I hate the combination of a short clutch lever with a short clutch arm - I usually swap one or the other out for a longer one. Also, be sure to check that the clutch cable is freely installed without being tied down or bent anywhere.
If you scroll down this page, you can see my method of routing the clutch cable over a roller.
I am not the originator of the design; simply copying someone else's design and modifying it to suit my application.