50mm Cylinder Head for 50cc 4-Stroke 139QMB ScootersINCLUDES: For Use With 81.3cc Big Bore KitValve Length: 64mmOverall Height: 59.5mmIntake Port Diameter: 18mmExhaust Port Diameter: 17mmIntake Bolt Hole Spacing: 44.5mmExhaust Bolt Hole Spacing: 50mm COMPATIBILITY: Amigo – 50cc 4-Stroke ScootersApollo – 50cc 4-Stroke ScootersBaotian – 50cc 4-Stroke ScootersBaron – 50cc 4-Stroke ScootersBintelli – 50cc 4-Stroke ScootersBMS – 50cc 4-Stroke ScootersCoolster – 50cc 4-Stroke ScootersCSC – 50cc 4-Stroke ScootersDiamo – 50cc 4-Stroke ScootersFlyscooter – 50cc 4-Stroke ScootersIce Bear – 50cc 4-Stroke ScootersItalica – 50cc 4-Stroke ScootersJCL – 50cc 4-Stroke ScootersJonway – 50cc 4-Stroke ScootersKandi – 50cc 4-Stroke ScootersKinroad – 50cc 4-Stroke ScootersKMD – 50cc 4-Stroke ScootersKymco – 50cc 4-Stroke ScootersLance – 50cc 4-Stroke ScootersLeike – 50cc 4-Stroke ScootersLinhai – 50cc 4-Stroke ScootersLongbo – 50cc 4-Stroke ScootersMotobravo – 50cc 4-Stroke ScootersMotofino – 50cc 4-Stroke