77mm NC250 Cylinder Head Gaskets For ZS177MM 250cc BSE KAYO Dirt Bike Replacement cylinder head gaskets designed for use with 77mm bore engines.Compatible with ZS177MM 250cc models including BSE and KAYO dirt bikes.Constructed to provide a seal between the cylinder head and engine block.Suitable for off-road motorcycles requiring standard 77mm head gaskets.proper compression and helps maintain engine performance under operating conditions. Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.