Ignition; Engine Idle Speed - Honda CRF450R Owner's Manual

4. SERVICE AND MAINTENANCE
6. 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 le-
ver in.
Coast to a stop, then remove and inspect the spark
plug. The porcelain insulator around the center elec-
trode should appear tan or medium gray.
NOTE:
• If you're using a new plug, ride for at least ten min-
utes before taking a plug reading; a brand-new plug
will not 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
70).
Check the carburetor, fuel system and ignition timing.
7. Install the spark plug by hand until finger tight, then
tighten with a wrench until the sealing gasket is com-
pressed ( 1/2 turn to compress a new spark plug gas-
ket, 1/8 – 1/4 turn to compress a spark plug with a
used gasket).
8. Connect the spark plug cap.
9. Install the fuel tank (page 18)
26

IGNITION

A CDI (Capacitive Discharge Ignition ) system is used
on your CRF; consequently, routine ignition timing ad-
justment is unnecessary. If you want to check the igni-
tion timing, refer to the Honda Service Manual.

ENGINE IDLE SPEED

Adjustment Procedure
1. Turn the pilot screw in until it is lightly seated and
record the number of turns. Turn the pilot screw out
the same number of turns.
(1) PILOT SCREW
2. If the engine is cold, start it and warm it up 3 min-
utes. Then shut it off.
3. Connect a tachometer to the engine.
4. Shift into neutral. Start the engine.
5. Keep the motorcycle in an upright position.
6. Adjust idle speed with the throttle stop screw.
Idle speed:
1,700 ± 100 rpm
(1) THROTTLE STOP SCREW