Clutch slipping

spam16v

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#1
‘14 S10, swapped to Barnett pressure plate and Off The Road slave cylinder. Used 3 light & 3 medium springs in the pressure plate.

Removed slave after short ride to make sure rod was seated in slave. Seems to be.

Is it possible something isn’t seated between the push rod and the part that seats in the pressure plate? I can’t suspect it’s inadequate spring pressure. Did an oil change as well with some fresh T6 which I doubt had any effect.

Suggestions before I lie it on the floor or drain the oil to inspect the clutch and possibly swap in the original pressure plate?
 

steve68steve

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#4
I vaguely remember reading some issues with the ball bearing getting lost or misaligned. I think if you lost the ball, tho, it wouldn't have a problem slipping, it would never push the plates apart.

AFAIK, the spring pressure of the plate is THE thing holding the plates together with enough friction to turn together. So, wouldn't a lower force spring exert less pressure on the pack and allow slippage? Eagerly awaiting education.
 

EricV

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#5
Did you pull the plates at all? Or just pull the pressure plate and swap in the Barnett? The slave cylinder swap should not have any impact on slippage, positive or negative. It's job is to release, not to hold.

In a recent post Tabasco mentioned he was using med springs, if I recall correctly, but also that they exerted more force than the OEM part, so a mix of light and med shouldn't necessarily be an issue.

As I recall, there is a specific way to install the pressure plate, just off from the other plates? I'd have to pull out the FSM and check, but it's dinner time right now.
 

Bigbore4

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#6
Not on the Super Tenere but I have run into this twice. Once on the FJR after a lever swap. Stroke adjustment was wrong and it was not uncovering one of the ports in the master. Was holding the fluid in the line and as it warmed and expanded it would slightly apply the slave and the clutch would slip.

The other was on a Ducati Monster. There was crud in the bottom of the master and one of the ports was clogged. Same results as above.

Crack the bleeder and try it, see if it is better for a bit.
 

spam16v

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#7
Plates stayed in place @EricV. I’ll hunt down my ball when I pull the cover tomorrow and go through the install again to make sure it’s still there.
 

spam16v

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#8
@Bigbore4 thought crossed my mind. I have a speed bleeder in place. Going to rebleed and retry before pulling the cover. Removed and inspected the slave when I got home. Yard work called before I could pull the cover tonight.
 

EricV

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#9
Just a silly thought, but you do know you can't vacuum bleed with a speed bleeder in place, right? I know, why would you, but people try.

And +1 to what BigBore said. I too have seen over filled masters cause slippage when things warmed up more than when it was filled.
 

~TABASCO~

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#10
New Barnett pressure plate is probably not seated correctly or “totally seated”.
Seen this before with ‘slipping’

Also, check the wear on the throw out bearing shaft. I’ve recently posted pictures. It’s a pretty sensitive clutch (wear) part.
 

spam16v

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#12
Rebleed clutch, no change. Checked seating of push rod into Barnett pressure plate, no fault found. Changed to all medium springs, no change. Changed bleeder back from speed bleeder, no change. Removing Off The Road slave currently. I sure hope I’m not chasing an issue from switching from T5 syn blend to T6 full syn oil...
 

spam16v

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#13
Root cause of issues: Off The Road slave cylinder. Lame... I really liked this part. Going to put light springs back in the pressure plate and ponder what went wrong with this part.
 

spam16v

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#14
So the light springs won’t hold, the medium ones are stiffer at the lever and the Off The Road slave won’t allow the clutch not to slip. What a waste of time, effort and money.
 

spam16v

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#16
Found the problem.... Measured the depth to the piston in the slave through the banjo fitting hole with the spring installed on the OTR slave. Fully compressed is ~0.670”. Removed the spring and installed the slave dry and pushed the piston in against the clutch rod and got a measurement of ~0.578” showing when the return spring is fully bound is causing a 0.092” interference or preload on the release rod. This would definitely keep the springs from fully applying pressure on the clutch pack. Going to trim a coil, verify compressed depth through fitting hole and retest.
 

spam16v

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#17
Trimmed a coil & a half which should be around 0.030” free play, 2 light & 4 medium springs holding the Barnett pressure plate and it’s rock solid. New gaskets coming tomorrow for the cover and I’m going to try 3 light & 3 medium springs to see if they hold before I seal it up for good with a fresh gasket.
 

EricV

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#18
Good on you for sticking it out and figuring out what was going on. Nice diagnostic process too. Far too often people shotgun the diagnostics and lose sight of the real problem, just throwing parts/$$ at the problem until it goes away. Well done, Sir.
 

Bdubbs033

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#19
Trimmed a coil & a half which should be around 0.030” free play, 2 light & 4 medium springs holding the Barnett pressure plate and it’s rock solid. New gaskets coming tomorrow for the cover and I’m going to try 3 light & 3 medium springs to see if they hold before I seal it up for good with a fresh gasket.

I'm having issues with my clutch as well and I'm considering the Barnett pressure plate and new discs? After all you've been through with this, do you think it is worth the extra cost and work involved with replacing of the pressure plate?

I like to use 2 fingers to work the clutch but it won't fully disengage and shifting is a bit notchy using this method now. The clutch with disengage fully if I pull the lever all the way to the handlebar and shifting is normal. That would be worn plates correct?
 

EricV

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#20
I'm having issues with my clutch as well and I'm considering the Barnett pressure plate and new discs? After all you've been through with this, do you think it is worth the extra cost and work involved with replacing of the pressure plate?

I like to use 2 fingers to work the clutch but it won't fully disengage and shifting is a bit notchy using this method now. The clutch with disengage fully if I pull the lever all the way to the handlebar and shifting is normal. That would be worn plates correct?
What you like to do is an incorrect procedure. Nothing is wrong with the bike. You said it yourself, if you pull the clutch lever all the way to the handlebar then shifting is normal. That's what you are supposed to do, pull it all the way to the bars. "all the way" fully implies exactly that, ALL the way, not part of the way.

Changing disks and the pressure plate won't change the need to pull the clutch lever in all the way to fully disengage the clutch.
 
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