Riders take a secondary clutch apart for the obvious reasons - flat spotted rollers, a tired spring, a helix swap. Then they put it back together without ever looking at the small rubber dampener sitting in the middle of it. On a lot of Polaris machines, that part is already cracked by the time anyone thinks to check.
What the Dampener Actually Does
Polaris secondaries with the EBS design use a dampener to take the shock out of the moment the helix and the sheave load against each other. Every time you get on and off the throttle, every time engine braking grabs on a downhill, that load has to go somewhere. The dampener absorbs it. Without it, the same shock loads go straight into the helix and the clutch hardware.
It is a cheap part doing a job that protects expensive parts, which is exactly the kind of component that gets skipped during a rebuild.
Why the Factory One Cracks
The stock dampener is a lower quality material than the loads it sees, and heat inside a clutch box does not help it. It hardens, then it splits, and then it stops absorbing anything. Machines that see hard engine braking on descents and machines with more power than the factory planned for chew through them fastest - which is why 2014-2015 Polaris RZR XP 1000s and RZR XP 900s with big bore engines are the ones that show up with broken dampeners most often. The four seat RZR XP4 900 and RZR XP4 1000 belong in that same group.
What a Failed Dampener Sounds and Feels Like
The tell is noise you cannot locate. A clatter or knock from the clutch area that comes and goes with throttle transitions, most obvious when you lift off and the machine settles. Engine braking may feel abrupt instead of progressive. In a lot of cases the rider chases driveline noises, chain cases, and bearings before anyone pulls the clutch cover.
The confirmation is visual and it is easy: split the secondary, look at the dampener, and look for cracks, chunks missing, or material that has gone hard and shiny instead of pliable.
The Replacement
The HD Polaris Secondary Clutch Dampener replaces the lower quality stock piece with a heavy duty version built to keep from cracking and breaking the way the factory part does. At $35 it is one of the least expensive things you can do for a secondary that is already going to be open on the bench.
Fitment note worth reading carefully: it can be used on Polaris vehicles with the EBS style secondary clutch, but not on 2016 models. It is primarily used on 2014-2015 RZR XP 1000s and RZR XP 900s with big bore engines, including the XP4 900 and XP4 1000.
You Will Need a Spring Compressor
This is not a roadside job. A secondary spring compressor is required for the install, because the secondary spring is under real preload and the clutch has to come apart in a controlled way. Trying to pry it apart is how people damage the helix, the sheave, or themselves.
Add It to the List
Anytime a Polaris secondary is coming apart - rollers, spring, helix, bushing - the dampener should be inspected in the same sitting. It costs almost nothing relative to the labor of getting in there, and a cracked one quietly puts shock load into everything around it until something more expensive gives up.