Honda CB650R 2021 Owner's Manual page 92

Coolant Adding Coolant
u
Remove the reserve tank cap and add
1.
fluid while monitoring the coolant level.
Do not overfill above the UPPER level
u
mark.
Make sure no foreign objects enter the
u
reserve tank opening.
Securely reinstall the reserve tank cap.
2.
WARNING
3
Removing the radiator cap while the
engine is hot can cause the coolant to
spray out, potentially scalding you.
Always let the engine and radiator cool
down before removing the radiator cap.
88
UPPER level
Reserve tank cap