Honda SH125 Manual page 321

Turn the ignition switch to
OFF.
Disconnect the CKP sensor 3P white connector.
Connect the lmrie diagnostic tester or peak voltage
adaptor probes to the CKP sensor side connector
terminals.
In the same manner as at the ECM connector, mea-
sure the peak voltage and compare
it
to the voltage
measured at the ECM connector.
If the peak voltage measured at the ECM is
abnormal and the one measured at the CKP sen-
sor is normal, the wire harness has an open or
short circuit, or loose connection.
If both peak voltages are abnormal, check each
item in the troubleshooting chart (page 18-4).
See page 12-9 for CKP sensor replacement.
Install the removed parts in the reverse order of
removal.
IGNITION COIL
REMOVAL/INSTALLATION
Remove the maintenance lid (page 2-4).
Disconnect the spark plug cap.
Remove the wire band from the stay.
Remove the spark plug wire from the engine.
Remove the two wire bands from the frame.
Disconnect the ignition coil wire connectors.
Remove the bolts, set plates and ignition coil.
Installation is in the reverse order of removal.