How does one go about tuning the Trabi carb? I've got a 28HB-2 and the only adjustments are idle mixture and idle speed. I don't quite get the interaction between the mixture adjustment and the throttle speed adjustment. The idle "mixture" adjustment seem to be more about how much of the mixture and not the richness of the mixture, as that's accomplished by the size of the idle air jet and idle fuel jet as far as I can tell. So what do I adjust the mixture for? Highest RPM sounds silly if it's just opening up the tap. The manual states it's tuned from factory for lowest CO but I can't measure that. On a "modern" carb you can tune for highest vacuum but the Trabi has no vacuum ports. Do you just set it to 2 turns out then tweak the rpm with the idle speed screw and just get on with it?