backfiring won't start
 

help!!!! bike will not start has fuel& fire when i try to start it she just backfires like timing is off checked that too all good Help!!!!!

Cam and ignition timing? Also valves in spec? What bike?

My bad 2006zx 10r

everything inline,Short story of prolbem, went for a short ride in the am ,then bike sat for about 3-4hrs. Thats when it started and shut off i did it again gave some gas and shut off again. Tryed to start it but would not start flooded so pushed back into the "bike house" let it sit over night went out the next day samething. SO went out got new plugs $45,put everything back! nothing crank..crank backfirecrank...crank backfire backfire crank.If I unplug fuel no moer backfire so I have spark and fuel. I also have checked them and I do have both. some say camsensor bad? ecu?cranksensor? Crank??? IT ran fine no loss of power not a sign @ all plugs were bad but have new ones?