Peugeot Speedfight 100 starts but then cuts out straight away?

When I start my moped in the mornings, with the electric start, It stays on for about 2-5 seconds and then cuts out straight away. It even does this with the Kickstart. I try giving it some revs once its started and it still cuts out, even whilst reving!

I have had the carburetta cleaned, the fuel system cleaned, the fuel tap replaced, the automatic choke unit replaced, and the resistors replaced. And it still hasn't fixed the problem. The guy who fixed my moped said the battery was fine, and it was keeping a stable current all around the bike. I don't know what could be the cause of the problem.

The ped is a Peugeot Speedfight 100 Prost 100cc, and is a 2000 model. My previous owner (only 1 owner) had only used it for a year (2000-2001) and then kept it in a garage up until now.

If someone could help, I would be must appreciated. Thanks :)