• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

No Clutch Freeplay on K75

timtyler

New member
I've been a part of an unresolved discussion at http://www.motobrick.com/index.php?topic=4439.0

Capture.JPG

Carl and I have K75RT bikes and after transmission maintenance and reassembly we've both found it impossible to get clutch freeplay using the recommended procedure.

It seems that with new clutch cables installed in the most relaxed configuration (adjustment screw on hand lever in all the way) resulting in a ~90mm cable length at the cable bottom, then the clutch lever #7 is already touching the piston/bearing/pushrod #1,2,3 even without the adjusting screw #10 installed.

If the screw on the hand lever is unscrewed a few turns as recommended so that the exposed cable bottom length at the clutch lever is set to the recommended 75mm then the clutch piston/bearing/pushrod is depressed enough to perhaps slightly disengage the engine from the transmission.

What are we missing?
 
Check the lengths of the old and new cable sheaths. Are they the same?

Most importantly, compare the lengths of the difference between each sheath and the cable within it. That is, how much longer is the actual cable than the cable sheath. Those comparisons will tell you if differences in the cables account for the difference. For example, if you have 6 inches of exposed cable length on the old and 5 inches of exposed cable on the new one - bingo.

If there are no differences then you need to consider what changed in the clutch assembly.
 
Thanks, Paul.

With about 90mm of exposed cable length at the bottom (spec is 75mm) it feels like the engine is engaged to the transmission 100%.

If I adjust the screw at the hand lever at all, even a couple of turns, the push rod is depressed enough to disengage the engine from the transmission some.

If I adjust the screw at the hand lever so that the exposed cable at the bottom is to spec (75mm) then the transmission is disengaged entirely from the engine.

This is the case with the #10 screw just barely protruding through the threads in the clutch lever.

It's weird.
 
I believe that your problem (and the other guy's on the motobricks forum) is that you are measuring to the wrong surfaces.

The measurement is SUPPOSED to be from the end of the metal on the sheath to the BARREL on the end of the cable (Not to the swage on the end of the cable).

With the lever end completely disconnected the cable should have about 125mm from the end of the sheath to the barrel:

cable 2.jpg


Properly adjusted, it should be 75mm between the same two points:

cable 1.jpg




:dance:dance:dance
 
Last edited:
Thanks, Lee.

I was measuring it properly. When installed the max possible sheath to barrel distance is about 90mm. If I adjust that using the hand lever screw even a little, the clutch lever starts to depress the push rod.

I'm in the process of removing the transmission from the bike now so we'll see how things look.
 
Here's what the lever-to-piston point looks like at rest.

The piston is inserted "finger tight". I suspect it should be flush with the housing?

P1020906.jpg
 
Not supposed to be totally flush. Can't get you the correct dimension until tonight or Monday.

Looks like end of push rod is not going inside throwout bearing or throwout bearing is defective.
Also look for bent clutch push rod or push rod not going fully into hole in spring or end of crankshaft. You didn't change pushrods did you?

Did you see my post just before your last one?


:dance:dance:dance
 
Thanks, Lee.

I was measuring it properly. When installed the max possible sheath to barrel distance is about 90mm.

Measure it with the lever end completly disconnected and the cable not going through the adjuster. You should get 125mm.


:dance:dance:dance
 
Pulled the clutch pack and cleaned it up. Friction disk is exactly 5mm thick.

Center hole in clutch housing is clear.
 
I mounted the friction disk by itself on the transmission input splines and spun it.

It did not show any signs of being warped or uneven.
 
I think the problem is at the back of the transmission where the throwout bearing interfaces with the clutch rod. I think it is hanging up and not engaging the rod correctly.
 
I've buttoned almost everything back up and the throw-out bearing as maybe 1mm more recessed in the transmission, but not much.

P1020917.jpg

I was extra careful center-aligning the clutch pack. It's a straight shot all the way to the drive shaft.
 
Can somebody who has been there recently confirm that the throwout bearing is being installed the right way forward and aft? The photo shows the clutch rod fully seated, but another shows a hollow assembly with the bearing at one end.

If perchance the assembly goes the other way round that would take up what appears to be about 15mm of space.
 
The clutch spring diaphragm points to the rear, right? It's outer edge contacts with the clutch housing / ring, right, not the pressure plate?
 
Back
Top