Backfiring

Alright u brute force guys I need some help I have an 08 brute force 750 and I've read a lot of yalls post regarding backfiring and I saw where a fuel pump was usually the problem mine when it warms up it'll start missing at half throttle and backfiring and as it warms up it gets worse and worse I've replaced fuel pump and has a new wiring harness on it all the works any ideas?

My dad has an 08 brute and it back fired bad... we got the carbs sync'd at the shop and it helped a lil.. then we realized there was a small hole in the exhaust.. once we welded that it never back fired again