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Thread: New style drive shaft in early K bikes

  1. #1
    3 Red Bricks
    Join Date
    Jan 2007
    Pleasanton, Ca.

    Lightbulb New style drive shaft in early K bikes

    I just discovered, while installing a NEW driveshaft in my '87 K75S that BMW had redesigned the drive shaft with a beefier universal. Thanks BMW.

    When I went to slide the drive shaft through the hole in the end of the swing arm, I discovered that the new style universal is about .030" BIGGER than the hole in the end of the swing arm. THANKS BMW!!!

    After calling both Cal BMW and Hansen's BMW, I was told that you have to remove the swingarm, install the driveshaft, then slide the swingarm over the driveshaft. They said that not only is it a real pain in the ass, but you must remove the swingarm every time in the future when you do a spline lube or not clean the whole drive shaft and forego lubing the front splines!!

    After removing the swingarm I discovered that the universal will slide all the way through the swingarm except for the first 1" at the final drive end. Once the universal is near the tranny end, the swingarm bore opens up and there is no issue.

    Since the ID of the hole on the final drive end does not locate anything (the dowel pins do that), I ground the hole at 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock until the universal would easily slide in and out.

    Yes, it's a little more work now but it will save me a ton of extra time over the course of all the subsequent spline lubes.

    In the future, anyone installing a new style driveshaft in an older K-bike does NOT need to remove the swingarm (and peg plates, etc.). All you need to do is stuff the swing arm with a rag to prevent grindings from getting far inside. Then grind the hole at 12,3,6,and 9 o'clock so the universal easlily slides in and out. Then clean out the chips and the rag. The grinding will take WAY less time than removing the swing arm and make future splie lubes a snap.

    I hope this helps someone else in the future.

    Now I'm going to have myself a well deserved beer.

    Last edited by 98lee; 05-11-2007 at 11:47 PM.

    Ride Safe, Ride Far, Ride Often

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

  2. #2
    Registered User
    Join Date
    Dec 2004
    Winnebago, Il

    Drive shaft spline lube

    Yup new drive shaft yokes are bigger but you don't have to remove the drive shaft and lube the front splines on the old "K" bikes. A snap ring holds them onto the transmission output shaft and there is little or no movement at this location. All you need to do is remove the final drive and lube the splines at that end.

    P.S. I found that a file and a couple of strokes on each edge of the drive shaft yoke gave me enough clearance on my old "K".

    Roy G.
    85 K100RT Ol Ruby "Gone but not forgotten"
    02 K1200LTC Hoss "Wrecked on 9/21/14"
    12 R1200RT

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