I have a 2002 kx 250.it is a good bike but the clutch is messed I think.it doesn't feel like it's slipping but when I am starting from stopped if I don't rev it realy hight it stalls.when I am relesing the clutch it doesn't feel like it's engaging until it is all the way out then it grabs.when it grabs it doesn't ease on like normal it just goes from fully dissingaged to fully engaged all at once.it is imposible toi start without getting jerked back.what's wrong?.thanx