First: How does a clutch work? Second: How do I fix it?

[Neep]

When I bought my '84 KZ650 CSR, the guy I bought it from said he thought the bike might need a new clutch because of how far you had to pull the clutch lever in before it fully depressed, and how the cable adjuster at the handle was out as far as it would go.

I had no worries about this because well if the clutch engages, isn't it pretty much good? I thought a worn out clutch would have so little friction that it no longer ever engages, not so much friction that it never disengages... I guessed that it was probably something wrong with the cable.

Well I've driven the bike around for a couple days now and could tell that not only do you have to crush the clutch lever to get it to disengage... it's not entirely disengaged when you do.

Not wanting to ruin my shiny(ish) new(to me) bike already, I break out my manual and try the clutch adjustment. Hey, this is great there's in interim connecter in the line I can use to take up some of the slack at the clutch lever.

Now I'm confident the bike just needs the cables adjusted. Loosen everything so there's lots of slack in the line just like the manual says, then I go take off the clutch adjustment cover and misread the manual, I backed out the screw a few turns at decent resistance and stopped when I heard a click thinking "Hmmm... let’s not break anything" and found out I was supposed to back out the lock nut, not the screw. Ok, screw in the screw until it meets resistance and... no resistance whatsoever. The screw will turn in until it bottoms out where we go from no resistance to infinite resistance.

Well whatever, maybe the clutch is worn and this bottoming out is the limits of its' adjustment. I leave it there, put the lock nut on and try adjusting the bike... Now I can't take up all the slack in the line for the clutch, even with everything adjusted all the way out...ok, let’s try that again.

This time I pretend the manual is misprinted and back the adjusting screw out until I feel resistance, then do the little half turn back it tells me to. Hey I can adjust the cable tension to something useful now yay! I set it up, put the bike on its' centerstand with the rear wheel up. Start the bike, clutch in, shift to first and the rear wheel turns... even with the clutch pulled in as far as possible... dmn.

I spend the next 10 minutes or so shutting the bike on and off, playing with the clutch adjuster screw (I left the cables as adjusted to speed up the process) and I could not find a situation where the rear wheel would not turn after adjustment. I didn't try and back out the screw too far through the resistance (had a bad experience with the idle screw in the carbs on a different bike... guess what I did... ) due to fears of breakage, but I can't get my bike's clutch to fully disengage. It's very aggravating.

So to simplify the implied questions in that narrative:

What does the clutch adjusting screw adjust? And what is the resistance I'm feeling?

Does a clutch no longer disengage when it's worn out? Or do I have some other problem with my clutch?

Thanks for any help you guys can offer.

[StarGate]

First you need to determine what bike you have because as far as I can tell, Kawasaki didn't make a 650 for the US market in 84. Once you you have that figured out use the parts breakdown on Kawasaki.com and your service manual to determine if you have any missing or worn parts in your clutch actuator.

[NCDave]

you adjusted it the wrong way and put too much play in the cable. You should expand the lower adjustment pretty much all the way out, then use the wheel at the clutch lever for fine adjustment leaving about 1/8 inch of play where the lever meets the base.

If correct, you should feel the clutch start to engage with just a slight squeeze and should be engaged by half way in (or there abouts). If you can't take out the slack with either of the adjustments, that means your friction plates in your clutch have worn down too much and it's time to replace them. You should order a clutch pack and replace it. Fairly simple to do if you are a competent shade-tree mechanic.

[StarGate]

Originally Posted by NCDave

If you can't take out the slack with either of the adjustments, that means your friction plates in your clutch have worn down too much and it's time to replace them. You should order a clutch pack and replace it.

Unless my senility is being hyper active today that is totally backwards from what would happen if your clutch had worn excessively. The first symptoms of worn out clutch plates would be slipping. With excessive wear your problem would be that you couldn't get the clutch to engage. The problem here is he can't get it to disengage because of slack in the cable. I might believe (but probably not) the cable had stretched too much but there is no way this problem could be caused by worn out clutch plates.

[NCDave]

Originally Posted by StarGate

Unless my senility is being hyper active today that is totally backwards from what would happen if your clutch had worn excessively. The first symptoms of worn out clutch plates would be slipping. With excessive wear your problem would be that you couldn't get the clutch to engage. The problem here is he can't get it to disengage because of slack in the cable. I might believe (but probably not) the cable had stretched too much but there is no way this problem could be caused by worn out clutch plates.

True dat! getting the slack out is definitely the first step!

[A2rider]

K28-8035 FITS MODEL: KZ650H 82-83 - Clutch $13.95

Most shops can order from Parts Unlimited. Get a new cable, they're cheap.

[Neep]

I don't think the cable is too stretched. I could be wrong, but the manual says I should be able to screw in the little screw until I feel some resistance. That's not possible on my bike. I screw in the screw (Turn it Clockwise), and then it bottoms out. When that happens the screw is so far in the case I almost couldn't get the lock nut back on it. When this happens, at it's limit, I cannot get the slack out of the cable. However if I unscrew the screw (Turn it counter clockwise) I will eventualy hit resistance and at this point I can easily take up the slack in the cable. However at this point of counter clockwise resistance, with no slack in the cable, pulling in the clutch does not seem to release the clutch fully.



I keep looking at this diagram in the hopes of figuring out how the little screw works, but it still doesn't quite make sense as to what it is supposed to be doing.

It seems like the end of the clutch cable would connect to 13102 (Clutch Release) when you pull in the clutch lever, the cable pulls the Clutch Release in a counter clockwise rotation, sliding it on 92045 and 13119 (Clutch Release Cam) the action of the Cam would push the Clutch Release, 13116A (Clutch Push Rod), 92001 (Clutch Spring Fitting Bolt) and finaly move 13187 (Clutch Spring Plate) off of the clutch plates allowing the engine to turn freely. So if I turn the little screw (92009) I should feel the resistance of... something (what part is supposed to suply that resistance) as I turn it in, but I never do. It just turns and turns and turns, then bam, no more turning.

Looking at the picture I can't figure out why my little screw works the way it does. If it's supposed to give you resistance turning in, like the manual says, where does that resistance come from? Also, how come you get more and more slack in the clutch cable as you turn the screw in? Seems strange to me.

Bah, it probably is the cable is stretched. I'll see if I can jurry rig something to get the clutch lever to work when I screw the screw in more, and see if that works. It's just strange when things aren't working how the manual told me they should. Staring at this parts diagram for so long, I think it might make sense.

[Kawa 1982]

The key is “SOME” resistance

I went through the very same nut roll. I finally got a friend to help me. Your description of what happens when you squeeze the clutch lever is correct. The resistance is supplied by the spring, part number 92081A. I was expecting SOME RESISTANCE. My friend explained that I was expecting far too much resistance. I guess a better description would be light resistance. Once I realized he was right the adjustment took about 15 minutes.

[LoudFastUgly]

K28-8035 FITS MODEL: KZ650H 82-83 - Clutch $13.95

+1 A2rider.

I agree with Kawa 1982 as well, but after the cable is replaced.