i know u said chain is lubed weekly but is it adjusted properly? may have too much play in it and its hitting the sliders on the swingarm, or ur sliders could be eaten up at the ends so the sound is chain rubbing the alloy swing arm vs. the plastic slider.

also check passenger pegs, they seem to get lose and rattle against the bracket, so u hear it when the bike isnt all revved up but still happens when u rev it more u just dont notice it.

check the rearset bolts and the one the hold the peg to the rear set.

any chance u can catch it on video?

also great miles for a 2013. a naked 2013 too, impressive. i need to get me one of these z1000s one day. good luck, hope u figure it out.

oh, sell it and get a motard