Adjusting The Pilot Air Screw; Adjusting The Engine Idling Speed; Checking The Exhaust Pipe - Yamaha YZ125 2009 Owner's Service Manual

6. Fill:
• Transmission oil
Recommended oil:
Yamalube 4 (10W-40) or SAE 10W-
40 type SE motor oil
Oil capacity (periodic oil change):
0.66 L (0.58 Imp qt, 0.69 US qt)
7. Check:
• Oil leakage
8. Check:
• Transmission oil level
9. Install:
• Oil filler cap "2"

ADJUSTING THE PILOT AIR SCREW

1. Adjust:
• Pilot air screw "1"
Adjustment steps:
a. Screw in the pilot air screw until it is lightly
seated.
b. Back out by the specified number of turns.
Pilot air screw:
2-1/4 turns out

ADJUSTING THE ENGINE IDLING SPEED

1. Start the engine and thoroughly warm it up.
2. Adjust:
• Engine idling speed
Adjustment steps:
a. Loosen the locknut "1".
b. Turn the throttle stop screw "2" until the en-
gine runs at the lowest possible speed.
c. Tighten the locknut.
To increase idle speed → Turn the throttle
stop screw "2" in.
To decrease idle speed → Turn the throttle
stop screw "2" out.

CHECKING THE EXHAUST PIPE

1. Inspect:
• O-ring "1"
Damage → Replace.
Install the O-rings with their depressed "a" fac-
ing outward.
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ENGINE