Checking The Drive Sprocket; Checking The Rear Wheel Sprocket; Installing The Drive Chain - Yamaha YZ250F Owner's Service Manual

4. Check:
• Drive chain rollers "1"
Damage/wear  Replace the drive chain.
• Drive chain side plates "2"
Damage/wear  Replace the drive chain.
5. Lubricate:
• Drive chain

CHECKING THE DRIVE SPROCKET

EAS1SM5193
1. Check:
• Drive sprocket
More than 1/4 tooth wear "a"  Replace the
drive sprocket and the rear wheel sprocket
as a set.
Bent tooth  Replace the drive sprocket
and the rear wheel sprocket as a set.
b. Correct
1. Drive chain roller
2. Drive sprocket
EAS1SM5194

CHECKING THE REAR WHEEL SPROCKET

Refer to "CHECKING AND REPLACING THE
REAR WHEEL SPROCKET" on page 4-8.

INSTALLING THE DRIVE CHAIN

EAS1SM5195
1. Install:
• Drive chain "1"
• Drive chain joint "2"
• Joint clip "3"
New
EWA
WARNING
When installing the joint clip, always keep
the direction as shown in the figure.
2. Lubricate:
• Drive chain
3. Install:
• Drive sprocket
• Lock washer
• Drive sprocket nut
Refer to "ENGINE REMOVAL" on page 5-1.
Drive sprocket nut
75 Nm (7.5 m·kgf, 54 ft·lbf)
ECA1DX1014
NOTICE
Never install a new drive chain onto worn
drive sprockets; this will dramatically short-
en the drive chain's life.
4. Adjust:
• Drive chain slack
Refer to "ADJUSTING THE DRIVE CHAIN
SLACK" on page 3-27.
Drive chain slack
50–60 mm (1.97–2.36 in)
ECA13550
NOTICE
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci-
fied limits.
4-65
CHAIN DRIVE
New