The first thing I did was remove the inserts. The cantilever accent by the head tube is held on by 3 tabs with rivets, 1 bottom 2 top (ground these off). the rack accent I threw away and replaced with 1" x 1/4" real oak strips ($7).
The seat that came on mine also rattles, vibration rattles the springs against the spring mounts.
One thing that is nice about these bikes... when I'm bored, I sit on the rack while riding! Need to move the seat back here, it's so comfortable I almost forget it's only rated for 26Lbs.
I did replace the wheel hubs and spokes as well. The rim rings are ok, a little badly built with a flat spot at the seams. I still use the rings but are pretty damaged, ride softly not a dirtbike yet! The bearings in those hubs however, should not hold up very long, maybe 6-months of heavy riding and they'll act little grains of sand in the grease!