Complete cylinder head for 50ccm-139QMB/QMA-Motor . Unlike many offered these cylinder heads come complete . That is, valves, valve springs , valve stem seals , etc. are assembled. The cylinder head can be installed directly and replacing the fiddly and grinding the valves eliminated in conjunction with required special tools. The head is supplied with secondary air system (SLS) . Comparison numbers: Neu & Originalverpackt.