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Thread: Do I need a clutch? '87 K75

  1. #1

    Do I need a clutch? '87 K75

    1987 K 75; approx 75K mile on the bike. Cannot set the cable, brand new, to effect enough throw out to get the bike to shift out of first or second into neutral while idling at a stop. Have followed all the instructions in the Clymer and the Haynes. The bike will shift fine up and down with normal riding with zero clearance/slack in the cable, but come to a stop in 1st or 2nd, and it feels locked into gear, ie too much drag on the clutch to shift into neutral is my guess. Shut the bike off, and the shifter will move into neutral. Could the clutch plate be so thin that I can't get enough throw-out? Just finished a clutch spline lube too.

    Any input/comments more than welcome and always appreciated.

  2. #2
    Registered User Recker1's Avatar
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    Quote Originally Posted by st3ryder View Post
    1987 K 75; approx 75K mile on the bike. Cannot set the cable, brand new, to effect enough throw out to get the bike to shift out of first or second into neutral while idling at a stop. Have followed all the instructions in the Clymer and the Haynes. The bike will shift fine up and down with normal riding with zero clearance/slack in the cable, but come to a stop in 1st or 2nd, and it feels locked into gear, ie too much drag on the clutch to shift into neutral is my guess. Shut the bike off, and the shifter will move into neutral. Could the clutch plate be so thin that I can't get enough throw-out? Just finished a clutch spline lube too.

    Any input/comments more than welcome and always appreciated.
    I'm sure others will have more definitive information but what happens if you "blip" the throttle a bit while you are trying to get it out of 1st or 2nd? My bike needed the clutch replaced and the only symptom was that to downshift (even at speeds) I had to increase rpm's by hitting the throttle prior to downshifting. Clutch replaced = problem 100% solved.

  3. #3
    A bozo on the bus deilenberger's Avatar
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    st3ryder.

    I've added the year/model of your bike to the thread title. It will help attract people to your thread who might have something useful to add. It also may help others in the future who are seeking this info. PLEASE consider doing this yourself in future tech forum postings - it's the smart thing to do.

    As far as your problem - sounds internal to the clutch. I suspect something has gone wrong. Dunno if it's related to the recent spline lube, but I have known them to go bad (but the bad is usually immediately obvious after doing the lube..)

    It's also possible your throwout bearing has collapsed - that's on the rear of the transmission under the rubber boot the clutch actuating arm goes into. It can be R&R'd without removing the transmission.

    Were there any shifting problems before the spline lube was done?
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders
    '12 R1200R - I love this bike!

  4. #4
    A clutch too thick is hard to release. A clutch too thin will release with less pressure plate movement. Thus, drag on the clutch preventing clean shifting will not be caused by a disk that is worn too thin.

    Suspect several possibilities:

    Stretching, unraveling cable.
    Worn throwout bearing.
    Worn contact area on the clutch rod.
    Clutch hub sticking on the splined input shaft.
    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://web.bigbend.net/~glaves/

  5. #5
    Thanks guys. More information for you.

    The clutch cable/clutch action has always been difficult to adjust, ie never could get it to shift properly using the instructions in the shop manuals. Have always had to add a little more tension/find a sweet spot as it were, but this time I can't dial it in without adding zero and even negative clearance, ie add a turn to the adjuster scew at the rocker arm. The cable needs to be way too tight to find a spot that works well this time. There was no shiftng problem since my previous spline lube, but as usual, I struggled to find that sweet spot after that one too, and once again, not to book specs, ie zero clearance.

    I thought about the throw out bearing too and pulled it out once the gear box was back on and it seems okay visually. The cup's outer diameter will sit flush with the housing when sliding it back it. But I could only pull the outer race/cup and the bearing, not the inner race. It seemed stuck on the rod and I didn't want to force it. Should the inner race be able to be pulled out easily, or would I have to pull the gear box and remove the push rod?

    By worn contact area on the push rod, would that mean it's worn too short?

    The cable I tried last night is my new spare, but I have the same "locked -in" problem at idle in first or second as the with old one when trying to find neutral at a full stop.

    I tried what I would call a spirited run, thinking it might free up a sticking plate, but that didn't seem to work.

    It seems to get worse as the engine heats up, ie okay when cold, but then I get the problem when warm/hot. It works fine on the center stand.

    Thanks again for any further comments/suggestions.

  6. #6
    chuck_donahue
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    Quote Originally Posted by st3ryder View Post
    1987 K 75; approx 75K mile on the bike. Cannot set the cable, brand new, to effect enough throw out to get the bike to shift out of first or second into neutral while idling at a stop. Have followed all the instructions in the Clymer and the Haynes. The bike will shift fine up and down with normal riding with zero clearance/slack in the cable, but come to a stop in 1st or 2nd, and it feels locked into gear, ie too much drag on the clutch to shift into neutral is my guess. Shut the bike off, and the shifter will move into neutral. Could the clutch plate be so thin that I can't get enough throw-out? Just finished a clutch spline lube too.

    Any input/comments more than welcome and always appreciated.
    Have you tried "double clutching" ? I have to do that some times.

  7. #7
    The more I read the more convinced I am that the clutch hub is binding on the input shaft. It usually ought not do this with a well lubricated spline. But it will if either the shaft ot the hub is badly worn and has irregular surfaces.

    But just to make sure you are following the right set of instructions:

    1. Adjust the knurled knob at the handlebar until there is 12mm of exposed thread between the adjuster and the snug lock ring.

    2. Loosen the locknut and adjust the adjuster at the back of the transmission to provide 7mm of free play measured between the lever and the housing at the handlebar.
    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://web.bigbend.net/~glaves/

  8. #8
    Quote Originally Posted by PGlaves View Post
    The more I read the more convinced I am that the clutch hub is binding on the input shaft. It usually ought not do this with a well lubricated spline. But it will if either the shaft ot the hub is badly worn and has irregular surfaces.

    But just to make sure you are following the right set of instructions:

    1. Adjust the knurled knob at the handlebar until there is 12mm of exposed thread between the adjuster and the snug lock ring.

    2. Loosen the locknut and adjust the adjuster at the back of the transmission to provide 7mm of free play measured between the lever and the housing at the handlebar.

    I've always been one to pay attention to the clutch splines, ie every 2 years since my ownership tenure began about 12 years ago, using Honda Moly60. I pull the gear box right off and clean both the clutch spline and the input shaft splines very well before applying new grease, and they seem fine to me, ie nothing really stands out to me using the same criteria for judging final drive spline condition, like stepped or spiked or wavy splines.

    I will try your cable tension method, but just to clarify:

    should I back the rear adjuster screw out all the way before setting the 12mm gap at the threaded/knurled cable adjuster, or set it to the "contact" position?

    If I decide to pull the clutch to measure the plates/visual inspection, how hard is it to align again? I've read that simply using an appropriately sized deep socket between the housing and the plates is all that's needed?

    Should the clutch housing splines, engine side, be lubed regularly too?

    Thanks again, much appreciated.

  9. #9
    Quote Originally Posted by chuck_donahue View Post
    Have you tried "double clutching" ? I have to do that some times.
    Can't double clutch at a full stop in 1st gear.

  10. #10
    Quote Originally Posted by st3ryder View Post
    I've always been one to pay attention to the clutch splines, ie every 2 years since my ownership tenure began about 12 years ago, using Honda Moly60. I pull the gear box right off and clean both the clutch spline and the input shaft splines very well before applying new grease, and they seem fine to me, ie nothing really stands out to me using the same criteria for judging final drive spline condition, like stepped or spiked or wavy splines.

    I will try your cable tension method, but just to clarify:

    should I back the rear adjuster screw out all the way before setting the 12mm gap at the threaded/knurled cable adjuster, or set it to the "contact" position?

    If I decide to pull the clutch to measure the plates/visual inspection, how hard is it to align again? I've read that simply using an appropriately sized deep socket between the housing and the plates is all that's needed?

    Should the clutch housing splines, engine side, be lubed regularly too?

    Thanks again, much appreciated.
    There is no need to touch the bottom adjustment until you set 12mm of thread showing at the top. Then loosen the locknut and adjust the adjuster bolt to get 7mm free play at the top. Then pull the clutch and hold it while you tighten the locknut. The pressure on the bolt keeps it from turning while you tighten the nut.

    Splines: two are critical on the K75. Splines at the rear of the driveshaft where it mates with the shaft of the final drive. Every tire or every second tire depending on tire life. Certainly every 20K miles.

    Clutch hub splines where the clutch disk hub attaches to the transmission input shaft. I do them every 40K miles.
    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://web.bigbend.net/~glaves/

  11. #11
    So I tried the above cable/adjuster settings, and there was so much drag that the bike wanted to roll forward, lever fully engaged when in 1st at idle. I set it up as best I could which is to say the cable is set very tightly with +1/2 a turn at the adjuster screw, (approx 8 mms at the cable threaded adjuster, zero slack at the lever-housing). This will give me very good shifting and I can get into neutral from 1st and 2nd many times, and "blipping" does help, but blipping my K75 is almost impossible. I think next clutch spline lube I will pull the clutc. First time for everything I guess.

    Thanks again for all the input.

  12. #12
    A bozo on the bus deilenberger's Avatar
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    I would consider it wise to open it up and see what's wrong. If what I suspect is wrong (a bent clutch disk) continuing to ride it this way will damage the transmission, and probably the transmission input shaft splines. Plus with zero play in the system, your throwout bearing is likely to give out rather soon.

    Just me - but having BTDT, something is seriously amiss..
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders
    '12 R1200R - I love this bike!

  13. #13
    Heeding the above advice, I took everything apart say for the clutch housing which I guess is not involved in the shifting problems I'm having. I'll look forward to suggestions on centering the clutch. I hope my marks will help because the only balance mark I saw was on the cover, ie nothing on the pressure plate or housing.

    What I found is the clutch friction plate is approx 5.5 mms thick at 6-8 diferent random spots after taking measurements 2 times. The Haynes states to replace it at 4.5, so I guess it's still okay thickness wise. I then placed it on the input shaft of the gear box, and used a wooden shim I had laying around as my feeler gage between the clutch friction plate face when the plate was pushed all the way on to the shaft and the head of a botton head bolt near the top of the box. The thinest part of the shim is approximately 5mm and then it gets wider from there. I eyeballed it up, and it's pretty consistent in shape. I started at what was the tighest/narrowest gap between the clutch disc and the bolt head, and then rotated the disc while pushing in on it and sure enough, it, ie the gap, opened up to the point where the widest gap would allow my feeler gauge to be lowered into the gap down to 3/4's of its length. I don't know how much of an increase in gap that represented from the narrowest gap, but I figure it opened up 2-3mm at least.

    Should I replace it? If so, any recommendations beside OEM?

  14. #14
    3 Red Bricks
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    Since you have been running zero clearance (freeplay), I would also look very carefully at the tip of the clutch release rod and the pocket in the spring plate that it rides in for any signs of wear or galling.




    LONG MAY YOUR BRICK FLY!

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

  15. #15
    A bozo on the bus deilenberger's Avatar
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    At this point - I'd do the disk for sure (I suspect the center hub is slightly distorted, the diaphram spring, and as Lee suggested - the pushrod and throwout bearing. The rest should be OK since there weren't any reports of slipping. Order new bolts for the clutch housing, and if you marked the components before disassembly - just use your marks to line it back up.

    When reassembling - people have used electrical tape wrapped on a screwdriver to center the disk but I'd suggest trying to beg/steal/borrow/make a real centering tool.

    When I owned a K bike, I had access to a lathe and it took about 30 minutes to make an acceptable centering tool. The problem with eyeballing it or other McGuiver fixes - if you get it wrong, you stand a chance of bending the center hub on the disk - which can cause exactly the symptoms you're currently experiencing (BTDT, learned not to do it..)

    You really don't want to do the job again.. I used to loan out my centering tool - but last time I got it back it was bent, and a PITA to straighten out, so it doesn't get used now unless I'm using it. If you were near NJ, I'd ride over and center it for'ya..

    Best,
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders
    '12 R1200R - I love this bike!

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