use turpentine oil to clean the chain and after that use chain lube from a popular brand like Motul, wax pool or gear 90 oil ...

Then leave it alone until the solvent evaporates. Chain lube resists water, dust and dirt better than ordinary oil. Use it for chains on bicycles, motorcycles, scooters, garage door openers and ...

You can purchase the Royal Enfield Chain Cleaner and Chain Lubricant spray or you can even try a much reputed company Motul Chain Cleaner and Chain Lubricant Spray.Motul is available in Amazon ...