TWM Induction / Borla Induction - Air Funnel Mikuni / Solex - 40PHH Carburetor - 75mm O/L Full Radius. Priced and Sold Individually. Flange Mounting Hole Center to Mounting Hole Center = 65mm. Borla #201009 TWM Induction #2900-4075. Produced on a CNC lathe from 6061 T6 aluminum, these air horns have a full radius top to maximize airflow.