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I read somewhere that the reason the 400’s clutch slips at high rpm is because Kawasaki used the same springs as the 300 and they don’t clamp hard enough to handle the increase in power.
This is the old argument that Kawasaki & DCC don't know how to build a clutch for a 46 hp motor. The 400 does not use the same springs as the 300, the part numbers are different.
The ramp function on the 'assist' portion of the clutch provides the majority of the clamping force. The clutch lever has great mechanical advantage to make the clutch slip, that is it's job. With such light lever pull even small maladjustment, a little cable drag or a hand with just a little pressure on the lever will cause slippage, and failure.

Kawasaki Racing at an event out west said the problem is mainly in the US and is believed to be related to adjustment issues. This clutch may not be up to track duty but is fine for street duty. If it wasn't don't you think Kawasaki would have changed something for their next production year.

(hint: they didn't)
 

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Kawasaki Racing at an event out west said the problem is mainly in the US and is believed to be related to adjustment issues. This clutch may not be up to track duty but is fine for street duty. If it wasn't don't you think Kawasaki would have changed something for their next production year.

(hint: they didn't)
This my feeling now too. That it is very susceptible to mis-adjustment and by the time riders realise it's too late. Poor pre delivery set up by the dealers perhaps?
Kawasaki New Zealand have said that there has been no issues in this country so maybe it is more of a US problem. Seems kinda odd though. :icon_scratch:
 

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I’m sure Kawasaki knows how to build a proper clutch for a 46hp bike, but I don’t think the EX400 is proof of it. I also know motorcycle manufacturers share parts between similar models (and often don’t fix non-safety related issues if it’s cheaper to simply blame the customer), so I don’t think it’s any more of a stretch to think that could be the case here than to think Americans are unique in our ignorance of the proper way to adjust a clutch cable (and uniquely on this bike), the part numbers notwithstanding.
 

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when i took delivery of my 400 last summer i noticed that it felt like i had a little bit of slip when shifting gears (and not even using the clutch).. Turns out the clutch was not adjusted properly from the dealership ..
If you want to make sure that it doesn't slip try going in second gear at mid rpms, off throttle then step back on it and watch how the rpm goes up .. you will know right away if it's slipping
 

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I read somewhere that the reason the 400’s clutch slips at high rpm is because Kawasaki used the same springs as the 300 and they don’t clamp hard enough to handle the increase in power.
Haven't read that anywhere, but that's interesting to know! Explains a bit.
I personally haven't had any problems yet, it's more for preventative maintenance
 

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... If you want to make sure that it doesn't slip try going in second gear at mid rpms, off throttle then step back on it and watch how the rpm goes up .. you will know right away if it's slipping
Also grab the clutch lever and pull it back towards you. There should be 2 - 3mm of slack/slop before the cable goes tight putting more pressure on the lever.
And therein lies the problem: The clutch pressure on this bike is so goddamn light that it's hard to clearly feel the difference between cable slack and clutch pull.
I believe this has created the bulk of these clutch plate failures. It would appear even dealers are struggling to set the clutch free play correctly.
 

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Haven't read that anywhere, but that's interesting to know! Explains a bit.
I personally haven't had any problems yet, it's more for preventative maintenance
As Holoquest pointed out above, the part numbers are different, thus debunking that theory. I can’t for the life of me find where I read it, but it would appear to be incorrect information and I now regret passing it along without doing more research first.
 

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The springs are too soft regardless of their origin. A finger resting on the lever is enough to cause it to slip. Even with the Spears return cable it wasn't enough on my bike to allow the arm to overcome the pressure from the clutch lever idiot switch and fully retract . I used a zip tie to preload the spring to get enough tension. Tomorrow I plan to install the Spears clutch springs and be done with the problem.
 

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I'm another slipper ! ! ! !

Bought my bike used with 12 miles on it. At about 1000 miles I actually started to get on it a little since the break-in was done, and sure enough, if I get on it hard from 3rd up in high RPMs it starts slipping. I can take it on the highway and get to 70mph and then hit the throttle hard and it will start slipping. Just wanted to go on record here. I'm contacting Kawasaki Customer Service to see what I can find out from them. My bike is a 2019 BTW.

UPDATE:
I called Kawasaki Customer Service and they sent me to the dealer. They said they could do nothing without talking to the dealer.

Starting to regret leaving the Honda fold... My first venture not buying Honda and this is what I get. Lesson learned.
 

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Sounds like it’s maybe time to consider trading it for a cbr500. We all know the cbr500 is a much better bike than these junk kawasaki 400s.
 

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Yeah, that's a tough one moving from another favorite brand. The good news is that it is an easy fix for the dealer.
 

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11818


the pic above shows two clutch pull rods, which the lower unit will give you .040 more usable wear on your clutch plates before bottoming out.The factory unit bottoms out with very little wear on the clutch plates, letting the clutch slip prematurely (@ .024 clutch plate wear)
There is a very interesting article or sales pitch for the repair of Ninaj 400 clutch and shifting issues:
 

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View attachment 11818

the pic above shows two clutch pull rods, which the lower unit will give you .040 more usable wear on your clutch plates before bottoming out.The factory unit bottoms out with very little wear on the clutch plates, letting the clutch slip prematurely (@ .024 clutch plate wear)
There is a very interesting article or sales pitch for the repair of Ninaj 400 clutch and shifting issues:
Yeah Jesse posted a link to that info a while ago. I'm going to machine mine back in the lathe at work when I find a spare hour to get the dang thing out.
 

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Yeah Jesse posted a link to that info a while ago. I'm going to machine mine back in the lathe at work when I find a spare hour to get the dang thing out.
Sorry Kiwi, I didn't see the earlier post. Hope all is well with you. Have about 8700 miles on the 400 presently. I thought that Kawasaki may fix the clutch issue with the 2020 edition 400, but the article advises they didn't and keep on selling the clutch that will slip at 24 thousandths of an inch wear.....I can see why people are disturbed about this and wonder why Kawasaki hasn't offered the repair to all 400 owners/users. I mean at .024 wear, it is just a matter of time before the clutch gives it up. I don't ever sit at a stop light with my bike in gear and the clutch pulled in, I found out a long time ago that is just asking for a premature clutch failure.
 

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Sorry Kiwi, I didn't see the earlier post. Hope all is well with you. Have about 8700 miles on the 400 presently. I thought that Kawasaki may fix the clutch issue with the 2020 edition 400, but the article advises they didn't and keep on selling the clutch that will slip at 24 thousandths of an inch wear.....I can see why people are disturbed about this and wonder why Kawasaki hasn't offered the repair to all 400 owners/users. I mean at .024 wear, it is just a matter of time before the clutch gives it up. I don't ever sit at a stop light with my bike in gear and the clutch pulled in, I found out a long time ago that is just asking for a premature clutch failure.
Yeah that's pretty bad two years on. Can't understand why they have their head in the sand on this one. There has been too may cases to ignore. Apart from that Achilles heal though the engine seems to be trouble free.
 

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UPDATE: I have a good friend who used to be a motorcycle mechanic and has moved on to doing cars. But I mentioned my slippage issue while we were out riding and had taken a break in a parking lot. He looked at my mechanism while squeezing the clutch several times, and immediately pointed out that the arm down on the side of the motor wasn't even retracting all the way in when I let the clutch out. In other words, when I fully released the clutch lever, you could still take the arm down on the motor and move it another 1/4" or so until it bottomed out. (See image.. in that view, the arm would not lock out to the left)

So I bought the $10 spring from norton-motorsports.com and installed it, and now all of my slipping issues are gone.

11828
 

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Hi N_I_N!

Are you referring to this? this:

Also, do we need the heavy duty detent spring also?

Planning to buy these too:
Barnett Clutch Spring Kit
Part# 501-58-0312

Many thanks!
 

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Hi N_I_N!

Are you referring to this? this:

Also, do we need the heavy duty detent spring also?

Planning to buy these too:
Barnett Clutch Spring Kit
Part# 501-58-0312

Many thanks!
Regarding clutch, I'd get the below. I've installed them all as preventative measures.

Spears also have them

 

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Hi N_I_N!

Are you referring to this? this:

Also, do we need the heavy duty detent spring also?

Planning to buy these too:
Barnett Clutch Spring Kit
Part# 501-58-0312

Many thanks!
I was talking about the clutch cable spring, not the detent one. I will install more as needed (if needed) but for now I'm working fine. My only beef was that they charge $9.99 or something for the part and $10 to ship it... In my mind, I'd rather you just charge me $20 and give me shipping for free so I don't know 50% of my money is going for shipping... :)

11840
 
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