The type of oil can be found on a sticker under the seat. It is SAE 10-40. As for capacity, the engine can hold 3 quarts. When I change the oil on mine, I generally put about 2 1/2 quarts in or a bit more.
GN-4 10w-40 Honda motor
You can use any kind of 10w-40 oil for a nighthawk
10W-40 nukka
10w-40 specifically for motorcycles.
SAE 10w30 full synthetic.
1.6 quarts
I'm still looking for what kind of fork oil is available, but the manual says you can use Dexron ATF
I own a 94 Nighthawk 250 and my owners manuel says to us 10w-40. It also says to "Use only high detergant, premium quality oil cerified to meet API Service Classification SF or SG."
Flying insects primarily.
If you want to keep the engine clean and long life, 3,000 miles for oil changes ( 5,000kms) and 10w40 is good.
One Is a nightingale, another Is a nighthawk.
750 cc800 if dissembled recently10w-40