colorado_conti_gt
Assuming the CGT is like other Royal Enfields, your motorcycles vibration might be due to a cracked/broken/loose "head steady".
That is the bar that connects to the rear of the cylinder head and extends towards the rear, up to the frame where it is bolted on.
The other thing that can greatly increase engine vibration is a loose or broken engine mount bolt.
These connect the lower part of the engine to the frame and if one is broken or loose the engine will shake a lot.
On the standard RE's, several people (including me) have had one of these lower bolts fail.