Have fun

I'm going to put my money on it being something simple. If the valves were open then you'd feel a lack of compression when you kick it over and from what you've said, the bike has been well sorted.
A quick bush mechanic way to see if it's starved for fuel is to take out the plugs, tip about a teaspoon of petrol down each plughole, put them back in and give her a few kicks. If there's any sign of life then you need to look to your carbies.
Cheers!
Rudi