Hey there, off-road enthusiasts! If you're diving into the world of the 2020 Polaris Sportsman 850 motor, you've come to the right place. This powerhouse of an engine is known for its reliability and performance, but like any mechanical marvel, it sometimes needs a little TLC. Whether you're troubleshooting issues, planning maintenance, or just curious about what makes this engine tick, let's get started!

Understanding the 2020 Polaris Sportsman 850 Motor

The 2020 Polaris Sportsman 850 boasts a robust engine designed to tackle tough terrains and demanding tasks. Before we get into the nitty-gritty, let's cover some basics. This engine is a liquid-cooled, 4-stroke twin cylinder, known for delivering impressive power and torque. Understanding its core components and how they interact is crucial for effective maintenance and troubleshooting.

• Engine Specifications: The 850 engine typically features an 850cc displacement, providing a significant amount of power for various applications, from recreational riding to heavy-duty work. Knowing the exact specs for your model year helps ensure you use the correct parts and fluids. The bore and stroke dimensions are essential for calculating displacement and understanding the engine's overall geometry, influencing its power and torque characteristics.
• Key Components: Key components of the engine include the cylinder heads, pistons, crankshaft, camshaft, and valve train. Each of these parts plays a critical role in the combustion process. The cylinder heads house the valves and spark plugs, facilitating air and fuel intake and exhaust gas expulsion. Pistons move within the cylinders, compressing the air-fuel mixture and transmitting power to the crankshaft. The crankshaft converts the linear motion of the pistons into rotational motion, which is then transferred to the transmission. The camshaft controls the opening and closing of the valves, synchronizing them with the piston movements to ensure optimal combustion efficiency. The valve train includes valves, springs, and rocker arms, all working together to regulate the flow of gases into and out of the cylinders. Understanding how these components work together is fundamental for diagnosing and resolving engine issues.
• Fuel and Ignition Systems: The fuel system is responsible for delivering the correct amount of fuel to the engine, while the ignition system ignites the air-fuel mixture to initiate combustion. Modern Polaris Sportsman 850 models often use electronic fuel injection (EFI) systems, which provide precise fuel metering for improved performance and fuel efficiency. The ignition system includes the spark plugs, ignition coil, and electronic control unit (ECU), which work together to generate and deliver the spark at the precise moment needed for combustion. Issues with either the fuel or ignition system can lead to a variety of problems, such as hard starting, poor idling, and reduced power. Regular maintenance, such as cleaning or replacing fuel injectors and spark plugs, can help keep these systems in top condition.

Common Issues and Troubleshooting

Even with Polaris's reputation for reliability, the Sportsman 850 motor can encounter issues. Recognizing these problems early can save you time and money. Here are some common issues you might face:

• Starting Problems: If your engine cranks but doesn't start, it could be due to a dead battery, faulty spark plugs, or a problem with the fuel system. Check the battery voltage first, then inspect the spark plugs for fouling or damage. If the spark plugs are in good condition, investigate the fuel system, including the fuel pump, fuel filter, and fuel injectors. A clogged fuel filter or a failing fuel pump can prevent fuel from reaching the engine, while dirty or malfunctioning fuel injectors can disrupt the fuel spray pattern, leading to poor combustion. Also, consider the possibility of a faulty crankshaft position sensor, which can prevent the ignition system from firing properly.
• Overheating: Overheating can occur due to a low coolant level, a malfunctioning thermostat, or a clogged radiator. Start by checking the coolant level and ensuring there are no leaks in the cooling system. If the coolant level is adequate, inspect the thermostat to ensure it is opening and closing properly. A faulty thermostat can restrict coolant flow, leading to overheating. Additionally, check the radiator for any obstructions, such as mud or debris, that could be blocking airflow. If the overheating persists, there may be an issue with the water pump or a more serious problem, such as a blown head gasket.
• Loss of Power: A sudden loss of power can stem from various sources, including a clogged air filter, a faulty fuel pump, or worn spark plugs. Begin by inspecting the air filter to ensure it is clean and free of obstructions. A dirty air filter can restrict airflow to the engine, reducing power output. Next, check the fuel pump to ensure it is delivering an adequate supply of fuel. A weak or failing fuel pump can cause the engine to run lean, leading to a loss of power. Also, inspect the spark plugs for wear or damage, as worn spark plugs can result in poor combustion. Other potential causes of power loss include a clogged exhaust system, a malfunctioning throttle position sensor, or issues with the engine's internal components, such as worn piston rings or damaged valves.
• Unusual Noises: Strange noises like knocking, ticking, or whining can indicate serious internal problems. Knocking noises often suggest issues with the connecting rods or main bearings, while ticking noises may be caused by worn valve train components. Whining noises can indicate problems with the transmission or differential. If you hear any unusual noises, it's important to investigate them promptly to prevent further damage. Use a stethoscope or a long screwdriver to help pinpoint the source of the noise. Depending on the nature of the noise, you may need to disassemble the engine to inspect and repair the affected components. Ignoring unusual noises can lead to catastrophic engine failure, so it's always best to err on the side of caution.

Maintenance Tips for Longevity

Regular maintenance is key to keeping your 2020 Polaris Sportsman 850 motor running smoothly for years. Here’s what you should focus on:

• Oil Changes: Change your engine oil and filter according to the manufacturer's recommendations, typically every 25 hours of operation or every six months. Use the recommended oil type and viscosity for your specific model. Regularly changing your oil removes contaminants and ensures proper lubrication, preventing wear and tear on critical engine components. Always dispose of used oil properly to protect the environment. Documenting each oil change with the date, mileage, and type of oil used helps maintain a detailed service history.
• Air Filter Maintenance: Clean or replace the air filter regularly, especially if you ride in dusty or muddy conditions. A clean air filter ensures proper airflow to the engine, maximizing performance and fuel efficiency. Inspect the air filter housing for any cracks or damage that could allow unfiltered air to enter the engine. Using a pre-filter can help extend the life of the main air filter and reduce the frequency of cleanings. Proper air filter maintenance is essential for preventing engine damage and maintaining optimal performance.
• Spark Plug Inspection: Inspect your spark plugs periodically and replace them as needed. Worn or fouled spark plugs can cause misfires, reduced power, and poor fuel economy. Check the spark plug gap and adjust it to the manufacturer's specifications. Inspect the spark plugs for signs of wear, such as rounded electrodes or carbon deposits. Using the correct spark plug type for your engine is crucial for optimal performance. Replacing spark plugs at the recommended intervals ensures reliable ignition and efficient combustion.
• Coolant Checks: Maintain the correct coolant level and periodically flush and replace the coolant to prevent corrosion and overheating. Use the recommended coolant type for your Polaris Sportsman 850. Inspect the cooling system hoses and clamps for any leaks or damage. A well-maintained cooling system is essential for preventing overheating and ensuring the engine operates at the correct temperature. Regularly checking the coolant level and condition can help prevent costly repairs.
• Fuel System Care: Use fuel stabilizer, especially if you store your ATV for extended periods. This prevents fuel from breaking down and clogging the fuel system. Clean or replace the fuel filter regularly to ensure a clean fuel supply to the engine. Inspect the fuel lines and connections for any leaks or damage. Proper fuel system care helps maintain optimal engine performance and prevents fuel-related problems.

Upgrades and Performance Enhancements

Looking to boost the performance of your 2020 Polaris Sportsman 850 motor? Here are a few popular upgrades:

• Performance Exhaust: Upgrading to a performance exhaust system can improve exhaust flow, resulting in increased horsepower and torque. Look for a system that is designed specifically for your model and riding style. A performance exhaust can also enhance the sound of your engine. Ensure that the exhaust system complies with local noise regulations. Installing a performance exhaust is a common upgrade for riders seeking to maximize their engine's potential.
• ECU Tuning: Tuning the engine's electronic control unit (ECU) can optimize fuel and ignition settings for improved performance. A professional tuner can adjust the ECU to match your specific modifications and riding conditions. ECU tuning can also improve throttle response and fuel efficiency. Ensure that the tuner has experience with Polaris Sportsman 850 models. ECU tuning is a complex process that should be performed by a qualified technician.
• Air Intake Modifications: Upgrading the air intake system can increase airflow to the engine, resulting in improved horsepower and throttle response. Look for an aftermarket air intake kit that is designed to fit your model. Ensure that the air intake system provides adequate filtration to protect the engine from contaminants. Air intake modifications are often combined with other performance upgrades to maximize their effectiveness.
• Clutch Kits: Installing a clutch kit can improve the transfer of power from the engine to the wheels, resulting in better acceleration and overall performance. Choose a clutch kit that is designed for your specific riding style and terrain. A clutch kit can also improve low-end torque and responsiveness. Ensure that the clutch kit is properly installed and adjusted. Clutch kits are a popular upgrade for riders who want to fine-tune their ATV's performance.

Safety First

Before you start any maintenance or repair work, always prioritize safety:

• Disconnect the Battery: Disconnect the negative terminal of the battery to prevent electrical shocks or shorts.
• Use Proper Tools: Use the correct tools for the job to avoid damaging components.
• Wear Safety Gear: Wear safety glasses and gloves to protect yourself from injury.
• Work in a Well-Ventilated Area: Work in a well-ventilated area to avoid inhaling harmful fumes.
• Consult the Service Manual: Refer to the service manual for specific instructions and torque specifications.

Conclusion

The 2020 Polaris Sportsman 850 motor is a fantastic piece of engineering. By understanding its components, addressing common issues, and following a regular maintenance schedule, you can keep your ATV running strong for years to come. Remember, if you're not comfortable performing certain repairs yourself, it's always best to consult a qualified mechanic. Happy riding, and stay safe out there!