Those look like Mikuni VM slide carbs so the screw in question would be an air regulating screw. Turning it out lets more air in and would make things leaner. But, that air screw only provides adjustment for the idle or low speed circuit. If your problems are elsewhere, higher up in the RPM range, then you may need to make other changes (main jet size, needle position). Also, your pods are rather small and could be choking off air flow. Bigger is usually better for them.