+1 Especially if you were experiencing head shake before the mods.DucOwner said:.... pay close attention to the steering head, make sure the tire is proerly inflated. Check oil level and make sure the front end is straight too. If anything is loose that sort of thing can happen.
+1 on tire cupping as well.
Check the preload (if you have preload caps) on the forks, by that I mean run the adjusters all the way in (notice if the slots are pointing the same way or not) then back them out even number of turns or 1/2 turns.