You're gonna get a bunch of way more knowledgeable folks than me that chime in on this. But the first thing I'd look at would be the cable adjustment for the clutch lever. Mostly the lower adjustment. It is pulling the clutch arm enough to disengage the clutch? With help from a friend holding the rear wheel up you could move the clutch arm by hand and see where it needs to get to disengage the clutch. If the cable doesn't move it enough, adjust the cable. If the cable adjustment doesn't get it where it needs to be, take off the clutch cover and tighten the flower nut enough where it puts the throw of the clutch lever tight enough that the hand lever can achieve the throw or amount of movement needed to disengage the clutch.