On the underside of the engine you have a sensor for your crankshaft rotation.
Take it out, put an O ring spacer to have the sensor farther away from the crank. I’m not running DD2 but a tuned Senoir, one day I was next to a professional team in the pitlane, running DD2 , they had the same problem. They changed carb, wirings,ignition coil etc etc. Madness. Until the moment a technician from another team came in and he told them to place the o ring spacer.
10 minutes later , problem solved. I hope this will work for you ….
haven’t heard this one with my research, and will look into it. I did get the spare carbs from a friend and didn’t have a chance to try them. Got in some track time this week, and going leaner on the main helped, going richer hurt. Yet it still sounds better on choke. With the 178 the power was hitting maybe 8k and pulled strong, below that sounded like a loaded up old motorcycle.