Naraku 51mm Cylinder Head for 50cc 4-Stroke 139QMB ScootersCOMPATIBILITY: BMS – Apache 50 4T, Heritage 50 4TDiamo – Classic 50 4TLance – Charming 50 4T, GTR 50 4TRoketa – Bahama 50 4T, Maui 50 4T, Sicily 50 4TTank – Urban 50 4T, Sporty 50 4T, Viaggio 50 4TMany Other 50cc 139QMB Based Engines**This will not work on the QJ models 51mm NARAKU CYLINDER HEAD 139QMB GY6 50 UPGRADE ASSEMBLY. For Kymco 4t 50cc, Filly 4t, Agility 4T, QMB139 and others. A great replacement cylinder head for the 52.4mm 85cc cylinder kit (NK100.52). The cylinder head has significantly larger valves than what is found in the original cylinder head, thus improving cylinder filling and increasing performance. The head is specially designed for the 52mm big bore cylinder allows an optimal compression ratio. Please do not forget to order a gasket set (not included) when ordering this cylinder head. Attention: Does not include gasket, must be ordered separately. Note: Please make sure this scooter engine part fits your