Sticking clutch?

[Malcolm]

Hey guys, I've been having a minor problem with my ZXR for the last month or so. When I go to start the bike after having let it cool down (i.e. overnight or just a couple of hours during the day) the clutch will be stuck, and will often stall the engine when I try to shift in to gear, or at the very least will really crash in to gear. To get around this I've just been freeing up the clutch before I start the bike, by putting it in gear, pulling the clutch in and pulling the bike back to unstick it, but it would be nice to actually fix it.

I changed the clutch recently, and the sticking probably started a few weeks after that. I'm mechanically very experienced and followed the factory service manual just to be sure. The clutch is definitely disengaging properly because once it's unstuck the clutch functions normally, and there's definite free-play before it starts engaging.

So, any thoughts, or has anyone had any experience with this problem before?

[Jonno.]

I'm going to take a wild guess and say it has something to do with changing your clutch.

What oil are you using/when was it last changed? Also are you sure the plates were put in the correct order/side?

[CookMySock]

I bet the fibre is completely missing from some of the plates, and they are binding up on the steels.

Pull your clutch apart and have a looky.

Steve

[Malcolm]

I was very careful to make sure the plates were in the right order and around the right way.

The oil is definitely what I'm suspicious of. Before the clutch change I was using Castrol Activ 4T, I can't remember the weight but Castrol's site suggests it was probably 15W-50. After the change I'm using Motul 10W-40, which should be thinner than the Castrol at low temps, which seems like it should be less likely to be problematic. I'm only about 2,000km from another oil change so maybe I'll just get some of the Castrol oil and see whether the problem is still there.

I did a search on here which seemed to suggest the problem is moderately common for old Kawasakis.

[Malcolm]

I bet the fibre is completely missing from some of the plates, and they are binding up on the steels.

Pull your clutch apart and have a looky.

Steve

Why would the fibre be completely missing from the plates? I would expect if that happened that there would be a sudden and dramatic change in the clutch feel/travel due to the change in thickness of the clutch assembly.

[Warr]

Leave bike in gear. Pull clutch and rock bike backwards and forwards. When free keep clutch pulled and hit the starter, then drive off.
Seems too simple and you havent knocked any teeth off the cogs or anything

[SS90]

Hm, the fact this started happening AFTER you changed your plates is a worry, and would be the first place to suspect, but, as you say, when it is warm, it works as it should.

I too would suspect the oil, but their is also something else to consider.

The inner clutch basket.

When a clutch basket gets old, it develops wear where the steel plates run on the inner basket.

Do you remember what the inner basket looked like, was it nice and smooth where the steel plates ran on the inner basket?

If there is noticeable wear on this inner basket, you can quite often find that the plates will actually "hang up" on the inner basket, and instead of seperating, the plates will jam in their gooves, and simply "flex" when you pull the lever in.

Personally, I would just pull the clutch apart again, and inspect everything carefully.

[CookMySock]

Why would the fibre be completely missing from the plates? I would expect if that happened that there would be a sudden and dramatic change in the clutch feel/travel due to the change in thickness of the clutch assembly.

Don't know. Thats just what happens with clutches when they shit their fibres - the plates bind up and grab. As has been suggested, whip its cover off and check it. Sometimes there is one thick plate and the rest are thin, so make sure they are the correct way around etc.

Yeah thick oil will make the clutch feel real bad. It will bash into first gear real hard and make the other gears really stiff, and neutral nearly impossible to find.

Steve

[The Stranger:Me]

A couple of thoughts.
Did you soak the plates well first? Some say you need to soak them overnight.
Did you replace the steels at the same time? The steels need to be pretty bloody slippery (i.e. clean and smooth).
Other than that as people have suggested - oil.

[The Stranger:Me]

Why would the fibre be completely missing from the plates?

Shit like this just happens at random on hyodungs (oh no, more red rep from db for me).
You got a jappa, shouldn't be an issue.

[CookMySock]

Shit like this just happens at random on hyodungs (oh no, more red rep from db for me).

Hehe the random dung is far more prevalent in your posts.

Steve

[Mom]

So, any thoughts, or has anyone had any experience with this problem before?

The inner clutch basket.

I had problems with the clutch on my bike, and eventually pulled the clutch apart with a bit of help from my friends.

http://www.kiwibiker.co.nz/forums/sh...own-at-Laava-s

The inner basket had distinct undulations in it, which we sanded off with some wet and dry sandpaper, returning the edges to smooth again. The plates in the clutch were within tolerance according to the manual, but the springs were too short. I replaced them and hey presto, good as it gets clutch.

Good luck with getting it sorted. I know the frustration of a crappy clutch.

[Malcolm]

well fortunately at the moment the only real issue is having to free it up before I start the bike in the morning/before I go home. I did give everything a pretty thorough inspection when I did the clutch because I was also trying to track down the source of my fun-zxr-rattle (primary drive gears, btw). I specifically checked the clutch basket for excessive wear at the time, as it had been suggested the rattle could come from the clutch basket/plates - but I guess it wouldn't take much to make them bind up just a little.

I didn't change the steels but I did inspect them and made sure the thick and thin plates went in the right order. One thing that was mentioned that I didn't do was to soak the friction plates - I just gave them all a liberal coating of oil, but didn't soak them as such.

My plan of attack is: do an oil change back to the Castrol oil, see if that changes it (just because it's the easiest, not necessarily most likely to be the cause) - assumedly if the friction material has come off a plate it should be apparent in the oil; otherwise I'll open it up again and check over the suggested possible causes.

I'll update once progress is made, cheers for the suggestions so far.

[Malcolm]

oh forgot to mention, I did measure the length of the springs to ensure they were within spec too

[porky]

New fibre plates, have i read correct. Then problems started? A suggestion, take it apart again. Check between fibre segments. Is their heaps off goo or is it clean alloy? If not get a file. cut back to alloy 'Carefully'!!!!!!(takes aprox 4 hours from memory) and square edge of fibre. Check tabs .file off any of the rubbish left from casting. It should be square. Very common on older 2 stroke mx type bikes and this was the fix. We also used to run ATF in the box. Hope this may help.