12201-ZW5-000ZA Cylinder Head Sub As - Overview. The 12201-ZW5-000ZA Cylinder Head Sub As is a critical component of Honda marine engine systems. This sub-assembly houses essential parts such as valves and spark plugs that are vital for efficient combustion and power generation. Designed specifically for select Honda outboard motor models, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. OEM Cylinder Head Sub-Assembly designed to