Check the front wheel is tight, remove the caliper shake the wheel check for play in the bearings.
Inspect the clamps for cracks or damage. Check frame head stock for cracks or damaged ( ive found a 4 inch crack before after feeling vibration at the front.)
Check the stering head bearing for lay with the front wheel lifted rock on the fork tubes check for play,
Check bars & clamps are tight and rubbers are good.
Light vibrations could be headlights clocks indis not tight

Are your bearings all fresh in your steering stem and front and rear wheels