I had the same problem. Make sure the slave cylinder isn't leaky to begin with and you get a good bleed on it. Also grease up that little hole on the clutch fork while you're down there so you don't eventually get that squeaking cacophony.
Didn't think that was a part that needed greasing, but it makes sense. I think if bleeding the clutch doesn't work I will machine something to fit in between the slave cylinder rod and clutch fork. I wouldn't have thought of it if you didn't mention greasing it up. Thanks :laugh: