Honda CBR 125RW 2007 Owner's Manual page 93

Coolant
1. With the engine at normal operating
temperature, check the coolant level in
the reserve tank ( 1). It should be
between the UPPER (2) and LOWER
(3 ) level marks.
If the reserve tank is empty, or if
coolant loss is excessive, check for
leaks and see your Honda dealer for
repair.
2. Remove the front seat (page 69 ).
(4)
(4) reserve tank cap
3. Remove the reserve tank cap (4 ).
Always add coolant to the reserve tank.
Do not attempt to add coolant by
removing the radiator cap.
4. Add coolant to the reserve tank as
required to bring the coolant level to the
UPPER level mark.
Servicing Your Honda 83