Sherco clutch

Hi, I also need your help please. I have a sherc o SE R 300, the clutch on it is the standard one, with springs. I can't slide the clutch on any climb, if I hold it down it doesn't work, if I let go the motorcycle rises on one wheel.
I understood that the problem would be the clutch with springs, if you can help me with an advice on what I could modify to make it work normally.