its definitely a Garelli moped engine on it..
To be fair, its a clone garelli motor. I have mixed feelings on Avanti stuff. The ones ive seen had beefy / heavy wheels, somewhat decent plastics, and crap electrics / controls.
It would make a fun pit bike, but only if you can fix it on the cheap. I wouldnt advise spending much money on it as it just isnt worth much. But different strokes for different folks!