Bought this bike with a new top end rebuild. The guy that sold it started once but died and he thought it was an electrical problem. I got it running right away but it ceased after only about 30 seconds of running. After i tore into it i found a broken rod that had cracked the case and ruined the jug. I replaced the case, rod, piston, crank, and jug. After i got it back together it ran great for about for the ten minutes i had to ride it. I shut it off and put it away for then. Next time i got it out i started it up first kick and it ran for maybe five seconds and it ceased up, im completely sick about it and havent even bothered tearing back into it. Any idea what on earth could be causing this issue?