Scooterotica

easy way to check for fuel flow would be to remove the float bowl and turn the gas on. Fuel should come dumping out. If it does then move on to make sure your choke is working correctly. If it doesn't then you know where to start looking. Also try with out the gas cap on. If the air can't get in then the fuel can't get out.

Thanks for the help everyone

The problem appears to be getting fuel from the carb to the engine.

I have fuel getting to the carb so know its not that

I have checked all jets for a blockage so there ok

Fuel is ok as will fire up if I pour petrol in

If you use the hand over the carb method you should be able to feel the suction when you kick the engine over,if not then as you say there is something mechanical wrong and the carb is ok.

I had an air leak from a gasket on the cylinder a few yeas back. But it would fire up when cold, then die after a minute & not fire up again. Because the cylinder got hot & expanded the gap where the air was escaping from.

Looks like a leak test may be required. Pretty simple with a push bike inner tube connected to the exhaust U tube and the inlet manifold. Do a search there's a couple of decent threads about leak testing.

How big need a air-leak to be, that the engine does not suck any fuel out of th carb!? once i had a completely worn out 125cc vespa cylinder that could not generat enough under-pressure. but you wrote its a brand new kit.
I still think, there is only a air bubble in your carb. hands on, kick, hands off kick,... or much better, go and learn from the great Burt Monroe
https://www.youtube.com/watch?v=InZJrndNOho

Good news it was a air leak on the blanking plug for a centre spark plug on the Gt cylinder head.
That sorted it ran then died.
I now have no spark just waiting on a mate to bring me his spare Cdi, stator and rectifier.
My money is on the Cdi as it is an old one I had lying around.

Anyhow thank you everybody for your input it is appreciated

Sorted yet mate?

Yes all sorted. CDI and Stator no good replaced and now runs great