Honda TALON 2021 Owner's Manual page 168

3. Remove the front hood (page 129).
4. Remove the reserve tank cap.
Always add coolant to the reserve tank. Do not attempt to add
coolant by removing the radiator cap.
UNDER FRONT HOOD
RIGHT FRONT
reserve tank cap
5. Add coolant to the reserve tank as required to bring the coolant
level to the MAX level mark.
6. After adding coolant, install the reserve tank cap and install the
front hood.
Coolant
Servicing Your Honda 161