Yes, theres a accumulator inside the airbox.I found this diagram, but dunno if this is legit or not.
That circular object inside the 16V air box in your photo is called an oil separator, not an accumulator. It reduces the amount of blow-by oil vapor in the crankcase entering the intake air stream thereby reducing carbon buildup in the combustion chambers. Its function should be accommodated to promote engine efficiency when modifying the moto. The stock system does not have a pvc valve.
In other words . . .