The brake master cylinder requires brake fluid that meets or exceeds DOT 3 standards.
See Figures 1, 2 and 3
Wipe away any accumulated dirt or grease from the reservoir. Disengage the clamp securing the reservoir cap. Lift the cap up slowly and check the fluid. Add fluid if it is not up to the fill lines marked on the reservoir. Avoid spilling brake fluid on any painted surface as it will harm the finish.