Yamaha YZF-R125 Service Manual: Checking the fid (fast idle solenoid)
1. Disconnect:
- FID (fast idle solenoid) coupler
2. Check:
- FID (fast idle solenoid) resistance
a. Disconnect the FID (fast idle solenoid) coupler from the FID.
b. Connect the pocket tester ( 
× 10)
to the terminals
of the FID (fast idle solenoid).
- Positive tester probe
red/black terminal "1" - Negative tester probe
yellow/red terminal "2"
c. Measure the FID (fast idle solenoid) resistance.
Out of specification Replace
the throttle
body assembly.
Intake air temperature sensor
1. Check:
Intake air temperature sensor resistance
Out of specification Replace
the throttle
body.
a. Connect the pocket tester ( ×
1k) to the
throttle body sensor assembly co ...
Troubleshooting
...
Other materials:
Checking the camshaft sprocket and timing chain guide
1. Check:
Camshaft sprocket
More than 1/4 tooth wear "a" Replace
the
camshaft sprocket, timing chain and crankshaft
as a set.
a. 1/4 tooth
b. Correct
1. Timing chain roller
2. Camshaft sprocket
2. Check:
Timing chain guide (exhaust side)
Damage/wear Replace.
...
Checking the decompression system
1. Check:
Decompression system
a. Check the decompression system with the
camshaft sprocket and the decompression
cam installed to the camshaft.
b. Check that the decompression lever "1"
moves smoothly.
c. Without operating the decompression lever,
check that the decompression cam " ...
Checking the speed sensor
1. Check:
Speed sensor output voltage
Out of specification → Replace.
a. Connect the pocket tester (DC 20 V) to the
speed sensor coupler (wire harness end) as
shown.
Positive tester probe
gray "1"
Negative tester probe
gray/black "2"
b. Set the main switch to "ON".
c. ...