most all motorcycles use a wet clutch design. that is why you should always use four stroke motorcycle oil because it is designed to handle the extra stress and heat .if you add lubricants to make your engine oil "slicker" it will probably make your clutch start slipping especially if you have an auto clutch.
Use no oil additive. It is a waste of money and might actually do harm.
Lucas also makes a synthetic engine oil additive.. Yes.
10-30 motor oil with HTO additive
Don't. Add no oil additives to your engine. If oil additives were really that good, the oil companys would put them in their own oil.
you should use 10W-30 of any reputable brand of oil. With a car that old, I would also add an oil additive like Slick 50 or similar for older engines. They cost a lot, but definitely keep your engine running smoothly.
80w90...with a diff additive for the rear
manual says if harley oil 20-50 not available to use oil suitable for diesel trux...there's some kinda additive in it i guess...anyway in decending order of best choices 20-50,15-40wt. dont use rotella 15-40 as they quit putting the additive in it. hd oil is probabl over priced and not necceserry
I usually use 5w-30 in mine and put some oil additive so it can run smoother
I wouldn't recommend it. Replace the gasket.
You can use any kind of 10w-40 oil for a nighthawk
Baby oil
Most use Synthetic Oil.