Dakar 2007 starting problem

Hi guys. Hope you can help. My Dakar 2007 been standing for 12 months.The bike had a problem starting after that. I replaced the battery went for a ride bike was ok .Was standing for a month after that ride but had the battery on the charger so battery is ok. Now the bike does not want to start at all.I can hear the electrics are ok lights come on and click sound from instrument panel. It was fine until I stored it. I can hear a sound like gas release or pressure air bubbles from round or inside the oil tank in the front of the bike. I would appreciate it if you can help.
Thank you.