Spark Plug - Honda CR250R 2006 Owner's Manual & Competition Handbook

Spark Plug

Refer to Safety Precautions on page 19.
Spark Plug Recommendation
The recommended standard spark plug is
satisfactory for most racing conditions.
Standard BR9EG-N-8 (NGK)
Use only the recommended type of spark plug in
the recommended heat range.
NOTICE
Using a spark plug with an improper heat range
or incorrect reach can cause engine damage.
Using a non-resistor spark plug may cause
ignition problems.
48
Servicing Your Honda
1. Measure spark plug gap (1) with a feeler
gauge, and adjust by carefully bending the
side electrode (2).
The recommended spark plug gap is:
0.027 - 0.031 in (0.7 - 0.8 mm)
2. Check the electrode for wear or deposits, the
gasket (3) for damage, and the insulator for
cracks.
(2)
(1)
(1) plug gap (3) sealing gasket
(2) side electrode
3. To obtain accurate spark plug readings,
accelerate up to speed on a straightaway.
Push the engine stop button and disengage the
clutch by pulling the lever in.
If you're using a new plug, ride for at least
ten minutes before taking a plug reading; a
brand-new plug will not color initially.
4. Coast to a stop, then remove and inspect the
spark plug. The porcelain insulator around
the center electrode should appear tan or
medium gray.
If the electrodes appear burnt, or the insulator
is white or light gray (lean) or the electrodes
and insulator are black or fouled (rich), there
is a problem elsewhere (page 109). Check the
fuel/oil mixture, carburetor and fuel system,
and ignition timing.
5. Tighten the spark plug (4):
• If the old plug is good:
1/8 turn after is seats.
• If installing a new plug, tighten it twice to
prevent loosening:
a) First, tighten the plug:
NGK: 3/4 turn after it seats.
b) Then loosen the plug.
c) Next, tighten the plug again:
1/8 turn after it seats.
(3)

(4) spark plug

(4)