There's a metal sound coming from inside . piston jam ? 1st day the bike seems ok . Except rear break got problem .next day he when back that shop to repair break and handlelock . Otw to the shop , the bike seems pretty fine . When we went back , the bike do alot of problem . Metal sound coming from inside , rpm drop then when dead (need to keep trottle) , when changing gear to 3rd bike die.