69mm Length Valves, Fully Assemblied GY6 100cc 50mm Cylinder Head Intake Valve Diameter- 18.5mm Exhaust Valve Diameter-16mm Combustion Chamber Diameter-50mm This a Non EGR Head, Does Not Have the EGR Port Size:69mm Valve Length 1.This Cylinder Head Will Replace The EGR Head as long as You Have The Correct Valve Cover 2.Replacement for GY6 49cc 50cc to 100cc 4 Stroke 139QMB and 1P39QMB Engine with 69mm Valves Cylinder Head 3.Fits Most of Chinese Made Scooters and ATV. Such as JONWAY, JMSTAR, ROKETA, SUNL, TANK, PEACE, TAOTAO, Dongfang, Kazuma, JCL, BMS