I have a 1999 honda trx400ex i cannot get it to start its in time has spark complete top end rebuild all new exhaust new cdi new coil an plug new stator new rectifier an it keeps sucking air in the exhaust an blow everything out the back of the carb i was told its out of time so i reset the timing like 6 different times an still continues to suck air in thru the exhaust it has 180psi of compression this is the 400ex ive ever owned or worked on