Running problems

[Triumph43]

Can anyone offer some advice on sorting out my X-Sport 110 problems. I have a 110cc bought new just before Christmas and it starts OK and runs fine until it warms up.
When it is warm it then starts playing up : symptoms - doesn't rev cleanly , when stationary or moving.
Fuel starts dripping out through air filter and its coming from central small hole at rear of carb ( airfilter end )

I have inspected the plug which is sooty black ( sounds too rich to me )
I have had the carb off twice and checked all jets are clear. Checked float chamber is not flooding by lowering carb slowly into bowl of water. I have adjusted needle height to lower needle.

I am baffled. The only mod I have done is to fit an exhaust restrictor.

Help:confused:

[RUMotarded]

fuel coming through the air filter is a classic sign of a main jet that's too big. If it didn't do this before you fitted your restrictor then you need a smaller main jet.

[110cc_offroad]

if its warming up and not running right its your oil it needs changing oil presure is to high the bike carnt handle it just do an oil change and as for the petrol problem just set the carb up again