Aprilia's high-performance RSV Mille and Tuono motorcycles were equipped with Brembo brake calipers to provide ultimate braking performance on the street or racetrack. When these bikes are ridden aggressively, the single Brembo caliper mounted on the right side of the rear wheel can generate a significant amount of heat that creates condensation in the rear brake fluid. An excessive build-up of condensation will weaken the brake fluid's hydraulic properties, as is indicated by a soft-feeling brake pedal. The condition will continue to worsen over time unless the contaminated fluid is flushed, or bled, out through a valve built into the rear brake caliper.
Mount the motorcycle on a rear stand to support it in an upright position.
Remove the right side fairing panel bolts, using a 5mm Allen wrench. Pull the fairing away to reveal the rear master cylinder fluid reservoir mounted on the right engine crankcase cover. This step applies only to RSV Mille models.
Unscrew the rear master cylinder reservoir lid screws, using a Phillips screwdriver. Pull the lid and the inner diaphragm out of the reservoir. Fill the reservoir with DOT 3 or 4 brake fluid until the fluid level is even with the "Full" mark imprinted into the side of the reservoir.
Pull the rubber dust boot off the bleed valve located on the lower edge of the rear brake caliper. Clean the rear brake caliper, the caliper bleed valve and the surrounding area with a damp shop towel to prevent dirt and debris from entering into the rear brake caliper.
Slip a 10mm box-end wrench over the bleed valve, then push a 2-foot length of clear 1/4-inch inner diameter plastic tubing over the bleed valve outlet. Place the opposite end of the tubing into a small plastic bottle.
Turn the bleed valve counterclockwise a quarter-turn with your wrench to open the valve. Push down on the rear brake pedal to force a small amount of brake fluid out of the caliper and into the plastic tubing. Hold the brake lever in place and turn the bleed valve clockwise a quarter-turn to close the valve. Release the brake pedal slowly to draw in fresh fluid from the master cylinder reservoir.
Refill the rear master cylinder reservoir with DOT 3 or 4 brake fluid.
Open the bleed valve again with your 10mm box-end wrench, then push down on the rear brake pedal. Close the valve with your wrench after tubing has filled with more brake fluid, then slowly release the brake pedal. Repeat until the brake fluid is clear and free of air bubbles.
Tighten the bleed valve against the rear brake caliper, using your 10mm box-end wrench. Pull the plastic tubing off of the bleed valve, using a damp shop towel. Wipe away any spilt brake fluid immediately with the shop towel. Push the rubber dust boot over the bleed valve.
Refill the rear master cylinder reservoir with DOT 3 or 4 brake fluid until the fluid level is centred at the reservoir's midpoint. Push the inner diaphragm into the reservoir and reinstall the reservoir lid, using a Phillips screwdriver.
Reinstall the right side fairing panel onto the motorcycle. Screw the fairing bolts into place, using a 5mm Allen wrench. This step applies only to RSV Mille models.
Remove the rear stand and lower the motorcycle onto its kickstand.
Brake fluid is a solvent that can cause permanent damage to painted surfaces. Cover any sensitive areas with plastic dust sheets and wipe up spills immediately with a damp towel to avoid damaging your Aprilia motorcycle's fairings.