Yamaha YZF-R125 Service Manual: Circuit diagram
2. Crankshaft position sensor
4. Main fuse
5. Main switch
6. Radiator fan motor fuse
8. Sidestand switch
9. Battery
17.Engine stop switch
19.Intake air pressure sensor
20.Intake air temperature sensor
21.Throttle position sensor
22.Coolant temperature sensor
23.Lean angle sensor
24.Self-diagnosis signal connector
25.ECU (engine control unit)
26.Ignition coil
27.Spark plug
28.FID (fast idle solenoid)
29.Fuel injector
30.Fuel pump
32.Radiator fan motor relay
33.Radiator fan motor
63.Engine trouble warning light
64.Ignition fuse
66.Signaling system fuse
67.Speed sensor
Ecu self-diagnostic function
The ECU is equipped with a self-diagnostic function in order to ensure that
the fuel injection system is
operating normally. If this function detects a malfunction in the system, it
immediately o ...
Other materials:
Checking the horn
1. Check:
Horn resistance
Out of specification Replace.
a. Disconnect the horn connectors from the
horn terminals.
b. Connect the pocket tester ( × 1) to the horn
terminals.
Positive tester probe
horn terminal "1"
Negative tester probe
horn terminal "2"
c. Measure t ...
Checking the relays
Check each switch for continuity with the pocket
tester. If the continuity reading is incorrect, replace
the relay.
1. Disconnect the relay from the wire harness.
2. Connect the pocket tester ( × 1) and battery
(12 V) to the relay terminal as shown.
Check the relay operation.
Out ...
Checking the water pump
1. Check:
Water pump housing cover
Water pump housing
Cracks/damage Replace.
Impeller shaft
Cracks/damage/wear Replace.
Bearing
Rough movement Replace.
Radiator outlet hose
Cracks/damage Replace.
...