Suzuki King Quad 400 Asi Problems

The Suzuki King Quad 400ASi is a workhorse ATV, renowned for its reliability and ability to tackle tough terrain. However, like any machine, it's not immune to problems. Understanding these common issues, their causes, and potential solutions can save you time, money, and frustration, ensuring you keep your King Quad running smoothly for years to come. Let's dive into the most frequent challenges faced by King Quad 400ASi owners.

My King Quad Won't Start: Where Do I Begin?

A non-starting King Quad 400ASi can be incredibly frustrating, especially when you're counting on it for work or recreation. The good news is, the culprit is often something relatively simple. Here's a systematic approach to troubleshooting:

Check the Basics First: This might sound obvious, but ensure the fuel tank isn't empty, the fuel valve is open ("ON" position), and the engine kill switch is in the "RUN" position. It's surprising how often these simple oversights are the cause. Also, verify the battery is properly connected and has sufficient charge. A multimeter is your friend here.
Battery Blues: A weak or dead battery is a very common cause of starting problems. Even if the lights come on, the battery may not have enough amperage to crank the engine. Try jump-starting the ATV with a known good battery. If it starts, the original battery needs replacing or charging. Consider investing in a battery tender to maintain the battery's charge during periods of inactivity.
Spark Plug Inspection: A fouled or worn spark plug can prevent the engine from firing. Remove the spark plug and inspect it. Look for signs of excessive carbon buildup, oil fouling, or damage. A healthy spark plug should be clean and dry with a light tan color. If the spark plug is questionable, replace it with a new one of the correct type. Use a spark plug wrench to avoid damaging the threads.
Fuel Delivery Issues: If the fuel system is clogged, the engine won't get the fuel it needs to start.
- Fuel Filter: The fuel filter prevents debris from entering the carburetor or fuel injectors. Replace the fuel filter regularly, or more frequently if you operate in dusty or dirty conditions.
- Fuel Pump: The fuel pump is responsible for delivering fuel from the tank to the engine. Listen for the fuel pump priming when you turn the key. If you don't hear it, the fuel pump may be faulty.
- Carburetor/Fuel Injectors: A clogged carburetor or fuel injectors can restrict fuel flow. Cleaning the carburetor or fuel injectors may be necessary. Carburetor cleaner can be used for minor clogs, but a complete disassembly and cleaning might be required for more severe cases. For fuel injected models, a fuel injector cleaner additive might help.
Ignition System Problems: The ignition system provides the spark that ignites the air-fuel mixture in the engine.
- Ignition Coil: The ignition coil amplifies the voltage from the battery to create a spark at the spark plug. A faulty ignition coil can prevent the engine from starting.
- Stator: The stator generates the electrical power needed for the ignition system. A faulty stator can prevent the engine from starting.
- Crankshaft Position Sensor (CKP): The CKP sensor tells the ECU the position of the crankshaft. If this sensor fails, the ECU won't know when to fire the spark plug.
Check the Fuses: A blown fuse can interrupt the electrical circuit and prevent the engine from starting. Locate the fuse box and inspect all the fuses. Replace any blown fuses with new fuses of the same amperage. Be aware that repeatedly blowing fuses indicates a larger electrical problem that needs to be addressed.
Neutral Safety Switch: The King Quad 400ASi is equipped with a neutral safety switch that prevents the engine from starting unless the transmission is in neutral. If the switch is faulty, the engine may not start even if the transmission is in neutral. Try wiggling the shift lever while attempting to start the engine.

Transmission Troubles: Slipping, Jerking, and More

The automatic transmission on the King Quad 400ASi is generally reliable, but certain issues can arise:

Slipping Transmission: This is often a sign of worn clutch plates or low transmission fluid. Check the transmission fluid level and top it off if necessary. If the fluid is dark or smells burnt, it needs to be changed. If the slipping persists after changing the fluid, the clutch plates may need to be replaced.
Jerking or Erratic Shifting: This can be caused by a number of factors, including low transmission fluid, a faulty shift solenoid, or a problem with the electronic control unit (ECU). Start by checking the transmission fluid level and condition. If the fluid is okay, you may need to have the transmission diagnosed by a qualified mechanic.
Difficulty Shifting: This could be due to a binding shift linkage, low transmission fluid, or a problem with the shift solenoid. Lubricate the shift linkage and check the transmission fluid level. If the problem persists, you may need to have the shift solenoid replaced.
Transmission Overheating: Overheating can damage the transmission. This can be caused by low transmission fluid, excessive towing, or operating in hot conditions for extended periods. Check the transmission fluid level and ensure the transmission cooler is clean and free of debris.

Handling and Suspension Issues: A Bumpy Ride

A smooth ride is essential for comfort and control. Here's how to address common handling and suspension problems:

Wobbly Steering: This can be caused by loose wheel bearings, worn tie rod ends, or misaligned wheels. Check the wheel bearings for play and replace them if necessary. Inspect the tie rod ends for wear and replace them if necessary. Have the wheels aligned by a qualified mechanic.
Rough Ride: A rough ride can be caused by worn shocks, stiff springs, or overinflated tires. Inspect the shocks for leaks and replace them if necessary. Adjust the spring preload to soften the ride. Ensure the tires are inflated to the correct pressure.
Uneven Tire Wear: This can be caused by misaligned wheels, worn suspension components, or improper tire inflation. Have the wheels aligned by a qualified mechanic. Inspect the suspension components for wear and replace them if necessary. Ensure the tires are inflated to the correct pressure.
Loss of Control: This can be caused by a number of factors, including worn suspension components, loose steering components, or improper tire inflation. Inspect the suspension and steering components for wear and replace them if necessary. Ensure the tires are inflated to the correct pressure. If you experience a loss of control, stop the ATV immediately and have it inspected by a qualified mechanic.

Electrical Gremlins: Lights, Sensors, and More

Electrical problems can be particularly frustrating to diagnose. Here's a breakdown of common electrical issues:

Lights Not Working: Check the bulbs first. If the bulbs are good, check the fuses and wiring. A multimeter can be used to trace the electrical circuit and identify the source of the problem.
Sensor Failures: The King Quad 400ASi has several sensors that monitor various engine and transmission parameters. A faulty sensor can cause a variety of problems. Use a scan tool to read the diagnostic trouble codes (DTCs) and identify the faulty sensor.
Wiring Problems: Damaged or corroded wiring can cause a variety of electrical problems. Inspect the wiring harness for damage and repair any damaged wires. Clean any corroded connections.
ECU Problems: The ECU is the brain of the ATV. A faulty ECU can cause a variety of problems. ECU issues are often difficult to diagnose and may require specialized equipment.

General Maintenance is Key

Preventative maintenance is crucial for avoiding many of these problems. Here's a basic maintenance schedule:

Regular Oil Changes: Change the engine oil and filter every 100 hours or 6 months, whichever comes first.
Air Filter Maintenance: Clean or replace the air filter every 50 hours or 3 months, whichever comes first. More frequently in dusty conditions.
Transmission Fluid Changes: Change the transmission fluid every 200 hours or 12 months, whichever comes first.
Spark Plug Replacement: Replace the spark plug every 100 hours or 6 months, whichever comes first.
Grease Fittings: Grease all grease fittings every 25 hours or monthly.
Inspect and Adjust Brakes: Inspect the brakes regularly and adjust them as needed.
Check Tire Pressure: Check the tire pressure before each ride.
Inspect Hoses and Belts: Inspect all hoses and belts for cracks and wear.
Check and Tighten Fasteners: Check and tighten all fasteners regularly.

Frequently Asked Questions

Why is my King Quad backfiring? Backfiring is often caused by a lean fuel mixture. Check for air leaks in the intake system or a clogged carburetor.
How often should I change the oil? Change the engine oil and filter every 100 hours or 6 months, whichever comes first.
What type of oil should I use? Use a high-quality 10W-40 engine oil that meets the API service classification SG or higher.
Why is my King Quad overheating? Overheating can be caused by low coolant, a faulty thermostat, or a clogged radiator.
How do I adjust the carb on my King Quad 400 Asi? Carburetor adjustment requires precision. Consult the service manual or a qualified mechanic.

Conclusion

The Suzuki King Quad 400ASi is a reliable ATV, but understanding common problems and performing regular maintenance are essential for keeping it running smoothly. By following these tips and addressing issues promptly, you can enjoy years of trouble-free riding. Regular maintenance and timely repairs are key to the longevity of your King Quad.