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Discussion Starter · #1 ·
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Have you guys ever seen this before? The fluid I use is RBF 600 and new fluid was recenqtly flushed through the all the hydrolic lines. We went on a 500km ride last Saturday, canyon riding. For most of it we were going pretty hard and I cooked the clutch fluid.
I have always seemed to require flushing the clutch line more frequently then the brakes when the fluid starts getting dirty. But this time, **** me, I killed it in 600km.

So now its got me wondering if a quality aftermarket slave cylinder would be worth getting
(FYI, the rear brake is still working perfectly.)
 

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How would that fluid be getting cooked? Engine heat in that area doesn't seem like it would be near high enough to affected RBF 600 (assuming they aren't bs'ing the specs).

Curious how an aftermarket slave cylinder would help, though. If it is heat, it's still going to get just as hot, right?
 

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Discussion Starter · #3 · (Edited)
I know, thats what can't figure out. Maybe the constant heat from the crank case and heat transfer from the clutch rod is hot enough and long enough duration to cause the fluid to age prematurely. Or perhaps there is something wrong with the slave cylinder. I dont know, hence why I'm throwing out there. I have read that motorcycle oil can reach temps of 350⁰ F.

I was thinking a quality aftermarket slave maybe better insulated from the heat.
 

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A couple of things, Your fluid is not getting 'burnt' by heat, brake and clutch fluid can withstand way more heat than the engine can stand, your engine would probably seize before you 'cooked' the fluid. I've seen disk brakes on race cars glowing red at the track. brakes still work.

As Lee said, the black is a result of black rubber components, seals can wear and not leak, the line from reservoir to slave is black rubber, etc. etc.
Just the tiniest amount turns the fluid black.

'Is an aftermarket slave better?'
The stock slave is aluminum, normal, slight wear in piston and seals produces black residue, (wet sand a piece of aluminum, the water goes black.)
Some say the fluid lasts longer with aftermarket slave cylinder, that's because they use anodised aluminum, does not produce black residue with normal wear and have better quality seals etc. Vitron seals/o'rings are usually green or blue.

Clutches have a full range of movement which pushes the fluid back up into reservoir, unlike brakes which have tiny range of movement. Hence the clutch fluid mixes more than brakes.

The 1200 clutch design uses a sectioned pushrod to prevent spinning against slave, but as said, still not enough heat to burn the fluid.

It's actually quite normal for clutch fluid on a bike to go black quickly and nothing to really worry about, except of course, it looks bad.

My clutch fluid has been black for a couple of years with no bad effects, might get inspired to change it soon.
 

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Discussion Starter · #11 ·
A couple of things, Your fluid is not getting 'burnt' by heat, brake and clutch fluid can withstand way more heat than the engine can stand, your engine would probably seize before you 'cooked' the fluid. I've seen disk brakes on race cars glowing red at the track. brakes still work.

As Lee said, the black is a result of black rubber components, seals can wear and not leak, the line from reservoir to slave is black rubber, etc. etc.

'Is an aftermarket slave better?'
The stock slave is aluminum, normal, slight wear in piston and seals produces black residue, (wet sand a piece of aluminum, the water goes black.)
Some say the fluid lasts longer with aftermarket slave cylinder, that's because they use anodised aluminum, does not produce black residue with normal wear and have better quality seals etc. Vitron seals/o'rings are usually green or blue.

Clutches have a full range of movement which pushes the fluid back up into reservoir, unlike brakes which have tiny range of movement. Hence the clutch fluid mixes more than brakes.

The 1200 clutch design uses a sectioned pushrod to prevent spinning against slave, but as said, still not enough heat to burn the fluid.

It's actually quite normal for clutch fluid on a bike to go black quickly and nothing to really worry about, except of course, it looks bad.

My clutch fluid has been black for a couple of years with no bad effects, might get inspired to change it soon.
Thanks Rossi, that was very informative 👍👊👊
 

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Discussion Starter · #12 ·
Update: went for a short ride and the clutch was fading while waiting at the red lights. Apon arriving home, there was a fluid leaking from the slave cylinder. We all know what that means. Seals have deteriorated.
I'll let the bike cool then strip of the slave and get the seals replaced during the week.

Thanks for all your help guys and gals 🤟🤟
 

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Discussion Starter · #17 · (Edited)
So this week I learnt that the slave cylinder on my bike is not rebuildable.
That the genuine Ducati slave cylinder have been known to fail often.
Oberon, have a good reputation, and Ducabike and a few other brands are stupidity over price and look too bling for my liking.

I ordered myself a Oberon in titanium, along with 2 new o-rings for the pushrod. I installed them this afternoon. Love the look of the Oberon. Neat and clean, and the colour doesn't stand out like dogs balls
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