A2D 900 Big Bore Kit, Polaris 850 Patriot (AXYS/Matryx)

Product details

The A2D 900 Big Bore Kit takes a Polaris 850 Patriot to 900 cc using Polaris 9R components. It fits all 850 Patriot engines, AXYS (2019–2020) and Matryx (2021 and newer), and produces a 15–17 hp gain over the stock 850 in our on-snow testing. The base kit ships with the OEM 9R cylinder head; the SLP Power Dome billet head, the 9R OEM Y-pipe, the SLP 9R single pipe full exhaust and the A2D ECU flash are available as add-ons from the option menus above.

This is a bolt-on top end: the crankcase, crankshaft and electronics stay stock. The kit is the same combination we build and run at our Anchorage shop.

Fitment. All Polaris 850 Patriot two-stroke engines: 2019–2020 AXYS and 2021+ Matryx RMK, Pro RMK, Khaos, SKS, Switchback and Indy. Confirm your machine's year and model before ordering; call if you have questions about a specific sled.

What is included

• 1 × 900 cylinder
• 2 × Polaris 9R pistons (with rings, wrist pins and circlips)
• 1 × Polaris OEM 9R cylinder head
• 2 × lower exhaust valves
• 2 × upper guillotine exhaust valves
• 2 × inner O-rings and 2 × outer O-rings
• 1 × base gasket

Optional add-ons

• SLP Power Dome billet cylinder head (+$499) in place of the OEM 9R head: better cooling and a further 4–5 hp gain.
• Polaris 9R OEM Y-pipe (+$229): better exhaust flow, a further 2–3 hp gain.
• SLP 9R Single Pipe full exhaust (+$900): complete SLP single pipe set for the 900.
• A2D ECU flash (+$450): A2D custom calibration for the big bore and the exhaust you choose.

Specifications

Ordering and installation: built to order at our Anchorage shop; select in-store pickup at checkout if you are local, or we ship. A2D Motorsports installs and sets up the kit in-house, including clutching for the added power; call (907) 306-3062 to schedule.