Clutch does not disengage

[Mikeyx]

My bike is GasGas EC300, 2009.

The bike was in a cold storage for about 6 months after which the clutch does not disengage at all. There is enough fluid in the reservoir and I bled the slave cylinder. I changed transmission oil. There was plenty of gunk in the plug and the oil was turbid. I have no experience with dirt bikes, so I cannot tell whether the turbidity stemmed from clutch plate material or coolant ingress.

As I depress the clutch lever, I can hear a sound from the clutch casing resembling that of oil passing through an orifice.

Is there anything I can do w/o dismantling the clutch? Since the problem emerged during a long standstill, I am more inclined to believe that something has seized inside the engine, rather than a problem with the clutch slave cylinder.

[barossi73]

Have you had engine running since storage?
Might be worth running it till oil warms up,keep pumping clutch...
With engine off,put in gear and rock forwards/backwards vigorously so clutch gets a jerk in both directions.your plates may be sticking together despite the hydraulics being ok.the hydraulics dont force the plates apart,they just remove the spring tension in the clutch pack which allows plates to slide on each other.if engine runs fine id also consider getting it rolling in neutral then flick into 2nd,ride around for a bit throttling on/off trying clutch.you could also load it up by riding uphill with clutch lever depressed,that might release plates.
Unless it is a hydr problem...some hyd clutch's use mineral oil,not brake fluid.
Synthetic oils absorb moisture so must be changed regularly.could account for state of trans oil

[Mikeyx]

Running the engine thoroughly warm did the trick - thanks.

[Mikeyx]

Coming back to this...

The actual cause was that the adjustment screw on the clutch lever had unwound itself, and hence the master cylinder piston did not go deep enough.