For Haojue UH110 series underbone motorcycles, including models like HJ110-7, HJ110-7C, HJ110-7E, and HJ110-S. It is designed for a 114mL single-cylinder four-stroke engine with a cylinder bore of 51mm and a stroke of 55.6mm, serving as a core component to convert piston reciprocating motion into crankshaft rotational motion.