10/03/2026
Had this Polaris 850 engine come into the shop with a suspected slipped timing sprocket. After diagnosing from the outside and determining it likely needed a rebuild due to bent valves, it was decided to tear it down. You can see the valves struck the piston. The timing sprocket on the crank I removed, repositioned and timed, then welded in place. The rod bearings were replaced. The block cleaned, inspected, and honed. New pistons installed. The head was rebuilt with new valves, seals, and seats cut to clean up the damage. Thank you for your business, Justin!