2001 Yamaha YFM660 Raptor Factory Service Manual, Page 231Get this manual
INSTALLING THE PRIMARY DRIVE GEAR AND BALANCER DRIVEN GEAR 1.Install: Dowel pin Spring Balancer drive gear (onto the primary drive gear) NOTE: Align the punch mark on the balancer drive gear with the punch mark on the primary drive gear
2.Install: Primary drive gear Balancer driven gear NOTE: Align the punch mark on the balancer driven gear with the punch mark on the primary drive gear
3.Tighten: Balancer driven gear nut 1