Please tell us what you know about the bike. When was it restored ? How many miles since the rebuild. Was it re-bored ? Does it have a new top-end ?These bikes take time to break in when assembled. You may simply need a re-torque and valve adjustment. Sometimes several re-torques and valve adjustments till all is well. If you give us some simple information we may be able to help !
And, yea. We all have fallen in love with these bikes !