Yamaha YFM660R Owner's Manual page 286

3. Wait a few minutes until the oil settles, re-
move the engine oil tank filler cap, wipe the
dipstick clean with a clean rag, insert it back
into the filler hole (without screwing it in), and
then remove it again to check the oil level.
NOTE:
_
The engine oil should be between the minimum
and maximum level marks.
_
4. If the engine oil is below the minimum level
mark, add sufficient oil of the recommended
type to raise it to the correct level.
NOTE:
_
When adding oil, be careful not to overfill the en-
gine oil tank; the oil level rises faster starting from
the half-level-portion on the dipstick.
_
5. Insert the dipstick into the oil filler hole, and
then tighten the oil filler cap.
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