It is tempting to postpone a brake-fluid change when a motorcycle has covered few kilometres in a year. Yet most glycol-based brake fluids gradually absorb moisture from their surroundings even while the bike is parked. Brembo explains that this moisture alters the fluid’s properties. Low mileage alone therefore does not remove the need for brake-system maintenance.
Brake fluid transmits the force from the lever to the calipers. Prolonged or heavy braking heats the system. Water accumulated in the fluid lowers its boiling point; in sufficient heat it can form compressible vapour and compromise the feel of the lever. That is why the date of the last fluid change matters alongside the level in the reservoir. For ordinary road use, Brembo recommends changing the fluid about every one to two years, and more often for intensive track riding.
The practical next step is to consult the motorcycle’s service schedule and required fluid specification, which set the appropriate product and interval for that particular system. If the service history is unclear, establish it before a long ride. Replacing and bleeding brake fluid calls for the correct procedure; a qualified workshop is the sensible choice when there is any doubt. A lever that still feels normal is not, by itself, proof that the fluid is fresh.