Airhead Red Gen Light

Discussion in 'Airheads' started by pecos, Dec 9, 2009.

  1. pecos

    pecos BAM!!

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    When I start the r65 the red gen light comes on. Its not until I rev up a little that it goes away. From what I understand this is normal to some degree.

    There is a weird noise coming from the engine...Appears to be coming from the front cover. I am still testing but sounds like its coming from the rotor area. Sounds like a circular noise...maybe a bearing? Noise fads out on revving I believe. I almost would describe the noise as churping....yes, like a birdie. (no birds are behind the cover)

    Just got back from a 1000 miles 3 day trip, I ran my gerbings liner and gloves full tilt. Noise was present the entire time. Its been 10 days since I started the bike. Appears that the battery is not at full charge b/c I could not start the bike.

    And I guess I should say bike has had this light and noise for the past 8 months. Just now getting around to fixing it.

    Maybe the battery is going bad or the rotor or something else. I kinda think the battery is ok. Any ideas?
    #1
  2. bmwblake

    bmwblake upside down parker

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    the gen light should be on faintly at idle, but should go away when rpm's clime.
    on a stock system you are killing the battery running a gerbing liner and gloves full tilt. you might be able to recharge your battery but if you continue to discharge it using that much heated gear you will kill the battery.

    search around for a thread datchew did on his bike chirping. it was his brushes wearing in an odd manner against the slip rings.
    #2
  3. Ray of Sunshine

    Ray of Sunshine Meat Donut 2 Some

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    If you have a constant red light, there is definitely a problem in the charging system. I ran into this in my airhead's charging system years ago. Sounds like brush problems to me. If you can solder, they solder on fairly easily.

    Running two electric garments is death to these bike's electrical systems. They are barley adequate to keep the battery charged and light the lights. Yes, they can run a vest, but that really puts the rubber to the road if there is any flakiness in the system.

    Motoelectrik sells more powerful alternator for the airhead series, along with all of the ancillaries it requires. I believe that this increases the output from something like 40 amps from he stoker 20 amps.

    Some people claim that when BMW increased the ampereage of the alternator form the /5 series to the /6 series, the engines made less power. I cannot testify to this as truth.
    #3
  4. pecos

    pecos BAM!!

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    Yeah, so the light is working as designed. I was wondering if the heated gear was overkill.....it sure was cold though.

    Searching for the "datchew bike chirping"
    #4
  5. bmwblake

    bmwblake upside down parker

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    #5
  6. pecos

    pecos BAM!!

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    thanks blake. looks very similar. Will take a look at this tonight.


    Do brushes have to be ordered or can I picked them up from the local dealer?

    Just to confirm....the brushes are in the yellow circle. (easy on me now)

    Attached Files:

    #6
  7. bmwblake

    bmwblake upside down parker

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    you've circled the brush holder. the brushes are inside the brush holder. you can see pics of the actual brushes on the ME page here. rick even sells some that have ring terminals so you dont have to solder the new brushes on.


    #7
  8. PaulRS

    PaulRS Dutch fool

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    Is that copperdust, between the rotor and 3-phase connector?
    You might be wearing the rotor out.

    And on the opposite side, the insulation on the Y connector looks burnt?

    I think you're pulling too much load from an already weak generator.

    Paul.
    #8
  9. bmwblake

    bmwblake upside down parker

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    that pic is from datchew's thread that i linked earlier.


    #9
  10. pecos

    pecos BAM!!

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    New brushes and springs installed. No more birds chirping or rabbits squealing.

    Now the red gen light is on no matter what. Huh.....will double check the wires but I am pretty sure they are right.


    Confirmed wires are correct in the front.....maybe something pulled when I re-installed the tank?

    Just started snowing....yes in texas....so no test rides.
    #10
  11. datchew

    datchew Don't buy from Brad

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    Hey you stole my picture!!! :lol3


    When you replaced the brushes, did you take the white (bakelite?) brush holder apart? If so, there is a washer in there that isolates the circuit on one of the studs and if it's not put back together right, it won't work.

    Also, if you have corrosion on your rotor slip rings (or just gunk from age) a little xylene or mineral spirits and a scrubby pad will clean them up for a better connection.

    Make sure all your ground wires and stuff are connected properly. Good luck.
    #11
  12. pecos

    pecos BAM!!

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    Yes, I took the brush holder apart like a gorilla. Washers do come to mind now....

    I thought I had an extra one or I lost one or there was one from a previous project. HA.

    Will take a look.
    #12
  13. pecos

    pecos BAM!!

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    pic showing front. does that look correct? Manuals do not show the placement of washers.

    Attached Files:

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  14. pecos

    pecos BAM!!

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    pic showing back side. just one stud showing here. both have washers on the back side.

    Attached Files:

    #14
  15. AntonLargiader

    AntonLargiader Long timer

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    If the light stays on it could mean that you shorted the brushes or it might just mean that the system still isn't working.

    Shorted brushes - easy to look for with a multimeter. Lift the brushes and look for continuity between the terminals and the case.

    Otherwise, maybe you just left something disconnected.
    #15
  16. datchew

    datchew Don't buy from Brad

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    I don't know the correct stackup of the washers without taking mine apart again, but the parts fiche shows the stackup I think.
    #16
  17. bmwblake

    bmwblake upside down parker

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    i helped a friend with a gen light on all the time issue. i went thru all the tests in the ME charging book and it ended up being a washer issue. i think only 1 post is supposed to have a washer. call rick at ME and he can tell you. buy his book, it rocks.


    #17
  18. pecos

    pecos BAM!!

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    Parts fiche nor Haynes manual show the stack. Would have thought fiche would show it.
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  19. pecos

    pecos BAM!!

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    Original issue was the chirping. Like staying on is new issue. It doesn't even flicker. Which seems like the washer issu.e

    So you can short a brush? Is there something special inside it?
    #19
  20. pecos

    pecos BAM!!

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    That was the issue. I needed to isolate the DF side vs the D- (grounded side)

    Thanks. File this one away.
    #20