Airhead Charging System Secrets

Discussion in 'Airheads' started by StephenB, Apr 17, 2010.

  1. Solo Lobo

    Solo Lobo airhead or nothing

    Joined:
    Mar 16, 2004
    Oddometer:
    9,698
    Location:
    Shoreline, WA
    The question is, are you spinning your ST up to redline frequently? Mine failed after I did that a few times....:lol3
    #41
  2. charliemik

    charliemik Been here awhile

    Joined:
    Aug 30, 2007
    Oddometer:
    420
    Location:
    Flagstaff AZ
    For me it's been 12 yrs and 4 airhead bikes. I've lost 1 rotor and 2 diode boards in that time. I always carry these two spares on a long trip. I've added extra grounds for the diode board and make certain my connections are clean. I've currently got a MotoElektric rotor on my bike and an Omega diode board. Seems to me the better heat sink design on the diode board makes sense.

    On my 2nd diode board failure, I was riding in Utah with a friend and it was Sunday. We had about 300 miles left to get home so I disconnected the headlight and then we'd stop about every hour and swap batteries. It was a PITA but it got me home. My battery would slowly drain down just running the ignition system but after an hour it still had enough juice to start my buddy's bike. I'd put his fully charged battery in my bike and let his bike put a full charge on my battery. Back and forth a few times did the trick. We got the battery swap down to about a 5 minute procedure.
    #42
  3. hardwaregrrl

    hardwaregrrl ignore list

    Joined:
    Jan 26, 2006
    Oddometer:
    8,183
    Location:
    Atlanta
    Ha, I ride like a grandma:evil But seriously, no red-lining before failure!
    #43
  4. RecycledRS

    RecycledRS Along for the ride

    Joined:
    Nov 2, 2008
    Oddometer:
    1,048
    Location:
    Vancouver Island
    Your rotor consuption could just be luck of the draw, but....... after three failures one has to be a little concerned that something else maybe the root cause.

    Have you tested the electrical load (amperage) of the system while running and when any accessories are added one by one? This may tell you if there is an unusally high draw for a particular component and over loading the system.

    Also, since the voltage regulator controls power to the rotor it may be worth considering changing this out as a preventative measure (the unit is relatively inexpensive).
    #44
  5. hardwaregrrl

    hardwaregrrl ignore list

    Joined:
    Jan 26, 2006
    Oddometer:
    8,183
    Location:
    Atlanta
    Trust me, everything is right with the electrical. It has a brand new Omega 450. I have checked the load several times and I have a volt meter that I watch religiously. I'm just saying, they ain't bulletproof!
    #45
  6. RecycledRS

    RecycledRS Along for the ride

    Joined:
    Nov 2, 2008
    Oddometer:
    1,048
    Location:
    Vancouver Island
    Too true.
    #46
  7. norton73

    norton73 drinkin'

    Joined:
    Dec 20, 2003
    Oddometer:
    8,634
    Location:
    Beautiful Downtown Springville, Alabama
    All my rotor failures (3) were after running down the interstate for 6-7 hours. Running 4K or so on the R90S, 5.5K on the GS. So far (fingers crossed) the Motorradd ElecticK on the GS has held up well. But I carry a spare on any overnight trip.
    #47
  8. Stagehand

    Stagehand Imperfectionist

    Joined:
    Oct 6, 2004
    Oddometer:
    31,958
    Location:
    Shawangunks
    I've had three rotors go bad including one of Ricks 400w units.

    Had a hairline crack in a stator wire that would only stop charging when it got warm.

    Had it be the battery itself more than twice.

    Once or twice it was wires (including the main negative) that had just vibrated/corroded into oblivion forming a high impedance air gap.

    Have blown the charge light.

    dont think a diode board has given me trouble.. maybe once, maybe way back on the R60... Now I am Very grounded.

    Voltage regulator... just once I think.
    #48
  9. Stagehand

    Stagehand Imperfectionist

    Joined:
    Oct 6, 2004
    Oddometer:
    31,958
    Location:
    Shawangunks
    #49
  10. RecycledRS

    RecycledRS Along for the ride

    Joined:
    Nov 2, 2008
    Oddometer:
    1,048
    Location:
    Vancouver Island
    The mechanical stress I was referring to is due to the stator and rotor being linked magnetically.

    When the stator is loaded to 280 watts that equates to approximately 1/3 of a horsepower. That power has to come from some where and it is the rotor (via the magnetic link). This is in turn supplied by the cam shaft rotation. Since that magnetic link is ultimately produced by the coil winding, it too is stressed.

    In addition, the coil is also subject to AC harmonics induced from the stator (once electron flow occurs in the stator winds it also forms magnetic fields which induce counter electromotive force, EMF, into the rotor). Harmonics can set up substantial high frequency vibration within the coil and thus cause additional mechanical stress on the winding insulation.

    Of course these factors are in addition the centrifugal forces on the coil winding and vibration inherent from being mounted on the end of the cam shaft.
    #50
  11. Joerg

    Joerg Long timer

    Joined:
    Jul 10, 2001
    Oddometer:
    1,358
    Location:
    Lausanne, Switzerland
    :rofl :thumb :nod


    PS: I hope you're not into airline business :lol2
    #51
  12. Beemerboff

    Beemerboff Long timer

    Joined:
    May 23, 2005
    Oddometer:
    2,674
    Location:
    Adelaide, South Australia
    When the rotor goes it is often the last solder joint between the winding and the commutator.

    ESPECIALY IF YOU FIT A ALTERNATOR MOUNTED IGNITION AND FOLLOW THE INSTRUCTIONS TO CLEAN OFF ANY PROTRUDEING SOLDER ON THE END OF THE ALTERNATOR !

    You can check by lightly cutting the shellac on the wires as they exit from the coils with a box cutter blade and checking for continuity from there.

    I have heard of tales folks who have pressed off the commutator , unwound a coil of wire, refitted the commutator and resoldered the wires, but I havent seen it done outside of a rewinding shop.
    #52
  13. Wirespokes

    Wirespokes Beemerholics Anonymous

    Joined:
    Jul 26, 2002
    Oddometer:
    8,731
    Location:
    Jackson's Bottom Oregon
    The cam only drives the points or hall sensor, not the alternator, which is mounted directly to the crankshaft. This is the case on the /5 and newer airheads - earlier, I don't know how they worked.

    Stagehand - I doubt there's any stress from being pressed onto the crank. But you're right about it being subjected to vibrations and rotational forces, besides the magnetic loads we all know about.
    #53
  14. RecycledRS

    RecycledRS Along for the ride

    Joined:
    Nov 2, 2008
    Oddometer:
    1,048
    Location:
    Vancouver Island
    Crankshaft of course. Thanks for the correction.
    #54