Compatibility: intake & exhaust valve stem set fits vt250f vt250z spada xelvis250 vtr250 1982,1984-1991 motorcycle, offers standard fit for listed models material build: high-strength heat-treated alloy steel, withstand combustion high heat to avoid bending and deformation performance: finely ground smooth stem cuts friction loss, tight valve seal solves compression drop and blue smoke issues machining: precise unified dimension tolerance, no extra modification required during cylinder head overhaul installation usage scene: classic 250cc v-twin engine spare, fixes slow acceleration, unstable idle and aged worn original valves, Manufacturer: CNLJPHFHO