Bleeding the Brakes on a 2020 Kawasaki W800 (EJ800)
Shop parts for a 2020 Kawasaki EJ800 - W800 Motorcycle.
Start With the W800's Actual Brake Layout
Before you pick up a wrench, know what you're working on. The 2020 Kawasaki W800 (EJ800) runs hydraulic disc brakes at both ends — a single front disc and caliper fed by the handlebar master cylinder, and a single rear disc with its own master cylinder operated by the pedal. The bike also carries anti-lock braking. That ABS detail changes exactly one thing: a routine flush through the caliper bleeders is precisely what you want for refreshing fluid, but if air has found its way into the ABS unit itself — the reservoir ran dry, a hose was disconnected, the ABS hardware was removed or replaced — the system may need a dealer-level procedure or a diagnostic tool to purge properly. That is not a job to improvise in a home garage.
Why and When to Bleed
Brake fluid is hygroscopic, meaning it pulls moisture out of the air over time. Moisture lowers the fluid's boiling point, and boiling fluid creates gas bubbles in the lines — the same practical effect as air trapped in the system. Under hard, repeated braking that shows up as a lever that goes soft or a pedal that sinks toward the end of its travel. Even if you never notice a symptom, refreshing the fluid on a sensible interval is cheap insurance against a surprise.
Bleed the brakes when the lever or pedal feels spongy, when the lever travels closer to the grip than it used to, when the fluid in the reservoir looks dark or cloudy, or after any work that opened the hydraulic circuit — new lines, caliper service, master cylinder work. A lever that firms up only after several pumps is a classic air-in-the-system symptom.
Tools and Supplies to Have Ready
- Fresh brake fluid of the type marked on the master cylinder reservoir cap, poured from a sealed container. Don't substitute a different type, and don't use a bottle that's been sitting open on the shelf.
- A box-end wrench that fits the bleeder valve snugly. A six-point box end grips better than an open end and is far less likely to round the bleeder.
- Clear tubing that fits tightly over the bleeder nipple, plus a catch bottle to route the old fluid into.
- Rags or shop towels, and a syringe or turkey baster for pulling old fluid out of the reservoir.
- The correct driver for the reservoir cap screws.
- Optional but genuinely helpful: a one-way check-valve bleeder or a vacuum bleeder, which makes a one-person job much less fiddly.
Setting Up Without Damaging the Bike
Get the bike upright and stable on a stand. For the front, turn the handlebars so the reservoir sits level — a tilted reservoir lets fluid spill the moment you open it. Lay rags over the tank, the plastics, the instrument cluster, and anything else below the reservoir, because brake fluid attacks paint and plastic on contact. If a drop lands on a painted surface, wipe it up immediately and rinse the area with water.
Bleeding the Front Brake
- Clean the reservoir cap and the area around it, then remove the cap and the diaphragm.
- Draw most of the old fluid out of the reservoir with the syringe, leaving a little at the bottom so you don't push air into the master cylinder.
- Top up with fresh fluid.
- Push the clear tubing onto the caliper bleeder and run the other end into the catch bottle, routed so you can watch the fluid come out.
- Fit the box-end wrench onto the bleeder.
- Squeeze the front lever slowly and hold it against its stop.
- Open the bleeder about a quarter turn. Fluid and any trapped air will push out through the tube.
- Close the bleeder before you release the lever. Releasing with the bleeder open draws air straight back in.
- Release the lever slowly and let it return on its own.
- Check the reservoir and top it up. Repeat the squeeze-hold-open-close-release cycle, keeping the reservoir at least half full the entire time.
- Keep going until the fluid coming through the tube is clean and free of bubbles, then close the bleeder.
If you're working on a variant with more than one front caliper, bleed each caliper in turn, starting with the one farthest from the master cylinder.
Bleeding the Rear Brake
- Clean and open the rear reservoir, remove the diaphragm, and draw out the old fluid.
- Refill with fresh fluid, then fit the tubing and catch bottle to the rear caliper bleeder.
- Press and hold the brake pedal.
- Open the bleeder a quarter turn, let fluid and air escape, then close it before releasing the pedal.
- Release the pedal, top up the reservoir, and repeat until the fluid runs clean and bubble-free.
Finishing the Job
Tighten the bleeder snugly — firm, not cranked down hard, since overtightening can damage the seat. Fill the reservoir to the level marking, reinstall the diaphragm and cap, and wipe away any fluid residue. Look closely at the bleeder and at the banjo fittings at the master cylinder and caliper for weeping or wetness. Pump the lever and pedal a few times and recheck.
Testing Before You Ride
The lever and pedal should feel firm and consistent, and should hold pressure without slowly sinking. Spin each wheel and confirm the brake isn't dragging. Then ride at low speed in a safe, empty area and test the brakes gently before riding normally.
When to Stop and Take It to a Shop
If the lever won't firm up after several rounds of bleeding, if it only firms after pumping, if bubbles keep appearing no matter how long you bleed, or if you see fluid at the master cylinder or caliper, stop and have the bike inspected. Any situation where air may have entered the ABS unit also belongs with a shop that has the right equipment.
Related Shopping Categories
Shop Brake Fluid for a 2020 Kawasaki EJ800 - W800 Motorcycle.
Shop Brake Lines for a 2020 Kawasaki EJ800 - W800 Motorcycle.
Shop Brake Pads for a 2020 Kawasaki EJ800 - W800 Motorcycle.
Shop Stands for a 2020 Kawasaki EJ800 - W800 Motorcycle.
Shop Brake Tools for a 2020 Kawasaki EJ800 - W800 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.
