First thing to check is that there is no roughness on billhook assembly - polish with very fine emery cloth... Check to see that wiper/knife arm is making proper contact with heel of billhook for entire swipe of the arm. Make sure arm is completing the entire swipe clear past the billhook end. Make sure the hook assembly has enough space to allow the twine ends to slide out and under. Is twine tension too tight such that the twine is not being pulled too tight around billhook assy in the knotting cycle. Check entire twine path for smooth flow of twine from ball in box clear through to the knotter. Check twine fingers for proper travel in their cycle.
Did I miss anything, guys?