Most guys resolve this problem by running a vent line from the regulator port(hole) to the inside of the fuse. This solution presumes that the problem is a change in the atmospheric pressure reference when maneuvering which gererates achange in this ref pressure. The regulator sees venturi pressure on one side of the diaphram and atmospheric on the otherside. If this balance is changed the engine may run rich(or lean). A friend has a 3w-100 which does this and this correction did not resolve it. The engine does the same thing on the ground when rolled inverted-only when the engine is at reduced throttle. I'm beginning to think that the problem is fuel that is pooling above the carb when upright and runs in to the engine when rolled inverted. I have a 3w-140 which shows a slight hesitation when rolled inverted but very quickly returns to normal when held inverted. What we need is a fuel injection system which runs the same no matter what. If my theory is correct a rear induction system would be best like the ZDZ line