REBUILD KIT, CARBURETOR, MIKUNI BS30. Contains: a Japanese-made float needle, needle seat o-ring, Japanese-made float bowl gasket, Japanese-made pilot screw o-ring, vent tee o-ring, genuine Mikuni cold start slide shank seal, genuine Mikuni fuel screw well plug, two fuel feed pipe o-rings, two genuine Mikuni rubber throttle shaft v-seals, two stainless steel hexalobular throttle blade screws and instructions. All o-rings contained in this kit are FKM. NBR vs. FKM o-rings