Weber carb adjustment

As the title may suggest, I need to adjust the mixture a bit on the series 3 since I've fitted a modern air filter. It already had the ole weber when i got it. Which screw is it and whats the best way of going about adjusting the mixture (I reckon now it has better airflow it needs a bit more fuel, might be wrong).
Cheers guys.

I think you can only adjust the mixture at idle by turning screws. Changing the jets is probably the only way to adjust the mixture at higher revs and under load. Perhaps you could use a gas analyser to find out if the mixture is wrong, or keep an eye on the state of the spark plugs and fuel consumption.

as fenby sed - its a fixed jet carb - so you need to change those - and its a professional jobby. only adjustment is idle mixture.