Rich mixture problem, too much fuel used?

Recently, my Gilera dna 50 (02 plate) started using more fuel. Fuel consumption has doubled, and I'm running out of ideas. I have changed a (slightly) leaky fuel hose going to the carburettor but the problem goes on. I've recently removed the carb, to clean and inspect it, since carb flooding is a fairly common fault, but that seems ok. Got any ideas???