Sounds like tune to me, not knowing the history with you and that bike. But typical tune issues from things like, removing secondary flies, fitting a full system racing filter cam dialing etc, and also throttle bodies out of sinc.you ever figure out what was wrong with you’r bike? I have an 05 that pops and backfires in the low to mid range, but will pulls hard af after that. It’s like when you let the clutch out it stutters a little bit, coughs and pops then takes off. It’s got brand new plugs in it.