Well, as long as the cranks getting oil (I've run dirt bikes at 50:1 oil/gas without issue), at the end of the day isn't that what you want? As long as I've dealt with them (I'm 60), if I ran ANYTHING richer than 32:1 (oil-to-gas), I'd make sure to bring spare plugs, because I would need them on long rides (lotta tree-filled, slow-going trails here in the N.E.), so a lean gas/oil was kinda necessary for that kind of riding if lazy like me, and not wanting to rejet every time, so I mix for the conditions, and pretty much 'set-and-forget' the carbs air/fuel issues, if so equipped. So with this HP carb, which is new to me, from what I've read regarding them, and personal experience, however limited, I'm finding that tuning these carbs requires jetting for conditions (#66 at sea level), Premix ratio, cable-play, spark plug type (B5HS) and the single idle screw they both have, dictates how well the engine works from idle, all the way up...in my experience. Sorry for the book, but maybe I do have the terminology backward, just that by the philosophy I've always went with described above, I've never had any issues. I had my first real motorcycle (1974 Honda CR250M Elsinore) for almost 5 years, and only changed the top end once when I first got the bike, running it using what I know to get this Chinese crap dialed in. And I say 'crap' in the nicest of ways, as it IS a good running little engine, just needs more tweaking in places, simply because of what it is...cheap fun. RPM out...