Good news and bad news.  A-arms and bushings are fine.  Passenger side needed tightened, badly. Upon inspection and some fresh grease noticed considerable play in right rear wheel. Lug nuts are tight. So is is this a rear hub bearing gone bad?

Try this

https://m.youtube.com/watch?v=wZHbnuLqvuI

Looks like a bad wheel bearing.  There is good info on this site about where to get an aftermarket bearing.

[2015 Z Force 800 53/Trail EPS]

If you can do that and the knuckle...(the piece the a-arms are attached to)..doesn't move...then it's a wheel bearing.

the knuckle IS solid.  Just the wheel itself moving.  Any links to a wheel bearing?
I imagine it's not overly difficult to change.

I just ordered some NON CFmoto ones I followed the thread in the 800 section of the forum, I haven't gotten them yet but should be installed this weekend.

http://cfmoto-forum.com/800ex800/wheel-bearing-looks-for-reliable-ones/

I will tell you guys you WILL want to freeze the bearings to get them in.  They are a tight fit for sure.

I have to pull the knuckle off right?  I have a press I can use. Did you end up using these bearings Chud?

Yes you will have to pull the knuckle.  You can do it with a appropriate sized socket and a 3 lb sledge but a press is MUCH better.  For my rear bearings I went with CF Moto brand because its what I could get the fastest.  Im sure the others will work just fine though.

What size is the rear castle nut?

Ok 36 mm.
Now how do you get the knuckle off?

Ok a lil bit of tapping and prying and some patience. Got it ripped down soaked it with some WD. I'll be pressing out the bearing tomorrow.
The Kawi dealer says he has the bearing in stock. It replaces the DAC3055W or as listed the one for the Tyrex 750.  Going to match it up and see. If not my dealer said he should have them in tomorrow.  Just don't want to drive 1 1/2 each way for a $40 bearing. 
Yamaha wants $70. No freaking way will I give them that for a $17 bearing.