1997 Yamaha YFM600FWAK ATV Service Manual, Page 287Get this manual
ELECTRIC STARTING SYSTEM
5.Measure: Brush length (each) Out of specification Replace the brushBrush length: 12.5 mm (0.49 in) Wear limit: 5 mm (0.20 in
6.Measure: Brush spring force Fatigueout of specification set
Replace as