2006 Yamaha Neos starting problem

Hi,

I was wondering if someone can shed some light on the problem im having with my Neos, basically since the weekend Its having trouble starting, it takes approx. 5mins of turning over it finally starts, it dosnt matter when I try it early morning or evening, once its running all is well even if left for a few hours it starts straight away, it just don't start if left overnight, I have a new spark plug installed but makes no difference to the cold start problem, I am thinking poss a choke issue(autochoke) or water in carb bowl/tank, any suggestions?

2006 Yamaha neos
70cc kit(installed professionally)
Matrakit exhaust
everything else is standard