Oh quit it, CroMagnum. You're wrong and you're trying to save face. You said it can't be done and you know it. That was a home-made expansion chamber. I'm sure a professional one with pressure meters and better welding could be near perfect. This was hydroformed.
(Even more pics and info
As far as perfection... how many people slap some random 50cc pocket bike pipe onto their 66cc china girl with decent results? I've seen it more than once. Yes, it's great to be precise, but these engines aren't very precise to begin with.