Yamaha YFM660FS Owner's Manual page 139

1. Radiator cap
5. Remove the radiator cap.
6. Remove the coolant reservoir cap.
7. Disconnect the hose on the coolant res-
ervoir side, and then drain the coolant
from the coolant reservoir.
1. Coolant reservoir drain hose
8. After draining the coolant, thoroughly
flush the cooling system with clean tap
water.
9. Replace the coolant drain bolt washer if it
is damaged, and then tighten the coolant
drain bolt to the specified torque.
Tightening torque:
Coolant drain bolt:
10 Nm (1.0 m·kgf, 7 ft·lbf)
8-24