What brand of oil to use in a Harley?

For Harley-Davidson motorcycles, it's recommended to use Harley-Davidson's own brand of oil, such as the Screamin' Eagle or V-Twin Synthetic oil, which are specifically formulated for their engines. Alternatively, high-quality motorcycle oils from reputable brands like Mobil 1, Amsoil, or Castrol that meet the necessary specifications can also be used. Always check the owner's manual for the specific oil type and viscosity recommended for your model.