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Discussion Starter #1
Hi folks. I am hoping someone can help me solve a problem I am having with a perpetually leaky clutch slave.

I bought my '98 ST2 about a year ago, and it had a minor slave leak when I got it. Eventually the fluid ran low and my clutch stopped working, so I decided to upgrade the slave.

I put on an aftermarket slave, which didn't leak, but it also had a larger piston for lighter effort, and therefore didn't move far enough to completely disengage the clutch.

So, I put the original slave cylinder back on, and replaced the piston with an aftermarket with two o-rings (can't remember where I got it). Everything seemed to be fine for a while, but eventually it started leaking again.

2 weeks ago, I took my bike to a Ducati dealer (3 hours away) in order to get valves done, new steering head bearing, and to get this leak fixed. They told me that the piston was leaking (duh), and needed to be replaced with a new factory piston. I needed the leak fixed in a hurry for a trip, so rather than buy new seals for the aftermarket piston, I just told them to replace the piston.

I picked up the bike the next weekend, and took it two blocks to a Starbucks to get a coffee before the 250-mile ride home. When I came back to the bike, there was fluid leaking all over the sidestand. I went back to the dealer, and sure enough the new slave piston was leaking.

They took it apart and showed me that the cylinder was a little scored and scratched, so we went ahead and replaced the cylinder as well. At this point I had a totally new factory slave unit. It still leaked before even leaving the shop.

The pulled the control rod and put it in a drill (they said), and it spun true, so it seemed to be OK. They pulled the clutch pack and noticed that I had Barnett clutch plates in there. They said the Barnett plates are thicker than stock, and theorized that the rod was effectively "shortened", because the pressure plate was farther out than with a stock clutch. This, they thought, causes the slave piston to have to move too far in the cylinder, and therefore allows some fluid to get past the seal. To compensate, they put a ball bearing between the rod and the piston, to effectively lengthen the rod.

No leaks after this was done, so I headed home. Unfortunately at a fuel stop about 150 miles away, I noticed that it was leaking again. Not quite as bad, but still leaking.

Now I am stuck on what to do next. I really can't afford to lose another day or two days with my family going back and forth to this distant dealer (even though they did offer to take it back for another round). Does anyone have any ideas or suggestions on how I can fix this thing? Or am I just going to have to carry a bottle of DOT4 everywhere I go?
 

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you may want to have a look over at desmotimes, theres some talk about an adjustable clutch lever. it sounds like it can alter the stroke. i think it was in the clutch section.
here is the details.
1. Ensure the clutch system is fully bled
2. Adjust your clutch lever all the way out. If you have a non-adjustable lever, purchase an adjustable one. Desmo Times sells them -- look under "Billet" for the CRG levers or "Modification" for the older 12mm pivot Brembo levers.
3. If you are installing an aftermarket slave cylinder at the same time as upgrading clutch packs, prepare for some troubleshooting. In short, try solving an equation when you change two or more variables is an effort in futility.
 

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The days are getting longer!
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Put your aftermarket slave back on. Remove the clutch pack. Only install one of the 2 steel disc's as shown in the diagram.. Bleed your clutch system real good.
If finding neutral is still difficult replace the curved plae with a standard. As the clutch beds in you may need to reinstall the plates over time. It has worked for me so far.
Good luck.
 

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Va_Duc is right!

Put back your aftermarket slave. The trick with your plates is to have a stack height of 38mm.

Check if your aftermarket Slave is the kind that works with longer push rod, appeared in 2000. That would explain it doesn't work with your pushrod, which should be a shorter one.
 

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Discussion Starter #5
Put your aftermarket slave back on. Remove the clutch pack. Only install one of the 2 steel disc's as shown in the diagram.. Bleed your clutch system real good.
If finding neutral is still difficult replace the curved plae with a standard. As the clutch beds in you may need to reinstall the plates over time. It has worked for me so far.
Good luck.
I sold my aftermarket slave, so it is not available right now. Would the clutch assembly directions apply (only 1 steel plate at the bottom) even with the stock slave?
 

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If you start with at least 1 steel and finish with 1 steel, the order doesn't matter. The main figure to respect is the stack height, around 38 mm.
So, you can do a Steel/Steel/Friction/Steel/Friction (...)/Friction/Steel/Pressure plate OR Steel/Friction/Steel/Friction (...) Friction/Steel/Steel/Pressure plate.
 

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Discussion Starter #7
If you start with at least 1 steel and finish with 1 steel, the order doesn't matter. The main figure to respect is the stack height, around 38 mm.
So, you can do a Steel/Steel/Friction/Steel/Friction (...)/Friction/Steel/Pressure plate OR Steel/Friction/Steel/Friction (...) Friction/Steel/Steel/Pressure plate.
I pulled apart the clutch pack and found a couple of problems. First, the bearing in the spring retainer plate (or whatever it's called, the plate that the rod pushes on) was really tight. I removed the grease seal and it was pretty gummy and dry in there. I cleaned it out and packed it with grease, and now it turns easily and smoothly. I'm sure that it was spinning the rod, since I could hardly turn it with my fingers.

Next I checked the clutch pack, and there was an extra friction plate in there. Basically if you go by the Barnett diagram, there was a friction plate between the first two steel plates, and the stack was over 40mm. So I removed it and put it back together with two steel plates at the bottom. The stack was about 37mm high in this configuration.

I put everything back together and it seems to be working fine. We'll see if it fixes my leak or not...I'll post after I have a chance to ride around a bit. I just added a 2008 CBR1000RR to the stable, so the ST2 doesn't get a lot of attention these days.
 

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Mr Leakered
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How the hell were both of those issues missed? After issues with two separate slaves, you'd think the shop. . . Oh wait, I just answer that question.

BTW, the plate with the bearing in it is called the pressure plate.

Have a good one.
 

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Discussion Starter #9 (Edited)
How the hell were both of those issues missed? After issues with two separate slaves, you'd think the shop. . . Oh wait, I just answer that question.

BTW, the plate with the bearing in it is called the pressure plate.

Have a good one.
Uhh, yeah, that wasn't the only thing they screwed up. When they replaced my steering head bearings, they put the front back together all wrong. The speedo cable was routed incorrectly and they put the forks in all the way up to the underside of the handlebar mounts, which resulted in me putting a huge gouge in my front fender as it bottomed against the voltage regulator which was relocated under the lower triple clamp. So now I have to lower my forks too. Did I mention the new scratches on the gas tank?

Thanks for clarifying the terminology. I have an aftermarket spring retainer / pressure plate. The retainer sits on top of all the springs, I was thinking that was the pressure plate. Looking at the service manual, I can see that the stock pressure plate uses individual retainers for each spring, so there is only one "plate".
 

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Mr Leakered
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I just installed one of those spring retainers recently. It does improve clutch feel a bit.

I've complained several times about this type of issue that my ST suffered from the last shop that serviced it for the previous owner. I too found wires and lines routed willy-nilly, fasteners greatly overtorqued or partially stripped, etc. Not good.

I do believe that you will find out over time that your bike will perform better the more work you personally do on it.

Have a good one.
 

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Discussion Starter #12
Update:

I had to put the "extra" friction plate back in, because the clutch was slipping under acceleration without it. Besides that, it didn't seem to correct leak anyway.

So I'm back to marking my territory every time I park the bike.

I would like to verify if I have the correct control rod in my clutch. Can anyone tell me what the correct length of the rod is on a 98 ST2? I understand that later models have a different rod...

Thanks!
 

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Discussion Starter #13
OK maybe rod length is a lot to ask for, since you'd have to pull it out. How about this...can someone with an ST2 pull off the clutch slave and measure how much of the rod is protruding from the engine? Thanks.
 
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