Weber 45 DCOE Choke Tube 40mm (Replacement)
Weber (Replacement) 45 DCOE Choke Tube 40mm
The main venturi is primarily is the first step in determining the appropriate jetting for your carburettor/engine combination. The smaller the venturi, the higher the air speed entering the engine. This equals more low end torque and response. Larger venturi will flow more volume and have the potential to create more top end power, however this is often at the expense and low-mid range driveability therefore the venturi size needs to be evaluated for your particular application.
Please note:- A change in venturi size will most certainly result a change in main jet, air corrector or idle jet.