Liquid cooled vs Air Cooled Clutch Slave Cylinder - Ducati.ms - The Ultimate Ducati Forum
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post #1 of 12 (permalink) Old Jul 3rd, 2019, 8:20 am Thread Starter
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Liquid cooled vs Air Cooled Clutch Slave Cylinder

Hi all , I have a Monster1200R that suffers from the same problems as my previous bike (1098) in the clutch slave cylinder dept. The clutch gets progressively softer until you can't find neutral or shift from neutral to first. It requires bleeding yearly and sometimes more often. Its easy enough to do and I know that an aftermarket cylinder would solve the problem.

My 1100s Hyper (which appears to have the same slave cylinder) never has this problem. I only bleed it when doing maintenance. IIRC It has only been done once in the last few years and that was just to refresh the fluid. Performance was fine.

What gives ?

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post #2 of 12 (permalink) Old Jul 5th, 2019, 1:55 am
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Originally Posted by Shawn of the Dead View Post
Hi all , I have a Monster1200R that suffers from the same problems as my previous bike (1098) in the clutch slave cylinder dept. The clutch gets progressively softer until you can't find neutral or shift from neutral to first. It requires bleeding yearly and sometimes more often. Its easy enough to do and I know that an aftermarket cylinder would solve the problem.

My 1100s Hyper (which appears to have the same slave cylinder) never has this problem. I only bleed it when doing maintenance. IIRC It has only been done once in the last few years and that was just to refresh the fluid. Performance was fine.

What gives ?
How would an aftermarket slave cylinder solve this problem?

Thanks
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post #3 of 12 (permalink) Old Jul 5th, 2019, 6:54 am Thread Starter
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How would an aftermarket slave cylinder solve this problem?

Thanks
My understanding is the aftermarket slave cylinders have a better seal to prevent contamination of the fluid. They also have more surface area for a lighter clutch pull.

I was more curious as to why my air cooled bike doesn't have this issue but my 4 valvers do.

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post #4 of 12 (permalink) Old Jul 5th, 2019, 1:30 pm
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My understanding is the aftermarket slave cylinders have a better seal to prevent contamination of the fluid. They also have more surface area for a lighter clutch pull.
Lighter pull = less throw, doesn't it? If so that may create creep at stops. Maybe ... or not ... or something.


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post #5 of 12 (permalink) Old Jul 5th, 2019, 1:51 pm Thread Starter
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Lighter pull = less throw, doesn't it? If so that may create creep at stops. Maybe ... or not ... or something.


Lighter pull do to more surface area , same throw... I've already had creep ...or I am a creep ... and I just remembered I forgot to bleed at the master cylinder as well as the slave ..... facepalm :/

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post #6 of 12 (permalink) Old Jul 5th, 2019, 8:43 pm
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Lighter pull do to more surface area , same throw...
The laws of physics would say otherwise. If the slave has more surface area and the master hasn't changed, you get less throw (at the clutch) with lighter action.
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post #7 of 12 (permalink) Old Jul 7th, 2019, 11:35 am
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Could the rod be rotating the slave piston in the bore? Are there any signs of rotation where the slave piston and the clutch rod contact indicating that the bearing on the clutch end of the rod is failing?

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post #8 of 12 (permalink) Old Jul 7th, 2019, 11:50 am
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I was more curious as to why my air cooled bike doesn't have this issue but my 4 valvers do.
The air cooled 900ss eng in my Bimota as well as my 916 eat clutch slave seals for lunch every day. Well, OK, not THAT often, but it has happened on both bikes with the results that you describe. My amateur opinion is that these things live in the dirt and get used a lot so the seals are more prone to wear. I have since resorted to cleaning them regularly - like at each oil change - the seals, the shaft, new orings and lubing the shaft as well as cleaning the tunnel with gun cleaning brushes. I also bleed them each time. Every time I take them apart, something is dirty and gritty. All this is relatively easy to do and has gone a long way to keeping the slave working.

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post #9 of 12 (permalink) Old Jul 7th, 2019, 7:12 pm
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Quote:
Originally Posted by Shawn of the Dead View Post
I was more curious as to why my air cooled bike doesn't have this issue but my 4 valvers do.
The air cooled 900ss eng in my Bimota as well as my 916 eat clutch slave seals for lunch every day. Well, OK, not THAT often, but it has happened on both bikes with the results that you describe. My amateur opinion is that these things live in the dirt and get used a lot so the seals are more prone to wear. I have since resorted to cleaning them regularly - like at each oil change - the seals, the shaft, new orings and lubing the shaft as well as cleaning the tunnel with gun cleaning brushes. I also bleed them each time. Every time I take them apart, something is dirty and gritty. All this is relatively easy to do and has gone a long way to keeping the slave working.
Do you run a case saver over chain/countershaft sprocket? They catch a lot of the dirt/grime flung off the chain. Might help the slave out and save your cases if you snap a chain. Desmotimes sells them.
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post #10 of 12 (permalink) Old Jul 7th, 2019, 7:44 pm
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Do you run a case saver over chain/countershaft sprocket? They catch a lot of the dirt/grime flung off the chain. Might help the slave out and save your cases if you snap a chain. Desmotimes sells them.
No I don't as I guess I didn't know they existed. Now I can't live without one. Or two. Thanks for chiming.

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