Honda CRF250RL 2017 Owner's Manual page 61

Inspect the electrodes and center
4.
porcelain for deposits, erosion or carbon
fouling.
If the erosion or deposit is heavy,
u
replace the plug.
Make sure that a 1.0 mm wire-type feeler
5.
gauge cannot be inserted between the
spark plug gap. If the gauge fits in the
gap, replace the plug with a new one.
Spark plug cap
Spark Plug
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.
Checking Spark Plug
u
Spark plug gap
Continued 59