[supomglol]

Greetings, I recently purchased a 2005 749 Dark. I was told when I purchased it that there was a problem with the clutch.
So far I have torn completely dismantled the clutch assembly (Friction, drive plates and springs are all within tolerance).
I've replaced the slave cylinder.
I've bled the clutch from top to bottom multiple times with new fluid - there is no air in the lines.

Basically the clutch disenguages fine now, but when held in for 15-30 seconds the pressure will slowly bleed off and the clutch will slowly re-engage the gear.
There's no leaks
Even when I have the bike in neutral with the engine running over about 60 seconds time with the clutch held in, you can hear the clutch slowly engage and then when I release the clutch handle there is no change in sound because the clutch is already fully engaged.

Any advice on this, my mind is wandering toward the throwout bearing or small piston contained in the handle (master calender?) I'm running out of pieces to replace here...

Thanks for any help!

 

[Bella749]

Check the bleeder (6mm bolt) inside the master cylinder reservoir. If it's not snug it will bleed off pressure like you describe. Otherwise, likely you have a m/c piston seal. I think rebuilt kits are available, and usually pretty inexpensive... but then again you can buy a used master pretty cheap anyway.

 

[Viper1]

Check the bleeder (6mm bolt) inside the master cylinder reservoir. If it's not snug it will bleed off pressure like you describe. Otherwise, likely you have a m/c piston seal. I think rebuilt kits are available, and usually pretty inexpensive... but then again you can buy a used master pretty cheap anyway.

I would agree!

 

[mad]

x2. It's in the master...somewhere.

 

[DMCTRUBY]

x3, it called a crappy master cyl, welcome to the club. A really good bleed including the last burp of the 6mm fluid res bolt will help....but only for so long. I have owned three 999 bikes, all had the same issue with the clutch master requiring replacement. At least on 05 or newer brembo does not make a seal kit. You can buy the res separately (dealer charged $12 for that), but that was not the issue for me, was internal to the lever and not fixable.

 

[supomglol]

Hey thanks for the replies.
I called Advanced Motor Sports out of Dallas today and talked to one of their techs. After explaining what I had already ruled out, etc... they came to the same conclusion of those who posted already.

Master cylinder is indeed in need of replacement, unfortunately they don't have any in stock and it will cost ~470$ for a new one. Does anybody have an suggestions for an aftermarket or used one?

Also it's been mentioned a few times about the 6mm bolt inside the reservoir, I have indeed bled using that one too so that can't be it.

Thanks again!

 

[Bella749]

Check out Motowheels (site sponsor, and great people to deal with) or Yoyodyne. They stock the OEM master cylinders for substatially less $$ than what you were quoted... Hell, for $470, you can prolly get a Brembo GP billet or forged master including labor to install!

http://www.motowheels.com/italian/myproducts.cfm?parentcategoryid=442%7CDucati&CategoryID=445|Clutch%20Master%20Cylinder&collection=165%7CClutch

 

[DMCTRUBY]

do a search on the clutch master or stalling. There was a recent thread with all the options priced out. I think a radial brembo and new res option was under $300.