Clutch engages to late after changing rod o-rings

[desiresa]

Hi!
In 2008 I got my Monster S2R Dark -05 and managed all the maintenance myself since then. This last winter I changed the o-rings on the clutch rod. I know it was not necessary, but since I was checking it out I thought I might as well do it. I also changed the break fluid. Now, after doing this the clutch has been engaging way to late, at the length of my middle finger, which doesn't give much of a good feeling when driving. The problem is actually the opposite of having air in the circuit, and the engagement of the clutch is really distinct and not spongy at all. Anyhow, I've tried changing the fluid again, tried filling it from the slave and up to the master, tried laying the bike down and pumping the lever to build pressure and exclude any risk of air in there. As far as I'm concerned I have no signs of air in the system, or can anyone see something I'm missing?

My other theory is that I've damaged something in the slave cylinder that gives the clutch this character. The reason is that when I changed the o-rings I first used a pair that had the right diameter but the wrong thickness of rubber, which made the rod not really fit in. It was not moving smoothly. I assembled the slave cylinder anyhow, and here is the point. Is it possible that this extra pressure form the rod to the slave cylinder caused the problem. I've changed the o-rings for new original ones, and when I took the rod out the wrong ones were split up. I've tried to google this problem but have not find anything helpful. I've talked to a workshop too, but they were of no help either. The slave cylinder has like a huge torx front, but I've read nothing about it being a way to adjust the clutch. Any ideas about what I can do, or if I should try changing the slave!?

I'm in the north of Sweden, 1000km from the nearest ducati workshop, so going there is not really an option now that winter is coming again 

[Howie]

Hard to tell over the internet, but you just might have fixed the bike.  You might have had a little air in there.  I'm assuming the clutch does not slip.  Any known good S2R 800s you can compare yours to?  There is no adjustment other than free play, which you should leave alone.  If you determine your bike is normal and are still unhappy, adjustable levers may be in your future.

[desiresa]

I can compare the bike to the way it was before I changed o-rings and the break fluid (the first time). There was a distinct difference before and after this work. I'd estimate a three centimeter difference between the point the lever engages the clutch. All the rest of the fluid work were attempts to fix this, but since it's given me no result, and the symptoms are not really symptoms for air in the system I think I've excluded the air theory.

What could have happened to the slave cylinder when the rod was pushed into it with force and kept like that for a while? I actually have found no symptoms with the clutch engaging in the wrong way like this. Any experiences?

[ducpainter]

What howie is saying, is that before you bled the system there may have been air in it, and it was not normal.

You can't do any damage to the slave cylinder by putting it under load. It's a hydraulic device, and it can only leak if damaged.

The only thing I can think of is maybe the push piece in the pressure plate came partially dislodged and hasn't gone all the way back in. That would effectively lengthen the push rod and change the engagement point.

[desiresa]

Aah, thank you, I get it now! With that approach I would have had the same amount of air in the system through and between all the other changes of fluid that I've done

The push plate sounds like something to investigate in this long-rod-experience-mystery. May I ask how to do that conveniently!?

Thanks for your thoughts, I really appreciate it!!!

[ducpainter]

As silly as it sounds, getting air out of a clutch system can be extremely difficult. It's more likely than anything else.

You would need to remove the right side cover to look at the pressure plate, the bearing, and the push piece. If the push piece has dislodged, you'll need to remove the pressure plate to remedy the situation. It won't be convenient, involves draining the oil or tipping the bike on its side, and it's a long shot (remote likelihood). You'll need to clean and reseal the cover with three-bond, or a similar sealer.

You can download, or view, the parts book to get an idea of the parts involved.

http://ducati.com/services/maintenance/index.do

If it doesn't slip and completely disengages your clutch is working. You need to decide if digging deeper to investigate is worth it.

[desiresa]

Thanks ducpainter!

I've opened the left side already, so the procedure is not frightening...actually more close to being interesting and fun Even though air is a stubborn problem I don't really see how it could have been a problem before this. Neither before or after  the change there was any feeling of having air in there. The distinct engagement of the clutch has moved but not been spongy at all.

Would there be any drawbacks of changing the rod for a shorter one?

[Speeddog]

If the system is working properly, a shorter rod will do nothing unless it's so short that the slave cylinder runs out of travel.

The hydraulic clutch and brake systems automatically compensate for length differences of components.
For example, the brake lever doesn't get closer to the bar as the pads wear.

Those of us who have had cable operated clutches know that the engagement point changes as the engine heats up, due to the expansion of the various metal parts.

If you've suddenly got a 3 cm difference in the engagement point, either you've removed air from the system, or dislodged a bit of debris that was compromising the function of the forward seal in the master cylinder.

[desiresa]

I'm back in the garage trying to figure out the clutch problem. I started with the slave cylinder mechanics. The rod stocks out 35mm from the motor block and the "free space" in the slave cylinder is 30mm. That is, as I put the cylinder on the bike the piston in the slave cylinder is pushed 5mm by the rod. In other words, there is no clearance here and the question is, should t

If the system is working properly, a shorter rod will do nothing unless it's so short that the slave cylinder runs out of travel.

The hydraulic clutch and brake systems automatically compensate for length differences of components.
For example, the brake lever doesn't get closer to the bar as the pads wear.

Those of us who have had cable operated clutches know that the engagement point changes as the engine heats up, due to the expansion of the various metal parts.

If you've suddenly got a 3 cm difference in the engagement point, either you've removed air from the system, or dislodged a bit of debris that was compromising the function of the forward seal in the master cylinder.

here be? With this amount of dislocation there could be a risk that the push plate is a little affected already? Has anyone measured these distances in the slave cylinder?

Further more, when I manually put pressure on the piston keeping the system open at the top, and then releases it, the piston returns to its fully extended position. Does that sound correct?

[ducpainter]

All sounds normal to me.

[desiresa]

Do you mean it's normal what the rod pushed the slave piston already when being mounted?

[ducpainter]

That, and the piston returning after you push it in.