Yamaha YZF-R125 Service Manual: Introduction

Yamaha YZF-R125 Service Manual / Chassis / Front brake / Introduction

WARNING

Disc brake components rarely require disassembly.

Therefore, always follow these preventive measures:

Never disassemble brake components unless absolutely necessary.
If any connection on the hydraulic brake system is disconnected, the entire brake system must be disassembled, drained, cleaned, properly filled, and bled after reassembly.
Never use solvents on internal brake components.
Use only clean or new brake fluid for cleaning brake components.
Brake fluid may damage painted surfaces and plastic parts. Therefore, always clean up any spilt brake fluid immediately.
Avoid brake fluid coming into contact with the eyes as it can cause serious injury.
FIRST AID FOR BRAKE FLUID ENTERING THE EYES:
Flush with water for 15 minutes and get immediate medical attention.

Checking the front brake disc

1. Remove: Front wheel Refer to "FRONT WHEEL" on page 4-6. 2. Check: Brake disc Damage/galling Replace. 3. Measure: Brake disc deflection Out of specification Correct the b ...

Other materials:

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 ...

Checking the turn signal relay
1. Check: Turn signal relay input voltage Out of specification →The wiring circuit from the main switch to the turn signal relay coupler is faulty and must be repaired. a. Connect the pocket tester (DC 20 V) to the turn signal relay terminal as shown. - Positive tester probe b ...

Checking the valves and valve guides
The following procedure applies to all of the valves and valve guides. 1. Measure: Valve-stem-to-valve-guide clearance Out of specification Replace the valve guide. Valve-stem-to-valve-guide clearance = Valve guide inside diameter "a" - Valve stem diameter "b" 2. Replace: ...