He says it idles fine. The idle screws should not be an issue.
Jets/rods, power piston, accelerator pump, secondary air valve should be isolated and tested.
Does it happen only when you stomp on it, or also when you gradually go to high rpm?
I didn't say 'idle screw'. I said 'mixture screws'. He said that his pipes were black and sooty..... And before he 'digs in' to the carb, I thought external adjusts were in order.
