Hhhmm.
Whats causing the wheeze? Too much air too fast?
Sort of: Here's the physics...
Mechanical carb slides opening too fast cause massive pressure rise in the carb throat. It's the differential pressure between carb throat and outside air that push the fuel through the carb jets. Less differential = less fuel. So, it's not exactly more air, it's that there is little to no fuel for the available air. Therefore, the wheeze instead of power. Accel pumps are the standard workaround for this issue. Squirt raw fuel into carb throats to avoid fuel starvation and rapid engine pickup. Note, the EPA didn't favor this approach, as it increased unburned hydrocarbons into the exhaust. Part of the reasons for pervasive fuel injection in vehicles for the general public.
Even when these bikes were new and in peak condition, snapping the throttle open from low speed let the engine fall flat until the throttle was reduced.
Some compensation for throttle twist wheeze can be had by tuning idle circuits very very rich. Of course, then you can't expect 50 MPG or keeping the spark plugs and exhaust from sooting up in a short period of time without adding some extended WOT operation to heat up the plug deposits.
Racing operations wouldn't care about this. A well mannered street bike would be improbable, though.
