Ok here’s one. The bike rides fine but when releasing the throttle to shift, the RPM’s do not reduce for a few moments. I have check to see if the throttle slides was sticking due to air flow, as I have heard , but this is not the case. Here are some details
Pason ignition set a 30 btdc at around 4 g's.
Mikuni TM 34 mm flatslide
This is what has changed. I added a MKiii timing cover. I switched the white/black and the Yellow/black at the terminals of the Pason trigger as instructed. The instruction said that it would be severely retarded the other way so I wanted to make it proper. I had it running well before with the wires swapped but maybe that was a matter or rotor position.

Anyway I do not know if this is an ignition curve issue or a carb issue due to the switch in wb and yb wires, or something else all together.