Yamaha WR250F(N) Owner's Service Manual page 232

SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION
1
SPROCKETS INSPECTION
1. Inspect:
Sprocket teeth a
Excessive wear
NOTE:
Replace the drive sprocket, rear wheel
sprocket and drive chain as a set.
DRIVE CHAIN INSPECTION
1. Remove:
Drive chain 1
NOTE:
Remove the drive chain using a chain cutter
2.
2. Clean:
Drive chain
Brush off as much dirt as possible.
Then clean the chain using the chain
cleaner.
CAUTION:
This machine has a drive chain with small
rubber O-rings 1 between the chain plates.
Steam cleaning, high-pressure washes,
certain solvent and kerosene can damage
these O-rings.
3. Measure:
Drive chain length (10 links) a
Out of specification
Drive chain length (10 links):
<Limit>: 150.1 mm (5.91 in)
4. Check:
Drive chain stiffness a
Clean and oil the chain and hold as
illustrated.
Stiff Replace drive chain.
3 - 33
INSP
ADJ
Replace.
Replace.