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Thread: clutch fluid bypassing- '06 R1200GS

  1. #1
    tntjoe
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    clutch fluid bypassing- '06 R1200GS

    Hi I have a 06 GS I am having trouble with the fluid bypassing in the handle my clutch lever feels real muchy the fluid level is good pulled the slave cyl off no leaks wonder if anyone else has had the same trouble about 66k on bike

  2. #2
    Polarbear Polarbear's Avatar
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    ?

    I do not clearly understand your description, but know mine has had fluid removed from the resevoir, because as the cliutch wears, the fluid "rises in the resevoir"! I have taken a spoonfull of mineral oil OUT of mine at about 50000m, just to prevent leaks or overfill. At 74000 now, still all fine. Maybe an issue with yours? Randy

  3. #3
    tntjoe
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    clutch lever

    The problem I am having is the clutch lever feels sloppy like the fluid is bypassing whan I pull the lever the dealer says its about a $350.00 part for a new resevoir was just wondering if anyone else has had this trouble

  4. #4
    Benchwrenching PGlaves's Avatar
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    If I understand, it is suspected that the master cylinder piston seal is leaking, allowing the piston to advance through the hydraulic fluid rather than pushing all the fluid ahead of its advance.

    If so, it is then behind the piston. Since the piston seal is a cup, presumably the retreating piston again slips through the fluid and doesn't force it out the master cylinder shaft seal.

    Yes, I've seen it happen with a badly torn piston seal following an ill executed bleeding of the brakes (in that case) forcing the piston deeply into the crud and corrosion in the normally unswept portion of the cylinder.

    That said - air in the system can cause exactly the same feeling.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  5. #5
    tntjoe
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    master

    that is exactly what is happening I wonder if BMW sell a rebuild kit or if you just have to get a new master which is $350.00 all ready power blead the clutch which worked for about a hour

  6. #6
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    Quote Originally Posted by PGlaves View Post
    If I understand, it is suspected that the master cylinder piston seal is leaking, allowing the piston to advance through the hydraulic fluid rather than pushing all the fluid ahead of its advance.

    If so, it is then behind the piston. Since the piston seal is a cup, presumably the retreating piston again slips through the fluid and doesn't force it out the master cylinder shaft seal.

    Yes, I've seen it happen with a badly torn piston seal following an ill executed bleeding of the brakes (in that case) forcing the piston deeply into the crud and corrosion in the normally unswept portion of the cylinder.

    That said - air in the system can cause exactly the same feeling.
    That is exactly what seems to be happening with mine. I bled it every conceivable way and although the lever feels right at first, after a few seconds, it sinks to the grip and the bike stalls.

  7. #7
    A bozo on the bus deilenberger's Avatar
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    Sounds like new cylinder time for both of you. BMW stopped selling hydraulic rebuild kits some years ago (probably for liability reasons - and since dealers won't rebuild anything on-site since then they own the part for life..) but..

    On some of the bikes people have found kits or suitable seals by searching for the original manufacturer's parts.. BMW doesn't build hydraulic parts, they typically farm this out to Magura or Tocico. As a WAG - Magura probably made the clutch master cylinder, and there are Magura rebuild kits available. The trick to figuring out what one might work is to know the bore of the cylinder and the stroke of the piston, then try to match that up with a kit for another brand bike.

    That may be more chancy then you want to deal with, or more trouble then it's worth.. so it's a do this at your own risk. You may well end up buying a new cylinder anyway.

    BTW - hopefully you haven't used brake fluid in the circuit. It is only spec'd for use with mineral fluid (sold by Magura..) Brake fluid will probably destroy the seals in the system.
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders New Sweden BMW Riders
    '07 R1200R (current ride) and some bimmers.. and a Porsche

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    Quote Originally Posted by deilenberger View Post
    Sounds like new cylinder time for both of you. BMW stopped selling hydraulic rebuild kits some years ago (probably for liability reasons - and since dealers won't rebuild anything on-site since then they own the part for life..) but..

    On some of the bikes people have found kits or suitable seals by searching for the original manufacturer's parts.. BMW doesn't build hydraulic parts, they typically farm this out to Magura or Tocico. As a WAG - Magura probably made the clutch master cylinder, and there are Magura rebuild kits available. The trick to figuring out what one might work is to know the bore of the cylinder and the stroke of the piston, then try to match that up with a kit for another brand bike.

    That may be more chancy then you want to deal with, or more trouble then it's worth.. so it's a do this at your own risk. You may well end up buying a new cylinder anyway.

    BTW - hopefully you haven't used brake fluid in the circuit. It is only spec'd for use with mineral fluid (sold by Magura..) Brake fluid will probably destroy the seals in the system.
    That's what I'm thinking. Such a pricey part, too bad there's not a reliable test. And, at less than 9K miles. I pulled the slave again just to be sure and it looked fine. The lady at west Valley Cycles suggested a new clutch line but that seems an unlikely culprit. I'll probably trailer it to a pro (Lior) on Monday. I hoping to do a long, possibly overnight ride next week end (my first). I can understand a comment I heard a long time ago made by the winner of one of the first California lotteries. The press asked how it felt to be a millionaire. His reply was "It doesn't do you much good if your bike is in the shop"........

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    Quote Originally Posted by rhafe View Post
    That's what I'm thinking. Such a pricey part, too bad there's not a reliable test. And, at less than 9K miles. I pulled the slave again just to be sure and it looked fine. The lady at west Valley Cycles suggested a new clutch line but that seems an unlikely culprit. I'll probably trailer it to a pro (Lior) on Monday. I hoping to do a long, possibly overnight ride next week end (my first). I can understand a comment I heard a long time ago made by the winner of one of the first California lotteries. The press asked how it felt to be a millionaire. His reply was "It doesn't do you much good if your bike is in the shop"........
    Got a replacement clutch master cylinder installed today and that fixed the problem. Got it at Lior's Moto Ride in Corona, Ca. Excellent mechanic and hell of a nice guy.

  10. #10
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    All this is why I prefer a cable operated clutch. 170,000+ trouble free clutch operation miles on my RS with a cable operated clutch. Simple. Direct. No seals. Good feel. VERY easy to service. When the cable does anything wierd you feel it directly.

    Makes me wonder about my next project bike, a 2007 R1200RT rebuild.

    Too bad there isn't a clutch cable conversion kit for the newer R's.

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