2015 Polaris Snowmobiles Include New 800 H.O. Engine

2015 Polaris 800 H.O. Engine

The all-new Axys chassis isn’t the only big news from the 2015 Polaris snowmobiles lineup, there’s also a new 800cc engine. Polaris officials claim the new 800 H.O. two-stroke engine is 3.5 pounds lighter, more powerful, more economical, runs better and is quieter than the company’s existing 800cc twin. The new engine will be exclusive to Axys-based models in 2015.

Displacement stays the same at 795cc, but a new crankshaft is 2.5 pounds lighter, which translates to quicker revs that will bring the engine to peak RPM sooner. This crankshaft debuted on the 2014 Polaris 600 IQ race sled.

Polaris 800 H.O. engine
The new Polaris 800 H.O. engine shares only the top half of the crankcase and the 85mm bore and 70mm stroke with the existing 800 Cleanfire engine.

Three-stage exhaust valves are tied to the engine control unit for more accurate operation and better fuel economy. Similar to the system used on Rotax two-stroke engines, the first stage opens at about 6200 RPM and the main valves open at about 7200 RPM. All valves are closed at less than 6200 RPM.

Other new components of the Polaris 800 H.O. engine are an electronic oil pump for more accurate oil delivery, less throttle effort and compensation for changes in altitude and temperature. New, lightweight intake duct material that’s widely used in the automobile industry reduces noise, provides better airflow and increases power.

The Cleanfire semi-direct fuel injection system feeds air to each cylinder through new, more durable VForce reeds and a lighter set of 48mm throttle bodies; two injectors shoot fuel into each cylinder’s boost ports. Other ways airflow improved was by employing a more direct intake tract, and a flatter position for the Y-pipe improves flow out of the engine. Polaris’ 600 twin benefits from the same airbox and oil pump upgrades, but the engine itself is unchanged.

Click here for complete information about the 2015 Polaris snowmobiles lineup.

And click here to read about Snow Goer‘s 2015 Polaris Axys snowmobiles test ride.

3 thoughts on “2015 Polaris Snowmobiles Include New 800 H.O. Engine

  • Avatar for nervyn jennett

    i own a 2010 polaris 800 dragon rmk, problem is nobody will take this sled on trade with 1300 km polaris dealer said he wasn,t taking trades this year & so on because of the motor. i have added amsoil to the gas ever since i found out about this engine have had no problems so far. but why buy a product from a manufacturer that takes 5yr or more of consumers complaints to get it right while the consumer suffers were still not sure yet if the new 800 will be reliable.

  • Avatar for Doug Nichols

    Recently traded my 2012 ProR 600 in on a 2015 ProS 800 and with just 150 miles on it, it straded me on my first trip.

    There is a small pressed in fitting in the front of the cylinder head which carries antifreeze to the heads for cooling that came out causing the engine to over heat, forntunately I believe I got it shut down before major issue.

    Called my dealer who was very helpful and felt terrible, unfortunately nothing he could do but have me get it to the shop. Not sure the outcome BUT I’m hoping my short season isn’t lost.

  • Avatar for Matt

    I own a 2020 Indy XC 800, in the 1800km’s I’ve accumulated since purchasing it I have had zero issues beyond a random code and check engine light that doesn’t correspond to any code listed in the manual. No drops in performance, reasonably good fuel economy, excellent on oil and it accelerates like a angry bull on steroids. I knew Polaris would phase out the 800 once the Patriot 850 was in its sophomore year. I like to think I bought the most refined version of this engine.


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