Polaris RZR: Rebuilding the Legends with Wiseco

October 7, 2020 / by Rick Sosebee

Wiseco's forged piston kits for RZRs cover every need from improved reliability to overbore, high-compression builds!

It is hard to believe that the product which started a revitalization for the off-road industry is turning 11 years old in 2019. This product is the Polaris Ranger RZR800. We now know the name as just RZR, but in the beginning, the RZR800 was no more than a “sub-culture” to the popular Ranger utility UTV line, and so it was named as such. Who would have ever guessed that this machine could turn our industry on its head by introducing a narrow, sporty two-up rig for husbands, wives, friends and family to enjoy off-road trails in a way that had not previously been, entirely possible?

The Polaris RZR800 was seemingly the turning point that led to the massive growth of the UTV market among weekend warriors and racers alike.

Sure, there were Yamaha Rhinos and some Kawasaki Mules that could be driven in similar fashion, but the Polaris RZR brought with it a sleek, low slung, low CG and performance-based platform with a bit longer suspension travel to which anyone could become a superhero and drive into the wild with a big grin. Not to mention a superbly powerful inline twin cylinder engine just begging to be unleashed in a trail raging dust storm.

The wildfire-like growth of the 800 model lead to Polaris' release of the new and improved 900 model in 2011.

It is those same machines by Polaris that were produced from the model years of 2008 into the evolution of the 88HP 900XP in 2011, that we found a new way to ride the trails of off-road. So, from simple trail riding to working, as well as an all-out performance based Pro-Star engine platform, the Polaris RZR has given us a generation of memories.

However, the memories of a fast, reliable and still powerful machine begin to fade over the years due to worn engine components. At the core of these, you might find things like low cylinder pressures due to tired factory pistons and rings. Some might fear the thought of tearing into the top end of their engine, but with the RZR800 mill, it is much easier than you might anticipate. There are no timing chains to worry about and getting this engine opened up for a top-end service is relatively simple for those with a general mechanical ability.

Now that RZR models have evolved into 1000cc turbos, there is a surplus of used 800s and 900s. These machines are still a blast to drive, and with a fresh top-end rebuild, can provide many more years of fun at a bargain.

Wiseco has put together a variety of options for top-end rebuilds with forged piston kits and top-end gasket kits for Polaris RZRs. These are not only stock displacement replacement parts, but also boast a variety of choices of higher compression and over-sized bores for those who want more seat of the pants thrust from the inline twin. Overbore options are critical in situations where the cylinders have worn beyond spec and need to be bored and replated to regain performance.

Wiseco forged pistons for RZR 800 and 900 models are available in various compression ratios and bore sizes, from standard and up!

Find pistons for your RZR here!

If you’re rebuilding a RZR800, ease of parts ordering can be found in either individual piston kits or complete piston and gasket kits. Wiseco’s single piston kits include a forged piston, rings, wire locks, and a wrist pin, while the complete piston and gasket kits come with two piston kits for both cylinders as well as a complete gasket kit with all the seals and gaskets you’ll need for the top end.

Top end kits for RZR 800 models from Wiseco include a pair of forged pistons, rings, pins, wire locks, and a complete top end gasket kit. All this in one box, under one part number!

For the RZR800, you have your choice of the stock compression ratio of 10.2:1, or you can bump it up 11:1 for a little more fun, or 12:1 for a lot more fun. All these CRs are even available in standard or 2.00mm overbore.

Back to front: standard, slight increase, and high compression. Pick your poison.

Thinking about tearing into that tired RZR900? You can find piston kits in three levels of compression ratios as well. Ranging from the stock CR of 10.6:1, to 11:1, to 12.5:1, you can choose how wild you want to get when breathing new life into the UTV’s powerplant. Much like the 800, these are available in standard and 2.00mm over-bore sizes as well. Complete top-end gasket kits are also available for the 900s separately from Wiseco.

RZR 900 Wiseco piston kits are also available in two different levels of high compression and a 2.00mm-over bore size. Complete top-end gasket kits make it easier to know you have all the pieces necessary for your rebuild.

Because all Wiseco pistons are forged in-house in the U.S., the piston life and strength is multiplied for years of reliability. Forging greatly improves the tensile strength of the piston by aligning the grain structure of the alloy, which means its durability in regard to high cylinder pressures and high combustion temperatures will be much improved for the life of the off-road rig.

Components that go into making a great performance piston must include highly defined functional areas such as the piston skirt. This area of the piston not only provides stability to the entire piston for smooth operation in the cylinder bore, but exact tolerances and proper forging must be met to ensure longevity. Wiseco also adds their proprietary ArmorGlide skirt coating, a dry-film lubricant that helps reduce friction in the cylinder as well as a reduction in potential operating noise. This coating is incredibly tough and is designed to last for the life of the piston. These two key components alone make this piston worth the investment.

ArmorGlide skirt coating reduces operating friction and noise for the life of the piston.

See more on Wiseco's coatings here.

When you look at the racing scene, UTVs are continuously creating a larger space for themselves. Serious racers may freshen up the engine once or even twice during the season, depending on the situation and conditions of each race. Pushing the engine to high RPM and running under load for extended periods—sometimes up to 2.5hrs at a time—the engine needs dependable parts to survive that abuse. Wiseco has built a reputation for reliability and performance in racing across many disciplines in motorsports, from drag racing to motocross. The Wiseco crew is full of racers and enthusiasts themselves, so they know what it takes to breathe new life into the pipes of that OG off-road rig.

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Topics: NEWS, NEW PRODUCTS, featured, Powersports, UTV

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Written by Rick Sosebee