Yamaha YZF-R125 Service Manual: Checking the spark plug cap
1. Check:
Spark plug cap resistance
Out of specification 
Replace.
a. Remove the spark plug cap from the spark plug lead.
b. Connect the pocket tester (
× 1k)
to the
spark plug cap as shown.
c. Measure the spark plug cap resistance.
Checking the diode
1. Check:
Diode
Out of specification Replace.
NOTE:
The pocket tester or the analog pocket tester
readings are shown in the following table.
a. Disconnect the diode from the wire harness.
...
Checking the ignition coil
1. Check:
Primary coil resistance
Out of specification Replace.
a. Disconnect the ignition coil connectors from
the ignition coil terminals.
b. Connect the pocket tester ( × 1)
to ...
Other materials:
Introduction
WARNINGDisc brake components rarely require
disassembly.
Therefore, always follow these preventive
measures:
Never disassemble brake components unless
absolutely necessary.
If any connection on the hydraulic brake
system is disconnected, the entire brake
sy ...
Replacing the fuses
Replacing the fuses
Fuse box
Spare fuse
Headlight fuse
Signaling system fuse
Ignition fuse
Radiator fan fuse
Main fuse
The fuse box is located under the rider
seat.
If a fuse is blown, replace it as follows.
Turn the key to "OFF" and turn off
the electrical circuit i ...
Installing the piston and cylinder
1. Install:
Top ring "1"
2nd ring "2"
Oil ring expander "3"
Lower oil ring rail "4"
Upper oil ring rail "5"
NOTE:
Be sure to install the piston rings so that the
manufacturer marks or numbers face up.
2. Install:
Piston "1"
Piston pin "2"
Piston pin clips "3"
NOTE:
...