Yamaha YZ450FW Manuel D'atelier Du Proprietaire page 500

FRONT FORK
Base valve
1. Inspect:
• Base valve 1
Wear/damage → Replace.
Contamination → Clean.
• O-ring 2
Wear/damage → Replace.
• Piston metal 3
Wear/damage → Replace.
• Spring 4
Damage/fatigue → Replace base valve.
• Air bleed screw 5
Wear/damage → Replace.
Collar
1. Inspect:
• Piston metal 1
Wear/damage → Replace.
EC554400
Fork spring
1. Measure:
• Fork spring free length a
Out of specification → Replace.
Fork spring free length:
Standard
454 mm (17.9 in)
5 - 31
CHAS
<Limit>
449 mm (17.7 in)