Is this while its runnig or not, sometimes the cluctch wont engage while the bike is not runnig, but will engage when running. its common. if not they may just be stuck. did you drain the oil and have the plates exsposed to elements while the engine was out of the frame. open the clutch plate cover, check that they look fine. other than that if the clutch is hydrolic check for air in the system. and also the fluid level. good look.