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

Billet Head Kit for Polaris Patriot 850, 9R, & Boost // SKU: 04-318 Maintain maximum track horsepower and protect your engine against heat-induced power fade with the Bikeman Performance Billet Head Kit for Polaris Patriot 850, 9R, and Patriot Boost engines. Factory single-piece heads suffer from restricted water passages and tight squish bands that cause localized hot spots, triggering the OEM detonation (DET) sensor and throwing your snowmobile 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. Each kit includes two (2) billet domes tailored to your riding style and elevation, allowing your engine to hold timing, run cleaner, and deliver up to 8+ horsepower gains in steep terrain. Key Performance Features Includes Two (2) Domes: Comes standard with a complete set of 2 CNC-machined domes included in the base kit price. Increased Cooling Capacity: Expanded water jackets lower overall operating temperatures to suppress detonation and maintain peak horsepower on long pulls. Eliminates DET Sensor Triggering: Optimized squish band profiles and combustion chamber geometry prevent hot spots, keeping your engine out of limp mode. Proven Horsepower Gains: Delivers +4–5 HP on low-altitude setups and up to +8–9 HP mid-range / +7–8 HP peak gains on high-altitude mountain builds. Modular Interchangeable Design: Easily swap domes later if you change riding elevations, boost levels, or fuel octanes without buying a new head shell. Elevation & Dome Selection Options Select your preferred dome configuration at checkout based on your primary riding elevation: Low Elevation Dome Set: Engineered for sea-level to mid-elevation trail/crossover riding (0–6,000 ft). Optimized for pump gas reliability while delivering +4–5 HP gains. High Elevation Dome Set: High-compression mountain domes engineered for high-altitude deep powder (6,000+ ft). Restores lost atmospheric horsepower in thin air for up to +8–9 HP gains. Need Extra Domes? Additional or replacement individual domes for other elevations and applications can be purchased separately for $90 each. Product Specifications & Notes SKU: 04-318 Compatibility: Polaris Patriot 850, Patriot 9R, and Patriot Boost Engines (AXYS & Matryx Chassis) Package Includes: CNC Billet Outer Head Shell + Two (2) Billet Domes (Low or High Elevation Choice) Additional Domes: $90.00 per individual dome Recommended Spark Plugs: NGK BPR9ES