessarily, Taking it to full load and getting it good and hot will sometimes show any potential issues
    '
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    It's all about the details.

  11. #11
    Alps Adventurer GlobalRider's Avatar
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    Quote Originally Posted by GSAddict View Post
    Not necessarily, Taking it to full load and getting it good and hot will sometimes show any potential issues
    As in a rectifier diode, but getting it "good and hot" will not tell you that the brushes are almost at the end of their life.

    The only way to tell is to take it apart and do a visual inspection (or replace it with a new unit), otherwise we are just guessing...and I can take it to shop for that.

  12. #12
    Pepperfool GSAddict's Avatar
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    Quote Originally Posted by GlobalRider View Post
    As in a rectifier diode, but getting it "good and hot" will not tell you that the brushes are almost at the end of their life.

    The only way to tell is to take it apart and do a visual inspection (or replace it with a new unit), otherwise we are just guessing...and I can take it to shop for that.
    It will show vibration caused connection problems, regulator problems, and allow the trained ear to hear a bearing going bad, that was my point.
    I never said anything about brush or slip ring condition, obviously that needs visual inspection.
    I have repaired countless alternators in my career and have an associate that owns a Alternator/Starter repair shop. Running them up and load testing them will expose problems - maybe not all but for what it costs doing it in situ it's not a bad idea.
    '
    Ufda happens..........

    It's all about the details.

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