1991-1993 Yamaha Exciter II-570 Service Manual, Page 347Get this manual
IENG ENGINE ASSEMBLY AND ADJUSTMENT Screw (stator plate): Nm (0.7 kg, 5.1 ft Ib) 2Install: Magneto rotor Washer Nut (magneto rotor)
Pass the magneto leads through the hole, and install the grommet into the crankcase
Be sure to remove any oil andor grease from the tapered portion of the magneto rotor using dampened cloth with thinner