if i were you mate i would remove the float bowls on the carbs and clean the jets. put them back together and remove the spark plugs, clean all 4 with a wire brush and put them back. obviously tank would've been removed, make a quick tank, using a funnel tie rapped virtually to the frame will be fine. fill the funnel with fuel and turn it over, should fire up fine.
if it doesn't its probably electrical, check all of the fuses, bandits are renowned for blowing fuses. if all is ok im guessing it could be coils or cdi. while the soark plugs are out for cleaning you may as well Check the spark, if only 2 are sparking 1 coil will have had it.
Sent from my GT-I9505 using Tapatalk