Sportsman 800 Engine Rebuild

Polaris SPORTSMAN 800 engine

PART 1 – CYLINDER DIAGNOSTICS

In the latest episode of Project X, Josh tears into the Sportsman 800‘s engine in this two-part series. We will do some diagnostics on the cylinder before pulling the engine. But first, there are a lot of parts to remove before we can tackle the engine side. We have to pull the covers and clutch, disconnect the fuel system and release any pressure in the line. The parts we use in this video are supplied by Bronco ATV-UTV. Be sure to see check us out on Instagram and Facebook for more.

PART 2 – Cylinder and Namura Piston Install

In this episode of Project X, Josh takes us through, step-by-step, showing the process of removing the engine and components (i.e., clutch) from our Polaris Sportsman 800 before getting to work on the big mill. Then we show you how to remove the engine from the chassis and pull the cylinder head and cylinder jug. Be sure to check this one out for a few special tips that make the job easier. All the parts used in this series are provided by Bronco ATV & UTV Components.

MOS2 (Teflon/Molybdenum) Coated Skirts
A rolled-on application process provides a bond that is 10 times stronger than other spray on coatings. Benefits include increased heat transfer, reduced friction, and helping to eliminate cold seizures.

Machined Smooth Heads – 
Reflects combustion heat and reduces carbon buildup, protecting the top of the piston. Some tests have shown this feature can increase horsepower and fuel economy by up to 6%.

Anodized Domes – 
Increases heat resistance and durability; pistons with anodized domes are 75% stronger than non-anodized pistons.

AC8A Aluminum Alloy – 
Our pistons are made from AC8A aluminum alloy which is ideal for use in performance pistons. Due to its high tensile strength, high wear resistance and low thermal expansion rate at high temperature, AC8A aluminum alloy makes Namura pistons a smart choice for any rider.

Namura Gasket Set

GASKET SET – NAMURA TECHNOLOGIES BRANDED, THE TOP END GASKET SET INCLUDES ALL COMPONENTS
NEEDED TO REBUILD YOUR TOP END INCLUDING THE HEAD GASKET, BASE GASKET, EXHAUST GASKET, INTAKE/CARB GASKET, O-RINGS AND VALVE STEM SEALS.

PART 3 – CYLINDER HEAD AND VALVE INSTALLATION

Last week, we were finishing the engine teardown so we could install the new cylinder jug and rings (among other things) to bring the compression back to specifications. This week, we are going to get it all back together and installed in the Polaris chassis and hopefully get it started. But before we do that, we will be replacing both the intake and exhaust valves in the cylinder head as well as installing a new coolant temperature sensor. The parts we use for this project are supplied by Bronco ATV & UTV Components.