Clutch slave cylinder

[Ben Fischer]

Hey guys I'm new here so redirect me if this has been covered, but I've done a quick check and wanted to get some advice for my particular situation. I've got an 05 Hayabusa that I've just bought and the clutch is engaging after a very short pull towards the handlebars. I bled the fluid - which was old - and the clutch was great for a day. Engaged/disengaged correctly and had a longer period of engagement if that makes sense, not just on/off as I've seen mentioned in other threads. Second day after the bleed, the clutch is the same as it was before, so I was thinking it's an air leak somewhere. After looking at other threads I went ahead and checked the slave cylinder for movement and lo and behold it moves ever so slightly when I pull and release the clutch lever to and from the handlebar. Am I looking at an air leak? A problem with the slave cylinder? Old hoses? Thanks guys.

 

[Kiwi Rider]

If you can see the slave cylinder moving when operating, you may have a cracked sprocket cover, the same cover the slave is mounted on, if it’s cracked it will allow the slave to move instead of staying put and making the push rod move, which in turn pushes the clutch hub.
Look for cracks, can you make a short vid showing the movement? Then upload to YouTube and paste the link here so we can see it.

 

[Ben Fischer]

If you can see the slave cylinder moving when operating, you may have a cracked sprocket cover, the same cover the slave is mounted on, if it’s cracked it will allow the slave to move instead of staying put and making the push rod move, which in turn pushes the clutch hub.
Look for cracks, can you make a short vid showing the movement? Then upload to YouTube and paste the link here so we can see it.

There's no way you'd be able to see the movement on a video. It's more of a pressure I can feel when I have my fingers against the slave cylinder; maybe I am being too cautious about this piece and this is normal?

 

[Ben Fischer]

I also have a tear in the boot where the clutch lever pushes the piston under the reservoir. To my understanding this is a dust cover and it is not an airtight piece, but I am thinking this may be where a possible air leak is coming from. If the sprocket cover was cracked would a fresh bled system make a difference?

 

[rubbersidedown]

If you can see the slave cylinder moving when operating, you may have a cracked sprocket cover, the same cover the slave is mounted on, if it’s cracked it will allow the slave to move instead of staying put and making the push rod move, which in turn pushes the clutch hub.
Look for cracks, can you make a short vid showing the movement? Then upload to YouTube and paste the link here so we can see it.

I also have a tear in the boot where the clutch lever pushes the piston under the reservoir. To my understanding this is a dust cover and it is not an airtight piece, but I am thinking this may be where a possible air leak is coming from. If the sprocket cover was cracked would a fresh bled system make a difference?

Kiwi is right.Cover should not move,if it does,there's yer prob.
You are correct,a torn boot means sqwat but should be replaced.
If you can feel the master within' the cover,start there.
Has the bike been down? Sometimes improper install after removal can crack the the cover or bend the accuation rod. Take the cover off,have a look,prolly needs a good cleaning under there anyway.A chance to reverse bleed the system here will help if there is air in the system.
Rubb.

 

[bigoltool]

Schnitz and a few others have clutch slave supports just for this problem.

 

[Ben Fischer]

Kiwi is right.Cover should not move,if it does,there's yer prob.
You are correct,a torn boot means sqwat but should be replaced.
If you can feel the master within' the cover,start there.
Has the bike been down? Sometimes improper install after removal can crack the the cover or bend the accuation rod. Take the cover off,have a look,prolly needs a good cleaning under there anyway.A chance to reverse bleed the system here will help if there is air in the system.
Rubb.

Bikes never been down to my knowledge, but I'll take look in there anyway. When you say take the cover off do you mean the slave cylinder?

 

[rubbersidedown]

Bikes never been down to my knowledge, but I'll take look in there anyway. When you say take the cover off do you mean the slave cylinder?

You got it bro.Take the cover off that you feel has the movement under it.Then you can check the rod and around the cover for any cracks. Make sense? Rubb.

 

[rubbersidedown]

You got it bro.Take the cover off that you feel has the movement under it.Then you can check the rod and around the cover for any cracks. Make sense? Rubb.

Do you need a couple pics and a bit of a walk thru?

 

[Ben Fischer]

Do you need a couple pics and a bit of a walk thru?

I will get back to you for that, thanks for offering. I'm gonna replace the clutch hose first as I was planning to already. If the system stays good problem solved. I am not convinced its not an air leak as the first bleed with new fluid solved the issue for a day, not something I would think was happening with a cracked sprocket cover. I just don't know if the flex in the slave is within normal parameters, I said it wouldn't show up on video but I just went out there and you can't see it with the naked eye either. When I say minimal movement I mean it. The only other place I can think of air leaking through would be the bleed nipple? or the reservoir? But there is no fluid on any parts. Maybe air getting in around the piston seals on the master cylinder? Idk, because like I said there's no fluid anywhere and everything looks really clean.

 

[rubbersidedown]

I will get back to you for that, thanks for offering. I'm gonna replace the clutch hose first as I was planning to already. If the system stays good problem solved. I am not convinced its not an air leak as the first bleed with new fluid solved the issue for a day, not something I would think was happening with a cracked sprocket cover. I just don't know if the flex in the slave is within normal parameters, I said it wouldn't show up on video but I just went out there and you can't see it with the naked eye either. When I say minimal movement I mean it. The only other place I can think of air leaking through would be the bleed nipple? or the reservoir? But there is no fluid on any parts. Maybe air getting in around the piston seals on the master cylinder? Idk, because like I said there's no fluid anywhere and everything looks really clean.

OK dude. If there is no evidence of fluid anywhere,chances are no leak.(unless its under the cover and the leak is mixing with all the crud under there from dirt and excessive chain lube).The sprocket cover is what houses the clutch slave and rod I am talking about. If you want to go ahead with the headache and cost of changing out the clutch line go for it. My check costs nothing but a little time. Change the hose,problem remains,then you have to move on.I can post a video walk thru, pics, and help. There are a few things to be wary of. Like remove the 4 bolts on the cover as you would head bolts. Cross hatch pattern a little turn at a time on each bolt.Same for re install so you don't crack the cover.A chance to push the piston for the slave back in to remove air. A chance to inspect and clean the rod. This cover gets removed if any previous owner wanted to fug with the gearing...a favourite mod.
But hey...fire away on that hose. I dont know shi7 anyway.
Rubb.

 

[Ben Fischer]

OK dude. If there is no evidence of fluid anywhere,chances are no leak.(unless its under the cover and the leak is mixing with all the crud under there from dirt and excessive chain lube).The sprocket cover is what houses the clutch slave and rod I am talking about. If you want to go ahead with the headache and cost of changing out the clutch line go for it. My check costs nothing but a little time. Change the hose,problem remains,then you have to move on.I can post a video walk thru, pics, and help. There are a few things to be wary of. Like remove the 4 bolts on the cover as you would head bolts. Cross hatch pattern a little turn at a time on each bolt.Same for re install so you don't crack the cover.A chance to push the piston for the slave back in to remove air. A chance to inspect and clean the rod. This cover gets removed if any previous owner wanted to fug with the gearing...a favourite mod.
But hey...fire away on that hose. I dont know shi7 anyway.
Rubb.

Well I may end up doing that anyway. I just don't know why a bleed with new fluid would fix the problem for a day if it is an issue with the slave/cover/piston/rod.

 

[rubbersidedown]

Well I may end up doing that anyway. I just don't know why a bleed with new fluid would fix the problem for a day if it is an issue with the slave/cover/piston/rod.

Perhaps there's yer leak,clutch slave...air back in the system in 24 hrs..

.

 

[Ben Fischer]

Perhaps there's yer leak,clutch slave...air back in the system in 24 hrs..View attachment 1618986

.

My clutch hose doesn't come for a couple days so I'm gonna open up the sprocket cover today and look for cracks, leaks, bent actuator, anything that looks Abby normal. Least I can do is clean it up I know its gonna be dirty as hell under there. Thanks for the pointers

 

[rubbersidedown]

My clutch hose doesn't come for a couple days so I'm gonna open up the sprocket cover today and look for cracks, leaks, bent actuator, anything that looks Abby normal. Least I can do is clean it up I know its gonna be dirty as hell under there. Thanks for the pointers

..... Any probs/questions...post up.When you go to re-install push the slave cylinder piston all the way back into it's bore,thus removing any air in the system (reverse bleed) Do it with the lid off the clutch master in case some bozo has over filled you can monitor the level and look for air bubbles.Push the piston slowly thou. Be qwik to re-position the cover back in place as the slave piston will naturally start to move out on its own.Then follow the bolt pattern tightening sequence I mentioned earlier, If you were thinking about a gearing change for reasons like its worn out,or you want more speed (up a tooth) or want a wheelie machine (down a tooth) this is a great oportunity.
Rubb.

 

[Ben Fischer]

Well everything looks fine in there, no leaks, slave cylinder looks great, no bent actuator rod, just some gunk buildup from the chain which I was able to remove.

 

[Ben Fischer]

..... Any probs/questions...post up.When you go to re-install push the slave cylinder piston all the way back into it's bore,thus removing any air in the system (reverse bleed) Do it with the lid off the clutch master in case some bozo has over filled you can monitor the level and look for air bubbles.Push the piston slowly thou. Be qwik to re-position the cover back in place as the slave piston will naturally start to move out on its own.Then follow the bolt pattern tightening sequence I mentioned earlier, If you were thinking about a gearing change for reasons like its worn out,or you want more speed (up a tooth) or want a wheelie machine (down a tooth) this is a great oportunity.
Rubb.

Shoulda checked this before I put it back together. I pushed the piston in a bit to check for leaks at the slave and it seemed fine but I probably didn't give it a full reverse-bleed. I dunno I guess we'll see next time I flush the fluid when the hose comes if the problem comes back.

 

[Ben Fischer]

I actually think my fluid level dropped a little bit so I may well have pushed some air out of that slave cylinder. I'm gonna get the fairing on here and go for a spin and see how it does.

 

[rubbersidedown]

Shoulda checked this before I put it back together. I pushed the piston in a bit to check for leaks at the slave and it seemed fine but I probably didn't give it a full reverse-bleed. I dunno I guess we'll see next time I flush the fluid when the hose comes if the problem comes back.

not to sound like a smart Alec...but there is a wealth of knowledge on here amongst the brothers.On a scale of 1-10 as far as smarts and wrenching goes I'm a 1. These boyz know there shi7 from a fuse change too an' 800 HP Turbo install. The men from Auz and the land of Kiwi etc,can be found on-line in the wee hours of the morning along with me and others (I'm PST) so chances are you always have an' ear if need be.Goes for you and everybody.A PM usually attracts attention faster.I've been looking for and providing answers as best I can since 2003.It can be frustrating as fug when out in the garage at 3AM trying to diagnose a prob so you can ride with your bro's in the morning.Been there,done that. Rubb.

I actually think my fluid level dropped a little bit so I may well have pushed some air out of that slave cylinder. I'm gonna get the fairing on here and go for a spin and see how it does.

Bonus...

 

[Ben Fischer]

not to sound like a smart Alec...but there is a wealth of knowledge on here amongst the brothers.On a scale of 1-10 as far as smarts and wrenching goes I'm a 1. These boyz know there shi7 from a fuse change too an' 800 HP Turbo install. The men from Auz and the land of Kiwi etc,can be found on-line in the wee hours of the morning along with me and others (I'm PST) so chances are you always have an' ear if need be.Goes for you and everybody.A PM usually attracts attention faster.I've been looking for and providing answers as best I can since 2003.It can be frustrating as fug when out in the garage at 3AM trying to diagnose a prob so you can ride with your bro's in the morning.Been there,done that. Rubb.

Bonus...

I get it! I was about to say thanks for checking back on this post so often, you're carrying the team! Just took it down the road and the clutch is still engaging with the slightest pull, no play at all. Makes blipping the throttle rough and really all shifts are catching like an on/off switch. I'm gonna keep digging.