Sticky clutch

[millosman]

Hi everyone

I've got a bit of clutch trouble and could do with advice on a couple of things.

My bike is a '92 3XW.

I rebuilt the motor and its been back on the road about 18 months now.

Prior to the rebuild, the clutch tended to stick a bit when cold.
I was running it on 20w50 pre-rebuild, so I suspected that was the issue, ie oil too thick. It's been on 10w40 since rebuild and I'm about to switch to 10w30 as it's cold here in the UK now, < 5 degrees centigrade mostly. I use oils with JASO MA2 spec, tried various brands, all semi-synthetic.

Since the rebuild which included all new clutch plates, both plains and frictions, the clutch is very difficult to disengage from cold. I have to warm it up in neutral, turn it off and rock it in gear with the clutch pulled in. It can take 2 minutes plus to free it off.
Once it's separated, it's fine, maybe a bit notchy changing gear for the first few minutes but otherwise fine.

I've bled the clutch multiple times including by vacuum method, and by pushing the slave piston right in to expel any air to the master cylinder, etc.
That side of things look good. The slave is only a couple years old. There is no air in it.

The lever moves about 1cm before actuating the master cylinder piston, yet the pivot and lever look to be in good condition.

I've stripped the clutch twice since rebuild in a bid to find the cause. The last time I did this I changed the configuration as per the method suggested on this site, ie 7 friction plates, lose the back narrow plate, spring and spring seat. No benefit obtained.

There are wear marks in the basket where the plate "fingers" rub, but these are visual only, I can't feel notches as such when I rub my finger over them.

Researching last night I came across an article for an fjr clutch whereby pink spots on each friction plate finger should be placed in the basket slot that resides between two triangles marked on it.
It made me wonder if the plates need to be aligned in some way on the fj too. I noticed my friction plates do have a green mark on one finger of each plate.

Have I missed something here as my Haynes manual makes no mention of positioning the plates in specific slots in the basket?

The other question is whether anybody knows how much movement of the clutch push rod should occur when the clutch lever is pulled in? Mine moves around 2.5mm. Is that enough to fully disengage the clutch or might there be an issue still with the hydraulics?

Hope some of you folks can offer me some advice on these two queries as I'm banging my head on the wall now.  

Many thanks

Andy.

[FJmonkey]

I had sticking clutch plates, found out they were aftermarket. They started to slip so I installed OEM clutch parts. No sticking after that, regardless of viscosity.

[millosman]

Hi FJMonkey

Thanks for your speedy reply. My friction plates are aftermarket too.

The plates that were in it prior to the rebuild may have been originals. That belief is based only on the fact that they have a green blob on one "finger". Other yam parts seem to carry similar markings. Not much to go on.

If they are oem, and the new ones definitely aren't oem, then that would mean I have the same issue with both types albeit to a lesser degree with the the old plates.

New oem plates are over £20 each which seems extortionate so I've been resisting that option.

Confusing!

Thanks again

Andy

[FJmonkey]

Did you soak the new plates in oil over night before installing them? How many miles do you have on the new plates?

[Millietant]

Hi everyone

I've got a bit of clutch trouble and could do with advice on a couple of things.

My bike is a '92 3XW.

I rebuilt the motor and its been back on the road about 18 months now.

Prior to the rebuild, the clutch tended to stick a bit when cold.
I was running it on 20w50 pre-rebuild, so I suspected that was the issue, ie oil too thick. It's been on 10w40 since rebuild and I'm about to switch to 10w30 as it's cold here in the UK now, < 5 degrees centigrade mostly. I use oils with JASO MA2 spec, tried various brands, all semi-synthetic.

Since the rebuild which included all new clutch plates, both plains and frictions, the clutch is very difficult to disengage from cold. I have to warm it up in neutral, turn it off and rock it in gear with the clutch pulled in. It can take 2 minutes plus to free it off.
Once it's separated, it's fine, maybe a bit notchy changing gear for the first few minutes but otherwise fine.

I've bled the clutch multiple times including by vacuum method, and by pushing the slave piston right in to expel any air to the master cylinder, etc.
That side of things look good. The slave is only a couple years old. There is no air in it.

The lever moves about 1cm before actuating the master cylinder piston, yet the pivot and lever look to be in good condition.

I've stripped the clutch twice since rebuild in a bid to find the cause. The last time I did this I changed the configuration as per the method suggested on this site, ie 7 friction plates, lose the back narrow plate, spring and spring seat. No benefit obtained.

There are wear marks in the basket where the plate "fingers" rub, but these are visual only, I can't feel notches as such when I rub my finger over them.

Researching last night I came across an article for an fjr clutch whereby pink spots on each friction plate finger should be placed in the basket slot that resides between two triangles marked on it.
It made me wonder if the plates need to be aligned in some way on the fj too. I noticed my friction plates do have a green mark on one finger of each plate.

Have I missed something here as my Haynes manual makes no mention of positioning the plates in specific slots in the basket?

The other question is whether anybody knows how much movement of the clutch push rod should occur when the clutch lever is pulled in? Mine moves around 2.5mm. Is that enough to fully disengage the clutch or might there be an issue still with the hydraulics?

Hope some of you folks can offer me some advice on these two queries as I'm banging my head on the wall now.  

Many thanks

Andy.

Hi Andy, I doubt if it's anything to do with the oil - I'm running Morris Ringfree 20w50 mineral oil in my FJ (always have) and was out on it this weekend, starting from early a.m. when it was only 3 degrees C or less,  without any clutch issues.

When you say the lever moves 1cm, is that at the ball end of the lever, or are the pivot end ? - 1 cm of free play at the ball end of a standard lever would seem OK, but that's about the most I'd ever be happy with. 1cm of free play at the end of an aftermarket "shorty" lever, would leave me feeling uncomfortable..

I can't recall what the total clutch pushrod movement is on my FJ, maybe Robert can give us some info.

As you're in the UK, where are you ?

[millosman]

Hi Dean & FJMonkey

Thanks for your replies.

I did not soak the plates overnight initially, just coated them in oil on fitting them. Since having the issue though I did strip them out and gave them an overnight soak maybe 1500 miles ago to no effect.
They are currently soaking in the 10w30 oil overnight for another test ride this weekend.
Note they are after market friction plates.

The motor has done approx 3000 miles since rebuild.

The 1cm lever movement I mentioned was measured at the ball end of the standard lever. There's no way to take up the slack, unless a master cylinder rebuild might improve this?

Thanks again for all your input,

Andy

[red]

Hi Dean & FJMonkey
Thanks for your replies.
The 1cm lever movement I mentioned was measured at the ball end of the standard lever. There's no way to take up the slack, unless a master cylinder rebuild might improve this?
Andy

Well, yes, you can kill a fly with a shotgun.  If you prefer, you could use just a BB rifle.  There is a brass bushing in the clutch lever.  As this bushing gets worn, clutch lever free-play increases.  A new bushing (Index #4) may be all you need.  While you are at it, check the lever pivot bolt hole for wear.  You can add a bushing there also, if needed, using brass tubing from the hobby shop.  Drill the pivot bolt hole to fit the brass tubing.  Otherwise, just replace the clutch lever with a new stock item.  Aftermarket clutch levers do not always work correctly, there.  RPM, the forum owner, sells the bushing separately.  Check the fiche:

https://www.ronayers.com/oemparts/a/yam/50043252f8700209bc78b255/front-master-cylinder-2
(Index 4)

You can even "help" a worn bushing temporarily if you can insert a tiny washer into the bushing itself.  The washer will reduce the free play in the clutch lever, until you get the new bushing. You do get a new bushing in the rebuild kit, but it is the one part (usually) that will improve your issue of clutch lever free play.  Keep us posted.

[millosman]

Hi again

Thanks for your thoughts Red. I had already checked the nipple in the lever, but had another look today to make sure I hadn't missed anything. Sure enough the nipple and the bush are in good condition.

Having rebuilt the clutch with freshly soaked plates (using the 7 plate configuration on this site - see http://www.fjowners.com/index.php?topic=1808.msg14307), unfortunately the problem is still there, ie it won't disengage from cold.

As I mentioned there is about 1cm free play at the lever (ball end). I made a temporary nipple for it today that had a much shallower hole into which the master cyl plunger fits. This was in a bid to reduce free play on the lever which indeed it did. Completely!

At that point I was hopeful that the clutch would now disengage, but it was absolutely no better whatsoever despite the extra 1cm of lever movement. The pressure plate was almost flat with the lever fully in so it could not be in a more disengaged position.

I am now at a loss as to what could be wrong with it.

The only other things to try that I can think of are to go back to the standard 6 plate set up and use oem friction plates. Could the non oem friction plates really be this bad?

Thanks for your suggestions people,

Regards
Andy.

[Old Rider]

I guess you already have checked that the little steel ball that sits in the end of the clutch push rod is not missing.if not take a look .

[millosman]

Hi Old Rider

Yes, balls bearing present and perfectly round.

I cannot envisage that the clutch push rod could move the clutch pressure plate any further out than it does now I've got rid of free play at the lever.

Conclusion, it must be the clutch pack itself, most likely the non oem friction plates. Otherwise the 7 plate mod is not allowing sufficient plate separation.

I'll rebuild clutch to standard configuration. If that doesn't fix it, I'll buy new oem plates.

Hopefully that will sort it out. Thanks everyone.

[Millietant]

OK Andy,

One last thing that we seem to have overlooked - even though you say the pressure plate couldn't move any further than it does now, are you absolutely sure of that ? - If pulling the clutch lever in doesn't move the plate far enough and you've checked everything else, what about the master cylinder piston and it's seal. If its not sealing properly, pulling in the clutch lever won't result in enough fluid being pumped to the slave cylinder. I've had this issue which affected the clutch long before I spotted any fluid escaping.

Maybe it's worth grabbing a refurb kit and doing that before you go much further - it's the only thing you don't seem to have sorted. If you're a member, as you're in the UK, the FJOC are your best source for the kit, and they give fitting instructions which includes tips for things that aren't included in the Haynes manual.

[millosman]

Hi again

Thanks for your thoughts Dean.

I understand what you're saying which is why I was asking earlier if anyone knew how far the clutch pushrod should move. I guess it's not the kind of information people are likely to know.

I had about 1cm free play at the ball end of the lever. The lever, nipple and pivot bolt are all in good condition. I rigged up a temporary nipple that took up the free play. Still no joy at that point. I've that in place for the moment.

I could see that the pressure plate was near flat when lever pulled in so cannot envisage further movement, if it were available, would be desirable.

I had done the 7 plate mod mentioned on this site. Yesterday I reversed that back to standard 6 plate set up with the two narrow plates, spring seat, spring, and wire.

Then for the first time managed to make the clutch disengage by rocking it in gear for a minute *without* warming it up first. So, some improvement at last but still not good enough.

I've literally just received a set of standard OEM friction plates, hoping they may cure the issue. They'll get a good soak in fresh oil over the weekend, then fit and test on Monday.

Again thanks for your input,

Regards
Andy
East Yorkshire UK.

[Old Rider]

You can try to place the bike on centerstand and handlebars to the right and then pull the clutchlever into the hanlebar and tie it up.Then let it sit over night often that will help.
You can also check the plates both friction and steel like in these pictures from manual

[RPM - Robert]

Sorry, I've never had the need to measure to get that information. IF I remember next time I have a clutch cover off I'll give it a measure.

I do, however, highly doubt the 7 wide discs have anything to do with this problem. I know of a dozen customers, not including the 4 FJs we alternate on, that live/ride with us that have this mod done and they have no such issue.

[millosman]

Hi Old Rider and Robert,


I'll certainly try the clutch lever trick thank you. The plates are all new and within spec as indeed are the other key components.

I may revert back to the 7 plate setup Robert if the clutch disengages ok with the new plates in. It's an easier setup to maintain. The thin wire in the standard set up seems like an accident waiting to happen! If it came loose.....

Thanks again. Will update you with the outcome,

Regards
Andy