yes you can
mine holds 2 and a half gallons of fuel, and 3 quarts of oil. I drive a 1985 450
10W-40
3 liters.
Just draining to change the oil = 2.6 quarts
10w-40 specifically for motorcycles.
GN-4 10w-40 Honda motor
An 82' nighthawk 450 takes 2.6 quarts of of sae 10w-40 SE or SF grade oil... Although I've heard from friends who ride say you should get motorcycle oil or Honda specified oil. The nighthawks have a "wet" clutch system and regular car oil will burn out your clutch.. that's from a ATV technician..
I have a 1982 Honda Nighthawk. If you remove the bolt in the front of the motor on the bottom the fins and bolt will drop down. You will then see the oil filter cartridge. It looks like an air filter but it is for oil. Change the cartridge and reinstall.
12.75 .oz #10 fork oil 6psi pressure
20w-50 indicates Synthetic-oil
185cc or 2.26 fl oz As per clymer manual.
20w-40 20w-50