Yamaha YZ125 2019 Owner's Service Manual page 75

4. Check:
• Drive chain stiffness "a"
Clean and oil the drive chain and hold as il-
lustrated.
Stiff → Replace the drive chain.
5. Install:
• Drive chain "1"
• Joint "2"
• Master link clip "3"
Be sure to install the master link clip to the
direction as shown.
a. Turning direction
6. Lubricate:
• Drive chain
Drive chain lubricant:
SAE 10W-40 motor oil or suitable
chain lubricants
ADJUSTING THE DRIVE CHAIN SLACK
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Check:
• Drive chain slack "a"
Above the seal guard installation bolt.
Out of specification → Adjust.
Drive chain slack "a":
48.0–58.0 mm (1.89–2.28 in)
Before checking and/or adjusting, rotate the
rear wheel through several revolutions and
check the slack several times to find the tightest
point. Check and/or adjust the drive chain slack
with the rear wheel in this "tight chain" position.
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CHASSIS