Honda CB125F 2017 Owner's Manual page 61

Check the spark plug gap using a wire-
5.
type feeler gauge.
If adjustment is necessary, bend the
u
side electrode carefully.
The gap should be:
0.80 - 0.90 mm (0.031 - 0.035 in)
Spark plug gap
Make sure the plug washer is in good
6.
condition.
Install the spark plug. With the plug
7.
washer attached, thread the spark plug in
by hand to prevent cross-threading.
8.
Side electrode
Plug washer
9.
Spark Plug
Tighten the spark plug:
If the old plug is good:
●
1/8 turn after it seats
If installing a new plug, tighten it twice
●
to prevent loosening:
a) First, tighten the plug:
1/2 turn after it seats.
b) Then loosen the plug.
c) Next, tighten the plug again:
1/8 turn after it seats
NOTICE
An improperly tightened spark plug can damage
the engine. If a plug is too loose, a piston may be
damaged. If a plug is too tight, the threads may
be damaged.
Reinstall the spark plug cap. Take care to
avoid pinching any cables or wires.
Checking Spark Plug
u
57