Yamaha BIG BEAR PROFESSIONAL 400 YFM400FPT Owner's Manual page 260

NOTE:
G
Recommended brake fluid: DOT 4
G
Brake fluid replacement:
• When disassembling the master cylinder or caliper cylinder, replace the brake fluid. Normally check
the brake fluid level and add fluid as required.
• On the inner parts of the master cylinder and caliper cylinder, replace the oil seals every two years.
• Replace the brake hoses every four years, or if cracked or damaged.
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