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Discussion Starter · #1 ·
So, let's discuss the clutch on these machines, please refer to the install video I did on this and note that I mentioned I may follow up on the cause for the replacement:


I finally took some time to look over the old clutch and took a few pictures (attached). Those are not burn marks (yet), they are simply the areas where the disks were sliding. But notice how little of the disk is actually scuffed, and notice the irregular pattern. I don't have a flat surface to give them a proper check, but I'm guessing they are not completely flat, or that their thickness varies. I assume this lead to the shuddering feeling I had when slipping the clutch out, and the over all weak engagement until the entire pack locked up after releasing the lever.

Still haven't ridden with the new clutch yet, hopefully in the next day or so. Waiting for paint to dry on a part so I can put the clip-ons back on.
 

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You can check flatness by placing a plate down on any surface and setting another one on top of it , then spin just the top plate at 15 degree intervals . the gap will change around to different locations if bad and check inside and outside of plates.

And if they check pretty flat that way then flip just the top plate in case they are Dished shape / then either the outside or inside will have a gap.
(two plates dished in the same direction will have no gap)
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Or most of the windows in a house are pretty flat or a thick mirror is even better, when you have nothing else. then use feeler gauges of course to check the flatness .
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I know you know Greg, but for others following, the service manual max out of flatness is .010 and be sure to check the inside as well as outside edges
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If the .010 feeler gage gos under the plate at ANY location outside or inside the plate is out of tolerance.
 

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Not just the 18's / bad clutches at 2.5 miles back in the 2016's here on the forum
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https://www.z125owners.com/forum/engines-discussions/7641-clutch-slipping-after-2-5k-miles.html
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Soooooooooo ............
Clutch free play setting (but shouldn't make it chatter only slip)
The plates are not flat (maybe only go out of flat at slipping heat up use)
The friction plates are not flat (the pads are adhered to a plate)
The springs are just to week
Motor Oil Type / synthetic's can to be slippery
Something is wrong with the whole stack up of designed tolerances (bad design)
Any others ?
KLX 110's share the same part numbers I wonder if they have same amount of week/bad clutches ?

If MrEvilpirate clutch is fine now after being replaced with the stock parts then it's looking like it has to be the PLATES or SPRINGS !
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And hes thinking most of same things from his post i see
https://www.z125owners.com/forum/en...55-transmission-design-flaw-5.html#post118199
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But ya, if yours is slippin or chattering . should just to the HD clutch upgrade . I Dont think Kawasaki is going to step up and do a Recall even if its just springs or plates
 

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Off subject a bit. Kawasaki watches these forums, as does all other manufactures too. They don't have a rep that chimes in... they should, as does GM and another manufacturer (can't remember who it was). The reps that do chime in gave good SOLID input and stated they would take info back to the higher-ups.
 

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Off subject a bit. Kawasaki watches these forums, as does all other manufactures too. They don't have a rep that chimes in... they should, as does GM and another manufacturer (can't remember who it was). The reps that do chime in gave good SOLID input and stated they would take info back to the higher-ups.
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Well then there's a ray of hope :rolleyes:
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So we all should do what MrEvilpirate did and take it back and have it fixed at least once so the repair's paper trail will show up for Kawasaki and they can see there might be a problem Provided we can convince them its a MFG defect problem and have it replaced for free.. I gotta think most owners will figure out the real problem through other people and forums and just do the upgrade route at our expense . :crying:
Then again I'm sure they know that .
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At $35 and a couple hours (because I was recording a video), it wasn't worth my time to drag the bike down and let it sit for days or weeks. Especially when I knew I would get the same old weak springs installed.
+1 :wink2: / It was just meant as a wishful metaphor
 

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Discussion Starter · #10 ·
So I took it for a spin tonight and some funny things. Started off fine and went through several stops just fine. Felt good compared to the wimpy stock clutch. Got many miles down the road and has another stop... engine slows and stalls. Mess with it a little more and figure out I need to keep the revs up and take off for home. Next stop and it's had to to change gears and I feel it dragging at the stop. Next stop a little bit later and I luck out with a green light but it is really hard to shift, can't get neutral to glide into a parking lot so gently run in first and kill switch to stop. The cable was now super slack and had to dial out a bunch of free play. The it was fine again. Not sure why it changed so fast, but it did, so take this as a warning to adjust several times in the first few stops after it gets hot.

Unrelated but my bike gets up to 60 (indicated) pretty quickly when I'm tucked behind the cheapo windshield.
 

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Yeah I wanted them to fix it on principle and to have a record in case it was something worse... but you can't get those "bikes in the shop" miles back :( .

Those were dark times...
 

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Exactly why I just logged on. Had similar happen just now. Installed the mnnthbx HD clutch Friday. Everything set and feels great and much better. Didnt get a chance to actually ride it more than a few miles until tonight. Riding it pretty hard and cutting up trying to figure out how to wheelie it not from a stop and such.
30 or so min in, I notice it feels a little odd, but just wrote it off in my head. Shortly after, I notice it not really wanting to shift smoothly, so I start paying attention to it more. Then did a little burnout (first one, so was actually easy and quick). Next light, I notice that it wants to go. Clutch fully in, feels light, and bike is trying to crawl away. Next thing I know, cant shift at all, and chokes out when I stopped. Somehow managed to get it to neutral to start it back. Give it a little throttle and hit 1st, and it takes off. Now I'm stuck in 3rd. Dodge lights, cut through parking lots avoiding having to stop.

Finally get to a safe place where I wont get mugged, kill switch, cant get out of 3. Managed to adjust it and get going straight to the garage. Full adjustment and now it seems good again. Have yet to get out and beat on it again though.
 

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Discussion Starter · #13 ·
I was in the middle of nowhere when it stalled the first time, almost went right into east nowhere which is really out there. Need to get it out again and see what's what but supposed to be crazy hot tomorrow, and then rain for the rest of the week.

At least your experience matches mine.
 

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In my case, I know cable free play was not an issue. When the clutch stated feeling funny (like 10 miles), I increased the free play to about 1/8 inch between cable housing and clutch lever. I think they just need heavier springs.
You "increased" the freeplay to ONLY 1/8 inch? That's the minimum you need, and it's also supposed to be measured when the clutch is still cold (i.e. before the bike has warmed up). If you were running less than that, especially with a cheap clutch like the Z125 has, it was not enough, and it possibly slipped the plates, overheated them, and thus permanently warped them.

Jim G
 

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You "increased" the freeplay to ONLY 1/8 inch? That's the minimum you need, and it's also supposed to be measured when the clutch is still cold (i.e. before the bike has warmed up). If you were running less than that, especially with a cheap clutch like the Z125 has, it was not enough, and it possibly slipped the plates, overheated them, and thus permanently warped them.

Jim G
Here is a quote from page 2-19 of the Service Manual:

Measure the gap between the lever and the lever holder
clutch lever free play
Standard: 2-3mm (0.08 - 0.12 in.)

I'm pretty sure that 1/8 inch (0.125 decimal) is a little above the maximum (not minimum) :wink2:

This warning is on page 2-20

WARNING
The engine and exhaust system get extremely hot during normal operation and can cause serious burns. Never touch the engine or exhaust pipe during clutch adjustment.

If the clutch is supposed to be measured when cold, why would Kawasaki include that warning in the service manual? >:)
Just Sayin.
 

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Here is a quote from page 2-19 of the Service Manual:

Measure the gap between the lever and the lever holder
clutch lever free play
Standard: 2-3mm (0.08 - 0.12 in.)

I'm pretty sure that 1/8 inch (0.125 decimal) is a little above the maximum (not minimum) :wink2:

This warning is on page 2-20

WARNING
The engine and exhaust system get extremely hot during normal operation and can cause serious burns. Never touch the engine or exhaust pipe during clutch adjustment.

If the clutch is supposed to be measured when cold, why would Kawasaki include that warning in the service manual? >:)
Just Sayin.
My comments were based on:

- past experience with clutches on a large number of motorcycles is that the freeplay in the lever decreases when the engine gets hot, and unfortunately most people adjust the clutch lever when it is still not fully warmed up, so their lever slack gets smaller when at operating temperature

- High quality clutches have truly flat plates of consistent thickness, so can tolerate smaller lever freeplay than lower quality clutches. But we all know the clutch on the Z125, Kawasaki's bargain basement offering, is NOT high quality (see the measurements others have taken of plate non-flatness)

- The freeplay gap on a high quality clutch control system (lever, cable, right angle fitting near clutch, and engagement/release mechanism) can be modest, but the Z125 does NOT have a "high quality" system. It's a system built to a low price point with plenty of stacked tolerances.

- An astute observer will see that the gap CHANGES as the bike is used in differing conditions (ambient temperature, engine temperature, traffic, number of stops and starts per mile, etc). Best to adjust the play for the worst conditions versus the best conditions, as the price of too much slack is merely slightly less smooth gearshifts while the price of too little slack is a set of burned clutch plates. Which sounds worse to you?

- The .08" to .12" might be fine if the Z125 had high quality clutch plates, or the clutch ran cool in operation, but neither is true for this bike. This .08" to .12" if truly in the manual was wishful thinking on some Kawasaki manual writer's part. I would never run with less than at LEAST 1/8" play in the lever at the cable end, and run about 3/16" on my own Z125. Even then, finding neutral is not as easy or consistent as it should be sometimes, depending on conditions at the time.

Run what you want, but understand this manual was likely written by the same guy who wrote the website and brochure ad copy that says the Z125 comes with a "sealed" chain, and we all know that is not true, and that Kawasaki's reply to my inquiry complaint via the dealership was "The small print on our websites, brochures, and manuals says we can change the specs anytime". :)

Jim G
 

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p.s. The installation of adjustable levers, whose "reach" from the handlebar to the lever can be adjusted, improves the clutch control and freeplay RADICALLY at minimal cost (I think I paid $22 Canadian for my set). The ability to change the reach and angle both made a HUGE difference to the smoothness of my shifts and starts from a dead stop.

Jim G
 

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Discussion Starter · #19 ·
Never had any issues adjusting the clutches on my other bikes, I assure you that something changed within this clutch and it no longer disengaged until I reset the free play. I won't guess why, but I have my suspicions, one of which would be considered my lack of attention to detail.
 

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Never had any issues adjusting the clutches on my other bikes, I assure you that something changed within this clutch and it no longer disengaged until I reset the free play. I won't guess why, but I have my suspicions, one of which would be considered my lack of attention to detail.
Sounds like the cable got somehow partially "jammed" during the adjustment process, and later "unjammed", which lengthened the effective length of the cable, which prevented full disengagement even with the lever pulled right back to the handlebar. This can happen with cheap clutch mechanisms.

A set of adjustable levers would give you the ability to make a "click lever" adjustment while riding, and that would have saved you,

Jim G
 
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