2004 Official factory service manual for Yamaha YFZ450S ATV Quad., Page 106Get this manual
CHECKING THE FRONT BRAKE PADS CHECKING THE REAR BRAKE PADS
2Check: brake pads Wear indicators almost touch the brake disc Replace the brake pads as setRefer to "FRONT AND REAR BRAKES" in chapter 7Brake pad wear limit 1.0 mm (0.04 in) 3Operate the brake lever4Install: front wheels Refer to "FRONT AND REAR WHEELS" in chapter 7