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Polaris ProStar S4 INDY Adventure, Just the right Time?

The 2023 ProStar S4 INDY Adventure came to us late in the winter of last year. This model is fitted with Polaris’ own proprietary four-stroke engine. It is built on a Matryx chassis and looks no different. If you did not see the bright “ProStar” decals, you could assume it was their Patriot 650 or Patriot 850.

When was Polaris going to re-enter the four-stroke market with a competitive engine for their snowmobiles? This was an ongoing question for almost a decade. However, many of their dealers would report they have been doing just fine with a broad line up of snowmobiles with two-stroke options.

prostar s4 indy adventure

The 2023 ProStar S4 options available to consumers are varied. First, there is our test unit, the INDY Adventure. Then, there is the Voyageur 146 and the INDY Adventure X2.

Polaris last offered consumers a four-stroke power plant in model year 2014. The German based Weber 750 cc power plants had not caught the attention of the market. Polaris was just not selling enough units in their overall business plan. So we think it made sense for them to refocus on future successful launches of their upgraded Patriot 850 (2019) and their very impressive Patriot 650 (2021).

My First Ride—Impressions

In April of 2023, I had the privilege of riding an identical 2023 ProStar S4 INDY Adventure. It came from my local Polaris dealer, Hawkins Equipment Ltd., in Fredericton, NB. As with most 2023 ProStar S4 models, they did not arrive to dealers or consumers until March 2023. Many locations had no snow left, but New Brunswick is generally always blessed with a later riding season.

I rode the dealer demo in early April of 2023 on packed forest roads, not on groomed snowmobile trails. The air temperature was warm—above freezing—and the surface was somewhere between slush and packed snow. I rode for a total of maybe 30 minutes, tops. There was plenty of snow but, I would qualify my riding that spring day as off-trail.

My First Impression

The new 2023 ProStar S4 INDY Adventure handled as well as the 2022 Matryx VR1 that I own. My VR1 has a Patriot 650 engine with a 137-inch skid. I am frankly in love with the handling and ease it takes to ride my personal Matryx. I was afraid I would lose that with the four-stroke engine’s extra weight, but its initial handling pleased me beyond my expectations.

What is the Same

The 2023 ProStar S4 INDY Adventure’s Engine

Going out on a limb to state this proprietary engine is also the same. Meaning this engine’s power claimed at just under 100 HP has a long lineage from Polaris’ proven 1000 cc engines in hundreds of thousands of RZR and Ranger SxS.

Yes, we know this snowmobile application is a dry sump lubrication system versus the off-road ProStar S4 applications. This engineering was achieved to ensure these snowmobiles would sit as low as possible on the Matryx chassis. The point being made here is that this is not another company’s engine, like the German-Weber 750 cc four-stroke engine in the Polaris Frontiers, IQs and Dragons of the past.

The Matryx Chassis

The ProStar S4 power plants are primarily in the Matryx chassis (exception is the Titan in 2024). That is important because the width of the 2023 ProStar S4 INDY Adventure is the same as all the Polaris two-stroke models. It is also important because it is narrower than the other OEMs who offer four-stroke options. It looks more manageable because when you ride it, it is.

prostar s4 indy adventure's handles and dashboard


This 2023 ProStar S4 INDY Adventure comes with Polaris’ smart warmers, LED lighting, and a 7S Display. These are all very desirable and functional components that I have been used to with my 2022 VR1. Polaris made huge strides in these three components when they introduced them with the 2021 Matryx chassis. It is nice to see them on their four-stroke models.

My Second Ride—Impressions

Our test unit is the 2023 ProStar S4 INDY Adventure. Sledmagazine.com was fortunate to receive it in late March 2023 and place a few kilometres on the 137-inch skid frame. There were already approximately 700 kilometres on the odometer at pick-up. This means it has surpassed the recommended break-in period of 500 kilometres.

My second ride on a 2023 ProStar S4 INDY Adventure, although my first ride on this test unit, took some patience. Patience that is … waiting for it to snow in 2024.

My second impression

This impression has been formed over three days in mid January of 2024. This time, I rode just over 300 km on new snow as there were no groomed trails. We were on large forestry roads with virgin snow containing a small crust on top. The other roads ridden were almost as packed as a groomed trail.

The 2023 ProStar S4 INDY Adventure’s handling is pleasant, being both precise and predictable. There are no unwanted surprises. The feedback from the new snow with a crust and on the hard-packed surfaces both give accurate feedback. Just like a Polaris Indy Matryx.

As stated earlier, the 2023 ProStar S4 INDY Adventure handles as well as my 2022 Patriot 650 INDY VR1 … and it is a four-stroke.

What is Most Noticeably Different


Polaris has built their own shocks for the ProStar S4 variations. They are labelled as “TS” shocks and are fully compression adjustable. These shocks—on the front and in the rear skid frame—have five distinct settings. These are not entry-level shocks. They have a 5/8-inch shaft diameter which makes them stronger and stiffer. The five settings are still simple enough to understand. They can be set to the appropriate compression for the four-stroke engine’s extra weight versus trail conditions.

prostar s4 indy adventure front shocks


Polaris has outfitted their ProStar S4s with a set of dually carbides up front. Dual runners have their place and make many snowmobiles better in the corners than outfitted with single runners. After a season, we will offer an opinion.

Exhaust Note

The ProStar S4 engine sounds different and that is all right. The benefits of a four-stroke engine have been documented by many riders for two decades now. So, some riders will really like the exhaust note, while others won’t. Sound alone does not change the performance of this snowmobile.

Throttle by Wire (TBW)

This is the biggest difference in the feel of riding this snowmobile. TBW is not new in the power sports industry, but this is a major departure from the feel of a two-stroke snowmobile. I am quite pleased to report initially that the throttle is very linear. In other words, it does not feel as if you are constantly surging when on the throttle. Conversely, it does not feel as if someone deployed a parachute when you let off the throttle. It is not choppy. Rather, it feels very linear as the clutches shift towards their peak performance.

A 2023 ProStar S4 Versus Its 2024 Equivalent

At Sledmagazine.com, we have been advised by Polaris that there are no differences, albeit colour and graphic choices, between the 2023 and 2024 ProStar S4 models. This makes this long-term unit very relevant to test this winter and report back to you.

Some Polaris dealers are still uncrating their 2023 ProStar S4s and they also have the 2024 models they ordered. We hope and expect they will sell every unit produced. However, when a 2023 model and the same 2024 model is available at your dealer, the pricing for a new leftover should be in the consumer’s favour. Thus, the impressions we gather from the 2023 ProStar S4 INDY Adventure will also apply to the 2024 models with the ProStar S4 power plant.

Longer Term—Future

As with all the snowmobiles we are privileged to ride and test at Sledmagazine.com, we will be reporting on our long-term impressions of this model. My 2023 ProStar S4 INDY Adventure will see primarily groomed trails, but also spend some time in the New Brunswick higher grounds also known as my camp.

It is a pleasure to see Polaris in the four-stroke snowmobile market again with their own proven power plant. This is especially important for consumers with the upcoming absence of the Yamaha power plants that are soon exiting the market.

Polaris ProStar S4—Just the Right Time

Polaris has been successful without a four-stroke snowmobile engine for a decade, so it is hard to criticize their strategic plan. They entered the off-road market decades ago. Remember when the RZR was just called Razor? They had new ideas on how to execute against established competition and we know how successful that has been.

We predict Polaris’ timing for entering the four-stroke market is … just right.

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