The latest news:
- The scooter runs just fine and it seems as though it doesn't sputter / consider dying at stops anymore. The ride wasn't terribly long so it's possible that it was just kidding about this :-)
- The surging issue is still there and it's now occurring at WOT / a bit under WOT around 45 MPH, whereas previously it only occurred at WOT above 50 MPH. A friend who knows bike engines should be coming over sometime in the next few days and hopefully we can figure something out. I'm guessing that it is related to the intake manifold, though, if that's the main thing that I played around with today (other than the diaphragm).