Increase jet even more or bigger carb after 70cc build?

Hi my lads gilera dna50 has now been treated to a 70cc cylinder. It already is unrestricted and is with a basic race exhaust so I reduced rollers from 4gr to 3.7gr to get the rpms up to the powerband. I upjetted the 17.5mm dellorto carb to 75 (was on 60) and increased the airflow through the stock air box. It now runs well but is overheating enough to concern me.
Am I better of increasing the main jet some more or fitting a 20mm carb instead.
Also do I need to increase the idle jet? It idles but not particularly smoothly.
Thanks

 

Up the main jet, adjust mixture screw to suit.