Checking The Engine Idling Speed; Checking The Throttle Grip - Yamaha WR450FN 2022 Owner's Service Manual

EAM30412

CHECKING THE ENGINE IDLING SPEED

TIP
• Because the air pressure is lower at high alti-
tudes, the air-fuel mixture will become richer. If
the idling speed is low, turn the idle screw
clockwise to increase the speed before the ad-
justment.
• Before adjusting the engine idling speed, make
sure that the air filter element is not clogged,
the engine compression is proper, and the
throttle grip free play is proper.
• Adjust the engine idling speed with the starter
knob pulled in completely.
1. Start the engine, and warm this up until the oil
has reached the specified temperature.
2. Measure the coolant temperature using the
Yamaha diagnostic tool.
Yamaha diagnostic tool USB (US)
90890-03269
Yamaha diagnostic tool (A/I)
90890-03264
FI diagnostic tool sub–lead
90890-03212
FI diagnostic tool sub–lead
YU-03212
OBD/ GST Leadwire kit
90890-03249
Coolant temperature
70–90 C (158–194 F)
3. Install:
• Digital tachometer
Digital tachometer
90890-06760
Digital tachometer
YU-39951-B
TIP
Get the high tension cord "1" of the ignition coil
pinched in the detector "a" of the digital tachom-
eter.
a a
1 1
4. Measure:
• Engine idling speed
Out of specification  Regulate.
Engine idling speed
1900–2100 r/min
5. Adjust:
• Engine idling speed
a. Turn the idle screw "1" to make an adjust-
ment.
EAM30475

CHECKING THE THROTTLE GRIP

TIP
Prior to adjusting throttle grip free play, the en-
gine idling speed should be adjusted.
1. Check:
• Throttle grip free play "a"
Out of specification  Regulate.
Throttle grip free play
3.0–6.0 mm (0.12–0.24 in)
3-12
ENGINE
1
a
1 1