You can use any kind of 10w-40 oil for a nighthawk
The kind of oil that you should use for the Honda CR 250 is Honda HP2 mixed at 32:1. You do not want to use regular motor oil in your bike.
10w40 is the oil that is recommended for a 2002 Honda Rebel 250. Do not use an oil that is lighter than 10w40.
10w40
synthetic oil about 500 ml per 20 liters , that what i use in my Honda cr-250 1997 , joe
10w40
NGK
The recommended oil for a 2004 Honda Rebel 250 is 10w40 for summer conditions. For colder climates or special use a different weight will be needed.
10W-40
Use Honda 10w40. Remember, the gears and clutch use from the same oil.
Use motorcycle oil, 15-40 W.
You can use PH3593A which is a Honda oil filter. There are also other sizes you can use that will fit but they are the Honda brand.
The motor is a Honda G300.