Yeah, the guy I bought it from said it was really finicky particularly with respect to elevation (he was at 0 and I'm at 1,300ish ft).  It is the stock carb.  To tell you the truth, once I got it running, I've been riding it like crazy without at issues.  Not a knock, ping, anything.  So at least for now, while the riding is still good here in the east, I'll keep riding.  I'll keep the race gas in mind.