OK, so we all know that cutting the crank to increase intake duration is important for a fast Vespa build, but I never really see people posting specific numbers. It seems like one of the nice things about rotary induction is that you can get usable intake timing numbers just using a degree wheel, without doing a port map and calculating blowdown and all that stuff (which I will admit I am still working to understand.)
vespa-ciao.nl suggests setting the intake to open at 134*BTDC and close at 56*ATDC (http://vespa-ciao.nl/page.php?id=187). Their grind looks relatively mild and I've seen pictures of waaay more aggressive ones, especially with respect to when the port opens. I have to believe that at least some of the people who are doing this aren't just hacking at their crank trial-and-error, and have done some timing calculations and experimentation. What works? What doesn't? How far can you go in either direction without totally killing the low end?