sv cuts out and revs bounce

https://youtu.be/Zn9cPlrc4oE
hello all, im fairly new so please excuse any mistakes in posting that I make.

I have an sv650s k8, recently I have had to get the engine swapped and now the bike acts a bit funny, sparks are slightly lean, bike gets hot fairly quickly and the exhaust pops and backfires(flames come out ...massive ones) a lot, I mean the instant I decal aroun 4-6k it will pop a loud pop then a few small pops. I can notice a very slight power loss( maybe its just in my head) and also the bike cuts out when I decel with the clutch pulled in or when I am in neutral and I rev and let go, lastly if I am coasting and downshifting I hear a scraping or grinding noise when I get to first gear with the clutch in, sounds a bit like brake disks scraping but it only happens when I downshift to first gear with the clutch in and I roll. this Is my first big bike so I would appreciate any help


ps I changed the sparks the other day and it worked fine, the bike didn't cut out and only popped slightly (scorpion end can) but the revs would still bounce down to 900rpm and back up to 1300rpm, I then propped up the tank the next day and fiddled with the wiring and hoses whilst rearranging my clutch cable because the clutch is very stiff and the problem came back, I also noticed that with the bike hooked up to my car (battery died so I had to jump it) the bike had a healthier exhaust note and it was harder to get it to cut out but it cut out eventually, I presume a kinked hose along with dying battery?

[DJ123]

Check for air leaks in the system. Ensure the inlet rubbers from the air box are securely pushed onto the top of the throttle bodies

[Bibio]

if your battery is goosed get a new one. the FI sv's need a healthy battery to run properly.