Clutch 1050 st

What I think is that you need to adjust the clutch cable to take up some of the slack. Do it in small amounts until you are confident the clutch is working correctly.

 

You should have between 1 and 2 mm free play max. I believe you can adjust at each end if you have run out of adjstment at the lever. Could also be a sign the cable is starting to fail or sticking.
If the levers have been replaced with adjustable span levers maybe the previous owner didnt put the brass bush in which fits round the pivot screw