Billet Head for Polaris Patriot 9R, 850, and Boost // SKU: 04-318

SKU: 04-318-L
No reviews
Choose Head Dome
$599.95 USD
DESCRIPTION QUICK LINKS

Billet Head Kit for Polaris Patriot 850, 9R, & Boost

Maintain maximum horsepower and protect your engine against performance-robbing heat with the Bikeman Performance Billet Head Kit for Polaris Patriot 850, 9R, and Patriot Boost engines. Factory head designs suffer from restricted coolant passages and tight squish bands that cause localized hot spots, triggering the stock detonation (DET) sensor and throwing your sled into power-limiting limp mode.

Bikeman’s CNC-machined billet head increases coolant volume and flow across the combustion chambers for drastically lower running temperatures. Combined with custom-contoured dome profiles and a wider squish band, this kit allows your engine to hold timing, run cleaner, and deliver up to 8+ horsepower gains across the mid-range and top end.

Key Performance Features

  • Increased Cooling Capacity: Expanded coolant passages lower overall engine operating temperatures to maintain peak horsepower on long, hard pulls.

  • Suppresses DET Sensor Activation: Optimized combustion chamber geometry and squish band profiles eliminate detonation hot spots, keeping your engine out of limp mode.

  • Proven Horsepower Gains: Delivers 4–5 HP gains on low-altitude setups and up to 8–9 HP mid-range / 7–8 HP peak gains on high-altitude configurations.

  • Replaceable Billet Domes: Allows you to swap dome sizes easily to adapt to elevation changes, compression needs, or turbo boost levels.

Available Dome Configurations

  • 850 NA - Low Altitude Dome (40.5cc / 11.8:1 Compression)

    • Elevation Range: 0 to 6,000 Feet
    • Performance Gain: +4 to 5 HP
    • Details: Slightly lowers stock compression to prevent the DET sensor from triggering, allowing safe fuel leaning via a controller for reliable power.
    • Part Number: 04-318-L

  • 850 NA - High Altitude Dome (36.5cc / 12.5:1 Compression)

    • Elevation Range: 6,000 to 9,000+ Feet
    • Performance Gain: +7 to 8 HP Mid-Range / +5 to 6 HP Peak
    • Details: High-compression dome engineered specifically to restore mountain horsepower in thin air.
    • Part Number: 04-318-H

  • Patriot 9R - Pump Gas Dome (42cc)

    • Elevation Range: 0 to 12,000 Feet
    • Details: Pump-gas friendly design for all-elevation riding without requiring race fuel blends.
    • Part Number: 04-318-9R

  • Patriot 9R - Race/Performance Dome (37cc)

    • Elevation Range: 0 to 12,000 Feet
    • Fuel Requirement: Requires 110 Octane Race Fuel (0–6,500 ft requires 100% 110 octane; 6,500+ ft requires a 30% 110 octane blend).

  • Patriot Boost - Turbo Dome (43cc)

    • Details: Lower-compression turbo dome engineered to prevent detonation when cranking up boost levels on Patriot Boost engines.

Product Specifications & Fuel Requirements

  • Compatibility: 2019+ Polaris Patriot 850, 9R, and Patriot Boost Engines

  • 850 Boost Fuel Requirement: 100 Octane Minimum Required. (When running this billet head on an 850 Boost, you MUST run race gas tunes. CANNOT run 91 pump fuel.)

  • 850 NA Fuel Requirement: Premium 91 Octane Minimum

  • Recommended Spark Plugs: NGK BPR9ES

  • Tuning Note: A BMP custom ECU tune is required when running this head in combination with a Bikeman expansion pipe.

  • Installation Support: Download Billet Head Kit Installation Instructions (PDF)