Yamaha YZF-R125 Service Manual: Installing the front brake master cylinder

Yamaha YZF-R125 Service Manual / Chassis / Front brake / Installing the front brake master cylinder

1. Install:

Brake master cylinder "1"
Brake master cylinder holder "2"

NOTE:

Install the brake master cylinder holder with the arrow mark "a" pointing forward.
Align the end of the brake master cylinder holder with the punch mark "b" on the handlebar.
First, tighten the front bolt, then the rear bolt.

Installing the front brake master cylinder

2. Install:

Copper washers "1"

Brake hose "2"
Brake hose union bolt "3"
Front brake light switch

WARNING

Proper brake hose routing is essential to insure safe vehicle operation. Refer to "CABLE ROUTING" on page 2-33.

NOTE:

Install the brake hose at an 101 angle to the front brake master cylinder as shown in the illustration.
While holding the brake hose, tighten the brake hose union bolt as shown.
Turn the handlebar to the left and right to make sure the brake hose does not touch other parts (e.g., wire harness, cables, leads). Correct if necessary.

Installing the front brake master cylinder

3. Install:

Front brake light switch

NOTE:

Before fully installing the front brake light switch, be sure to completely install the rubber cover over the switch. Also, be sure not to twist the front brake light switch lead when screwing in the switch.

4. Fill:

Brake master cylinder reservoir (with the specified amount of the recommended brake fluid)

WARNING

Use only the designated brake fluid. Other brake fluids may cause the rubber seals to deteriorate, causing leakage and poor brake performance.
Refill with the same type of brake fluid that is already in the system. Mixing brake fluids may result in a harmful chemical reaction, leading to poor brake performance
When refilling, be careful that water does not enter the brake master cylinder reservoir.

Water will significantly lower the boiling point of the brake fluid and could cause vapor lock.

CAUTION:

Brake fluid may damage painted surfaces and plastic parts. Therefore, always clean up any spilt brake fluid immediately.

5. Bleed:

Brake system Refer to "BLEEDING THE HYDRAULIC BRAKE SYSTEM" on page 3-20.

6. Check:

Brake fluid level Below the minimum level mark "a" →Add the recommended brake fluid to the proper level.

Refer to "CHECKING THE BRAKE FLUID LEVEL" on page 3-18.

Installing the front brake master cylinder

7. Check:

Brake lever operation Soft or spongy feeling → Bleed the brake system.

Refer to "BLEEDING THE HYDRAULIC BRAKE SYSTEM" on page 3-20.

Checking the front brake master cylinder

1. Check: Brake master cylinder Damage/scratches/wear Replace. Brake fluid delivery passages (brake master cylinder body) Obstruction Blow out with compressed air. 2. Check: Br ...

Rear brake

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Other materials:

Checking the thermostat
1. Check: Thermostat Does not open at 80.5-83.5 C (176.9-182.3 F) Replace. a. Suspend the thermostat "1" in a container "2" filled with water. b. Slowly heat the water "3". c. Place a thermometer "4" in the water. d. While stirring the water, observe the thermostat and th ...

Checking the piston rings
1. Measure: Piston ring side clearance Out of specification Replace the piston and piston rings as a set. NOTE: Before measuring the piston ring side clearance, eliminate any carbon deposits from the piston ring grooves and piston rings. 2. Install: Piston ring (into the cylind ...

Faulty lighting or signaling system
Headlight does not come on - Wrong headlight bulb - Too many electrical accessories - Hard charging - Incorrect connection - Improperly grounded circuit - Poor contacts (main or light switch) - Burnt-out headlight bulb Headlight bulb burnt out - Wrong headlight bulb - Faulty battery - Fau ...