Yamaha YZF-R125 Service Manual: Checking the lean angle sensor
1. Remove:
- Lean angle sensor
2. Check:
Lean angle sensor output voltage
Out of specification 
Replace.
a. Connect the lean angle sensor to the wire harness.
b. Connect the pocket tester (DC 20 V) to the
lean angle sensor coupler as shown.
Positive tester probe 
yellow/green "1"
Negative tester probe 
gray/black "2"
c. Set the main switch to "ON".
d. Tilt the lean angle sensor to 65.
e. Measure the lean angle sensor output voltage.
Checking the crankshaft position sensor
1. Disconnect:
Crankshaft position sensor coupler
(from the wire harness)
2. Check:
Crankshaft position sensor resistance
Out of specification Replace
the crankshaft
position senso ...
Checking the starter motor operation
1. Check:
Starter motor operation
Does not operate → Perform the electric
starting system troubleshooting, starting with
step 4.
Refer to "TROUBLESHOOTING" on page
8-9.
a. Con ...
Other materials:
Fuel
Make sure there is sufficient gasoline in
the tank.
WARNING
Gasoline and gasoline vapors are
extremely flammable. To avoid fires
and explosions and to reduce the
risk of injury when refueling, follow
these instructions.
Before refueling, turn off the engine
and be sure that no on ...
Bleeding the hydraulic brake system
WARNINGBleed the hydraulic brake system whenever:
the system is disassembled.
a brake hose is loosened, disconnected or
replaced.
the brake fluid level is very low.
brake operation is faulty.
NOTE:
Be careful not to spill any brake fluid or allow
th ...
Replacing the rear brake pads
NOTE:
When replacing the brake pads, it is not necessary
to disconnect the brake hose or disassemble
the brake caliper.
1. Remove:
Brake pads
Brake pad spring
NOTE:
To remove the inner brake pad "1", push down
on the brake caliper bracket so that there is
space to remove the brake pa ...