Piston Ring Bore 74mm 74.25mm 74.5mm 74.75mm 75mm For Honda XR250 79-80 XR250R 81-82 XL250S XL250R Engine Parts multi-size oversize piston ring pack compatible with Honda XR250 1979-1980 XR250R 1981-1982 XL250S 1978-1981 XL250R 1982-1983 covers 74mm 74.25mm 74.5mm 74.75mm 75mm bore overhaul sizes matched ring assembly restores stable cylinder compression lowers engine blowby oil consumption wear ring surface reduces friction with cylinder wall extends life of piston cylinder assembly pressure structure maintains sealing under temperature offroad riding conditions dimensional supports direct installation without grinding for two stroke end engine rebuild