HS2 SU Carburettors. For use with TWIN SU 1¼” Carburettors. "Keeping Carburettors in good working order saves you money". DAMPER SPRINGS. Piston Damper Cap. INCLUDES: 2 "LIGHT BLUE" DAMPER SPRINGS - Load of 2.5Oz @ 2.625" - AUC 4587.