Topic: WTF clutch...?!?

[babyfood1217]

Question about clutches.  In my unfortunate finding regarding my hydro conversion, I thought I may as well put my new HD springs in.  So I take the 10-12 phillips pan heads out, pull the cover off the pressure out, swap the springs, and reassemble.  I am going to have to (temporarily, just so I can get this beast rideable) put the cable clutch back in action, but I don't understand the mechanism at all.  The shaft coming out from the clutch rides rotary-cam style on some ball bearings inside, but what does the stupid little threaded post do?  I just don't get it, and Haynes manuals don't explain or diagram squat.  Getting frustrated here, as I cannot figure out how to get my clutch to engage/disengage.



-Chris

[babyfood1217]

did i mention this makes me feel pretty dumb?  moreso than usual at least

-C

[mystic_1]

The threaded stud pushes/pulls on one of the cam plates that sandwich the ball bearings in that little metal triangle carrier.

The other cam plate is connected to the clutch cable arm.

Adjusting the stud controls the distance between the plates.  You want some slack in there when you're not pulling on the cable.

When they tell you to screw the stud inwards until you feel resistance, the resistance you are feeling is the cam plate touching down on the ball bearings and starting to push inwards on the clutch lifter plate.  You then back off 1/8?? turn to provide the aforementioned slack.

If the stud is too far out (loose) then the cam plates aren't close enough together for the ball bearings to ride against the ramps, and the clutch won't disengage.

If memory serves, turning the stud clockwise runs it into the cover, pushing the outer cam plate inwards, giving less slack.  Counter-clockwise is the opposite.  Hold the stud with your screwdriver to keep it from moving when you tighten the locknut, and double-check after tightening as often the setting changes when you cinch things down.

hth

mystic_1

[ev0lve]

Freaking THANK YOU! A nice cogent explanation. I was wondering this myself.

[babyfood1217]

I'll give it a shot mystic_1.  The toughest part right now (for me at least) is trying to understand how the mechanics of the this clutch mechanism will work with the slave cylinder that will be on there when I can finally get the hydro clutch working.  With the hydro, the only action will be a thrust: no rotation, no cam action (not that I can establish anyhow), so I'm trying to figure out what will actually be moving against the clutch lifter plate to disengage the clutch.  By your description (and the looks of it) it will be internal portion of the threaded stud.  It's rounded, has a groove/o-ring seal between it and the cam it runs through, and appears to seat in the lifter plate.  When the cable arm rotates the cam plate, which rides up on the rotary rotary lobed bearings, this pushrod thrusts inward, thusly applying pressure against the lifter plate and allowing the clutch to disengage.  (I know I recapped everything you just said, but sometimes repeating it can help in understanding.)

So the lobed/cam ball bearing mechanism is simply there to transfer the rotary force of the cable turning the cable arm into a thrusting force necessary for the clutch to function... Correct?

[mystic_1]

OK, refreshed my memory with the parts list a bit.



The threaded shaft (#8) regulates the resting position of the cam plate (#6) relative to the clutch lifter plate.  The outer cam plate (#7) is stationary.  When you pull the clutch lever (#4) it rotates the plate (#6) and causes the ball bearings (#9) to ride up in the ramps, pushing the inner plate (#6) away from the outer plate (#7) which is attached to the case.  This pushes inwards on the adjuster bolt (#8) which pushes against the clutch lifter (next image).



The Clutch Lifter bone (#12) is connected to the throwout bearing bone (#19).  The throwout bearing bone is connected to the Lifter Plate bone.  The Lifter Plate is connected to the Pressure Plate bone (#7).

The pressure plate then moves inwards, moving away from teh fixed Clutch Center (#2) which is connected to the transmission mainshaft.  The clutch plates are no longer squeezed via the clutch springs (#9) which normally keep the lifter plate pushed away from the clutch center, and the two sets of discs (steels #6 connected to clutch center and friction plates #4 connected to the clutch basket (which is where power is input from the primary chains).

Thus, the clutch is released.

Mediate upon this.

mystic_1

[mystic_1]

Ok, and to answer your question, if you're doing what I think you're doing you can ditch everything in diagram #1 except for the actual clutch cover (#1).  Then machine the cover to hold whatever slave cylinder you're using, which should press inwards on the Clutch Lifter #12) piece in the second diagram.

Measure the movement in the ball ramps to get an idea how far you'll need to push.

cheers
mystic_1