FYI,
the Ninja 400 uses an 8mm thread size for its swingarm spools (rear stand spools). I believe my Ninja 250 used 10mm, so I ordered a set with 10mm threads...but too large
So 8mm threads it is. Obnoxiously, I could have found out sooner if I'd just pulled the spools off my 2011 Street Triple (they're also 8mm) but I was so sure the 400 would be the same as the 250...
In case there was any doubt the bike is all-new