It's an odd size carb. None of my many spare carbs would fit.
I can't remember what plug I finally ended up with, but each time I went hotter, it would idle and transition better.
It now idles great IF you warm it up well, but transition is still iffy. Don't play with the throttle unless you like dead sticks.
After about a gallon and a half of fuel, it still sounds like Thor is trapped in the engine tryin' to get out.
I e-mailed Justin at Sig, and he said to run it awhile and see what happens. I've been using Sig products since the mid seventies and
they have always been great to deal with. I have a feeling I'm gonna have to test their warranty on this one.