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Thread: K75S Maintenance

  1. #1
    Registered User detbmw's Avatar
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    K75S Maintenance

    I'm about to start a full service on my '88 K75S.

    I have a pair of Bridgestone - Battlax BT45V Sport Touring Tires on order. The Metzeler Lasertecs that came on it are both 5 & 1/2 years old.

    I also want to replace the valve stems. What size valve stems should I buy for this 1988 model bike that was built in July 1987?
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

  2. #2
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by detbmw View Post
    I'm about to start a full service on my '88 K75S.

    I have a pair of Bridgestone - Battlax BT45V Sport Touring Tires on order. The Metzeler Lasertecs that came on it are both 5 & 1/2 years old.

    I also want to replace the valve stems. What size valve stems should I buy for this 1988 model bike that was built in July 1987?
    BMW calls them 15mm which is the OD of the rubber.

    At the auto parts store get the smaller of the two sizes generally in stock. They are labeled as .453 inch which is 11.5mm. The .625 are way too big. These are hole sizes. Get them as short as you can: less wobble and much easier to put a hose on than long ones.
    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

  3. #3
    Curmudgeon At Large Bobmws's Avatar
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    Quote Originally Posted by PGlaves View Post
    BMW calls them 15mm which is the OD of the rubber.

    At the auto parts store get the smaller of the two sizes generally in stock. They are labeled as .453 inch which is 11.5mm. The .625 are way too big. These are hole sizes. Get them as short as you can: less wobble and much easier to put a hose on than long ones.
    And buy an extra set to carry with you.
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  4. #4
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by Bobmws View Post
    And buy an extra set to carry with you.
    Which is very easy since they often come as a package of four for your car.
    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
    BMW uber alles! Zagando's Avatar
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    Thumbs up

    Congratulations on choosing the BT45s; man, you are going to love those tires!

    Btw, I run DynaBeads in both of mine and can also highly recommend them---smooth as silk.
    ---Jeff '94 K75S Berlina

    ex: R100GS/PD , K100RS , R75/5 , R60/2

  6. #6
    Registered User detbmw's Avatar
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    Quote Originally Posted by Zagando View Post
    Congratulations on choosing the BT45s; man, you are going to love those tires!

    Btw, I run DynaBeads in both of mine and can also highly recommend them---smooth as silk.
    I will order the DynaBeads, i have heard several people recommend them.
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

  7. #7
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    My first tire change on my K75 I put in metal valve stems. They look a lot better(bling?) and no more worries about a stem breaking.

  8. #8
    Registered User argent brick's Avatar
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    anyone find the metal stems that have a 90 degree bend any easier to use?

  9. #9
    Registered User jwetering's Avatar
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    Hhmmm.

    I have the Bt45's on my bike and I'm finding they wear kind of fast. I think my fronts are cupping already after only abut 4 months of use.

    Maybe I'm riding 'em too hard?
    jasper
    north vancouver

    1990 K75S

  10. #10
    Curmudgeon At Large Bobmws's Avatar
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    Quote Originally Posted by jwetering View Post
    Hhmmm.

    I have the Bt45's on my bike and I'm finding they wear kind of fast. I think my fronts are cupping already after only abut 4 months of use.

    Maybe I'm riding 'em too hard?
    How many miles and what tire pressure?
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  11. #11
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    Quote Originally Posted by jwetering View Post
    Maybe I'm riding 'em too hard?

    what does that even mean?
    Ride Safe, Ride Lots

  12. #12
    3 Red Bricks
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    Quote Originally Posted by jwetering View Post

    Maybe I'm riding 'em too hard?
    There is no such thing!



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  13. #13
    BMW uber alles! Zagando's Avatar
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    Quote Originally Posted by ARGENT BRICK View Post
    anyone find the metal stems that have a 90 degree bend any easier to use?
    Easier to put air in but a bitch to install Dyna Beads with!
    ---Jeff '94 K75S Berlina

    ex: R100GS/PD , K100RS , R75/5 , R60/2

  14. #14
    Registered User jwetering's Avatar
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    Quote Originally Posted by Bobmws View Post
    How many miles and what tire pressure?
    I run 33/36 and the mileage is 60,000 miles.

    I think I know where you're going with this, and I'm right behind you.

    I have already figured out that my headstock bearings are worn...more correctly that there's a notch on centre. This may be either causing the very mild wobble I feel directly, or it may be causing the tires to cup prematurely.

    My plan is to rebuild it this winter.
    jasper
    north vancouver

    1990 K75S

  15. #15
    Curmudgeon At Large Bobmws's Avatar
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    Quote Originally Posted by jwetering View Post
    I run 33/36 and the mileage is 60,000 miles.

    I think I know where you're going with this, and I'm right behind you.

    I have already figured out that my headstock bearings are worn...more correctly that there's a notch on centre. This may be either causing the very mild wobble I feel directly, or it may be causing the tires to cup prematurely.

    My plan is to rebuild it this winter.
    Well, I meant miles on that tire, but yes, worn bearings will contribute to the wear. Your tire pressures are about 4 lbs low on each end, more of a factor in the rapid wear.
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

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