During our initial outings with the 2014 Polaris RZR XP4 1000, we had bittersweet results. As a whole, the machine is phenomenal- it has enough suspension and power to pull four full-grown adults through 3-foot sand whoops in complete comfort, but we couldn't drive it hard without fear of grenading a belt. We ended up changing four in the first few hundred miles- a costly, time-consuming hassle that had us quite frustrated. To remedy this, we called up the experts at EPI Performance to add some durability to our CVT.
From what we can gather, the problem with the stock clutch is that the helix angle does not allow the clutch to backshift properly, leaving the secondary clutch in too high of a ratio. This places excess strain on the belt, causing it to heat up and vulcanize. Once the belt is scalded, it becomes brittle, and it is only a matter of time before it turns into shrapnel.
EPI sent us out a pre-production clutch kit to test in our XP4 1000, and since the Baxter, Minnesota based company was snowed in, we set to work testing the kit in our sunny Southern California trail systems. With the kit, EPI sent us a set of machined clutch weights, a set of much stiffer primary and secondary clutch springs, and a machined aluminum helix. After installing the clutch kit using our EPI clutch tools, we set off for some serious endurance testing.
After 600+ miles in mixed terrain with our new setup, we have experienced zero belt failures. We have tested it in mud, sand, rocky hill climbs, Baja-style hard-pack whoops, and everything in-between. Initial clutch feel is very close to the stock system, but backshift and on-off throttle response is much improved. The RZR feels like it has even more midrange than it did in its stock form, and will pull well past 75 mph with four adults in the car.
EPI has yet to officially release the kit on their website, but a handful of kits have shipped to race teams and industry vets with great results. If you own a new XP4, the increased performance and reliability provided by the kit will definitely put a smile on your face. The kit should retail for around $330, and you can get your hands on one by calling EPI at (218) 829-6036.