After some advice from a few members on another post I had and watching NMK's shock absorber video I decided to pull mine off and clean them up and see how they functioned off of the machine and this is what I found. Unlike the CFMoto shocks which most of the machines come with the DNM shocks that the factory sometimes uses have the piggyback reservoir in line with the mounting bolts and on my machine this caused the reservoir to push against the plastic rear protector panel and the plastic was literally sawing through the aluminum reservoir. I cut away about 1/2" of the plastic and swapped the shocks left and right to keep the plastic away from the grooves it had already cut into the shock as it traveled up and down.

Servicing the shock was another story, the adjustment knobs were packed with dirt, sand, and dry mud and barely functioned, I flushed them out with cleaner and compressed air and now they work smoothly, I can feel the little indents click in position as I make adjustments. These shocks have rubber O-rings on the bushings to keep the dirt out which they didn't do, the Heim bearings were packed in dirt and basically frozen in place, 2 of them had some scoring from the sand that had got in there, I got those all cleaned out and greased and now the shocks work perfectly, without the springs on them I could make different adjustments, compress the shock and make sure that the compression and rebound rates actually changed.

Now I still have the problem with the springs being very stiff, even with zero preload and the compression set at the softest position I can't get these springs to compress when I jump on the back bed, are the CFMoto shocks that stiff as well, I am thinking about changing them out, does anyone know the spring rate on the factory spring which is 11" long with no load on it

I keep reading the posts on this forum and continue to learn from all of the experience that you guys have, thanks for putting out the effort to keep this forum interesting and educational.

you say you have 0 preload on them, but in the pictures the preload adjusters are about 1/3 of the way down on the strut. Did you change this? Or if you back off the preload does the shock not extend any further? I'm a little confused on that one. The Preload is set with the big adjuster on top of the spring the threads are on the strut housing itself.

The ride was very stiff so I previously backed the preload completely off, just enough to keep the springs from rattling and with no preload on the springs the shocks would barely compress by putting my weight on the bed and the ride was still very stiff, so after cleaning up the shocks I added in some preload to gain additional ground clearance. With the amount of preload in the picture when I (235lbs) sit on the very back of the roll cage I built the shocks compress 3/8" and bouncing on the cage gets me another 1/4" of compression and this is with the compression set at the softest position. I understand my weight is nothing compared to the upward force exerted on the shocks when hitting bumps and obstacles but is this amount of stiffness normal?

Oh ok, just wondering, I was a little confused. I can't say, I have an EX much different. I imagine with the short A-Arms and quite vertical position of the shocks that it would be pretty stiff. If you want softer I would measure the spring diameter and length and see if you can find a lesser spring rate, as long as you don't tow heavy stuff and load up the back with weight a lighter spring weight would do you a lot of good I imagine.

[2015 Z Force 800 53/Trail EPS]

I don't know the spring rates but on mine when the a-arm bushings were seized to the sleeves and turning in the a-arm tubes, it was so stiff I could not move the suspension by jumping on the trailer hitch...and I'm 220lbs..no matter how soft I set the preload or the compression on the shocks. But even now with everything working smooth as glass when the preload is set where I need it for proper ride height, it doesn't move all that far...but it does.. and it's smooth and quiet...when it's got lube. Seems to need lube way too often though....and if I don't jack it up before greasing the a-arms, it doesn't get all the way around. 

Sounds crazy but I am not sure what I have down here, the outside width tire to tire is 55" so my shocks are not as verticle as the 50" trail and not as angled as the Z8EX. My shocks function fine and I can move the a-arms up and down by hand when the unit is jacked up so I think the harsh ride is due to the springs on these DNM shocks. I have located a set of progressive springs that are the same length and 1/4" wider than what I have but I am concerned that the spring rate may be too soft and I can't find the spring rate listed for any of the Zforce models to compare.

[2015 Z Force 800 53/Trail EPS]

Wider or larger spring diameters may be a problem with the reservoirs. They can rub. 

Oh seeing them on the machine they are a lot less vertical than I pictured in my head. Sorry bud it looks like your machine is a little different than what our trails are like, trial and error may be the way you have to go. If everything is working, as it seems you have checked, nothing is binding and the shocks work I would go with changing the spring rate to get it softer.

I have 7/16 clearance between my spring and the reservoir, I am waiting to hear back from the seller about the OS diameter and unless the wire size is much larger than what I have now they should fit. I don't mind the trial and error but the shipping cost is as much as the springs so if they don't work there is no returning them.

I'm not sure if you want them, but my stock rears are just sitting on a shelf. The seal went out of one. You can have them for shipping cost. They are not progressive, that was another reason I went RZR shocks.

I'm not sure if you want them, but my stock rears are just sitting on a shelf. The seal went out of one. You can have them for shipping cost. They are not progressive, that was another reason I went RZR shocks.

Thank you for your generous offer, my struts are working fine so I took your advice from a week ago and found a pair of progressive springs on eBay and I just paid for them a few hours ago, they are exactly the same length and 1/8" larger diameter so they will fit perfectly, I only hope that they are not so soft that I am bottoming out all of the time.

You will.have to let us know.how it goes

I will, but unfortunately, it will take a month or so to get the springs here in Costa Rica.