Yamaha YZF-R125 Service Manual: Ignition system
Circuit diagram
2. Crankshaft position sensor
4. Main fuse
5. Main switch
8. Sidestand switch
9. Battery
17.Engine stop switch
23.Lean angle sensor
25.ECU (engine control unit)
26.Ignition coil
27.Spark ...
Other materials:
Checking the cylinder head breather hose
1. Remove:
Left side panel
Refer to "GENERAL CHASSIS" on page 4-1.
2. Check:
Cylinder head breather hose "1"
Cracks/damage → Replace.
Loose connection → Connect properly.
CAUTION:Make sure the cylinder head
breather hose is
routed correctly.
...
Checking the primary drive gear
1. Remove:
Primary drive gear
Refer to "BALANCER GEAR" on page 5-53.
2. Check:
Primary drive gear
Damage/wear Replace the
primary drive
gear and clutch housing as a set.
Excessive noise during operation
Replace
the primary drive gear and clutch housing as
a set
...
Chain drive
Removing the drive chain
1. Stand the vehicle on a level surface.
WARNINGSecurely support the vehicle so that there
is
no danger of it falling over.
NOTE:
Place the vehicle on a suitable stand so that the
rear wheel is elevated. ...