have anyone had any trouble with the rear bushings wearing out in the rear suspension control arms.

Are they the same yellow polyurethane bushings that the ZForce uses? 

[2015 Z Force 800 53/Trail EPS]

I have had an issue with my 50" Z8s lower rear bushings because of the manufacturer drilled two sets of holes in each tube for grease fittings. One was used for the grease fitting but the other when welded to the rest of the a-arm pointed into the tube headed to the knuckle. When greasing, no grease made it to the bushings - just went up the tube. Before I pulled it apart I thought they must have pierced it welding it but all four tubes?  Then when the bushing seizes to the sleeve and started rotating in the tubes making a god-awful squeaking (which you can hear in one of my last videos) I found this out. I then glued steel plugs (cut off nail heads) in the holes, cleaned-up and had to plasti-weld the bushing into the tubes because they didn't fit tight anymore. I also discovered that on all the lower bushings including the knuckle side, the mount had to compress the bushing quit a bit before making contact with the sleeve. That put pressure on the bushing and forced it to actually start rotating in the tube sooner and bind against the mount. So, I machined the bushing end down enough that about 5-thousands of an inch of the sleeve stuck out past the bushing on each side. That took the pressure off the bushing and actually made the suspension work freely...and much smoother....and trust me ...the short a-arms of the 50" need to move nice and easy

I also decided to go with a graphite based high pressure grease because reports show it works better on these types of applications.

I don't have much time on this fix, but so far I love it. It's ride is much improved and..of course that squeaking is gone.   

Did you try and get anything warrantied prior to making changes?

I'm just curious of whether or not the issue would've been addressed by CF Moto.

[2015 Z Force 800 53/Trail EPS]

No, I didn't...and they probably would have fixed it but I didn't feel like loading it up and leaving it at the dealership for probably a month just for that.

Understandable

All the rear bushings on my Z6 are sloppy. I was going to make up all new  ones out of Delrin. I will need to look at the issues that you had aswell. When I find design flaws, I never bring it to a dealer. In the past I have tried to explain or show them the flaw but they are never interested in hearing about it.

[2015 Z Force 800 53/Trail EPS]

All the rear bushings on my Z6 are sloppy. I was going to make up all new  ones out of Delrin. I will need to look at the issues that you had aswell. When I find design flaws, I never bring it to a dealer. In the past I have tried to explain or show them the flaw but they are never interested in hearing about it.

Another thing I noticed was that when I inspected the uppers which had not started turning in the tube yet, the bushings just push in by hand where with all other applications I know of requires some effort or help with a clamp or hammer...something more then just finger-pressure. The OD of the bushing needs to be a couple-thousands larger.

I generally make them .001 over sized. After installation I will ream the ID so I don't have to worry about being too tight or odd shaped. The tube is never perfectly round.