This could be completely normal but I have noticed when I apply the front brake on my BV350 there is a slight noise which I can only describe as sounding a bit like "Crickets". Like a Hydraulic hiss. I dont think it does it from the back brake, just the front. Its all the time as well when you brake, not just when its been used a lot or in certain conditions. Brakes work ok though although there is more play on the front than the rear (Leaver depresses slightly further).
Any thoughts?