Yamaha RAPTOR YFM660R Owner's Manual page 316

3. Refill with the same type of brake fluid.
Mixing fluids may result in a harmful
chemical reaction and lead to poor brake
performance.
4. Be careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in vapor lock.
5. Brake fluid may deteriorate painted sur-
faces or plastic parts. Always clean up
spilled fluid immediately.
6. Have a Yamaha dealer check the cause if
the brake fluid level goes down.
8-63