Follow these steps to flush old fluid and remove trapped bubbles using a motorcycle brake bleeder kit.

Step 1: Prep the Bike and Master Cylinder

1. Park the motorcycle on a level surface or center stand. Turn the handlebars so the front master cylinder reservoir sits level.
2. Cover the gas tank, fairings, and front fender with clean shop rags. Brake fluid acts as a paint stripper.
3. Clean the reservoir cap exterior to keep dirt out, then remove the screws, cap, plastic diaphragm plate, and rubber gasket.

Step 2: Connect the Vacuum Bleeder

1. Slip the correct-sized box wrench over the caliper bleeder nipple.
2. Push the flexible silicone hose of the vacuum bleeder securely over the nipple barb.
3. Ensure the collection bottle is placed upright so fluid does not enter the pump mechanism.

Step 3: Draw the Vacuum and Flush Fluid

1. Pump the vacuum bleeder until the gauge registers negative pressure (approx. 10–15 inHg).
2. Open the caliper bleeder valve by turning the wrench roughly a 1/4 to 1/2 turn counterclockwise.
3. Watch the fluid flow through the clear tubing into the catch bottle. Keep drawing vacuum to pull out aerated, dark fluid.

Step 4: Monitor the Master Cylinder Level

1. Never let the master cylinder reservoir run dry. As fluid gets drawn into the collection bottle, pour fresh fluid into the top reservoir continuously.
2. Continue the process until the fluid flowing through the clear discharge tube is clear, bright, and free of air bubbles.

Step 5: Tighten and Seal

1. Tighten the bleeder valve snug while the system is still under slight vacuum, then remove the silicone tubing.
2. Top off the master cylinder to the designated upper fill line, reinstall the rubber diaphragm and cap, and secure the screws.
3. Pump the handlebar lever 3–4 times. It should feel firm, not spongy.
4. Wipe down the caliper bleeder valve with isopropyl alcohol and reinstall the rubber dust cap.