Bleeding the Brakes on a 2014 Kawasaki Ninja 300 ABS

Shop parts for a 2014 Kawasaki EX300 - Ninja 300 ABS Motorcycle.

What This Job Covers on the Ninja 300 ABS

The 2014 Kawasaki EX300 Ninja 300 ABS uses hydraulic disc brakes at both ends, and the ABS designation confirms that an anti-lock braking system is part of the hydraulic layout. That gives you two separate circuits to service: a front circuit operated by the lever and a rear circuit operated by the pedal. Bleeding means pushing fresh fluid through each circuit while expelling air and old, moisture-contaminated fluid. It is not the same as replacing pads or rotors, though a pad, line, or caliper service is a common reason bleeding becomes necessary afterward.

On an ABS-equipped bike, a normal bleed at the caliper bleeders is the correct approach for routine fluid refresh and for air that entered at the caliper or line during ordinary service. If the reservoir ran dry, or if the ABS unit or its lines were disconnected, air may be trapped inside the ABS unit itself. That situation can require a dealer-level procedure or diagnostic tool, so stop and have the bike serviced by a shop rather than trying to force it out through the calipers.

When Bleeding Is Needed

A spongy or soft lever or pedal is the classic sign that air is in the system. So is a lever that pulls closer to the grip than it used to, or a pedal that feels vague before the brakes bite. Dark or cloudy fluid in the reservoir is another reason to bleed, even if the brakes still feel acceptable. Brake fluid absorbs moisture over time, which lowers its boiling point and can lead to brake fade under hard use, so many riders refresh the fluid on a regular schedule rather than waiting for a symptom. Bleeding is also required after any work that opened the hydraulic system, such as new lines, caliper service, or master cylinder work.

Tools and Supplies

  • Fresh brake fluid of the type marked on the master cylinder reservoir cap, from a sealed container
  • A box-end wrench that fits the bleeder valve
  • A length of clear tubing that fits snugly over the bleeder
  • A catch bottle for the old fluid
  • Rags or shop towels
  • A syringe or turkey baster for removing old fluid from the reservoir
  • A screwdriver or driver that fits the reservoir cap screws
  • Optional: a one-way check-valve bleeder or vacuum bleeder to make the job easier for one person

Preparation Before You Open the Reservoir

Support the bike securely upright on a stand so it cannot tip while you are working. Turn the handlebars so the front reservoir sits level before you open it. Cover painted surfaces, plastics, and the instrument area with rags, because most brake fluids damage paint and plastic on contact. If a spill happens, wipe it up immediately and rinse the area with water. Locate the rear reservoir as well, since the rear circuit has its own fluid supply and cap. Work in a well-ventilated area and keep the fluid container closed when you are not pouring from it.

Bleeding the Front Brake

  1. Open the front reservoir and use the syringe or turkey baster to remove most of the old fluid. Do not let the reservoir run dry.
  2. Refill the reservoir with fresh fluid of the type marked on the cap, leaving room for the diaphragm and cap to be reinstalled later.
  3. Attach the clear tubing to the front caliper bleeder valve and route the other end into the catch bottle.
  4. Squeeze and hold the front lever. Keep steady pressure on it.
  5. Open the bleeder about a quarter turn to let fluid and air escape through the tube. Close the bleeder before you release the lever.
  6. Release the lever, then repeat the squeeze-hold-open-close sequence. Check the reservoir often and top it off so it never draws air.
  7. Continue until fresh, clean, bubble-free fluid comes through the tube. If your bike has two front calipers, bleed each one in turn, starting with the caliper farthest from the master cylinder.

Bleeding the Rear Brake

  1. Open the rear reservoir and remove most of the old fluid without letting the reservoir run dry.
  2. Refill with fresh fluid of the type marked on the cap.
  3. Attach the clear tubing to the rear caliper bleeder valve and route it into the catch bottle.
  4. Press and hold the rear pedal.
  5. Open the bleeder about a quarter turn, let fluid and air out, then close the bleeder before releasing the pedal.
  6. Release the pedal and repeat. Keep the rear reservoir topped off throughout, since it is easy to drain a small reservoir quickly.
  7. Stop when the fluid in the tube is clean and free of bubbles.

Finishing, Testing, and Troubleshooting

Tighten each bleeder snugly without overtightening. Fill the reservoir to the correct level marking, reinstall the diaphragm and cap, and clean any spilled fluid. Check for leaks at the bleeder and at the banjo fittings. Before riding, the lever and pedal should feel firm and consistent, not spongy, and they should not slowly sink under steady pressure. Spin each wheel to confirm the brakes are not dragging. Test the brakes at low speed in a safe area before riding normally.

If the lever or pedal will not firm up after several bleeding attempts, if it firms only after pumping, if bubbles keep appearing, or if fluid leaks from the master cylinder or caliper, stop and diagnose the problem. Any situation where air may have entered the ABS unit, or where the reservoir ran dry, is best handled by a shop with the correct equipment. A brake system that will not hold pressure is not safe to ride.

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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.