Yamaha YZ250FM 2021 Owner's Service Manual

CHASSIS3-25brake several times.4. Check:• Brake hoseBrake fluid leaks  Replace the damagedbrake hose.Refer to “FRONT BRAKE” on page 4-13.EAM30498CHECKING THE REAR BRAKE HOSE1. Check:• Brake hoseCracks/damage/wear  Replace.2. Check:• Brake hose holderLoose connection  Tighten the holder bolt.3. Hold the vehicle upright and apply the rearbrake several times.4. Check:• Brake hoseBrake fluid leakage  Replace the damagedhose.Refer to “REAR BRAKE” on page 4-24.EAM30499CHECKING THE BRAKE OPERATION1. Check:• Brake operationBrake not working properly  Check thebrake system.Refer to “FRONT BRAKE” on page 4-13 and“REAR BRAKE” on page 4-24.TIPDrive on the dry road, operate the front and rearbrakes separately and check to see if the brakesare operating properly.EAM30477BLEEDING THE HYDRAULIC BRAKESYSTEMWARNINGEWA19140Bleed the brake system whenever:• The system is disassembled.• A brake hose is loosened, disconnected, orreplaced.• The brake fluid level is very low.• Brake operation is faulty.1. Remove:• Brake master cylinder cap• Reservoir diaphragm• Reservoir float (front brake)• Protector (rear brake)TIP• Be careful not to spill any brake fluid or allowthe reservoir to overflow.• Make sure that there is enough brake fluid be-fore applying the brake. Ignoring this precau-tion could allow air to enter the brake system,considerably lengthening the bleeding proce-dure.• If bleeding is difficult, it may be necessary to letthe brake fluid settle for a few hours. Repeatthe bleeding procedure when the tiny bubblesin the hose have disappeared.2. Bleed the brake system.a. Fill the reservoir to the proper level withthe recommended brake fluid.b. Install the reservoir diaphragm.c. Connect the plastic hose “1” to the bleedscrew “2” securely, and place a containerunder the end of the plastic hose.d. Slowly apply the brake several times.e. Fully pull the brake lever or fully pressdown the brake pedal and hold it in posi-tion.f. Loosen the bleed screw.TIPLoosening the bleed screw will release the pres-sure in the brake caliper and cause the brake le-ver to contact the throttle grip or the brake pedalto fully extend.g. Tighten the bleed screw and then releasethe brake lever or brake pedal.A. FrontB. Rear12122