Honda CRF250F 2023 Owner's Manual page 110

To check the chain's service limit, measure
the distance between a span of 41 pins, from
pin center to pin center. If the distance
exceeds the service limit, the drive chain is
worn out and should be replaced.
Measure a span of 41 pins
25.0 in (635 mm)
New Chain:
25.1 in (638 mm)
Service Limit:
This motorcycle has a staked master link
drive chain which requires a special tool for
cutting and staking. Do not use an ordinary
master link with this chain.
6. Inspect the front and rear sprocket teeth for
excessive wear or damage. If necessary, have
your dealer replace a worn sprocket.
Damaged Sprocket
Teeth
REPLACE
Normal Sprocket Teeth
Use of a new chain with worn sprockets will
cause rapid chain wear.
Drive Chain
Worn Sprocket
Teeth
REPLACE
GOOD
Servicing Your Honda
101