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Thread: 2004 R1150RT Alternator Problem

  1. #1
    Registered User roger 04 rt's Avatar
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    2004 R1150RT Alternator Problem

    Started up this yesterday, rode to get a newspaper. Stopped, went to start, wouldn't turn over. The battery was only charged enough to move the engine a quarter turn. I put it in 6th and rolled it down hill and it started, phew.

    Rode home. Shut off. Tried restarting, and it turned over and started..

    I noticed the other day that the Batt/Alt light bulb didn't turn on with the key but thought I'd look into it later. I was able to duplicate that symptom. When I measure the D+ wire at the alternator it's at 12 volts, which is coming from the indicator lamp, so it seems that the rotor, slip rings or voltage regulator isn't providing a ground. I the grounded D+ lead to make sure the bulb and wire were good and the bulb lit so everything is good up to the alternator. To me it appears that either the slip ring connection to the rotor is intermittent, or a wire is loose at the regulator or the voltage regulator has a problem.

    The bike is an '04 R1150 with just under 30K miles. How likely is it that the slip rings aren't making a good connection?

  2. #2
    K Bikes Complex by Choice cjack's Avatar
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    Quote Originally Posted by Roger 04 RT View Post
    Started up this yesterday, rode to get a newspaper. Stopped, went to start, wouldn't turn over. The battery was only charged enough to move the engine a quarter turn. I put it in 6th and rolled it down hill and it started, phew.

    Rode home. Shut off. Tried restarting, and it turned over and started..

    I noticed the other day that the Batt/Alt light bulb didn't turn on with the key but thought I'd look into it later. I was able to duplicate that symptom. When I measure the D+ wire at the alternator it's at 12 volts, which is coming from the indicator lamp, so it seems that the rotor, slip rings or voltage regulator isn't providing a ground. I the grounded D+ lead to make sure the bulb and wire were good and the bulb lit so everything is good up to the alternator. To me it appears that either the slip ring connection to the rotor is intermittent, or a wire is loose at the regulator or the voltage regulator has a problem.

    The bike is an '04 R1150 with just under 30K miles. How likely is it that the slip rings aren't making a good connection?
    Brushes?
    BMWMotorcycles, fun when they're running...
    My other bike is a BMW.
    Jack Hawley MOA and RA #224, KE9UW ("Chuck")

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    Registered User roger 04 rt's Avatar
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    Thanks. Could the brushes be worn out at 30,000 miles?

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    K Bikes Complex by Choice cjack's Avatar
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    Quote Originally Posted by Roger 04 RT View Post
    Thanks. Could the brushes be worn out at 30,000 miles?
    Not likely...but worth checking. I had brush issues at less miles than that once.
    BMWMotorcycles, fun when they're running...
    My other bike is a BMW.
    Jack Hawley MOA and RA #224, KE9UW ("Chuck")

  5. #5
    Registered User m_stock10506's Avatar
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    Always look at the last place you worked on.

    If the Alternator warning light doesn't light up, it either means you've got a problem with the charging system or the light itself has a problem. No light, no charging.

    Didn't you just replace your bulb with a higher wattage bulb? Last place you worked on?
    Michael Stock, Trinity, NC
    R1100RT, R100, R60/6

  6. #6
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by m_stock10506 View Post
    If the Alternator warning light doesn't light up, it either means you've got a problem with the charging system or the light itself has a problem. No light, no charging.

    Didn't you just replace your bulb with a higher wattage bulb? Last place you worked on?
    Always good to check the last change. I've been able to confirm that all is well in the D+ line going from the bulb to the alternator. There is +12V on the alternator (D+) side of the bulb and if I ground the D+ line the bulb lights up. So that's all okay.

    Something is wrong from that wire through the Alternator to ground. I don't know if it's the wire, D+ terminal, voltage regulator, brushes or slip rings. But something is blocking continuity in the ground path I guess.

  7. #7
    Nickname: Droid
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    Certainly should not be that the brushes are worn out or worn down. I had the alternator apart on my 94 RS at 120,000 miles and I compared the brushes against a warranty replacement alternator I got for parts. The warranty alternator had very low miles on it, practically brand new. When I compared the brushes, the ones from my original alternator still had over half the length remaining. That to me said the original brushes are good for an easy 200,000 miles on the bike.

    Perhaps a connection failed at the brushes.

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    My '04 GS at 17,000 miles began having intermittent starting issues characterized by not turning over and zeroing out the clock on the first try, but usually by the 2nd or 3rd try starting. This would reoccur at totally random intervals- days or weeks would separate incidents. Battery replacement was of no benefit. It turns out this issue was a detachment of one of the magnets in the starter. If you still have the original Valeo starter, they had some issues with the glue holding the magnets in starters made for the 2004 models.
    2004 R 1150 GS

  9. #9
    Registered User roger 04 rt's Avatar
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    Thanks for the suggestions.

    I won't be able to open it up for a couple days but I now think I have two problems. One is that the alternator D+ circuit has a problem which I have to step my way through.

    The second issue is that either the starter is drawing a lot of current sometimes or the battery, a less than one year old PC680, is defective and loses charge.

    I'll post again when I know more.

  10. #10
    Day Dreaming ... happy wanderer's Avatar
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    The bad Valeo starters were in a lot of bikes for several year models.
    Check the part number sticker on them.
    - If you have the D6RA-55 (bad) model you have the bad magnet design
    - If you have the D6RA-75 (good) model it has metal magnet retainers in the housing and even if the glue gives up the magnets will not get jammed into the stator like PetDocs did.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  11. #11
    Day Dreaming ... happy wanderer's Avatar
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    Quote Originally Posted by Roger 04 RT View Post
    Thanks for the suggestions.

    I won't be able to open it up for a couple days but I now think I have two problems. One is that the alternator D+ circuit has a problem which I have to step my way through.

    The second issue is that either the starter is drawing a lot of current sometimes or the battery, a less than one year old PC680, is defective and loses charge.

    I'll post again when I know more.
    I'll bet if you put the + side of the meter right to the big starter terminal and crank you'll see a huge voltage drop. When my Valeo died I was seeing less than 5V there and it was because one of the magnets had come off the housing inside. You can also confirm your battery is OK with a quick load test at any battery or service shop.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  12. #12
    Rally Rat
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    I have seen alternator brushes hang up in the holder. This would cause your symptoms.

    Open circuit in the field between the bulb and ground brush. I did have to put 3 rotors in my air head before I got one that lasted. All had developed an open circuit in the windings. Easy to tell with a test light or ohm meter.

    Good luck. Intermittent problems are more fun to figure out.

    David

  13. #13
    Registered User roger 04 rt's Avatar
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    It behaves exactly like a brush is hanging up. At Batt/Alt doesn't ground, then after a while of running, it does.

    The other problem, that the battery seems too be depleted to easily might be tricker. I'll check the cables and connections and if nothing's obvious, pull the starter and have a look around.

    Does anyone have a figure for the range of usual starter motor currents?

  14. #14
    Lucky motorradmike's Avatar
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    Hi Roger:

    2 related problems make things trickier. Divide and conquer, but you knew that.


    About the starter. I had this last year, my starter was sluggish and at times I wasn't sure the bike was going to start but it always did.
    Even if you've got a DC clamp-on ammeter you're going to have trouble deciding where the problem lies based on measurement.

    Here's what I ended up doing:
    I measured battery voltage at the starter while cranking, then re-measured with a good car battery jumped right to the starter.
    The 2 measurements were very close so I concluded the starter was drawing more than it should.

    A new starter put everything right. The magnets were fine in the old one and I'd already cleaned up the commutator.
    Mike Marr
    1978 Yamaha XS750 (Needs rings), 1996 BMW R1100RS, 2004 Honda CRF230F

  15. #15
    Registered User roger 04 rt's Avatar
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    Thanks MM. In the back of my mind, I'm thinking that if the starter's a problem I might just replace it.

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