Hello. i recently purchased a 400ex on facebook. they bump started it and it ran fine and drove fine and i came to the conclusion that it was the starter bc it didnt crank. i changed the starter and it cranks but wont start. the spark plug is new and getting good spark the carb is also new and getting gas and i have compression and adjusted the timing though i could have done it wrong. im not sure what is wrong can anyone help me out?