Are there some holes in the drive sprockets? I can't remember tbh.Just out of interest what timing marks are used for the knotters. I know the notches for the crank and packers but couldn't see anything for the knotters. Worked on one the other day that was breaking shear bolts because the knotters were a bit behind and the ram stop wasn't coming out in time. I just advanced the knotters 2 teeth until the ram stop cleared and its been fine since.