If you decide to use a big-bore carb, you will have to replace the restricted manifold with an unrestricted one. Otherwise the large carb will be useless since its venturi size is actually reduced to the diameter of the restricted manifold. Our manifolds will fit any Dell'orto carb up to 21 mm. The derestricted manifold gives better acceleration and better top speed. Compatible with: - Aprilia: Scarabeo 50 Piaggio_S, SR 50 04-Piag._S - Derbi: GP1 50 LC_S - Gilera: DNA 50 LC_S, Runner SP 50 -05_S, Runner SP 50 06-_S, Stalker 50 AC_S, Thyphoon 50 AC_S - Piaggio: NRG 50_S, Vespa 50 ET2_S, Zip 50 2000_S, ZIP SP 01-_S