Ducati Monster Forum

Moto Board => Tech => Topic started by: irridium on March 16, 2012, 10:07:11 AM

Title: clutch advice
Post by: irridium on March 16, 2012, 10:07:11 AM
So... I take the 696 out today for the first of the season.  Everything's going well, beautiful day, deer crossing the road, almost 50F but sunny.  I'm nearly back home when my clutch decides to stop engaging.  First it was just a little, then it got to the point where I had to push the rest of the way.  I can't find any leaking, reservoir is full, slave looks in tact but I did have a squeaky sound when pulling the clutch lever, not to mention it just didn't feel right.  After the bike cooled down, the squeak went away and lever felt normal again.  I started her up and sure enough, the clutch was working.  Any ideas on what the problem could be?
Thanks in advance!
Title: Re: clutch advice
Post by: Slide Panda on March 16, 2012, 11:28:01 AM
Pedantic moment-
Engaged is when the lever is out and the plates are pressed together applying the power from the engine to the wheel
Disengaged is when the lever is in/to the bar, clutch plates are spread and engine power is not going to the wheels.

So - you clutch would not disengage? If the engine was off, bike in gear and you pulled the lever you could not push it - correct? If that's the case - first thing I'd do is flush the hydraulic system with brad new fluid. 100% flush make sure all the old stuff is out.

It's my suspicion that you have some air in the lines AND very wet brake fluid. Air is compressible - steam is even more so. Knackered fluid can boil water out and create steam bubbles in the line. With enough you can't generate enough pressure to move the slave cylinder.

When the bike and system cools, the steam converts back to liquid and ta-dah the clutch works again.

So new fluid. It's cheap, easy and can be done at home. 
Title: Re: clutch advice
Post by: irridium on March 16, 2012, 11:43:00 AM
Yes, when I was in gear, the lever was out and no power at the wheels until it cooled, then everything worked fine again....
Title: Re: clutch advice
Post by: Drunken Monkey on March 16, 2012, 11:57:16 AM
My vote is for what Sad Panda described. Especially since the bike has been sitting for a while.
Title: Re: clutch advice
Post by: irridium on March 16, 2012, 12:55:31 PM
thanks for the replies!  Will try it out.  Is there a good tutorial on how to change the fluid somewhere?  It's a 2010 696 ABS.
Title: Re: clutch advice
Post by: Roaduser on March 17, 2012, 03:30:52 AM
maybe im reading this wrong, but i read that he is saying that the clutch is not engaging...
Quote from: irridium on March 16, 2012, 11:43:00 AM
Yes, when I was in gear, the lever was out and no power at the wheels until it cooled, then everything worked fine again....

air/water in lines would cause the opposite where the clutch would not disengage... so sounds like a spring or clutch plate issue to me. or maybe the slave cylinder is fulla crap and expanding/sticking when its hot  ???
Title: Re: clutch advice
Post by: brad black on March 17, 2012, 04:07:07 AM
not enough freeplay at the lever also, causing the piston to not return fully and the compensating port to be blocked.  if the port is open any pressure will flow back into the reservoir.
Title: Re: clutch advice
Post by: Thermite on March 17, 2012, 08:28:15 AM
Quote from: Sad Panda on March 16, 2012, 11:28:01 AM
Air is compressible - steam is even more so. Knackered fluid can boil water out and create steam bubbles in the line. With enough you can't generate enough pressure to move the slave cylinder.

When the bike and system cools, the steam converts back to liquid and ta-dah the clutch works again.

SP,  I've seen you post this many times.  The OP's master and clutch lines were <50F and if his slave hangs out like mine the area with fluid in it wasn't much warmer.  I've IR gunned my slave at 145F with the bike at full operating temperature and although it can be hot to touch its never boiling hot.

Is it possible to boil water on our clutch hoses?

C14
Title: Re: clutch advice
Post by: irridium on March 17, 2012, 09:32:51 AM
appreciate the replies, sounds like I'll need to bring it in for servicing.  it's still under warranty, hopefully they won't give me any issues as I moved the bike from the US to Europe.