What brand of oil is good for a Honda rancher 420?

For a Honda Rancher 420, a good choice of oil is Honda's own GN4 10W-40 motor oil, which is specifically formulated for their ATVs and provides Excellent protection and performance. Alternatively, you can use other high-quality oils that meet the API service classification of SG or higher, such as Mobil 1 or Castrol, as long as they are suitable for wet clutches. Always check the owner’s manual for specific recommendations to ensure optimal performance and longevity of your ATV.