Clutch freeplay disappears - ZX6R Forum
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post #1 of 13 Old 09-02-2019, 05:08 PM Thread Starter
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Clutch freeplay disappears

I started having an issue at the track over the weekend. Initially, I thought my clutch was slipping but after a quick once over I discovered the free play in the clutch lever was gone. So I readjusted it and road the rest of the weekend without an issue. But after getting home and checking it again, it appears to be getting too tight again. Shouldn't it be getting looser if the discs are wearing out? What would be causing this?
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post #2 of 13 Old 09-02-2019, 05:23 PM
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I can't say what is causing it but the free play disappears as the plates wear because the plate stack gets shorter and it pulls the actuating lever farther, taking the slack out of the cable.


Mark

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post #3 of 13 Old 09-02-2019, 05:32 PM
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Quote:
Originally Posted by zx6rguiy View Post
I started having an issue at the track over the weekend. Initially, I thought my clutch was slipping but after a quick once over I discovered the free play in the clutch lever was gone. So I readjusted it and road the rest of the weekend without an issue. But after getting home and checking it again, it appears to be getting too tight again. Shouldn't it be getting looser if the discs are wearing out? What would be causing this?
Pull the clutch cover, and check the thickness of the end of the throw out rod. I'd be willing to bet it is almost completely worn away.....

"Basic stuff fellas. Use your head for something other than to break your next fall."
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post #4 of 13 Old 09-02-2019, 05:48 PM
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Pull the clutch cover, and check the thickness of the end of the throw out rod. I'd be willing to bet it is almost completely worn away.....
This is a good place to start.

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post #5 of 13 Old 09-02-2019, 05:51 PM
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I've had two fail with this set of symptoms....

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post #6 of 13 Old 09-03-2019, 06:06 PM
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Check the cable, as well, make sure its not fraying and about to break. Prior to mine snapping, I had to continually back it off at the adjuster.
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post #7 of 13 Old 09-03-2019, 06:33 PM Thread Starter
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The throwout rod and the actuating lever are both worn to a certain extent. I actually replaced the throwout rod when I bought the bike as it was bent to the point where it almost fell off. Since then, I have put around 5000 miles on the bike, all at the track. The actuating lever looked almost the same then as it does now. Didn't measure the plates and discs yet.
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post #8 of 13 Old 09-04-2019, 12:14 AM
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I can see wear on the throw out rod...... $15, I'd replace it and apply grease to the surface that contacts the actuating lever. It will keep eating the head of that rod.

The mechanical advantage from moving the hand control full throw (30*? Working range, 5-15*?) to the point where the actuator pulls that rod 'out' by less than 90* rotation is pretty significant. I expect the force must be similar to a claw hammer prying a nail out of a board. All concentrated onto the sharp lip of the actuator that first makes contact.

I believe the bearing the other end of the rod rides on is not decoupling the rotation of the pressure plate adequately. The actuator mills off the back of the head as a result. I know the part number of that bearing has changed at least once. I don't see any mention of lubing that bearing in my shop manual, either. Grease near the frictions probably a bad idea.

I don't like the look of that steel, either....

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post #9 of 13 Old 09-04-2019, 07:20 AM
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Quote:
Originally Posted by RJ2112 View Post
Grease near the frictions probably a bad idea.

I don't like the look of that steel, either....
Since it's a wet clutch the grease would get washed off in short order anyway, everything should be heavily splash lubricated inside the clutch housing. I agree that steel looks somewhat cooked.


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post #10 of 13 Old 09-04-2019, 07:58 AM Thread Starter
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Quote:
Originally Posted by RJ2112 View Post
I can see wear on the throw out rod...... $15, I'd replace it and apply grease to the surface that contacts the actuating lever. It will keep eating the head of that rod.

The mechanical advantage from moving the hand control full throw (30*? Working range, 5-15*?) to the point where the actuator pulls that rod 'out' by less than 90* rotation is pretty significant. I expect the force must be similar to a claw hammer prying a nail out of a board. All concentrated onto the sharp lip of the actuator that first makes contact.

I believe the bearing the other end of the rod rides on is not decoupling the rotation of the pressure plate adequately. The actuator mills off the back of the head as a result. I know the part number of that bearing has changed at least once. I don't see any mention of lubing that bearing in my shop manual, either. Grease near the frictions probably a bad idea.

I don't like the look of that steel, either....
So you think the actuator looks okay? Or should I replace both?
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post #11 of 13 Old 09-04-2019, 08:28 AM
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So you think the actuator looks okay? Or should I replace both?
I'd do the throw out, and the bearing it rides on in the pressure plate. Get the updated design, I think it has more bearings. My actuator looks at least as bad as yours...... not saying that's a good reason to keep it.

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post #12 of 13 Old 09-04-2019, 10:32 AM
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It's not the worst I've seen, but I'd replace the throw out rod and keep that one as a spare. Might as well do the same thing for the lever. Clutch steel looks fine, they will always hot spot like that to some degree on track bikes due to the heavy slipper engagement from the repeated high RPM down shifts that street bikes aren't subjected to.
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post #13 of 13 Old 09-04-2019, 05:48 PM Thread Starter
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I measured the thickness of the discs and plates and they are all within spec. Total stack thickness is around 40.1-40.2mm. The manual states 40.6 for, I'm guessing, a brand new stack.

The only interesting thing I found was on the plates. They all have these 3 spots where they are discolored. I'm guessing that is from the slipper. When I measured the plates they were all around "0.100 thick. But on one spot, on every plate, their is a high spot that measures around "0.003-0.004 thicker than the rest of the plate. Is this normal?
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