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Discussion Starter #1
Well, here we are,

After having some troubles with the carbs past winter and the bike finally feeling good, I decided to check if I could remedy what felt like some slack in the clutch assembly or the transmission gears. LO AND BEHOLD: The outer clutch basket has about 3/8 to 1/2 an inch of play between the gear that drives it from the rear and the basket itself. I can turn it on either side without the gear ever moving.

When I was getting into first gear and letting the clutch out, it felt like there was some play causing a clunk during clutch engagement. It happens as well when releasing the throttle and going back on it. It hurts city driveability by a lot and it is half my riding commute.

Could anyone tell me if I'm going crazy or does the clutch basket need replacing? I've also heard of needle bearings failing on some honda dirtbikes but I believe the play would not only be rotational.

Cheers!
 

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I've never had my clutch apart, although I've adjusted the cable and lever :)

As for a clunk, putting the bike into first gear mine always clunks and I've been told here that's not uncommon. I'm not sure if this helps with what you are asking or not.
 

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Discussion Starter #3
Clicking the gear lever is not problematic, it is the clutch I feel through the crankcase when releasing the lever, when accelerating and letting off the throttle, it does it too. I am aware of the general clunkiness of Kawi gearboxes and am pretty used to em

My old ninja 500 never did this, and it is arguably as old school as the zr even though it os water cooled
 

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All I can suggest is take a look at the service manual and see if it's of any help. I can't say if replacing parts will help or not. Sorry.
 

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Firstable, in this type of motorcycle you have, rubber dampers on the secondary shaft, rubber dampers in one of the clutch baskets, and rubber dampers in the rear wheel hub. The dampers in the clutch baskets do same work as those small springs you have seen on dry clutches. You can have a problem with these rubber dampers, but usually happens at very advanced age, unless the motorcycle has been trashed.

I own the predecessor of the ZR-7, the Zephyr 750, and yes, I remember the clutch baskets have some play, but is normal, and the bike is 30 years old now.

I'd start by checking the play on the rear wheel hub, because those dampers are very easy to replace,. a few minutes...then is up to you about replacing the basket..I personally doubt you have a problem there. Replacing the dampers in the secondary shaft, are a big, big job.

This is a wet clutch, meaning is bathed in oil. The clunk and the lurch are normal due to the oil film dragging between disks. Same lurch you feel in a car with an auto tranny when engaging drive from neutral due to oi flowing in the torque converter turbines. The oil cools the clutch, making it far more durable than dry clutches, and the heat is taken away by the oil cooler (that's the reason for it, same as with cars with auto trannies).
 

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Discussion Starter #7 (Edited)
Thank you Hugo,

I checked the rubber dampers at the rear wheel and they have very little play, they seemed fine and not cracked, as for the secondary shaft dampers, I haven't checked them but I was able to replicate the sound somewhat by holding the outer clutch basket and rotating it.

It has about half an inch of play between the basket itself and the gear attached behind it.

Here is some visual support for you all to see, beware, as this short movie contains quebec french. I was showing it to someone I know 🧐

 

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The big gear behind, takes power from a smaller gear on secondary shaft, which in turn is attached to crankshaft by primary chain. The big gear is attached to outer basket by rubber dampers. I know there is a normal play there but can't tell you if what you have is excessive. My guess is that is not because the ZR-7s are not that old. How many miles (kilometers) on this bike?

The article below is not for this particular basket but would give you and idea what the dampers are.....and am not suggesting you need to replace yours.

 

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Discussion Starter #9 (Edited)
I will take a read and keep on getting informed.

If I ever need to replace the damper, I will replace the clutch basket unit all together, easier to find,

The bike has 47'000 kms on it

edit: I contacted an ebay seller and asked them to measure the play between the baket and gear, we should all have an approximate value now.
 

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Discussion Starter #10
The seller measured three clutch baskets in his stock, and this is the measurement he came with (see picture)

Play should be around the space between two gear teeth, which is half of the play that I have, I think we can all assume that the Clutch hub dampers are cracked (abuse) or shrunk (age)
 

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OK, I'd be interested in what you find..

.if you have never done this, these are my recollection, if they help.

The inner basket nut is tight to a gorilla territory 98 ft-lbs (130 N-m) of torque. That's about double what what the engine puts out., and is very difficult restraining the bike loosening it. Strongly suggest an impact gun, rather than a breaker bar. I believe the nut is also on purpose out-off round as locking method. Thus I'd also suggest getting a new one .....and also a limiting torque stick socket when putting back by mentioned impact gun.

Careful also tightening the spring bolts. They strip very easily.
 

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Discussion Starter #12
Alright,

2 months later.

I ordered clutch basket dampers from a nice fellow named Steve from the KZ forums who made vitton rubber basket dampers for the KZ750-fours.

I removed the clutch basket, drilled and removed the rivets as per his instructions and replaced the dampers with the new ones, the holes were tapped and machine screws were installed with his torques recommandations and generous amounts of red loctite.

The slack is way less than it used to be, there still is some drivetrain lash but it is way more bearable and way less clunky than it was. I stress tested the basket a couple times and it holds up fine.

So for anyone with the same issue as mine, look up TurboSteve on the KZ forums.

And remember to replace the clutch holder nut with a new one, some who haved reused it experienced it backing out on the freeway.
 

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Thanks for the update and the references.
 
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