Honda NRX1800 2004 Owner's Manual page 105

Engine Oil & Filter
Oil Recommendation
API
classification
viscosity
(weight)
JASO T 903
standard
96
Servicing Your Honda
SG or higher
except oils
labeled as energy
conserving on the
circular API
service label
SAE 10W-40
MA
＊
suggested oil
Pro Honda GN4 or HP4 (without
molybdenum additives) 4-stroke
oil (USA & Canada), or Honda
4-stroke oil (Canada only), or an
equivalent motorcycle oil.
＊
Suggested oils are equal in
performance to SJ oils that are not
labeled as energy conserving on the
circular API service label.