15mm carburettorfrom Polini. The carburettoris ideal as an OEM replacement carburettoror a lightly tuned carb for more powerful 50cc sport cylinders. The Polini CP D.15 offers a slight power increase as most OEM carbs are 12-13mm in diameter. Very easy to tune and adjust. Little to no effect if there is already a 14-15mm factory-fitted. We offer the full range of spares and replacement items for this carb. Connection diameter intake manifold: 25.5mm connection diameter. Air filter: 34mm. Main Jet: 70. Idle jet: 36. Needle: 14/22