How To Bleed 2022 Kawasaki EJ800 - W800 Motorcycle Brakes

Bleeding the Brakes on a 2022 Kawasaki W800 (EJ800)

The 2022 Kawasaki EJ800 – W800 uses hydraulic disc brakes at both ends and is equipped with ABS. That means the front lever and rear pedal each push fluid through a sealed hydraulic circuit, and both circuits need periodic bleeding to stay firm and responsive. The rear brake is not a mechanical drum, so it is bled like the front rather than adjusted with a cable. Because the W800 uses separate front and rear systems, you will service each end independently. The job is well within reach for a DIY rider with basic hand tools, provided you work methodically and never let the reservoir run dry.

Why and When the W800 Needs a Brake Bleed

Bleeding does two things: it removes air that has entered the hydraulic system, and it replaces old fluid with fresh fluid. Air is compressible, so even a small bubble can make the lever or pedal feel spongy, pull closer to the grip than it used to, or sink slowly under steady pressure. Old fluid is a quieter problem. Brake fluid absorbs moisture over time, which lowers its boiling point and can lead to brake fade under hard or repeated use. Dark, cloudy, or contaminated fluid in the reservoir is a clear sign that a flush is due.

You should also bleed the brakes after any work that opened the hydraulic system, such as installing new brake lines, servicing a caliper, or repairing the master cylinder. Many riders refresh brake fluid on a regular schedule even when the brakes still feel normal, because moisture uptake happens gradually and does not always produce an obvious symptom. On an ABS-equipped W800, a standard bleed through the caliper bleeders is generally enough to refresh fluid and remove air from the lines and calipers. If the reservoir has run dry, or if the ABS unit or its lines have been disconnected, air may have entered the ABS unit itself. That situation may require a dealer-level procedure or diagnostic tool, and the bike should go to a shop rather than being bled at home.

Tools and Supplies to Have Ready

• 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 used 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

A one-way check-valve bleeder or a vacuum bleeder can make the job easier when you are working alone, but the manual lever-and-bleeder method works fine if you take your time. Keep the catch bottle stable and route the clear tube so it slopes upward away from the bleeder before dropping into the bottle; that helps you see bubbles and keeps air from being drawn back in.

Setting Up the Bike and Protecting It

Support the W800 securely upright on a stand so it cannot tip while you are working. For the front circuit, 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. Brake fluid is also harmful to eyes and skin, so work carefully and keep it away from children and pets.

Before opening the reservoir, clean around the cap so dirt does not fall into the fluid. Remove the cap and diaphragm, then use the syringe or turkey baster to take out most of the old fluid. Do not pump the lever or pedal while the reservoir is open and low, and do not let the reservoir run dry at any point during the bleed. Once air is drawn into the master cylinder, you will have to bleed that much longer to get it out.

Bleeding the Front and Rear Brakes Step by Step

1. Remove most of the old fluid from the front reservoir, then refill it with fresh fluid of the type marked on the cap. Leave enough room to add more fluid as you work.
2. Fit the box-end wrench over the front caliper bleeder, then push the clear tubing onto the bleeder and route the other end into the catch bottle.
3. Squeeze and hold the front lever. With the lever held, open the bleeder about a quarter turn and let fluid and air escape through the tube.
4. Close the bleeder before you release the lever. Releasing the lever with the bleeder open can draw air back into the caliper.
5. Repeat the squeeze-hold-open-close-release sequence, topping off the reservoir as needed, until fresh, clean, bubble-free fluid comes through the tube.
6. If your W800 has a second front caliper, bleed each caliper separately. As a general practice, start with the caliper farthest from the master cylinder and finish with the closer one.
7. Move to the rear circuit. Remove most of the old fluid from the rear reservoir, refill with fresh fluid, and attach the clear tube and wrench to the rear caliper bleeder.
8. Press and hold the rear pedal, open the bleeder about a quarter turn, let fluid and air out, then close the bleeder before releasing the pedal. Repeat until the fluid runs clean and bubble-free, keeping the rear reservoir topped off throughout.

Check the lever and pedal feel as you go. A firm, consistent lever is the goal; a lever that still feels spongy after several rounds usually means more air is still in the system or the reservoir has been allowed to draw air in.

Finishing Up and Checking for Leaks

When both circuits run clean and bubble-free, tighten each bleeder snugly without overtightening. Fill each reservoir to the correct level marking, reinstall the diaphragm and cap, and clean any spilled fluid from the calipers, lines, and reservoir area. Check for leaks at the bleeder valves and at the banjo fittings. A dry fitting after several firm lever or pedal applications is a good sign; a weep or wet spot means you need to address it before riding.

Testing Before You Ride

The front lever and rear 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, and make sure the bike stops smoothly and straight. If anything feels vague, soft, or inconsistent, do not ride the bike until you have found the cause.

Troubleshooting and When to See a Shop

A lever that will not firm up after several bleeding attempts, a lever that firms up only after pumping, persistent air bubbles, or fluid leaking from the master cylinder or caliper all point to a problem that needs more diagnosis. On an ABS-equipped W800, any situation where air may have entered the ABS unit — such as a reservoir that ran dry or ABS lines that were disconnected — is best handled by a shop with the correct diagnostic equipment. If you are not confident in the result, stop and have the system inspected before riding.

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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.