Mind you ,......I have a first gen.....
I replaced the neck bearings, (progressives...although that doesn't really relate) and put a Condor super brace on as well. Everything is tight and shipshape.
BUT.....when I'm stopped and give the bars a shake back and forth, I get the same kind of "Echo" shake.
The members here just re-assured me that because we are talking about 2 tubes about 3 ft long with a joint in the middle, the front end WILL have a bit of flex or twist movement and it is normal.
It rides just fine ....so no problem!