All-New SnowCheck-Exclusive 850 Patriot™ Engine

Introducing the all-new Polaris®  850 Patriot™, designed for class-leading durability, responsiveness, unrivaled acceleration and industry's best power-to-weight. The most powerful snowmobile engine ever built by Polaris®. This engine is available exclusively on select SnowCheck models, and built with pride in the USA.
850 engine

Key Features

feature
Designed for durability … & power
DESIGNED FOR DURABILITY & POWER

World-class durability with class-leading power and Polaris' renowned responsiveness.

  • Real-world performance and reliability based on 25 years of Liberty® engine experience
  • Guaranteed quality with standard 4-year warranty
New piston
NEW PISTON

Optimized for reliability and durability.

  • +8mm compression height
  • +3mm thicker dome
  • More contact area with cylinder bore to improve heat transfer
  • PVD-coated steel single-ring design
  • High-capacity wrist pin
New lightweight crankshaft
NEW LIGHTWEIGHT CRANKSHAFT

All-new design is strong and stiff while maintaining low inertia.

  • Larger clutch taper design for durability and serviceability
  • High capacity bearing and pin design
  • Separate crankpins feature high grade steel
  • Symmetrical press fit webs for improved straightness
New cylinder & cylinder head
NEW CYLINDER & CYLINDER HEAD

All-new design optimized for maximum durability.

  • Advanced Cooling System based on Computational Fluid Dynamics which results in consistent flow velocities
  • 6-bolt cylinder structure optimized through Finite Element Analysis and features a patent-pending exhaust port design
  • One-piece head design allows for structural rigidity, engineered coolant flow, and optimized weight
  • Patent-pending combustion chamber design allows for complete combustion and ultimate performance through entire operating range
New water bottle with integrated thermostat
NEW WATER BOTTLE WITH INTEGRATED THERMOSTAT

All-new design maximizes durability and cooling efficiency.

  • Patent-pending simplified coolant bottle design minimizes vibration and maximizes thermostat life
  • Self-bleeding cooling system
  • 100 degree T-stat
  • Integrated by-pass for fast warm-up
New engine mounting
NEW ENGINE MOUNTING

Seamlessly integrates into 2019 AXYS® chassis.

  • Minimizes vibration transmitted to rider
  • Provides more consistent center distance to maximize belt life
New throttle body & throttle position sensor
NEW THROTTLE BODY & THROTTLE POSITION SENSOR

Features a lightweight, simple, durable design.

  • Contact-less TPS for reliable, consistent performance
  • Permanent set - no adjustment required
Powertrain controls
POWERTRAIN CONTROLS
  • Power Boosting Regulator for quicker starting; delivers maximum electrical power at Idle/Low RPM
  • Electrical ECU with faster processor, exhaust valve control integration, and greater input/output
New 3-stage e-ves-ii exhaust valve system
NEW 3-STAGE E-VES-II EXHAUST VALVE SYSTEM
  • Simplified coplanar valve with fewer parts and EV base that is lightweight, die-cast magnesium
  • Improved fit and sealing to piston and exhaust ports to control exhaust flow and optimize performance
  • Optimized water jacket and valve cooling
  • Integrated cooling with no external lines
Premium, integrated design & components
PREMIUM, INTEGRATED DESIGN & COMPONENTS
  • New exhaust system - pipe and resonator - improves flow and sound quality; EGT in full heat-shielded resonator improves calibration control
  • New wire harness routing for reliability and serviceability
  • Industry-exclusive, patent-pending fuel system temp and pressure sensor optimizes piston durability, increases control of fueling variability, improves starting in all conditions, improves diagnostic functionality for easier serviceability, and enhances engine protection modes in the case of low fuel pressure
  • New belt drive designed specifically for the 850 Patriot™ is optimized for durability and longevity
  • New VForce® reeds designed specifically for the 850 Patriot™ feature carbon fiber petals for ultimate performance, and industry-exclusive secondary seal on the inner cage for maximum durability

Browse 850 SnowCheck Models

INDY®

Legendary Performance. Simply Fun. 

RUSH®

Sharpest Handling. Quickest Accelerating.