Got to be detonation. Its rattling so bad its dropping porcelin. Jerry Hall is closest to you. Might want to get that dome checked. What are you mixing your fuel out? Look around the flat area around the carb whefe thr bowl meets up. Should tell you what size carb it is. Need to see what the internals are in it. Where exactly in the throttle position is this happening? Half throttle cruizing around. Idling or wide open?