Bleeding the Brakes on a 2020 Honda Monkey ABS
Shop parts for a 2020 Honda Monkey ABS Motorcycle.The 2020 Honda Monkey ABS uses hydraulic disc brakes at both ends, with separate front and rear hydraulic circuits and an ABS unit in the system. That means a complete fluid refresh or air-removal job can involve both the front caliper and the rear caliper. For routine fluid replacement, a standard bleed through the caliper bleeder valves is generally the right approach. If the reservoir has run dry, the ABS unit or its lines have been disconnected, or you suspect air has traveled into the ABS hardware itself, stop and have the bike serviced by a shop with the appropriate diagnostic equipment. The Monkey ABS is a small, simple street bike, but the ABS module is not a component to experiment with in a home garage.
When a Brake Bleed Is Due
Bleeding is not only for a brake system that has been opened for repairs. Brake fluid absorbs moisture over time, which lowers its boiling point and can make the brakes feel less consistent during hard or repeated use. A spongy lever, a front brake lever that pulls closer to the grip than it used to, a rear pedal that feels soft or travels farther than normal, or dark and cloudy fluid in either reservoir are all signs that fresh fluid and a proper bleed are due. The job is also necessary after installing new brake lines, servicing a caliper, replacing a master cylinder, or any other work that let air into the hydraulic system. Many riders refresh brake fluid on a regular schedule even when the brakes still feel acceptable, because clean fluid is cheap insurance for a safety-critical system.
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 on the caliper
- A length of clear tubing that fits snugly over the bleeder valve
- A clean catch bottle for old fluid
- Rags or shop towels, plus a syringe or turkey baster for removing old fluid from the reservoir
- A screwdriver that fits the reservoir cap screws
- Optional: a one-way check-valve bleeder or vacuum bleeder to make one-person bleeding easier
Use only fluid from a freshly opened container, and do not reuse fluid that has been bled out. Keep the container capped when it is not in use, and dispose of old fluid properly.
Preparation and Paint Protection
Support the Monkey securely upright on a stand so it cannot tip while you are working at the bars or the rear caliper. Turn the handlebars so the front reservoir sits level before you open it. Brake fluid damages paint, plastic, and instrument lenses on contact, so cover the area around each reservoir, the handlebar controls, the bodywork, and any painted surfaces below the work area with rags or shop towels. If a spill happens, wipe it up immediately and rinse the area with water. Work in a well-ventilated space, and keep the reservoir cap and diaphragm clean once they are removed.
The Bleeding Procedure
- Work on one hydraulic circuit at a time. Start with the front brake, then repeat the same process for the rear brake.
- Remove the reservoir cap and diaphragm, then use a syringe or turkey baster to draw most of the old fluid out of the reservoir. Do not let the reservoir run dry at any point.
- Refill the reservoir with fresh fluid of the type marked on the cap, leaving enough room to reinstall the diaphragm later.
- Push the clear tubing onto the caliper bleeder valve and route the other end into the catch bottle. Make sure the tubing fits snugly so air cannot be drawn in around it.
- Fit the box-end wrench onto the bleeder valve. Squeeze and hold the front brake lever, or press and hold the rear brake pedal, and keep steady pressure on it.
- Open the bleeder valve about a quarter turn. Fluid and air will flow through the tubing. Watch the tube, not the reservoir, while the bleeder is open.
- Close the bleeder valve before you release the lever or pedal. Releasing first can draw air back into the caliper.
- Check the reservoir level and top it off with fresh fluid. Repeat the squeeze, hold, open, close, and release sequence until clean, fresh fluid with no bubbles comes through the tubing.
- If your bike has two front calipers, bleed the caliper farthest from the master cylinder first, then bleed the other one. This Monkey uses a single front caliper, so you will service that caliper and then move to the rear circuit.
- For the rear brake, repeat the same steps using the rear brake pedal and the rear caliper bleeder valve. Keep the rear reservoir topped off throughout.
- When the fluid runs clear and bubble-free at each caliper, close the bleeder snugly. Do not overtighten it; snug is enough to seal it without damaging the valve.
- Refill each reservoir to the correct level marking, reinstall the diaphragm and cap, and wipe away any fluid residue from the calipers, lines, and reservoir area.
Finishing Checks and Test Ride
After the bleed, check for leaks at the bleeder valves and at the banjo fittings where the brake lines attach. The front lever and rear pedal should feel firm and consistent, not spongy, and they should not slowly sink while you hold steady pressure. Spin each wheel to confirm the brakes are not dragging. Before riding normally, test the brakes at low speed in a safe area, such as an empty parking lot, and make sure both ends slow the bike smoothly and predictably. If either brake feels different from what you expect, do not ride the bike until the issue is resolved.
Troubleshooting and When to See a Shop
A lever or pedal that will not firm up after several bleeding attempts, a lever that firms up only after repeated pumping, persistent air bubbles in the tubing, or fluid leaking from the master cylinder or caliper are reasons to stop and diagnose the system rather than keep bleeding. Because this is an ABS-equipped Monkey, any situation where air may have entered the ABS unit itself is a shop-level concern. The same applies if you are not confident that the correct fluid level has been maintained or if the brake system has been apart beyond a simple caliper bleed. A professional can pressure-test the system and use the appropriate equipment to remove air from the ABS hardware safely.
Related Shopping Categories
Shop Brake Fluid for a 2020 Honda Monkey ABS Motorcycle.
Shop Brake Lines for a 2020 Honda Monkey ABS Motorcycle.
Shop Brake Pads for a 2020 Honda Monkey ABS Motorcycle.
Shop Stands for a 2020 Honda Monkey ABS Motorcycle.
Shop Brake Tools for a 2020 Honda Monkey ABS 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.
