Bleeding the Brakes on a 2013 Kawasaki Ninja 300
Shop parts for a 2013 Kawasaki EX300 - Ninja 300 Motorcycle.
The 2013 Kawasaki Ninja 300 runs hydraulic disc brakes at both ends, so this is a two-part job: the front system fed by the lever-mounted master cylinder, and the rear system driven by the pedal master cylinder. Both use brake fluid, both collect moisture over time, and both benefit from a proper flush and bleed. ABS was an option on this model year, which changes one part of the conversation but not the basic procedure. Set aside a couple of hours, work slowly, and treat every drop of fluid as something that will damage paint if you let it sit.
First, Confirm What Your Ninja 300 Is Working With
Walk around the bike before you touch a tool. The front brake is hydraulic on every 2013 EX300, and so is the rear — there is no cable-operated drum hiding back there, so both circuits get bled. The front lever operates the front brake only and the rear pedal operates the rear brake only; this is a conventional, separate system rather than a linked one, so you can treat each circuit as its own self-contained job.
Next, check for ABS. If your bike has it, you will typically find an ABS indicator on the dash and a modulator unit plumbed into the lines. A standard bleed at the caliper bleeders is still the right way to refresh fluid and clear air from the calipers and lines. What you should not attempt at home is purging air that has worked its way into the ABS unit itself — that happens when the reservoir runs dry, when a line is disconnected, or when the modulator is removed. If any of those apply, stop and take the bike to a shop with the appropriate diagnostic equipment. A lever that never firms up on an ABS bike is a strong hint that this is the situation.
Signs the System Is Asking for a Bleed
The classic symptom is a lever that feels soft or spongy and pulls closer to the grip than it used to. A lever that slowly sinks while you hold steady pressure is another red flag, and so is a pedal with more travel than you remember. Pull the reservoir cap and look at the fluid: fresh fluid is clear and pale, while fluid that has been in service for a few seasons turns dark, cloudy, or murky.
Brake fluid is hygroscopic, meaning it absorbs moisture from the air over time. That moisture lowers the fluid's boiling point, and under hard or repeated braking it can boil and create gas in the system — which feels exactly like air in the lines. Many riders refresh the fluid on a regular interval as preventive maintenance rather than waiting for a symptom. You should also bleed after any work that opened the hydraulic system: new lines, caliper service, or master cylinder work.
Tools and Supplies to Have Ready
- Fresh brake fluid of the type marked on your master cylinder reservoir cap, from a sealed container
- A box-end wrench that fits the bleeder valve snugly
- Clear tubing that fits tightly over the bleeder nipple
- A small catch bottle for the old fluid
- Rags or shop towels, plus something to drape over painted and plastic surfaces
- A syringe or turkey baster for pulling old fluid out of the reservoir
- The correct driver for the reservoir cap screws
A one-way check-valve bleeder or a vacuum bleeder makes the job much easier when you are working alone, since you are not trying to coordinate a wrench, a lever, and a bottle all at once.
Setting Up So You Do Not Damage Anything
Get the bike secure and upright on a stand. On the front circuit, turn the handlebars so the reservoir sits level before you open it — a tilted reservoir spills. Drape rags over the tank area, the fairing panels, the instrument cluster, and anything else below the reservoir and calipers. Brake fluid attacks paint and many plastics on contact, so wipe up any spill immediately and rinse the area with water rather than letting it sit.
The Bleeding Procedure, Step by Step
- Open the reservoir and use the syringe or baster to draw out most of the old fluid. Leave a little at the bottom so you do not push air into the master cylinder.
- Refill with fresh fluid from the sealed container, using the type printed on the reservoir cap.
- Push the clear tubing onto the bleeder valve and route the other end into the catch bottle, positioned so you can watch the fluid and any bubbles coming through.
- Slide the box-end wrench onto the bleeder.
- Squeeze the front lever firmly and hold it. For the rear, press and hold the pedal.
- Open the bleeder about a quarter turn. Fluid and air will push out through the tube.
- Close the bleeder before you release the lever or pedal. Releasing first draws air back in through the bleeder.
- Release the lever or pedal slowly and repeat the squeeze-open-close-release cycle.
- Check the reservoir level every few cycles and top it off. Never let it run low enough to draw air into the master cylinder.
- Keep going until clean, fresh fluid with no bubbles comes through the tube, then move to the other circuit.
If your bike has two front calipers, bleed each one in turn rather than trying to do both at once. As a general practice, start with the caliper farthest from the master cylinder and work toward the closest.
Finishing Up and Proving the Job Is Done
Tighten the bleeder snugly with the box-end wrench — firm enough to seal, but not so hard that you damage the seat. Fill the reservoir to the correct level marking, reinstall the diaphragm and cap, and wipe down every surface you touched. Look for weeping fluid at the bleeder and at the banjo fittings.
Before you ride, the lever and pedal should feel firm and consistent, not spongy, and should hold steady rather than sinking under sustained pressure. Spin each wheel to confirm the brakes are not dragging. Then test at low speed in a safe, open area before riding normally.
If the lever will not firm up after several attempts, if it only firms up after pumping, if bubbles keep appearing, or if you find fluid leaking from the master cylinder or a caliper, stop and have the system inspected. On an ABS-equipped bike, any suspicion that air reached the modulator is a shop job, not a garage job.
Related Shopping Categories
Shop Brake Fluid for a 2013 Kawasaki EX300 - Ninja 300 Motorcycle.
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Shop Stands for a 2013 Kawasaki EX300 - Ninja 300 Motorcycle.
Shop Brake Tools for a 2013 Kawasaki EX300 - Ninja 300 Motorcycle.
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.