This aftermarket regulator valve repair kit is designed to service LPG vaporizer/converter systems commonly found in industrial forklifts powered by 4Y, K15, K21, and K25 engines. It replaces OEM part number 04221-U2030-71 and its variants (04221-U2030, 04221U2030, etc.) and includes the internal components required to rebuild the regulator: diaphragms, gaskets, o-rings, and valve springs. This kit helps restore correct fuel vapor regulation, resolving issues like rough idling, stalling, or poor cold starts in LPG-powered lift trucks. Built from fuel-grade materials and resistant to heat and vibration, it's ideal for routine maintenance or regulator failure recovery. This is an aftermarket replacement part. It is not manufactured by or affiliated with any original equipment brand. OEM part numbers are provided for reference only.