Originally Posted by Stretchah
Have you checked the ignition pick up is in the right resistance range? I'd give that a go first as easier to rule out rather than opening up the carbs again. I've had issues with pick-ups before and it tends to bog down in the upper rev range as the resistance builds and it steadily gets worse moving down the rev range over time...if it's not that and I think you said you'd swapped out cdi and coil then at least you know it's more likely to be fuelling issues, good luck
You happen to know what the resistance values are for the pick-up? I'm almost positive I checked that awhile ago, but been long enough that I'm uncertain.