REBUILD KIT, CARBURETOR, MIKUNI BST33, RIGHT. Full list of parts contained in the kit: Japanese-made float needle & pilot fuel screw o-ring, genuine Mikuni float bowl gasket & fuel feed tee seal, float needle seat o-ring, cold start enrichment feed pipe o-ring, slide guide o-ring, felt throttle shaft seal, two stainless steel flat hexalobular throttle blade screws and instructions. All o-rings in this kit are FKM. NBR vs. FKM o-rings