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:
Changing the coolant
1. Remove:
Lower side cowlings
Refer to "GENERAL CHASSIS" on page 4-1.
2. Remove:
Radiator cap "1"
WARNINGA hot radiator is under pressure.
Therefore,
do not remove the radiator cap when the engine
is hot. Scalding hot fluid and steam may
be blown out, which c ...
Checking the front brake lever free play
Checking the front brake lever free play
Brake lever free play
The brake lever free play should measure
2.0-5.0 mm (0.08-0.20 in) as
shown. Periodically check the brake lever
free play and, if necessary, have a
Yamaha dealer check the brake system.
WARNING
An incorrect brake le ...
Tachometer
Tachometer
Tachometer
Tachometer red zone
The electric tachometer allows the rider
to monitor the engine speed and keep it
within the ideal power range.
When the key is turned to "ON", the tachometer
needle will sweep once
across the r/min range and then return
to zero r/min ...