Nomads, Classics and, to a lesser extent Drifters produce a "clunk" soundĀ from the front when hitting bumps. This is, more often than not, traced to wiring connectors inside the headlight bucket. Remove the two screws holding the front trim ring on and pull the headlight (front) away from the bucket. Lay down carefully on a towel you've placed on your front fender. Use zip ties to tidy up the wiring harness (some even Velcro the connectors to the bucket) then put the headlight back on. Go hit a bump or two. Clunk gone right? If not you may have to dig a little deeper. Check the possibility of an improperly tightened steering stem nut by raising the front of the bike off the ground and trying to push and pull the wheel/tire assembly. If you feel any movement or hear a noise the stem is too loose.