SAFETY FIRST: Protective gloves and eyewear are recommended at this point.
Warning: Brake fluid is very caustic and can damage paint, chrome and plastic. Wipe up any spills immediately.
Pull back the rubber cover and remove the front brake hose banjo bolt from the brake master cylinder using a 12 mm wrench. Drain the brake fluid into a container.
Remove the master cylinder cover using a #2 Phillips head screwdriver.
If the screws are stuck, you may need to use a hand held impact wrench.
The hand held impact driver part number is 15-0625.
Remove the master cylinder clamp using an 10 mm wrench. The photo is not of a Kawasaki KLR650, but the procedure is the same.
Disassembly and Inspection
Remove the front brake lever lock nut and pivot bolt using a flat blade screwdriver and a 10 mm wrench.
Remove the rubber dust cover, being careful not to tear it.
Push in on the plunger against the spring pressure and remove the brake master cylinder snap ring using a pair of internal snap ring pliers.
Remove the master cylinder plunger and spring. Inspect the rubber seals on the plunger for tears or other damage. Replace as necessary.
Check the plunger bore for scoring or other damage. A small brake master cylinder hone can be used to remove minor scratches.
Reassembly
Clean the brake master cylinder and the other components thoroughly using aerosol brake cleaner and a lint free cloth. Before reassembling the brake master cylinder, coat the plunger bore, plunger and seals with a light layer of DOT 4 brake fluid from a tightly sealed container.
Place the plunger spring in the plunger bore, large end of the spring first. Push the plunger into its bore, being careful not to damage the seals.
While pushing the plunger in against the spring pressure, install the snap ring, making sure it is fully seated in its groove. Install the rubber dust seal. Place a thin film of waterproof grease on the front brake lever pivot bolt. Reinstall the brake lever, pivot bolt and nut.
Reinstallation
Install the master cylinder on the right handlebar with the arrow on the clamp facing up. Torque the top bolt to specification, then torque the lower bolt. There should be a small gap between the bottom of the clamp and the master cylinder.
master cylinder clamp bolt torque: 78 in-lb or 8.8 N-m)
Install the brake line banjo bolt using new sealing washers. Make sure to put one sealing washer on each side of the banjo fitting. Torque the banjo bolt to specification.
brake banjo bolt torque: 18 ft-lb or 25 N-m)
Bleed the brakes. See the Front Brake Bleeding topic for more information.