Bleeding the Front Brake on a 1987 Kawasaki EX250 Ninja 250
Shop parts for a 1987 Kawasaki EX250 - Ninja 250 Motorcycle.The 1987 Kawasaki EX250 Ninja 250 uses a hydraulic disc brake at the front and a mechanical drum brake at the rear. That distinction matters before you start: the front brake is the system that uses fluid, a master cylinder, a line, and a caliper, so it is the part you bleed. The rear drum brake is operated by cable or rod linkage and is adjusted rather than bled. This guide focuses on refreshing the fluid and removing air from the front hydraulic circuit on this specific model.
When a Bleed Is Needed
Bleeding is the process of pushing old fluid and trapped air out of the hydraulic system. Air is compressible, so even a small amount in the line or caliper can make the lever feel soft, vague, or closer to the grip than it used to be. A lever that slowly sinks toward the grip while you hold steady pressure is another sign that the system needs attention. Dark, cloudy, or contaminated fluid in the reservoir is also a reason to flush and bleed.
Brake fluid absorbs moisture from the air over time. Moisture lowers the fluid’s boiling point, which can lead to brake fade under hard or repeated use. Many riders refresh brake fluid on a regular schedule even when the lever still feels acceptable. A bleed is also required after work that opens the hydraulic system, such as replacing a brake line, servicing the caliper, or repairing the master cylinder. On a bike of this age, aged rubber seals and lines deserve a close look while you are in there.
Tools and Supplies to Gather
- Fresh brake fluid of the type marked on the master cylinder reservoir cap, from a sealed container
- A box-end wrench that fits the front caliper bleeder valve
- Clear tubing that fits snugly over the bleeder nipple
- A small catch bottle for used fluid
- Rags or shop towels, plus water for rinsing spills
- A syringe or turkey baster for removing old fluid from the reservoir
- The correct driver for the reservoir cap screws
- Optional: a one-way check-valve bleeder or vacuum bleeder for one-person work
Brake fluid damages paint and many plastics on contact, so keep rags handy and wipe up spills immediately. Rinse the area with water if fluid reaches painted bodywork, the instrument area, or the reservoir surround.
Preparation Before Opening the System
Support the 1987 EX250 securely upright on a stand so it cannot tip while you work. Turn the handlebars so the front master cylinder reservoir sits as level as possible before you remove the cap. Cover the area around the reservoir, the handlebar, the instrument cluster, and any painted or plastic surfaces below it with rags. Clean the reservoir cap and surrounding area before opening it so dirt does not fall into the fluid.
Remove the cap and diaphragm, then use the syringe or baster to draw most of the old fluid out of the reservoir. Do not pump the lever while the reservoir is empty, and do not let the reservoir run dry at any point during the job. Air drawn into the master cylinder is exactly what you are trying to remove.
Step-by-Step Front Brake Bleeding Procedure
- With the old fluid removed, refill the reservoir with fresh fluid from the sealed container, leaving room for the diaphragm and cap later.
- Slide the clear tubing over the front caliper bleeder nipple and route the other end into the catch bottle. Position the bottle so the tubing stays clear of the caliper and wheel.
- Fit the box-end wrench onto the bleeder valve. Keep the wrench in place for the whole procedure so you can open and close the bleeder quickly.
- Squeeze the front brake lever slowly and hold it firmly against the grip. Do not release it yet.
- Open the bleeder about a quarter turn. Fluid and any trapped air will move through the clear tubing. Watch the tubing for bubbles and for the color of the fluid.
- Close the bleeder before you release the lever. Releasing the lever with the bleeder open can pull air back into the caliper.
- Release the lever slowly, then check the reservoir level and top it off with fresh fluid. Repeat the squeeze-hold-open-close-release sequence.
- Continue until the fluid coming through the tubing is clean and free of bubbles, and the lever feels firm. Keep topping off the reservoir throughout so it never drops low enough to draw air.
- If bubbles persist, let the bike sit for a few minutes, then gently tap the caliper and the brake line with a screwdriver handle to help dislodge trapped air, and repeat the sequence.
- When you are satisfied, close the bleeder snugly with the box-end wrench. Tighten it firmly without overtightening, since the bleeder and caliper threads can be damaged by excess force.
Finishing, Testing, and Leak Checks
Fill the reservoir to the correct level marking, then reinstall the diaphragm and cap. Wipe any fluid from the caliper, bleeder, line fittings, and reservoir area, and rinse with water if fluid reached painted or plastic surfaces. Check for leaks at the bleeder and at the banjo fittings on the master cylinder and caliper. A dry fitting after several lever squeezes is a good sign; a wet fitting or a drip needs attention before riding.
The front lever should feel firm and consistent, not spongy, and it should not slowly sink while you hold steady pressure. Spin the front wheel to confirm the brake is not dragging. Test the brake at low speed in a safe area before riding normally, and make the first few stops gentle until you are confident in the lever feel.
Troubleshooting and When to Visit a Shop
If the lever will not firm up after several bleeding attempts, or if it firms only after repeated pumping, air may still be trapped or the master cylinder may be bypassing internally. Persistent bubbles, fluid weeping from the master cylinder or caliper, a damaged bleeder, or a reservoir that ran dry are all reasons to stop and diagnose rather than keep pumping fluid through. This 1987 EX250 does not use an ABS unit or a linked brake system, so the front hydraulic circuit is straightforward, but a worn master cylinder or a leaking seal is not a bleeding problem and should be handled by a qualified shop. If you are unsure about the condition of the brake line, caliper seals, or master cylinder, have the system inspected before you ride.
Related Shopping Categories
Shop Brake Fluid for a 1987 Kawasaki EX250 - Ninja 250 Motorcycle.
Shop Brake Lines for a 1987 Kawasaki EX250 - Ninja 250 Motorcycle.
Shop Brake Pads for a 1987 Kawasaki EX250 - Ninja 250 Motorcycle.
Shop Stands for a 1987 Kawasaki EX250 - Ninja 250 Motorcycle.
Shop Brake Tools for a 1987 Kawasaki EX250 - Ninja 250 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.
