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Discussion Starter · #1 ·
Hi All,

Clutch was slipping for a while and I have only just got arround to changing it... it was slipping in 3rd and above by the end at arround 1/2 throttle. Now my problem is the clutch is exactly the same (if not worse) than before!

Bike is a Kawasaki GPz600r and I used Walker clutch Kit with friction plates, steel plates and new springs, everything is adjusted correctly at the lever and the clutch end (cable type), and all torqued up correclty, but the clutch still slips??!!

Does anyone have any idea whats going on??

p.s. The only thing I can think of is the oil, I used the same oil type for the last oil change and for changing the clutch, Its 10w40 part -synthetic (UK- Halfords shop own brand).
 

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Discussion Starter · #3 ·
Yeah, 100% adjusted correctly, and it doesn't say anywhere on the oil about modifiers, but it is a motorcycle specific oil.
 

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Right hmmm well if your sure it's adjusted correctly I'd be tempted to give it an oil change and use a branded oil like castrol or motul and see if it gets any better.


Sent from my iPad using Tapatalk
 

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Is my bike ok?
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When an old clutch gets to the point of slipping, you need to do a little more maintenance than just swapping in new fibers. The previous slipping could have glazed/polished the steels, so those will need to be cleaned up and scuffed up with some scotchbrite to allow the new fibers to grip. Also, if it was slipping bad enough, you could have warped steels, which simply just need to be replaced. You'll likely never to get a warped steel to lie flat again. Also, although the seem/ basically are flat, the steels typically have a slight curvature to them due to the stamping process of manufacturing them, so they all need to be facing the same direction or you can end up with a spongy, weak clutch. Each steel will have a smooth, rolled edge and a sharp edge from being stamped. There is no right or wrong way the point them, just point them all the same direction so that the slight curvature works together, rather than against each other. I know you bought new steels, maybe next time you won't need to. Even new steels will have this stamping curvature to them, so it needs to be checked.


Also, new parts or not, you need to check the stack height of the clutch pack. The FSM will give a spec you need to adhere to. If your new fibers are too thin then the clutch will never be able to grasp them properly. I've brand new seen clutch fibers not stack up to spec more than once. You can add extra steels if needed. You can stack steels together to increase stack height, but it's not recommended to stack fibers together to do this.

You also need to check the free length of the springs. Dead springs will never grasp even the healthiest clutch pack. That info will be in the FSM as well. Again, just because your springs are new, that doesn't mean they are the proper length.

So many clutch kits are assembled from mixed bags of random universal parts. Sometimes I think the companies selling aftermarket clutch kits often don't do their homework. Good luck dude :)
 

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Definitely check the "stack height". If the stack is too short, the spring won't push hard enough on it, resulting in slippage.

As Shiny said, if the clutch had been slipping for a long time previously, there's a good chance the steels are glazed over/ worn thinner than spec. Generally you'd inspect them for bluing- a sign they got hot enough to warp, in which case you're best off replacing all of them. Check the thickness with calipers, there's a spec in the service manual. If it's below or at the lower limit, they need to be replaced.

I've had aftermarket kits where the thickness of the fiber plates was slightly less than OEM, so when all put together, the stack is a few mm short, but that adds up to significantly less spring pressure.

As long as you're not using an "energy conserving" oil (typically they're only 0-20 or 5-20, weights rarely used in bikes anyway), you should be fine there.
 

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I don't know about your GPZ but on most bikes there is an adjuster for the clutch activator rod. So there is more to it than just the cable.

Should be an easy fix. There needs to be a tiny bit of free play in there so the plates can really stick together.




Jon
 
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