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Thread: Clutch Adjustment

  1. #16
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    on the hydraulic clutch bikes, there is no adjustment.
    Fluid level in the master cylinder rises as the clutch wears. If it was over filled when last flushed, there have been cases where it completely filled and caused clutch issues, in which case you need to remove some fluid.

    Rod

  2. #17
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    This thread seems to be the best place to pose my questions about my situation.

    1995 R1100RS with 33,000 miles. I just had to replace a leaking rear main seal on the engine. As part of the repair, I replaced the clutch friction disc (it wasn't contaminated by the RMS leak, but the thickness measured 5.1 mm compared to a new thickness of 6.0 mm and a service limit of 4.5 mm). I did not replace the other clutch parts, because with only 33k I did not think the cone wear would be an issue yet. Thanks to a suggestion by Paul Glaves (Thanks, Paul!) this past weekend at the BMW Club of Houston rally in Schulenburg, I installed the clutch release push rod from the back after the transmission was installed (which required removing and reinstalling the clutch release lever).

    After I got the transmission, clutch release push rod, and clutch release lever reinstalled, I found that I could move the clutch release lever by hand almost completely across the hole in the transmission case without feeling the strong increase in tension from contacting the clutch diaphragm spring. Thinking I might have installed the spring backwards, I just removed the transmission and clutch and saw that I had installed the spring correctly, with the concave side facing the engine.

    OK, so I don't just keep installing the clutch and transmission, using up these "one use only" bolts, and hoping that the next reassembly will do the trick, does anyone have any thoughts on what I might be doing wrong? Since the only clutch part I changed was the friction disc, I would have thought that it would go back together essentially as it came out.
    Mike White
    MOA Life Time Member #57882
    '95 R1100RS, '88 K75S, '75 R90S, '97 Ducati 916, '95 Ducati 900SS CR, '09 Aprilia SR50 Factory

  3. #18
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    mike,
    you did use a clutch centering tool, yes?
    Ride Safe, Ride Lots

  4. #19
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    Look at that assembly again. The spring is forward of the pressure plate. The pressure plate is forward of the disk. You put in a thicker clutch disk. That moved both the pressure plate and the center of the spring forward away from the back of the transmission. The clutch rod didn't get longer. So the adjusting bolt at the back of the transmission needs to be readjusted.

    Start at the top. Adjust the knurled adjuster at the handlebar so there are 12mm of threads exposed between the adjuster and its locknut with the locknut against the perch.

    Then go to the bottom. Loosen the 13mm lock nut and adjust the 10mm (head size) adjuster bolt so that there is 7mm free play between the lever and the perch.

    Then try the clutch action.
    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. #20
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    Quote Originally Posted by bikerfish1100 View Post
    mike,
    you did use a clutch centering tool, yes?
    Yes, I used the BMW metal clutch centering tool (and quite the nice tool it is!).
    Mike White
    MOA Life Time Member #57882
    '95 R1100RS, '88 K75S, '75 R90S, '97 Ducati 916, '95 Ducati 900SS CR, '09 Aprilia SR50 Factory

  6. #21
    Benchwrenching PGlaves's Avatar
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    Additional thought: the disk goes in so the extended side of the hub points to the rear of the bike. I'm not sure it will even go in the other way on that bike, but if it did it would push forward on the spring I think.
    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

  7. #22
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    Quote Originally Posted by PGlaves View Post
    Look at that assembly again. The spring is forward of the pressure plate. The pressure plate is forward of the disk. You put in a thicker clutch disk. That moved both the pressure plate and the center of the spring forward away from the back of the transmission. The clutch rod didn't get longer. So the adjusting bolt at the back of the transmission needs to be readjusted.
    Thanks Paul. Yes, I considered the effects of the new, thicker clutch disc, but wasn't sure if a 0.9 mm increase in thickness could have that much effect on the clutch lever adjusting bolt (even considering the geometry of the clutch release lever). I was looking for some confirmation before I put everything back together and started screwing in the adjusting bolt.

    The throwout bearing currently runs almost to the bottom of the bore when it engages the push rod (maybe 3-4 mm shy; did not measure). If that allows enough additional movement to release the clutch spring tension, then the bearing and rod will move backward as the clutch disc wears. Over time, the adjusting bolt will have to be adjusted out to compensate.

    Quote Originally Posted by PGlaves View Post
    Start at the top. Adjust the knurled adjuster at the handlebar so there are 12mm of threads exposed between the adjuster and its locknut with the locknut against the perch.

    Then go to the bottom. Loosen the 13mm lock nut and adjust the 10mm (head size) adjuster bolt so that there is 7mm free play between the lever and the perch.

    Then try the clutch action.
    Sounds like a plan. Once I get the clutch and transmission reinstalled I can adjust the clutch lever and cable free play before I put the rest of the bike back together (the adjusting bolt will be much easier to access) to make sure it is correct.
    Mike White
    MOA Life Time Member #57882
    '95 R1100RS, '88 K75S, '75 R90S, '97 Ducati 916, '95 Ducati 900SS CR, '09 Aprilia SR50 Factory

  8. #23
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    Quote Originally Posted by PGlaves View Post
    Additional thought: the disk goes in so the extended side of the hub points to the rear of the bike. I'm not sure it will even go in the other way on that bike, but if it did it would push forward on the spring I think.
    Thanks. Yes, I got the clutch disc in correctly also (with the extended hub pointing toward the transmission). That's why I was puzzled by what was the problem.

    Will reinstall everything once my new clutch bolt lock washers come in. On the plus side, the input shaft splines looked perfect, with residual lubrication and no apparent wear (still had machining marks on the top edge of the splines).
    Mike White
    MOA Life Time Member #57882
    '95 R1100RS, '88 K75S, '75 R90S, '97 Ducati 916, '95 Ducati 900SS CR, '09 Aprilia SR50 Factory

  9. #24
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    According to BMW the clutch disk changed in 1997 to a thinner disk. When changing the disk in an earlier RS the pressure plate must be replaced with the new one. The new one is thicker.

    This may or may not be a contributing factor to what you are observing.

  10. #25
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    Quote Originally Posted by limecreek View Post
    According to BMW the clutch disk changed in 1997 to a thinner disk. When changing the disk in an earlier RS the pressure plate must be replaced with the new one. The new one is thicker.
    Thanks. There is a note on the realoem web page next to the clutch friction disc [SI 2100896(737)], but I did not check it. I'll do so at the dealer when I pick up some additional parts in the next day or so, and see if it says anything relevant to this.

    However, the new disc I installed is thicker than the old one I took out (6.0 mm vs. 5.1 mm), so even if the new, new disc is thnner than the old, new disc (I could not find a spec for new thickness, only the wear limit), it is still thicker than the one I took out.
    Mike White
    MOA Life Time Member #57882
    '95 R1100RS, '88 K75S, '75 R90S, '97 Ducati 916, '95 Ducati 900SS CR, '09 Aprilia SR50 Factory

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