Clutch grabbing when cold

[CamdenGuy]

I have had a long standing problem with my 2006 (22K miles) Z750 where the clutch grabs when cold. Once the bike has warmed up the action is much better. I have had two mechanics look at it and both have changed the clutch plates to no effect (the last set being replaced about 1500 miles ago). I have also changed the oil recently (MOTUL 5100 10W40 MA2 SEMI SYNTHETIC) again without effect. I have played around with the clutch cable adjustment again failing to stop the problem.

The symptoms I am getting is as the clutch starts to bite I hear a high pitch sound coming from the clutch but minimal power is being transmitted to the back wheel. As I let the clutch fully out it the noise stops just as the clutch suddenly bites fully causing the bike to lurch forward. The problem quickly stops once I am riding and with in a minute or two the clutch responds normally.

I am now trying to see if I can work out what the problem is.

Given that I have have had two sets of friction plates and a new thrust plate to no effect I don't think the problem is with them.

I have also tried several different makes of oil over the years and again no effect.

I have recently read that the clutch basket can get grooves on it which cause the friction plates not to slide smoothly and that the groves can be filed out. This seems like a plausible explanation for the problems I am having.

I am now trying to work out if I would be better off...

1. Disassembling the clutch and trying to file down the groves

2. Replace the whole unit with a second hand clutch

3. Just replacing the basket with a stock or pattern one (if they exist), The Kawasaki part seems very expensive however.

Have anyone else experience anything similar or has suggestions on what might be the best solution?

[mikestrivens]

Hello and welcome, I can't help but it would be helpful if you could provide more details of bike, e.g. age, model, etc, so that others could help

[CamdenGuy]

Sorry I left off the manufacturer! It is a 2006 Kawasaki Z750 with 22,000 miles on the clock, owned since new.

[fastbob]

I don't like the sound of that especially the whining noise and the sudden lurching . These two mechanics , are they experienced and qualified and why did they both return the bike with the fault unresolved ? Just a hunch, has this clutch got heavy duty springs in it ? If it does then it may be worth putting standard ones back in . If you do attempt to fix this yourself I would begin by checking the total stack height followed by a careful examination of every plate on a guaranteed flat surface such as an engineers marking out table . You could have a warped steel plate or several that are only working when compressed fully by the springs . I found this site that seems to cover everything. Good luck.https://www.diymotofix.com/blog/how-to-properly-inspect-a-clutch

Edited September 22, 2018 by fastbob

[fastbob]

Sorry I left off the manufacturer! It is a 2006 Kawasaki Z750 with 22,000 miles on the clock, owned since new.

 

Cheers, hopefully most of us know what a ZED is .

[CamdenGuy]

Both mechanics ran their own bike servicing businesses and gave plenty of confidence when dealing with them. But they were both singularly ineffective in solving the problem, neither is currently trading at their original premises however. Apart from the clutch I was very happy with the other work they did.

What makes me think it is not the plates is that the problem reoccurred within days of the plates being changed (and they have been changed twice by two different mechanics!).

I am tempted to get a second hand clutch on ebay

https://www.ebay.co.uk/itm/Kawasaki-Z750-Z-750-Clutch-basket-plates-hub-complete-FREE-UK-POST-Z258/323424758552?hash=item4b4d9e2b18:g:9B0AAOSwbmFanXHd

and replace the whole assembly. I am tempted to do it myself, partly to save money but also because I have discovered that I rather enjoy tinkering with bikes. Having read through the process in the service manual it looks straight forward.

[Justarn]

I've recently had problems with motul. Changed the plates and done an oil change and it's fixed mine. Some mechanics down here won't touch motul.

[TimR]

have the plates been installed correctly .

if i remember there is a specific pattern on the zeds that most installers get it wrong a few times .

is it cable clutch or Hydraulic ? i thimk i saw you mention clutch adjuster but wanted to make sure as they hydraulic ones can have issues with the slave cylinder seal leaking slightly which once warm/ used a few times after cold seals up till next time

[fastbob]

Looks like all the friction plates have the same part number as do all the steel plates which suggests that there is no particular sequence to installation.

[TimR]

Looks like all the friction plates have the same part number as do all the steel plates which suggests that there is no particular sequence to installation.

 

if i remember correctly the first plate has to be in a different alignment to the rest ie

look at the image the tang of first plate is not in alignment with the rest

[fastbob]

Looks like all the friction plates have the same part number as do all the steel plates which suggests that there is no particular sequence to installation.

 

if i remember correctly the first plate has to be in a different alignment to the rest ie

look at the image the tang of first plate is not in alignment with the rest

 

But it slides in the same slot in the basket so it has no choice other than to align with all the rest .

[Tango]

Maybe the basket is notched, so the plates aren't moving smoothly....especially when it's cold?

[TimR]

Looks like all the friction plates have the same part number as do all the steel plates which suggests that there is no particular sequence to installation.

 

if i remember correctly the first plate has to be in a different alignment to the rest ie

look at the image the tang of first plate is not in alignment with the rest

 

But it slides in the same slot in the basket so it has no choice other than to align with all the rest .

i got my ends mixed up ( would be the last plate )

is how they should be .. the top plate is offset by one slot

 

is how most install

[iangaryprice]

I was about to suggest that the last plate (outer) goes in the shallower slot.

I suspect it in someway helps the plated seperate and prevent drag when you pull the clutch lever in.

I would also check the release bearing is in good condition, this may be the cause of the noise.

[CamdenGuy]

Thanks for all the advice and comments. From what everyone is saying it seems like I need to take the clutch apart and just do a thorough inspection of all the components looking for signs of excessive wear before deciding what remedial action to take.

A bit of a dumb question; I've just done an oil and filter change on the bike to see if changing the oil made any difference, if I drain the oil again to disassemble the clutch can I pour it back in the engine once I have reassembled it or should I only use new oil?

[megawatt]

Put the oil back in if its not old oil.

Check basket and backplate for grooves and file them smooth if they have sharp edges. Check cush springs and spacers at back of basket. Shake it to see if it sounds like a tambourine. Check release bearing.

[Mr Fro]

I'd reuse it so long as it's clean - i.e. no chunks of clutch in it.

[fastbob]

if i remember correctly the first plate has to be in a different alignment to the rest ie

look at the image the tang of first plate is not in alignment with the rest

 

But it slides in the same slot in the basket so it has no choice other than to align with all the rest .

i got my ends mixed up ( would be the last plate )

s-l300.jpg is how they should be .. the top plate is offset by one slot

clutch.jpg

is how most install

Oh yeah, I see what you mean now it IS on the parts drawing I posted but I was looking without seeing . I've never had a clutch like that . I have a good feeling about this , I reckon you just might have cracked it !

[Tango]

Some bikes (mine included) you can remove the clutch cover without draining the oil if the bike is on the sidestand. .....

[fastbob]

Some bikes (mine included) you can remove the clutch cover without draining the oil if the bike is on the sidestand. .....

 

And mine , but to be on the safe side I put a plank under the back wheel to increase the lean angle a little further.

[Justarn]

For the sake of a £60 set of plates, I would personally change them and dump all that motul, I'm never using again.

Believe it or not there's a lot of fake oil on eBay ect, Google it.

Opies oils are a reputable castrol dealer on eBay.

Soak ya new plates in oil over night if you do it.

Good luck.

[CamdenGuy]

Thanks for all the advice. I am in the process of getting all the bits I need

Torque wrench - any recommendations?

feeler gague

Clutch tool

clutch nut

gaskets, grease etc.

Once I have them I'll dive in and post pictures....

[Tango]

For tools, look at the Halfords Professional range.......lifetime guarantee......and they're pretty good tools too......