Engine vibey

[crickleymal]

I had the valve clearances done recently and the carb rubbers changed. They said they'd balanced the carbs. Since then there is a horrible vibration between 5000 & 6000 rpm. It comes right up through the seat and is very uncomfortable. Of course that happens to be between 60 & 70 mph. Before the work it was beautifully smooth. So is this normal?