Fixed up a 2003 sv650 recently, only has 6000 miles. The engine simply will not rev over 7000 rpm. It also sticks on 3000-4000, sitting there until you rev it again to higher than 5000. Won't maintain any rpm between 2000-3000, just jumps higher.
The problem is not the STV, problem persists even when they are fully open and disconnected.
When you do try revving it beyond 7000, it is like there is a rev limiter. The bike just sits there, very consistent at 7000. After having done this, the bike starting making an unusual knock/tick at random intervals. Here is a video of such:
https://drive.google.com/file/d/1gwF...w?usp=drivesdk
The plugs are new, the coils in excellent condition.
The fuel pump and injectors are also new.
At the moment I know for sure that it is not air, but could be fuel or spark.
My best guess is that there is debris or a gasket in the fuel tank that is blocking fuel after a certain point, but the limit is so consistent that it makes me doubt such.