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Discussion Starter · #1 ·
Clutch slipping. It came on all of a sudden. So much for a beautiful day to ride.

25K on a 2006. 8K of that by me in the last year. Prior to me, it wasn't ridden a lot but it wasn't completely ignored. I did all the maintenance a year ago when I got the bike. So it's reasonably up to date (oil is now due) and I used the right fluids. Nothing done recently to point a finger at.

In all gears, if I give it a good bit of throttle (firm, doesn't have to be HUGE), the engine revs up and the speed not so much. I have to stay with moderate acceleration to not wind up in the friction/slippage zone.

I saw this thread (among others) and this post in particular:
Clutch slip
that focuses on a specific port as a likely suspect for the clogging. Elsewhere in the thread, drive shaft rubber omes up in the list of suspects.

@Waldo or anyone, do you the image from that old post handy? It's gone now. The one about the port to unclog.

Drive shaft at 25K seems unlikely to me. Other opinions?

I've got a little crud around the boot where the lever / pushrod / piston are in the master cylinder. I though that might be at fault but, while not pretty, the pushrod/piston seems to be moving without sticking.

Here's what the service manual suggests. Most of it looks beyond me. Hoping for a hydraulic miracle.

374438
 

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What kind of oil you using?
 

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Discussion Starter · #3 ·
P.S. I tried to test the driveshaft by turning the rear wheel by hand. Nope. No slippage. It's not that far gone. I see the other diagnosis (@techdude2000 's I think) of feeling the u joint while you use the brake to stop the wheel. That will take a bit more work to get there, but maybe soon.
 

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My thoughts:

  • Pull the dip stick and smell it. Any indictions of burnt smell ???
  • What kind of oil is being used ???
  • Anything feel funny about the clutch lever ... does it have an even, smooth pull in and out ???
  • Is an OEM lever being used ???
  • Don't over look proper lever action. Does the lever need removed, cleaned, inspected, any worn parts replaced, and lubed ???
  • Have you tried bleeding the clutch ???
  • Is the clutch fluid level to high ??? Proper hight is at the top of the sight glass.
 

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I think what tamathumper and greg are asking is. Synthetic or Dino?

My only other thought would be something wrong with the slave cly.


Rayjoe

PS I assume you have checked the clutch lever mechanism to make sure it's not binding.

Something else just occurred to me. The long rod that the slave pushes on could have developed a rust ring that would not let it fully disengage. I have only seen this on dirt bikes, but anything is possible. Hydraulic pressure forces the rod (with the rust ring) into the seal and bearing but the clutch springs do not have enough strength to fully return it. Hope that makes sense?
 

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Discussion Starter · #7 ·
Almost certain it's got Honda GN4 in the engine. I checked the level and look/feel. It's due and it looked it, but not bad. Didn't notice a smell but will re-check. I may even do one of those oil analysis things.

I'll probably try to flush the clutch some night this week unless I keep getting bludgeoned by life like I have been lately. Hopefully that works. Though I'm tempted to heavy up and order the piston set (#3 here), wait for that to show, and do it all once rather than in installments. Like I said, there's a little crud around that area and my boot is degraded, but things move smoothly. Bushings were in good shape and I greased them last flush about a year ago.

I will re-check there's an air gap in the master cylinder.

I'm hopeful and optimistic this isn't the guts of the clutch at fault. Thanks for the rudder.
 

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Hey Big_Bird, I just noticed your post about the bike not starting in gear. These two problems could be related. Is it possible one of the switches is holding the lever just enough to cause the clutch to slip?


Rayjoe
 

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Possibly the return port on the master cylinder is partially plugged, not allowing all the fluid to return when you release the clutch.
when you you bleed the clutch, pull all the fluid out of the master cylinder and remove the saml metal clip over the return hole. You can push a small wire into the return hole to clear the blockage.
And as Elmer thud said, make sure the master cyl in not over filled. That will cause the same effect.
 

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It is mostly in the engine. The end of it sticks out into the slave cylinder area and there is a seal that it slides in at its exit point.
 

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P.S. I tried to test the driveshaft by turning the rear wheel by hand. Nope. No slippage. It's not that far gone. I see the other diagnosis (@techdude2000 's I think) of feeling the u joint while you use the brake to stop the wheel. That will take a bit more work to get there, but maybe soon.
I had the drive shaft separate at the rubber internal coupling on my 01. I thought it was the clutch but after closer investigation it was indeed the driveshaft. I kinda remember putting the bike on the center stand and checking to see if the forward porting of the driveshaft under the boot was spinning while releasing the clutch (easily) and blocking the rear wheel from turning.
 

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I had the drive shaft separate at the rubber internal coupling on my 01. I thought it was the clutch but after closer investigation it was indeed the driveshaft. I kinda remember putting the bike on the center stand and checking to see if the forward porting of the driveshaft under the boot was spinning while releasing the clutch (easily) and blocking the rear wheel from turning.
I was showing off and tried to wheelie when it happened. There, I told on myself.
 

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Friction modifiers in the oil or driveshaft... my lucky guesses.
 
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Discussion Starter · #17 ·
Hey Big_Bird, I just noticed your post about the bike not starting in gear. These two problems could be related. Is it possible one of the switches is holding the lever just enough to cause the clutch to slip?
I wondered about that coincidence, too.

When I was diagnosing things fiddling around, I made sure to push the lever all the way out and still slip happened. There may be something else hanging up, but it's not the lever.

Isn’t the push rod concealed inside the engine it’s self ??
The pushrod I was talking about is the little one that the lever pushes against to activate the piston at the master cylinder.

----

I'll try the flush, port poke, and driveshaft diagnosis as soon as I get the time, then report back.

Thanks, all, for the info and ideas. It's comforting to know there are so many things that could be wrong. Ha ha, I mean short of a problem deep inside the case. I'll eventually trip over a solution with your help. Much appreciated.
 

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Hey Big Bird, the push rod we mentioned goes thru the clutch in the engine. Elmer thud is probably right. It should be protected from crud behind the slave cylinder. On older dirt bikes it was more exposed.

I real curious to know what the problem is. Please post the solution when you figure it out!
Thanks,


Rayjoe
 

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Discussion Starter · #19 ·
Yup. I thought you were keying on something I said then saw you were exploring something else. I hope it's not that. Sounds like it is unlikely though I do a little mudding on my 'Wing.

I'll follow up when I chase it down.
 

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Greg mentioned too high of a level of clutch fluid. Check that! As the clutch wears, that fluid level RISES; just the opposite of brake pad wear on the brake masters. If the fluid fully floods the reservois, the clutch will be partially disengaged and as it heats up the disengagement will worsen. Oil pressure being too low can also cause the clutch to slip, especially in higher gears.

prs
 
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