Here's my two cents on Xchambers...
The hot exhaust expands as it flows out, the front cone of the Xchamber helps suck it out.
the end cone on the chamber sends a pressure wave back up the pipe to force some of the fuel charge back into the cylinder that has passed through, with the exhaust going out.
the size of the chamber, the length of the header to the chamber, and the reverse cone at the end of the chamber are variables similar to playing different notes on a trombone.
Longer, you get a deeper resonant note.
Shorter, it makes a high pitch resonance.
Resonance is the power band.
the actual outlet from the chamber is important.
stock, they are too small. mostly to avoid noise.
about 11mm is a good place to start testing.
LOUD is gonna be the fastest, most powerful.
but yah gotta try to balance things between power you might like to have, and sitting alongside the road discussing things with enforcement people called by your neighbors.
It's gonna be the noise, more than the blinding flash of speed, that draws enforcement attention to you, on a motorized bicycle!
Yes, I'm a proud member of the 20mph club! lol
Good luck
rc
Oh, increasing the header length to abt 20" to the muffler can seems to help.