NGK is the leader in Motorcycle Spark Plugs, with spark plugs for virtually every Motorcycle application in the world. Utilizing a wide variety of materials, from standard copper-core type to Iridium, NGK is the world's leader in spark plug engineering and technology. OEM Approved Specified by More Motorcycle Manufacturers: Including Honda, Kawasaki, KTM, Suzuki, and Yamaha, Than Any Other Spark Plug Company.