Spark Plug - Honda CRF150R 2020 Owner's Manual & Competition Handbook

Spark Plug

Spark Plug

Refer to Safety Precautions on page 19.
Spark Plug Recommendation
The recommended standard spark plug is
satisfactory for most racing conditions.
CR8EH-9 (NGK)
Standard
U24FER9 (DENSO)
CR9EH-9 (NGK)
Optional
U27FER9 (DENSO)
Use only the recommended type of spark plugs 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.
Spark Plug Inspection & Replacement
1. Pull the dust cover (1) back.
2. Disconnect the direct ignition coil connector
(2).
3. Disconnect the direct ignition coil (3).
4. Clean any dirt from around the spark plug
base.
5. Remove the spark plug (4).
52
Servicing Your Honda
(4)
(1)
(2)
(3)
(1) dust cover (3) direct ignition coil
(2) direct ignition coil connector (4) spark plug
6. Check the electrodes for wear or deposits, the
sealing gasket (5) for damage, and the insulator
for cracks. Replace if you detect them.
7. Check the spark plug gap (6) using a feeler
gauge, and adjust by carefully bending the side
electrode (7).
The recommended spark plug gap is:
0.031 – 0.035 in (0.8 – 0.9 mm)
(7)
(6)
(5) sealing gasket
(6) spark plug gap
(7) side electrode
8. 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.
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 you're using a new plug, ride for at least 10
minutes before taking a plug reading; a brand-new
plug will not show color initially.
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 122).
Check the carburetor, fuel system and ignition
timing.
9. With the sealing gasket attached, thread the
spark plug in by hand to prevent crossthreading.
10. 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:
NGK: 1/2 turn after it seats.
DENSO: 1 turn after it seats.
b) Then loosen the plug.
(5)
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, the piston may be
damaged. If a plug is too tight, the threads may be
damaged.
11. Connect the direct ignition coil. Take care to
avoid pinching any cables or wires.
12. Connect the direct ignition coil connector.
13. Install the dust cover.