Honda CRF250RL 2017 Owner's Manual page 79

# Checking the Drive Chain Wear
Check the chain wear label when adjusting
the drive chain. If the indicator groove on the
chain adjuster plate enters the red zone on
the label after the chain has been adjusted to
the proper slack, the chain is excessively worn
and must be replaced.
Chain: DID 520VF
If necessary have the drive chain replaced by
your dealer.
Drive Chain Adjusting the Drive Chain Slack
u
Indicator
groove
Red zone
77