piaggio nrg mc2 liquid cooled wont start?

i have a 98 nrg 50 lc, the bike will start and run but it then seems as though it isnt getting enough fuel and it dies down. If you keep it wound on the bike will cut out. If you ease it gently it sometimes picks back up. But as soon as you turn it off, it will not start again unless you have some easy start to hand. I have cleaned out the carb and fitted a new temperature sensor on the head but the connections seem lose! Is it the choke, linked to the temp sensor, or is it not pulling through enough fuel. Im stuck on it now and its been sat still for 9 months. I just cant get rid of peggy any ideas, thanks