New airhead owner, hello: question about wheel turning in neutral

Discussion in 'Airheads' started by seldredg, Nov 3, 2010.

  1. seldredg

    seldredg Basic Black BMW

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    Hi all. I have a 1985 R100-ish airhead. I noticed wen the bike is idling on the stand in neutral, the rear wheel turns. It can be stopped with foot or hand. Clutch lever and arm have play in them. Is there something else to adjust? Or is this normal.
    #1
  2. bmwrench

    bmwrench Long timer

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    It's normal. The gear oil is driving the gears-sort of an accidental viscous coupling.
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  3. seldredg

    seldredg Basic Black BMW

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    Thanks. I hoped it was something like that. Had an R90S for a number of years and never noticed this. Scott
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  4. Sniper X

    Sniper X De Oppresso Liber

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    Even some older chain driven bikes do that.
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  5. danedg

    danedg Horizontally Opposed

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    ...my R60 does it....
    means there's oil in it.....
    just don't let the 3 year old stick his fingers in it....he'll try!:lol3
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  6. Country Doc

    Country Doc Wanderer

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    My R100GS did it, my R75/6 and R75/5 do not. :dunno.

    dc
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  7. R11STEW

    R11STEW ADVrider Wanna-be

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    Uhh, Ive owned many a bike and the all did that. :scratch
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  8. BMW Kurt

    BMW Kurt Bluesman

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    +1
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  9. kraut.burner

    kraut.burner "Fun Club" President

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    I still don't see how that would cause the wheel to spin.... I always thought is was just the vibration :dunno
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  10. bmwrench

    bmwrench Long timer

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    In neutral, all the gears are placed so that they can't drive, but the input and intermediate shafts still turn, as well as the gears on the output shaft. The oil between the output gearS and shaft can cause the shaft to rotate. This varies depending on the viscosity of the oil and the fit of the gear to the shaft-and probably how much drag there is in the RDU. Some bikes can spin the rear wheel surprisingly fast, but just touching the rear brake or the side of the tire with your boot will stop it. I don't think I'd ask a 3 year-old to try it, though.

    "Then he'll stick his fingers in the fan" John Sebastian
    #10
  11. P B G

    P B G Long timer

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    Heck most manual cars will turn the rear wheels while running in neutral.

    Ditto tractors.

    As mentioned there is a certain amount of drag between spinning plates of metal with oil between them.
    #11
  12. kraut.burner

    kraut.burner "Fun Club" President

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    Heck, you learn something new everyday.... Thanks
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  13. danedg

    danedg Horizontally Opposed

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    I don't think I'd ask a 3 year-old to try it, though.....

    I didn't ask him to do anything...he was just fascinated by having that rear wheel spin, with the bike idling on the centerstand.....couldn't help himself...
    ... Just like Ol' Uncle Dan!....:lol3

    [​IMG]
    #13