Hey guys! So, you're the proud owner of a Polaris Sportsman 850 – awesome choice! These ATVs are beasts, built to handle some serious off-road action. But, like any machine, they need a little TLC to keep them running smoothly. This guide is your one-stop shop for everything you need to know about repairing and maintaining your Sportsman 850. We'll cover everything from the basics to more advanced stuff, so whether you're a seasoned mechanic or just starting out, you'll find something useful here. Get ready to dive in and keep your ATV in tip-top shape!

Understanding Your Polaris Sportsman 850

Before we jump into the nitty-gritty of repairs and maintenance, let's get acquainted with your ride. The Polaris Sportsman 850 is a powerful ATV known for its performance and durability. It typically features an 850cc, liquid-cooled, four-stroke engine, which provides plenty of power for tackling tough terrain. They often come with electronic fuel injection (EFI) for optimal performance and fuel efficiency. You'll find features like automatic transmission (CVT), on-demand all-wheel drive (AWD), and independent rear suspension (IRS) to enhance the riding experience and handling. Understanding these key features is essential for proper maintenance and troubleshooting. For example, knowing how your AWD system works is crucial if you encounter issues with traction. Likewise, familiarity with the EFI system can help you diagnose problems like starting difficulties or poor fuel economy. The Sportsman 850 is a workhorse, designed to handle a variety of tasks, from recreational riding to utility work. The Polaris Sportsman 850 is a versatile machine, and it is designed for a variety of users. Whether you're a weekend warrior hitting the trails or using it for work around your property, understanding its capabilities and limitations is key. Regular inspection and servicing are critical to ensuring its longevity and performance. The engine is at the heart of the ATV, so familiarizing yourself with its operation and maintenance needs is paramount. The automatic transmission simplifies operation but requires specific maintenance procedures. The AWD system is a highlight feature, providing enhanced traction when you need it. Lastly, the suspension plays a vital role in ride quality and handling. Understanding these components and systems will help you identify issues, perform repairs, and maintain your ATV effectively, ensuring you get the most out of your investment. It’s also crucial to consult your owner’s manual for detailed specifications, maintenance schedules, and safety guidelines specific to your model year.

Key Components and Systems

Let’s break down the major components and systems you’ll be dealing with:

• Engine: The heart of your ATV. Regular oil changes, air filter maintenance, and spark plug replacement are essential. Watch for any unusual noises or performance issues.
• Transmission (CVT): This automatic transmission needs regular inspection and maintenance, including belt replacement when worn. Keep an eye out for slipping or erratic behavior.
• All-Wheel Drive (AWD): This system provides enhanced traction. Check for proper functionality and inspect the front and rear differentials.
• Suspension: The suspension system, particularly the shocks and springs, takes a beating. Inspect them for leaks, damage, and wear. Proper suspension maintenance ensures a comfortable ride and optimal handling.
• Brakes: Your safety depends on the brakes. Inspect brake pads, rotors, and brake lines regularly. Make sure the brake fluid is at the correct level and that the brakes are functioning properly.

Routine Maintenance: Keeping Your ATV in Top Shape

Regular maintenance is the key to keeping your Polaris Sportsman 850 running smoothly and extending its lifespan. Think of it as preventative medicine for your ATV. By following a consistent maintenance schedule, you can catch potential problems early, avoid costly repairs, and ensure your machine is always ready for action. The owner's manual is your best friend here, as it provides specific recommendations based on your model year and usage. However, here's a general overview of the key maintenance tasks you should perform.

Oil and Filter Changes

This is one of the most crucial maintenance tasks. Regular oil changes are essential for lubricating the engine and removing contaminants. Always use the correct type of oil recommended by Polaris. Typically, this involves changing the oil and filter every 100 hours of use or annually, whichever comes first. This interval can vary depending on the severity of your riding conditions. If you ride in dusty or muddy environments, you may need to change the oil and filter more frequently. Replacing the oil filter at the same time is a must, as it removes the debris that can damage your engine. It's best practice to warm up your engine before changing the oil; this helps the oil flow more freely, making it easier to drain and removing more contaminants. Use a torque wrench when tightening the drain plug and oil filter to avoid over-tightening. Record the date and mileage of each oil change in a maintenance log to keep track of your service intervals.

Air Filter Maintenance

The air filter protects your engine from dirt and debris. Inspect the air filter regularly and clean or replace it as needed. The air filter on your Polaris Sportsman 850 can get clogged quickly, especially if you ride in dusty conditions. A dirty air filter restricts airflow, reducing engine performance and potentially causing damage. Most air filters can be cleaned, but some are disposable. If your air filter is washable, use the appropriate cleaner and oil it properly after cleaning. If it's a disposable filter, replace it with a new one according to the manufacturer's recommendations. Check the airbox for any signs of water or debris, as this could indicate a problem with the air filter seal or intake system. Cleaning or replacing the air filter at the right intervals will help the engine to perform better.

Spark Plug Inspection and Replacement

Spark plugs ignite the fuel-air mixture in your engine. They should be inspected periodically for wear and tear. Damaged spark plugs can lead to starting problems, poor fuel economy, and reduced engine performance. Inspect the spark plugs for wear, cracks, or fouling. Use a spark plug gap tool to ensure they are gapped correctly. Replace them as recommended in the owner's manual, typically every 100-200 hours of use. When replacing the spark plugs, be careful not to overtighten them, as this could damage the cylinder head. The right spark plugs can make the engine work better.

Checking and Maintaining the Cooling System

The cooling system prevents your engine from overheating. Check the coolant level regularly and top it off as needed. Make sure you use the correct type of coolant recommended by Polaris. Look for leaks in the radiator, hoses, and water pump. If you notice any leaks, repair them immediately. Periodically flush the cooling system and replace the coolant. This is typically recommended every two years. Overheating can cause severe engine damage, so it's critical to maintain the cooling system properly. Examine the radiator fins for any obstructions that could restrict airflow. Clean them as needed. The coolant level has to be at the correct level.

Checking and Maintaining Brakes

Your brakes are critical for safety. Inspect the brake pads, rotors, and brake lines regularly. Check the brake pads for wear and replace them if they are worn down to the wear indicators. Check the brake rotors for any signs of damage or warping. Check the brake fluid level and top it off as needed. Brake fluid absorbs moisture over time, which can reduce its effectiveness. Replace the brake fluid periodically. Check the brake lines for leaks or damage. Any issues with the brakes should be addressed immediately. Maintaining your brakes is essential for your safety and the safety of others.

Checking and Maintaining Tires

Your tires provide traction and impact your ride quality. Check the tire pressure regularly and inflate the tires to the pressure recommended by Polaris, usually found on a sticker on the ATV or in the owner's manual. Inspect the tires for any signs of damage, such as cuts, punctures, or uneven wear. Replace tires if necessary. Make sure your tires are properly inflated for the terrain you are riding on. For example, you may want to lower the tire pressure when riding in soft conditions like sand or mud. This increases the contact patch and improves traction. Tire pressure is very important.

Battery Maintenance

The battery provides power to start your engine and run the electrical system. Check the battery terminals for corrosion and clean them as needed. The battery must be in good shape. Make sure the battery cables are securely connected. Check the battery voltage regularly and charge it if necessary. If you store your ATV for an extended period, disconnect the battery or use a battery tender to keep it charged. Properly maintaining the battery will ensure your ATV starts every time you need it.

Common Problems and Troubleshooting

Even with the best maintenance, problems can arise. Here are some common issues and how to troubleshoot them:

Starting Problems

• Won't Start: Check the battery, spark plugs, fuel supply, and fuses. Ensure the kill switch is off. If the battery is weak, try jump-starting it. If the spark plugs are fouled, replace them. Make sure the fuel valve is open and that the fuel pump is working. Check the fuses to make sure none are blown. The start problem can be so many things.
• Starts but stalls: This could be a fuel delivery issue, a vacuum leak, or a problem with the idle circuit. Check the fuel filter, fuel pump, and fuel injectors. Inspect the intake manifold and vacuum hoses for leaks. Adjust the idle speed if necessary. Make sure there are no vacuum leaks.

Engine Performance Issues

• Loss of Power: This could be due to a clogged air filter, dirty fuel injectors, or a problem with the CVT belt. Check the air filter and replace it if necessary. Clean the fuel injectors or have them professionally cleaned. Inspect the CVT belt for wear and replace it if needed. Also, check the spark plugs.
• Rough Running: This can be caused by a variety of issues, including a faulty spark plug, a vacuum leak, or a problem with the fuel system. Inspect the spark plugs and replace them if necessary. Check the intake manifold and vacuum hoses for leaks. Check the fuel pressure and fuel injectors.
• Overheating: This is a serious issue that can cause engine damage. Check the coolant level, radiator, hoses, and water pump. If the coolant level is low, top it off. Look for leaks in the radiator, hoses, and water pump. If you find any leaks, repair them immediately. The water pump might need to be replaced.

Transmission Problems

• Slipping: This often indicates a worn CVT belt. Inspect the belt and replace it if needed. Check the CVT clutch for wear or damage.
• Erratic Shifting: This could be due to a problem with the CVT system or the gear selector. Inspect the CVT system for wear or damage. Check the gear selector for any issues.

Suspension and Steering Problems

• Rough Ride: This could be due to worn shocks or springs. Inspect the shocks and springs for leaks, damage, or wear. Replace them if necessary. Check the tire pressure. If the tire pressure is too high, it can make the ride rough.
• Poor Handling: This could be due to a variety of issues, including worn suspension components, low tire pressure, or a misaligned steering system. Inspect the suspension components for wear and tear. Check the tire pressure and adjust it as needed. Check the steering system for any issues. Make sure the steering is aligned.

Major Repairs: When to Call in the Big Guns

Sometimes, things go beyond routine maintenance, and you'll need to tackle more significant repairs. These might include:

Engine Rebuilds

If your engine has suffered significant damage, such as a seized piston or a broken crankshaft, a rebuild might be necessary. This is a complex process best left to experienced mechanics or those with significant mechanical aptitude. It involves disassembling the engine, replacing worn or damaged parts, and reassembling the engine. You'll need specialized tools and knowledge. Make sure the engine is rebuilt by a pro.

Transmission Repairs

Major transmission problems, such as a broken gear or a damaged clutch, often require professional repair. This involves disassembling the transmission, replacing worn or damaged parts, and reassembling the transmission. Again, this is a complex task. The transmission requires an expert.

Suspension Overhauls

If your suspension is severely damaged or worn, you might need to overhaul it. This might involve replacing shocks, springs, bushings, and other components. This can be a challenging task that may require specialized tools. This is a tough job and the suspension must be in good shape.

Tools and Equipment You'll Need

Having the right tools is essential for any repair job. Here’s a basic list:

• Basic Hand Tools: Wrenches, sockets, screwdrivers, pliers, etc. A good set of these is a must-have.
• Torque Wrench: To ensure bolts are tightened to the correct specifications.
• Multimeter: For electrical testing.
• Specialty Tools: Such as a clutch puller or a spark plug gap tool.
• Service Manual: Your go-to guide for specific procedures and specifications.

Safety First

Always prioritize safety when working on your Polaris Sportsman 850. Wear appropriate safety gear, such as eye protection, gloves, and a mask. Work in a well-ventilated area. Disconnect the battery before working on electrical components. Be careful when handling fluids, such as oil and coolant. If you're unsure about a repair, consult a professional mechanic. It’s always better to be safe than sorry, so don’t hesitate to ask for help when needed. Always work in a safe environment.

Final Thoughts: Keep on Riding!

Maintaining your Polaris Sportsman 850 doesn't have to be daunting. With a little knowledge and some elbow grease, you can keep your ATV running smoothly for years to come. Remember to follow the maintenance schedule in your owner's manual, address problems promptly, and don’t be afraid to seek professional help when needed. Enjoy the ride, and keep exploring! Your ATV will thank you for the care and attention you give it.