Yamaha YZF-R125 Service Manual: Troubleshooting
If the fuel pump fails to operate.
NOTE:
- Before troubleshooting, remove the following part(s):
1. Rider seat
2. Fuel tank
Circuit diagram
4. Main fuse
5. Main switch
9. Battery
17.Engine stop switch
25.ECU (engine control unit)
30.Fuel pump
64.Ignition fuse ...
Electrical components
1. Main switch
2. Clutch switch
3. Front brake light switch
4. Ignition coil
5. Throttle body sensor assembly (intake air
pressure sensor, intake air temperature
sensor, throttle position se ...
Other materials:
Checking the cylinder and piston
1. Check:
Piston wall
Cylinder wall
Vertical scratches Replace the
cylinder,
and replace the piston and piston rings as a
set.
2. Measure:
Piston-to-cylinder clearance
a. Measure cylinder bore "C" with the cylinder
bore gauge.
NOTE:
Measure cylinder bore "C" by takin ...
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 ...
Troubleshooting
Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur during
operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting charts
repre ...