That explains it. Now for the wrap up. What is wrap? Wrap is a science that goes like this. Why am I taking a racing trick, where this has the characteristics of a faster speed event at high rpm.
The simple science is when you heat something up [wrap a pipe], the molecules bang off of each other, cause more friction, and that means a faster speed out of the pipe. Lets put this in racing perspective. At high rpm, that muffler system is slowing things down so you speed things up at the other end with header wrap.
When that rpm is feeding fresh fuel, it does not want the muffler to keep the spent gas from coming back in, so it's a push out the pipe assist is the wrap. Think of how fast those cars are moving and the plumbing, the muffing there of, and this heating up of the air is to move the spent out and away from the fresh charge in.
The next thing is removing that fresh charge when both valves are open and this is called, 'overlap' where that wrap is pulling out the fresh, as you just putt around the streets and it has poop for power. You sucked out some of the fresh in the overlap [speed of it], and the science of speed down the tube just made one more bad move as if revving piss out of it standing still.
You lost so much grunt at the bottom end, the speed event is stealing the fresh. Schooled me so ask me how I know we wrap this up?
