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Thread: clutch stuck

  1. #1
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    clutch stuck

    Hi Group,
    I started the 77 R100RS today to go for the first ride of the season.
    All seemed fine but when I engaged the clutch and selected 1st gear, the bike lurched forward. The clutch doesn't engage when I pull the lever back. I tried adjusting the lever by backing the nut all the way back, then resetting the bottom end. Nothing seemed to help. When the bike is in gear the lever moves normaly and the arm moves normaly at the tranny but the clutch won't engage. I tapped the tranny with a rubber mallet and everything started working again. I took the bike out for a ride and all is well. Did something get stuck due to the winter layup?
    Is this common or do I need to think about taking things apart and replacing clutch parts. Not sure when the splines were lubed last. Bike has 87000 km, the last 10,000 by me.I adjusted the clutch and went for a test ride and all is working well. No slipping at low or high gears and the tranny shifts well( for a bmw,lol)
    I checked the archives but did not find anything...
    Thanks for your help with this.
    Louie..._/)....

  2. #2
    Left Coast Rider
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    Quote Originally Posted by LouieSkretas View Post
    Hi Group,
    I started the 77 R100RS today to go for the first ride of the season.
    All seemed fine but when I engaged the clutch and selected 1st gear, the bike lurched forward. The clutch doesn't engage when I pull the lever back.
    I think you mean the clutch doesn't dis-engage. I would hazard a guess that your clutch friction plate is stuck to the driven plate. Here's what's worked for me in the past...Hopefully you have a small nearby hill or are in good enough shape to push your bike up to a more-than-walking speed. With no traffic around, start the bike, start rolling downhill, pull the clutch lever, snick it into gear and as you're rolling along give it a quick twist on the throttle. Should break the plates loose and you'll be on your way. Remember to keep the clutch lever pulled in while doing this.

    If you have any doubts about your ability to do the above - DO NOT ATTEMPT.

  3. #3
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    Correct, sorry I always get those terms backwards. When I pull the lever back to dis-engage the clutch, power was still being transferred to the rear wheel. I eventualy got it to work and it was fine for the rest of the day. Was it just stuck due to the winter storage since November or does this indicate a problem in the clutch system?
    Thanks
    Louie..._/)....

  4. #4
    Benchwrenching PGlaves's Avatar
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    I am going to guess that the bike was stored over the winter at a location with somewhat high humidity. Occasionally the clutch disk material will stick to either the pressure plate or clutch cover as rust starts to form in these conditions.

    I think you already fixed it. Once it broke loose normal clutch action would polish the surface rust that was starting to form.

    However, next time you have the transmission loose for a spline lube take it all the way out and disassemble the clutch parts (mark their positions with paint before taking them apart)to inspect the pieces.
    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
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    Thanks Paul, It was parked in an unheated garage in Toronto Canada. This year it was rather wet and milder than most winters.
    Seems to be fine now.
    cheers
    Louie..._/)....

  6. #6
    Registered User NavyCWO's Avatar
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    This is why, when I park my tractor, I always use a block of wood to keep the pedal pushed down. This disengages the clutch as for some reason, tractor clutches tend to stick in areas of high humidity like East Texas. I was told to do this years ago by several old-time farmers. Never had a problem with my BMWs because I ride them frequently enough even in the winter to avoid the problem apparently!

  7. #7
    Administrator 20774's Avatar
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    Quote Originally Posted by NavyCWO View Post
    This is why, when I park my tractor, I always use a block of wood to keep the pedal pushed down.
    This might be the tip of the day!! I wonder though, if there would be any "harm" as a result of having tension on the clutch cable and/or pressure on the clutch spring fingers for an extended period of time.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  8. #8
    Luddite Looney wecm31's Avatar
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    Quote Originally Posted by 20774 View Post
    would be any "harm" as a result of having tension on the clutch cable and/or pressure on the clutch spring fingers for an extended period of time.
    I would think this would shorten the life of the diaphragm spring.

    It normally is only depressed a few hours a year, not several months.
    Seems to me it would start to compress permanently a bit.
    Gerald P
    The last thing I want to be is just like everyone else...
    1985 R80RT
    1969 Sport Fury Convertible

  9. #9
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    One more clutch question.
    I read the 50+ posts on clutch adjustment, and mine is working well but I see a few different numbers floating arround.
    Should the 201mm measurement be from the back of the tranny case to the front edge of the lower lever or to the front edge of the brass barrell that holds the cable? I have seen references and a picture showing the latter.
    Also the freeplay at the handlebar lever is stated as 2mm in one book and 4-5mm in another. which one is correct? Or do you go by feel by doing a high gear slip test?
    Thank you.
    Louie..._/)....

  10. #10
    Administrator 20774's Avatar
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    The 201mm measurement is from the backside of the tranny boss that the cable slips through...it's got the slit to allow the inner cable through so that the rest of the cable can be slipped into place. From there you measure to the front side of the barrel that is in the movable clutch arm.

    As for the handlebar freeplay, I think that is just user choice. Obviously it needs to be something...if it's zero, then the throwout bearing is potentially spinning all the time. It can't be huge otherwise, you'll run out of hand lever before it bottoms out on the grip. So, 5-6mm or 0.25 inches is probably fine.

    In the end, I'm not sure how super important the measurment is. Ideally, the back-of-tranny lever should be either parallel to the back of the tranny or ideally have the cable-barrel end of the lever slightly more aft. Then with the 6mm free play at the hand lever, the clutch should work fine. However you can get to that point should be OK.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  11. #11
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    201mm Meaurement

    Only works for "newer" Airheads. . .

    Obvious when you look at the /7 that this 201mm won't be right, and you use the "right angle" eyeball gauge between cable and lever-arm at the back of the tranny.

    Walking Eagle

  12. #12
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    grabby clutch

    My 1977r100rs has a grabby clutch on engagement, but not every time? any ideas, thanks

  13. #13
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    Quote Originally Posted by homere View Post
    My 1977r100rs has a grabby clutch on engagement, but not every time? any ideas, thanks
    First thing is to check the adjustment of the clutch lever. There is a specific procedure for doing this. Links to the procedure are available.

    When is the last time you did a spline lubrication on the transmission input shaft? It's likely that when the clutch is disengaged, the spinning clutch disk doesn't float very well on the splines and can be making contact on the engine side resulting in uneven forces.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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