GT80 Pro Racing ENGINE ONLY 66cc/80cc- 4.5 HP with Ported CylinderGT80 Bicycle Racing Engine 66cc 4. 5 HP Ported cylinder High Performance Reed Valve High Performance CNC Head Keihin Carburetor clone Added power and performance with a 4 petal reed box. Reed box is designed for 32mm intake stud spacing and features a Large 16mm Keihin Carburetor. Works with the standard throttle cable. This cylinder body is ported for better flow and performance. A cut trench port was also added to give maximum efficiency. How to