NRG Power 70cc starting problem's

I bought a NRG power 70cc from a lad the guy said when he put a new bore kit 70cc on it he couldnt get it running. Well I got it back to my shed kicked it over once it started straight away for about 20 SEC's then cut out. So I tried a couple more times kicking over and nothing. I bought a new 17.5mm carb and a open air filter and gaskets also a spark plug. Has lovely spark and compression but nothing. Can anyone help before I pay out to be put in a garage?
It's a NRG 50cc / 70cc power 2006

 

Get an airbox on it instead of the cheap open filter.
Sounds like it's too lean on the mixture maybe?
It's starting up on the rich choke, then the choke shuts off and it's too lean.
Or possibly the vacuum hose for the fuel is split?

 

Welcome by the way!

 

It doesn't start now when had the old carb and the new....

 

It did once I had the old carb. But kept pissing out of petrol from the overflow.

 

What main jet should be out intp the carb

 

It's not un-common for people to fit the 70 kits and then rag them straight off and wreck the piston rings within minutes.
So from my point of view, I would do a PROPER compression test to make sure the cylinder psi is where it is supposed to be, above 100psi, preferably 120-130psi with a new kit.
Start with the basics then move forward from there.