Horrible noises from my airhead engine

Discussion in 'Airheads' started by dino1, Sep 2, 2010.

  1. dino1

    dino1 Been here awhile

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    Aug 3, 2010
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    415
    Location:
    cen tex
    1987 r80 unkown miles, oil pressure seems good, screechy noise when reving to 4K, sounds like an accessory belt slipping on a car. Gen light flickers when it happens. Any ideas? TIA
    #1
  2. matman1972

    matman1972 Lost in the woods.

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    May 30, 2010
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    710
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    Georgia
    check your alternator rotor/ stator. I'm wondering if they are hitting?


    i'm betting main bearing. Shaft moves under stress due to worn bearing, rotor hits stator, and viola, lamp flickering. Check it out before riding.
    #2
  3. dino1

    dino1 Been here awhile

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    So is that bad? Or is that just like getting a new alternator? Not the main bearing for the crank correct?
    #3
  4. zenben

    zenben all roads are one

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    Alternator brushes worn out. About $3 to replace.
    Check 'em quick, or you may have to buy a new rotor too.
    Rotor may be slightly loose and cause the same symptom.
    #4
  5. matman1972

    matman1972 Lost in the woods.

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    [​IMG]If you look at the picture, your rotor for your alternator rides on the front of the main crankshaft. When the bearings on the crank start to go, the crank will wobble, causing the rotor to touch the stator, making your gen light blink and making the noise you are hearing. Open up your front cover, unplug and remove your stator, and inspect it and the rotor. A new alternator will not do it, it will just wobble with the crank and do the same thing.

    Buuut, I have been vodkaing up the lemonaid tonight, so someone else tell me if there is a simpler, less major cause I am overlooking.:ear
    #5
  6. matman1972

    matman1972 Lost in the woods.

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    Orrrr, could be that too. That's what I get for offering alchohol induced technical info. That would be a muuuuuuuch cheaper fix. Same advice, pull the front cover and check them out. I will be praying for ya, My r50 was the bearing.

    BTW, If I made you worry and it turns out to be something cheap, I owe you a beer.
    #6
  7. DaveBall

    DaveBall Long timer

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    Oddometer:
    1,165
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    Vancouver Island
    2 years ago had a very similar sound coming from the front of my 81 R100RT. Pulled the cover and found the brushes had disintigrated. Basically worn way past recognition and ground bad grooves into the rotor. There was also a bad electrical smell coming from it.

    Could have replaced the rotor and brushes, which would have been cheaper, but as I had wanted to upgrade the output anyway, I replaced the whole charging system with the Enduralast system. Been extremely happy, and now much warmer on winter days.

    So advice would be to check those brushes a little more often. Saves you $$ in the long run.
    #7
  8. datchew

    datchew Don't buy from Brad

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    #8
  9. airheadpenguin

    airheadpenguin Danger to himself

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    Merrimack NH
    I have a complete airhead alternator from a '78 R80 I believe. PM me if you need one.
    #9
  10. photomd

    photomd Been here awhile

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    Sep 29, 2007
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    Can I get the Cliff Notes?
    #10
  11. dino1

    dino1 Been here awhile

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    Thanks for the help, I'll get into this this weekend, somewhat bummed when I heard the noise but hey I only have like 1K in the damn thing so if I need to tear it down for MB then I'll learn a lot more a lot quicker. But I'm hoping for brushes so I can ride it more. : )
    #11