The Polaris Assault 800, a snowmobile celebrated for its aggressive trail performance and off-trail capabilities, has earned a loyal following among riders seeking a potent and versatile machine. However, like any complex piece of machinery, the Assault 800 isn't without its quirks and potential pitfalls. Understanding these common issues, from engine concerns to suspension adjustments, can equip riders with the knowledge to maintain their sleds, troubleshoot problems effectively, and ultimately maximize their riding experience. Let's dive into some of the most frequently encountered challenges faced by Polaris Assault 800 owners, and explore practical solutions to keep you tearing up the trails.

The Heart of the Matter: Engine Issues on the Assault 800

The 800 Liberty engine, while a powerhouse in its day, can be a source of frustration if not properly maintained. Let’s break down some of the most common engine-related problems:

Piston Failure: A Persistent Worry

One of the most talked-about issues with the Polaris Assault 800 is piston failure. This can stem from a few factors, but lean fuel conditions and overheating are the primary culprits.

  • Lean Fuel Condition: Insufficient fuel delivery can cause the engine to run hot, leading to piston damage. This can be caused by clogged fuel filters, faulty fuel injectors, or even air leaks in the intake system. Regularly inspecting and replacing fuel filters is crucial. Consider upgrading to higher-quality fuel injectors if you frequently experience lean conditions, especially after modifications like exhaust or intake upgrades.
  • Overheating: Maintaining proper cooling is paramount. Ensure the cooling system is functioning correctly. Check for coolant leaks, a malfunctioning thermostat, or a clogged radiator. Snowmobiles rely heavily on snow for cooling, so avoid prolonged operation on hard-packed or icy surfaces where adequate snow spray isn't available. Consider installing temperature gauges to monitor engine heat and catch potential problems early.

Crankshaft Woes: A Costly Repair

The crankshaft is another area prone to problems. Bearing failure within the crankshaft can lead to catastrophic engine damage. This can be caused by several factors, including:

  • Poor Lubrication: Using the correct oil and maintaining proper oil injection system function is vital. Synthetic oils are generally recommended for their superior lubrication properties and resistance to breakdown at high temperatures. Regularly check the oil level and ensure the oil pump is delivering the correct amount of oil.
  • Excessive Vibration: Excessive vibration can put undue stress on the crankshaft bearings. This can be caused by unbalanced clutches or other engine components. Regularly inspect the clutches for wear and balance and address any vibration issues promptly.

Electrical Gremlins: When Things Just Don't Spark

Electrical issues can be a real headache to diagnose. Here are a few common electrical problems experienced by Assault 800 owners:

  • Stator Problems: The stator generates the electricity needed to power the engine and electrical system. A failing stator can cause a no-start condition, intermittent running, or poor performance. Testing the stator with a multimeter is the best way to diagnose a problem.
  • Voltage Regulator Issues: The voltage regulator maintains a stable voltage to the electrical system. A faulty regulator can cause overcharging or undercharging, leading to battery problems and other electrical issues.
  • Wiring Harness Problems: The wiring harness can be susceptible to damage from vibration, moisture, and abrasion. Inspect the harness regularly for frayed wires, loose connections, and corrosion. Use dielectric grease on all electrical connections to prevent corrosion.

Suspension Setups: Taming the Terrain

The Polaris Assault 800 is known for its aggressive suspension, but it can be tricky to dial in the perfect setup for different riding styles and conditions.

Shock Adjustments: Finding the Sweet Spot

The Assault 800 typically comes with adjustable shocks, allowing riders to fine-tune the suspension for optimal performance.

  • Understanding Shock Settings: Familiarize yourself with the different shock adjustments, such as compression and rebound damping. Compression damping controls how quickly the shock compresses, while rebound damping controls how quickly it extends. Experiment with different settings to find what works best for your riding style and the terrain.
  • Sag Adjustment: Setting the correct sag (the amount the suspension compresses under the weight of the rider) is crucial for proper handling. Consult the owner's manual for the recommended sag settings.
  • Spring Preload: Adjusting the spring preload can affect the ride height and the stiffness of the suspension. Increasing the preload will raise the ride height and make the suspension stiffer, while decreasing the preload will lower the ride height and make the suspension softer.

Rear Suspension Issues: Keeping the Track on the Ground

The rear suspension is responsible for providing traction and absorbing bumps. Here are a few common issues:

  • Broken Springs: Rear suspension springs can break due to fatigue or excessive stress. Inspect the springs regularly for cracks or other signs of damage.
  • Worn Bushings: Worn bushings can cause excessive play in the suspension, leading to poor handling and increased wear on other components. Replace worn bushings promptly.
  • Idler Wheel Problems: Idler wheels support the track and help it move smoothly. Worn or damaged idler wheels can cause vibration and increase track wear.

Clutch Concerns: Power to the Track

The clutch is responsible for transferring power from the engine to the track. Maintaining the clutch is essential for optimal performance and longevity.

Clutch Maintenance: Keeping Things Smooth

Regular clutch maintenance is crucial for preventing problems.

  • Cleaning and Inspection: Clean the clutch regularly with compressed air and inspect the components for wear. Look for worn bushings, rollers, and springs.
  • Belt Inspection: The drive belt is a critical component of the clutch system. Inspect the belt regularly for wear, cracks, and fraying. Replace the belt when necessary.
  • Clutch Alignment: Proper clutch alignment is essential for optimal performance and belt life. Check the clutch alignment regularly and adjust as needed.

Common Clutch Problems: Troubleshooting Issues

Here are a few common clutch problems experienced by Assault 800 owners:

  • Belt Slippage: Belt slippage can cause a loss of power and overheating. This can be caused by a worn belt, contaminated clutch faces, or improper clutch settings.
  • Clutch Engagement Issues: Problems with clutch engagement can cause jerky starts or difficulty getting the sled moving. This can be caused by worn clutch components or improper clutch settings.
  • Excessive Clutch Noise: Excessive clutch noise can be a sign of worn or damaged clutch components.

Fuel and Carburetion: Keeping the Fire Burning

While many Assault 800s are fuel-injected, older models may have carburetors. Both systems require attention to ensure proper fuel delivery.

Fuel Injection Issues:

  • Injector Clogging: Fuel injectors can become clogged with deposits, leading to poor performance and fuel economy. Clean the injectors regularly with a fuel injector cleaner.
  • Fuel Pump Problems: A failing fuel pump can cause a loss of power or a no-start condition. Test the fuel pump pressure and flow to diagnose a problem.
  • Sensor Failures: Various sensors, such as the throttle position sensor (TPS) and the oxygen sensor (O2 sensor), provide information to the engine control unit (ECU). A faulty sensor can cause poor performance and fuel economy.

Carburetor Issues (for older models):

  • Dirty Carburetors: Carburetors can become clogged with dirt and debris, leading to poor performance and fuel economy. Clean the carburetors regularly.
  • Improper Jetting: Improper jetting can cause lean or rich fuel conditions, leading to poor performance and engine damage. Adjust the jetting based on the altitude and temperature.
  • Float Problems: Problems with the carburetor float can cause fuel leakage or flooding.

Frequently Asked Questions (FAQ)

Q: My Assault 800 is hard to start. What could be the problem? A: Hard starting can be caused by a weak battery, a faulty stator, or fuel delivery issues. Check the battery voltage, test the stator output, and ensure the fuel system is functioning correctly.

Q: My engine is overheating. What should I do? A: Overheating can be caused by low coolant, a clogged radiator, or a malfunctioning thermostat. Check the coolant level, inspect the radiator for debris, and test the thermostat.

Q: My sled is bogging down at high speeds. What could be the cause? A: Bogging down at high speeds can be caused by a lean fuel condition, a worn belt, or a clutch problem. Check the fuel system, inspect the belt, and ensure the clutch is functioning correctly.

Q: How often should I service my Polaris Assault 800? A: Regular servicing is essential for maintaining the performance and longevity of your snowmobile. Consult the owner's manual for the recommended service intervals.

Q: What type of oil should I use in my Assault 800? A: Synthetic oil is generally recommended for its superior lubrication properties and resistance to breakdown at high temperatures. Refer to the owner's manual for the specific oil requirements.

Conclusion

The Polaris Assault 800 is a capable snowmobile that delivers exhilarating performance, but understanding its common issues is key to minimizing downtime and maximizing your enjoyment on the snow. By proactively addressing potential problems and maintaining your sled properly, you can ensure that your Assault 800 continues to provide you with years of thrilling adventures.