Post by: frankenduck on May 15, 2011, 12:52:35 PM
1 - How they work
2 - How to adjust them
3 - How to replace the clutch plate and/or O-ring
1 - How A K Bike Clutch Works
(http://i236.photobucket.com/albums/ff192/owrstrich/2010/Duck%20Oct/083.jpg)
See K-BikeClutch.jpg below
The following is a general description of how K75, K100 and K1100 clutches work. The basic design is the same although some of the individual parts vary between the models.
The clutch assembly is attached to the engine output shaft via the clutch housing. (Yellow) In addition, the clutch housing provides some rotational inertia to the clutch assembly.
The clutch has two pressure plates. (Blue) The rear pressure plate is fixed to the clutch housing and does not move. The front pressure plate “floats” on three flat arced springs around it’s perimeter. (Red)
The diaphragm spring (Purple) pushes the front pressure against the clutch plate (Green) and the rear pressure plate to engage the clutch.
When you pull in the clutch lever, the clutch lever arm on the back of the transmission pushes the clutch push rod (which goes through the transmission input shaft) into diaphragm spring and compresses it. The front pressure plate can then “float” away from clutch plate and the clutch is disengaged.
2 - How To Adjust A K Bike Clutch
The following is a page from a BMW service manual that describes how to adjust the clutch:
See clutchadjustk.jpg below
This page is also attached to this thread as a PDF file at the bottom of this post if you want to print it out separately.
3 - Replacing The Clutch Plate or Clutch Nut O-ring
My procedure for doing this is attached as a PDF file at the bottom of this post.
UPDATE: Oct. 22, 2012: In my write-up I mention using a wider one of these to help pry off the outside pressure plate but a guy who I was helping with his clutch came across this thinner version which looks much better suited to the job. It can' be found at Home Depot, Pep Boys and various places online.
Tool Choice 5" Utility Pry Bar - Part number 17516 (see attached pics)
updated by scott_ 10-15-13 to update missing photo's
Post by: frankenduck on March 15, 2012, 04:24:19 PM
Post by: jimmyd on May 13, 2012, 06:39:41 PM
I'm using hand tools and my first couple of attempts ended in the entire assembly spinning while I tried it remove the bolts securing the rear pressure plate.
Post by: frankenduck on May 13, 2012, 07:14:56 PM
Post by: TimTyler on August 11, 2012, 06:09:19 PM
I didn't feel like cutting a wood block to fit, and my hammer has a comfy rubber handle, so I used the non-U part of a bicycle U-lock which fit perfectly.
You'll also need a 30mm or 1-3/16" socket for the nut.
Post by: Dbltour on February 04, 2015, 11:11:08 PM
Post by: kris on February 17, 2015, 09:45:44 PM
Thanks!
Post by: rbm on February 18, 2015, 12:18:47 AM
Post by: kris on February 18, 2015, 07:14:18 AM
Thanks again
Post by: JVDH on April 19, 2016, 01:06:16 AM
Also, has anyone had experience with the heavy duty, oil resistant pressure plates made of a kevlar material?
Trying to do all that is necessary for long life while it is open!
Post by: Scott_ on April 19, 2016, 06:37:29 AM
Post by: johnny on April 19, 2016, 07:47:15 AM
j o
Post by: JVDH on April 19, 2016, 10:41:10 AM
Post by: Laitch on April 19, 2016, 11:58:58 AM
Post by: johnny on April 19, 2016, 01:04:48 PM
ride it often and it wont leak in the 1st place... low miles is the problem... if it had a hundert grand or more on it you would be out getting some yeeehaaa instead of saying how few miles your 23+ year old motobricks has on the odo...
j o
Post by: JVDH on April 19, 2016, 03:58:27 PM
It sat with the previous owner, I put about 8k miles on it in the first year! Just want to do things right while its accessible.
Had to replace the transmission, 2nd gear was no longer functioning.
Any insight into what the problem could be on the transmission?
Post by: Laitch on April 19, 2016, 06:09:24 PM
Any insight into what the problem could be on the transmission?Not enough info on that one, JVDH, or interest either from my perspective. If you've got the old case, take it apart and work out the reason.
The time for riding is here. Button up that bike's drivetrain and go.
Post by: jonas_105 on June 06, 2017, 08:32:06 AM
Thanks!
Post by: Laitch on June 06, 2017, 09:17:35 AM
What size is the o-ring?Welcome, Jonas! Put your bike's year in your profile.
Clutch o-ring from MAXBMW parts fiche..png (52 kB . 511x256 - viewed 4207 times)
Post by: jonas_105 on June 06, 2017, 11:30:51 AM
Post by: wally.fisher on June 06, 2017, 05:01:17 PM
What size is the o-ring?19 mm inside diameter 4 mm section = (27mm) dia.)
Thanks!
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Post by: qwertymotobrick on March 07, 2018, 02:50:21 AM
Post by: Martin on March 07, 2018, 06:13:22 AM