Castrol is owned by the BP (British Petroleum) oil spill company. Not one new car or truck comes from the factory with Castrol in the crankcase. Motorcycles need Motor Cycle oil as it has a much higher level of anti-wear additives zinc and phosphorous.

The maker of your bike can tell you what the oil viscosity should be.

Most biker clubs and motorcycle pros use AMSOIL.

Just about any name brand oil will work. Castrol is a well respected brand. Make sure you use the correct grade; check the owners manual.

Is it a wet clutch? Do not use car oil if it is. Either motorcycle specific oil or diesel oil.

Just make sure you are using oil that is meant for motorcycles... NOT car oil. Car oil has additives that are not good for your motorcycle engine.