First post on this forum, not sure if this has been covered. I purchased a 2016 FZ07 last fall with about 2200 miles on it. Previous owner had installed fender delete, small LED turn signals, aftermarket headlight and M4 Exhaust (not the header back style). They also removed the baffle from muffler. This is how I got it, I loved the way it sounded, I like loud. Besides a little backfiring when you left off the throttle or downshift quick, it seemed to run great. This spring I took it out, gave it an oil change, new filter and washed it up. It started fine and ran fine for a little while. I’m now at about 3400 miles and it’s barely driveable. The last few times I took it out I’ve noticed some hesitation and hickuping upon trying to take off. I didn’t think much of it, thought maybe just the no back pressure thing made it happen and it’d be fine. But it’s gotten drastically worse, I took it for it’s last ride last night when I could go WOT in first and it was completely bogged down. RPMs wouldn’t go above 3500. After slowly trying to increase throttle I could get the bike to come out of it at around 4500RPMs and it seemed fine. I started up a small hill and could feel it starting to bog down, so I downshifted to 5th and it was still bogging. I pulled over and it stalled. Now it wouldn’t start back up. I sat for a minute l, kind of pissed, and it started back up. I turned around at this point to bring it back home and same thing, it just bogged down trying to take off. I managed to get it home and it died pulling into the driveway, so I pushed it into its parking spot. Now I’ve been searching the internet for an answer. I’ve seen people with similar issues say they had to have the CPU reflashed, I emailed one of the companies that does that and they said that doesn’t sound like my issue, although it would help the bike if it was done. What could this be, anyone dealt with this? Plugs, filter, solenoid, ignition? I’ve got no idea. I’m going to borrow a friends stock exhaust and put that on to see what it does, but I find it hard to believe that’ll make that significant of a difference. I’ve owned a couple street bikes one a 96’ and an 06, both straight piped, with no issues for a few thousand miles. Please help.