Big Bore 900 Kit / Patriot 850 - SKU: 09-311 /
Patriot 900 Big Bore Top End Kit (Fits Polaris Patriot 850 Models)
Transform your Polaris Patriot 850 into a high-horsepower monster. This 900cc Big Bore Kit delivers insane arm-stretching power, massive mid-range pull, and the kind of torque that makes it hard to keep your skis on the ground.
Performance & Features
- Massive Power Output: Realize 195 to 215 Horsepower (depending on your chosen exhaust configuration and tuning).
- Premium Components: Comes loaded with factory OEM Polaris 9R pistons for ultimate reliability.
- Fitment: Engineered to fit all Polaris Patriot 850 models.
- Unmatched Gains: Drastic increases to both mid-range pull and overall torque.
Recommended Performance Upgrades
For the absolute best results, maximum horsepower gains, and a seamless installation, we highly recommend matching this kit with our complete performance package. These options include:
- Exhaust: BMP Performance Manifold & Fatt Azz Pipe
- Tuning: Torque Link ECU Tune or Hard Flash
- Clutching: Upgraded Clutch Kit / clutching changes
Tuning Support Policy: We can only provide tuning support if you purchase our complete performance package. If you choose to order the big-bore cylinder kit as a standalone item without the performance kit, we cannot provide tuning assistance.
Cylinder Core Exchange Options
Please select your core preference from the drop-down menu before checkout. Unless purchasing outright, you must send in your stock cylinders and exhaust valves (blades only).
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Option 1: Purchase Outright (+$1,800)
No core cylinders, heads, or exhaust valves need to be sent in. We supply everything. -
Option 2: Core Exchange (Ship After)
We ship your new kit immediately. You must ship your usable core cylinder and exhaust valves back to us within 14 business days to receive your core deposit refund. Cores received after 14 business days will not be credited, and the customer will be responsible for return shipping. -
Option 3: Core Exchange (Send First)
We hold your order until your exchange cylinder and exhaust valves arrive at our shop. Once we inspect and accept your cores, we will assemble and ship your kit. No upfront core charge is applied.
Lead Times & Shipping Instructions
- Standard Turnaround: 3–5 business days.
- Variable Lead Times: Turnaround can vary from 1–15 business days depending on our current inventory of core cylinders.
- Peak Season Note: During peak riding season, please call us to verify cylinder availability. If we are out of core stock, we will need to use your exact cylinders for boring and porting, which will extend lead times.
How to Send Your Parts:
When shipping your cylinders and exhaust valves to us, you must include a completed work order form so our shipping and receiving team can identify your parts.