Changed the gas not the plug changed that not the coil all brand new same as the black box were the copil goes. When i had it before the moped blew up so i replaced it Well when it blew up a peiace of metel broke a little peiace of the bottom of the head were it slides into the engine and also Srahed the piston, So me and my father sanded the cylinder down so it didnt scorched anything. Yet it runs godd yet when it warms up and you at top speed it sounds like a pieace of metal is being thrown around in the piston. Ive. ruled out the tran. Would thicker trans fluid work or would replaceing the head and piston be best. When it gorged the piston it was beside the piston and i changed the trans oil no metel came out good sign.