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:
Disassembling the rear brake caliper
1. Remove:
Brake caliper piston "1"
Brake caliper piston dust seal "2"
Brake caliper piston seal "3"
a. Blow compressed air into the brake hose joint
opening "a" to force out the piston from the
brake caliper.
WARNING
Cover the brake caliper piston with a rag.
Be careful no ...
Checking the fuel pressure
1. Check:
Pressure regulator operation
a. Remove the fuel hose connector cover "1"
and disconnect the fuel hose "2" from the fuel
pump.
CAUTION:Although the fuel has been removed from
the fuel tank, be careful when removing the
fuel hose, since there may be fuel remaining
i ...
Catalytic converters
This vehicle is equipped with catalytic
converters in the exhaust system.
WARNING
The exhaust system is hot after operation.
To prevent a fire hazard or
burns:
Do not park the vehicle near
possible fire hazards such as
grass or other materials that
easily burn.
Park the vehic ...