Honda 2013 NSS300 Owner's Manual page 25

Instruments
Average fuel consumption meter
Except E, U, KO type
Shows average fuel consumption in km/ℓ or
SELECT
ℓ/100km based on the tripmeter A.
Select the km/ℓ or ℓ/100km, press and hold
the MODE button with the tripmeter.
RESET RESET
After you reset the tripmeter A, the average
fuel consumption meter shows " ".
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