Changing the span adjuster (outwards) would allow you to pull the lever further thus disengaging the clutch further.
Could be several things, clutch slave cylinder (is it leaking, or an aftermarket version?) could be air in the line, could be your clutch basket being worn, and sticking when disengaging.
Could be the selector forks in your gearbox
How old and how many miles has your bike covered?
Several things to go on there...