Kawasaki Vulcan Clutch Odd Behavior

[rebeltaz]

I need to explain quite a bit here, so please bear with me.

On my 2002 Kawasaki Vulcan VN1500 Classic Fi, the clutch started slipping big time. I rebuilt that, replacing most everything in there. It seemed to be ok for a while, but then started slipping again, a little more at a time until I almost couldn't get it back to my shop.

I've seen something similar happen to brakes when the slave cylinder will stick, so I took that apart, cleaned it, rebuilt it and put it back on. Again, it seemed ok for a while and then started slipping more and more just like last time.

This time, as soon as I got it back to the shop, I broke open the bleeder valve and, sure enough, a stream of fluid shot out as the piston was pushed back by the clutch springs. I took the bike back out immediately and, once again, the clutch was fine. I figured that the clutch hose was clogged. I blew that out and couldn't find anything clogged, so I went ahead and replaced it in case it was collapsing.

Once again, ok and then slipping. This time I broke the banjo bolt loose at the master cylinder. The fluid pushed out the bolt and the clutch worked again. The only thing left was the master cylinder, so I rebuilt that last night. I didn't see anything wrong with that while I was in there - nothing clogged and the rubbers looked fine.

I haven't taken it back out yet, but I have a strong suspicion that I am going to still have this problem. Both because I didn't see anything wrong, but also because after the last to repairs (the clutch line and the master cylinder), when I bled the system it was really odd. I use a vacuum bleeder. I could not get the system to bleed using that, so I reverted to the old pump/hold/bleed/release method. No air, but I still couldn't get a good solid pressure. The weird thing is that if I quit trying to bleed it, the pressure would build up and it will stay that way, unless I break open the bleeder valve, at which time it acts like air is being sucked in and it looses that pressure until it's built back up.


Does anyone have any ideas for if/when this clutch starts slipping again?
____________________
Derek Tombrello
www.ShelbyCycle.com (for profit)
www.RobotsAndComputers.com (just for fun)

[doggone]

My Bandit 1200 had me changing plates when there was no need, it was the little pushrod which goes through close to the sprocket needed cleaning.
Is the VN shaft though, still might be similar.issue.

[rebeltaz]

[Robby]

Well clearly something is wrong in the hydraulic system. Blocked return hole in the master cylinder could cause it.

[Polarbear]

I agree with Robby.

I would be overhauling the mastercylinder as the fluid pressure has to release back into the reservoir which it obviously isn't doing if you have pressure in the system when the clutch lever is released.
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Triumph Trophy Launch Edition

[Nobby the Bastard]

Thirded, clearly an issue in the master cylinder retaining pressure.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[rebeltaz]

Well, like I said... I rebuilt that yesterday. I'm going to take it back out tomorrow and see how it does. Thanks everyone.
____________________
Derek Tombrello
www.ShelbyCycle.com (for profit)
www.RobotsAndComputers.com (just for fun)

[Stalk]

Probably a stupid question but, is the lever binding? Has it been changed for one that is slightly different? Have you put on a custom lever?
The point is, could it be the lever not allowing the master cylinder to return fully to its rest position, and therefore retaining a bit of fluid pressure.
You seem to have tried everything else.
Hopefully you will sort it.

[rebeltaz]

[twanny]

Hi, did you ever solve you clutch problem? I am wondering since I am experiencing similiar issues.

Thanks for any help.
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Just ask.

[sickpup]

Clean the slave piston and fit new seals, buy a new braided steel clutch hose, rebuild master cylinder.

That pretty much covers it all assuming the clutch stack is within spec.

[twanny]

Thanks for coming back to me. So really a pretty much full rebuild will fix the problem as long as the plates are good.

Thanks again
____________________
Just ask.

[sickpup]

Try it after each step, that's what I would do and the order I'd do it.