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Thread: 1985 K100RS possible rad fan replacement.

  1. #1
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    1985 K100RS possible rad fan replacement.

    Has anyone here seen these yet? Bearing-style, 10 blades and runs at 3000 RPM according to FlatRacer. The stock unit is 7 blades and runs at 4500 RPM (according to an old post I read). I don't have the ability to determine air flow differences but I wonder if the FlatRacer unit would move enough air running at 2/3 the speed of the OEM fan even with more blades?

    https://www.flatracer.com/radiator-f...diator-fan-kit

  2. #2
    Bluenoser
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    If you go to Motorworks site in the UK you will see the same or similar fan for the early K bikes. I can't comment on the specific fan you show, but that style of fan ( even has the stock mount ) is a common aftermarket fix for the BMW fans on these bikes. I haven't had to replace the fan on my K bike, but from what I've read on various K bike sites, that style of fan works fine.

    If you are having fan issues, fan is hard to turn, take it out and lubricate the bearings/bushing at the front and rear. A little lubrication goes a long way. That's all I had to do to mine and it freed right up and turns very easy.
    1986 K100RT

  3. #3
    Dances With Sheep GREGFEELER's Avatar
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    Quote Originally Posted by mcmlcccvrs View Post
    Has anyone here seen these yet? Bearing-style, 10 blades and runs at 3000 RPM according to FlatRacer. The stock unit is 7 blades and runs at 4500 RPM (according to an old post I read). I don't have the ability to determine air flow differences but I wonder if the FlatRacer unit would move enough air running at 2/3 the speed of the OEM fan even with more blades?

    https://www.flatracer.com/radiator-f...diator-fan-kit

    Looks like a nice fix to me, and I can't disagree with anything they said in their product description.
    Greg Feeler
    Ambassador & amateur K-Bike collector, it seems
    1972 R75/5, 1990 K75, 1990 K1, 1992 K75S, 2003 K1200RS

  4. #4
    3 Red Bricks
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    My first impresssion is that the center hub of the fan LOOKS to be a bit larger than the stock fan. IF so, it might block some wind flow when the fan is not on, requiring the fan to run more.





    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

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