TOPIC:

Well then, I guess you have eliminated everything but the pusher and the rod. Since the rod is clearly the shorter one, replacing it with a pepper one should do the trick. Still doesn't explain why the short one got installed or how the bike could be ridden with it. Crazy. 
Gotta love old bikes.

You say the pusher sits on top? On top of what?

rapfl wrote: The clutch pack will be thinner, correct, but the push plate will not sit lower. Like a lid on a pot, with less water it still sits on top. And with 11 plates my clutch is slightly slipping. 

It sounds like you may be confused about the clutch configuration.  Unless it actually bottomed out, with fewer clutch plates the clutch spring plate (push plate) would sit deeper in the housing since it rests against the clutch plates.  That should enable the clutch rod to disengage it from the clutch plates when the clutch lever is pulled in.  Of course, a longer clutch rod might do the same thing assuming there is sufficient room in the clutch for a longer rod.

There could be several reasons for your slipping clutch.  Using the wrong motor oil will make than happen as will worn out clutch friction plates, weak or poorly adjusted springs, etc.    Ed

In the interest of clarity, when I write pusher, I mean part number 20 in the diagram above. Spring plate or pressure plate refers to number 13.
Are you saying that with two clutch plates removed, that number 13 is bottoming out on number 10 and is not then able to supply sufficient pressure?
Number 20 is inside the clutch assembly so it can push on the inside of number 13, pushing it away from number 10, right?

650ed wrote:

rapfl wrote: The clutch pack will be thinner, correct, but the push plate will not sit lower. Like a lid on a pot, with less water it still sits on top. And with 11 plates my clutch is slightly slipping. 

It sounds like you may be confused about the clutch configuration.  Unless it actually bottomed out, with fewer clutch plates the clutch spring plate (push plate) would sit deeper in the housing since it rests against the clutch plates.  That should enable the clutch rod to disengage it from the clutch plates when the clutch lever is pulled in.  Of course, a longer clutch rod might do the same thing assuming there is sufficient room in the clutch for a longer rod.

There could be several reasons for your slipping clutch.  Using the wrong motor oil will make than happen as will worn out clutch friction plates, weak or poorly adjusted springs, etc.    Ed

The clutch is not slipping, it is dragging. Pulling the lever won't disengage it. After adding a piece of metal to the push rod it does disengage, but not fully. 

TexasKZ, that's right, number 13 bottoms out on 10. In the North American KZ200 with 6/5 plates, 10 is also a little shorter to compensate for that. 
20 is inside of 10, the clutch hub, pushing on 13 from the inside, pushing it away from 10 so that the plates can get free. Here's another diagram which makes all of the above clearer. It's a cross-section of the clutch assembly. 



And here's how my clutch looked like with a fully pulled clutch lever (sorry for the bad photoshop, but I guess it illustrates the case):


Now what I've done is put a piece of metal in between the push rod and the spring plate pusher (you can nicely see on this picture where that sits, between 7 and 13). This moves the pusher towards the plate and compensates for the play.

And yeah, it doesn't explain why this happened or how it was ridden before that. Sadly I never met the previous owner as it was sold to me by a guy who sells broken bikes. 

However I'm still a bit worried that I just treated a symptom now and that the actual problem will haunt me later on. Do you think something can happen with this solution? 

I think adding the extra little piece was a good way to test your theory, but I could not comfortably ride it that way. I would always be imagining some way that little piece could get hung up or dislodged in a way that would cause me more grief. I think it would be prudent to get a properly sized pushrod. That way you would have more confidence that there is not some hidden gremlin waiting to bite you when you least expect it.
I wonder how long the perpetrator of this "fix" rode the bike this way? I am constantly amazed at how some people can spend so much time and energy buggering up the simplest mechanism in an attempt to avoid fixing it properly. I look forward to seeing what other creative fixes you uncover.

That is true, I should definitely get a proper solution. 

If you‘re interested in the story of this bike (at least the one I had with it), check out this thread:  www.kzrider.com/forum/11-projects/608996...etely-wrecked-piston

One of the other weird things was the spark plug, some NGK Racing Plug - in a KZ200 with 18hp. So yeah, quite some mysteries... 

What was the thickness of the extra piece. I would also woryy it cou ld come loose and wreck other bits. The ball bearing method I described earlier used in 650's would have the same effect without the worry.

That‘s a good idea. I‘d just need more than one, as it‘s around 0.6cm... But I‘ll definitely try for a longer push rod and compensate any residual play with a ball. 

For anyone coming along this thread in the future.

As mentioned there are two versions of the clutch, one with six plates up until Engine Number 005063, from then on one with seven plates.
The one with six has a shorter push rod and a smaller clutch hub as well.

So I got a push rod for the seven plate version of ebay (part number 131161002). Installed it and the clutch worked perfectly fine. Undoubtedly a very uncommon fix for an uncommon issue.

Nice job.

Thanks for the report.



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