ma mini moto starts but the cuts out?

i think it is the gasket coz i war raceing one of my firends and wen i got up to top speed the motor started back fireing so i shut the motor off or i tryed to shut it off more like coz the wee red buten diding work for like 5 secs can some one plz help me a wana put the motor on a go kart and get riding lol plz contact me by emale wich it