2004 Official factory service manual for Yamaha YFZ450S ATV Quad., Page 238Get this manual
FRONT AND REAR WHEELS
INSTALLING THE FRONT WHEEL HUB BEARINGS 1Install: bearings NOTE: Face the oil seal side of the bearing inward
INSTALLING THE FRONT BRAKE DISCS 1Install: brake discs NOTE: Install the brake disc with its spot-faced side facing the bolt heads