I just put a 2000 bottom end on a 89 banshee. runs fine. But when I pull clutch in and shift to 1st, it takes off while clutch is still in. I see the clutch lever on engine moving about an inch and I have the clutch all the way out for adjustment. Do I need a shorter clutch cable to give it more throw? or are the clutches bad?

 

Sounds like you may have missed a washer on the install. Heres a clutch assembly vid if you wanna check it out. Did you set the clutch adjustment? Its included in the vid.
Yamaha Banshee Clutch Side Assembly How to - YouTube