Hello and welcome. It would be great to see some photos and hear a bit about the life of the bike.
If this is your first vintage bike, and you are used to riding modern bikes, there my be nothing unusual at all in the vibration from this solidly mounted parallel twin. If anything is awry, crank/rod/piston imbalance seems the most likely cause. If you can find a shop or friend with A10 experience to help with a frame of reference, that would be a good thing.
Richard L.