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Thread: signs of falty alternator/regulator 1976 R60/6

  1. #1

    signs of falty alternator/regulator 1976 R60/6

    Hi folks, yesterday my alternator light stopped coming on with switch on or motor running. Load test good. No increase in voltage with motor reved to 2,000 RPM. I say alternator. Any ideas please. Cheers

  2. #2
    Liaison 20774's Avatar
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    This will require some checking rather than starting to throw money at it!! Could be a voltage regulator...could be bad battery. Check out Snowbum's somewhat lengthy but in depth article on alternator troubleshooting.

    https://bmwmotorcycletech.info/trbleshootALT.htm

    Motorrad Elektrik has (I think they still have them in stock) a nice handy booklet for troubleshooting the charging system.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
    Registered User Guenther's Avatar
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    Rotor or brushes! Can easily be checked with an Ohmmeter. Details needed on how or what to measure?

    /Guenther
    2017 F700GS - I wish she had a drive shaft

  4. #4
    ABC,AMA(LIFE),MOA,RA,IBMW MANICMECHANIC's Avatar
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    Check the bulb first.
    F.O.G.Rider, Rounder #6,
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  5. #5
    Quote Originally Posted by MANICMECHANIC View Post
    Check the bulb first.
    Good idea. But the most common cause is an open rotor. Use an ohm meter to measure from one slip ring to the other. This test should be a few ohms. If it reads infinity it is open. Check from each slip ring to the steel body of the rotor. This should be INFINITY.

    Edit: I fixed it.
    Last edited by PGlaves; 07-07-2021 at 09:53 PM.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
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  6. #6
    Quote Originally Posted by PGlaves View Post
    Good idea. But the most common cause is an open rotor. Use an ohm meter to measure from one slip ring to the other. This test should be a few ohms. Check from each slip ring to the steel body of the rotor. This should be Zero ohms.
    Zero ohms or infinity?
    -Live as fully as you can as long as you can-

  7. #7

    Faulty alternator / regulator signs.

    Thank you everyone for taking the time. I talked to the guru Shail, my mechanic. He believes after my exploration that the problem lies with the rotor. I have a battery booster to travel from Vancouver Island to Shail's Motorcycles 200 miles away.If I can start I can get there. Cheers

  8. #8

    Bulb

    Going from memory, once you have the front cover off, remove both leads to the rotor and short them together. With the key on, if the bulb lights, it's the rotor. If it doesn't light, its the bulb.

  9. #9
    Registered User jad01's Avatar
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    Quote Originally Posted by bikebombs View Post
    Hi folks, yesterday my alternator light stopped coming on with switch on or motor running. Load test good. No increase in voltage with motor reved to 2,000 RPM. I say alternator. Any ideas please. Cheers
    Quote Originally Posted by RPGR90s View Post
    Going from memory, once you have the front cover off, remove both leads to the rotor and short them together. With the key on, if the bulb lights, it's the rotor. If it doesn't light, its the bulb.
    I agree with RPGR90s. Did you verify that the indicator bulb in the instrument cluster is good? I think that is part of the charging circuit and it will prevent charging when burned out; might be worth a look.
    Jim (MOA 83200)
    '78 R80/7 (Anastasia) and '84 R100RS (The Millennium Falcon), '86 K75C (Icy Hot)
    '90 and '93 Mazda Miatas (Jelly Bean and Red Hot), '97 Nissan XE PU (Mighty Mouse)
    '96 Giant Upland (big Kendas, baby!)

  10. #10
    Quote Originally Posted by OldCamper View Post
    Zero ohms or infinity?
    Oops! Infinity. Not zero ohms. Infinity!! My bad!
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://web.bigbend.net/~glaves/

  11. #11
    Registered User STEVENRANKIN's Avatar
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    Airhead weakness

    One of the biggest weaknesses of the airheads is the bulbs for the warning light and the sockets they fit into.

    The plastic instrument gauge cluster is not difficult to take apart to get to the bulb and socket. Be careful when putting it back together to go easy on tightening the various screws holding it together, they don't like being over tightened.

    A lot of people have ditched the bulbs and the sockets entirely and have gone to the Katdash system.

    Open rotor would be my next quickest thing to check. It doesn't need to be removed to check. Unplug the two brush connectors and you can measure continuity through the brushes, the rotor all in one shot. This will give you an idea if the brushes are making proper contact as well as showing if the rotor is open internally. St.

  12. #12
    BMWMOA #24809 jhall's Avatar
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    Maybe Voltage Regulator

    When I installed the OMEGA 600 charging system, it came with a larger capacity VR. Within 10,000 miles, the RT's charging indicator needle began to lag, and did not act as it did initially. This happened one day before I was to leave on a trip. The only spare part I had on hand was the original VR, so I installed it. The problem was fixed, though the needle no longer comes up as high as it initially did with the OMEGA install. That was about 10,000 ago, and all is still well. So I bought another OEM VR, as a spare.

    My point to the OP, don't discount the VR as the possible problem.
    BMWMOA #24809

  13. #13
    Quote Originally Posted by bikebombs View Post
    Thank you everyone for taking the time. I talked to the guru Shail, my mechanic. He believes after my exploration that the problem lies with the rotor. I have a battery booster to travel from Vancouver Island to Shail's Motorcycles 200 miles away.If I can start I can get there. Cheers
    Good luck. I hope you make it

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