The Yamaha Grizzly 660, a powerhouse of an ATV, earned a reputation for its ruggedness and reliability. However, even the toughest machines have their quirks. While generally a dependable workhorse, the Grizzly 660 isn't immune to problems. Understanding these common issues, from electrical gremlins to carburetor woes, can save you time, money, and frustration, keeping you riding instead of wrenching.

Common Issues You Might Encounter with Your Grizzly 660

The Grizzly 660, while a legend, isn't without its potential pitfalls. Knowing what to look for can help you diagnose and address problems early, preventing more serious (and expensive) repairs down the line. Let's dive into some of the most frequently reported issues.

1. Carburetor Conundrums: A Grizzly's Achilles Heel?

The carburetor is arguably the most common source of problems on the Grizzly 660. These issues often manifest as:

  • Hard starting: Especially in cold weather, a dirty or poorly adjusted carburetor can make starting a real chore.
  • Rough idling: An inconsistent or stalling idle is another classic symptom of carburetor trouble.
  • Poor performance: Hesitation, bogging, or a general lack of power can indicate a fuel delivery problem.
  • Fuel leaks: Overflowing fuel can be a sign of a stuck float valve or other carburetor component issues.

Why is the carburetor so problematic? The Grizzly 660 carburetor is a relatively complex unit, and it's highly susceptible to issues caused by:

  • Old fuel: Ethanol-blended fuels can degrade quickly, leaving behind varnish and deposits that clog jets and passages.
  • Dirt and debris: Contamination from the fuel tank or air intake can wreak havoc on the delicate internal components.
  • Altitude changes: The carburetor may need adjustment to compensate for changes in altitude, especially if you ride in mountainous areas.

What can you do about it?

  • Regular cleaning: Disassemble and thoroughly clean the carburetor at least once a year, or more often if you ride in dusty or dirty conditions. Use carburetor cleaner and compressed air to clear all jets and passages.
  • Fuel stabilizer: Add a fuel stabilizer to your gas tank, especially when storing the ATV for extended periods. This helps prevent fuel degradation and varnish buildup.
  • Inline fuel filter: Install an inline fuel filter to prevent dirt and debris from entering the carburetor.
  • Professional tuning: If you're not comfortable working on carburetors, take your Grizzly to a qualified mechanic for tuning and adjustment. Consider a Dynojet kit for improved performance.

2. Electrical Gremlins: When the Lights Go Out

Electrical issues can be frustrating, as they can be difficult to diagnose and often involve multiple potential causes. Some common electrical problems on the Grizzly 660 include:

  • Battery problems: Weak or dead batteries are a frequent complaint.
  • Charging system issues: A faulty stator, regulator/rectifier, or wiring harness can prevent the battery from charging properly.
  • Faulty switches and connections: Corroded or loose connections can cause intermittent electrical problems.
  • Starter problems: A failing starter motor or solenoid can prevent the engine from cranking.

Why do electrical problems occur?

  • Exposure to the elements: The Grizzly 660 is often used in harsh conditions, which can lead to corrosion and damage to electrical components.
  • Age: Over time, wiring can become brittle and connections can loosen.
  • Poor maintenance: Neglecting to clean and protect electrical connections can accelerate corrosion.

Troubleshooting tips:

  • Check the battery: Ensure the battery is fully charged and in good condition. Have it load tested to rule out internal damage.
  • Inspect the wiring: Look for any signs of damage, corrosion, or loose connections. Use a multimeter to check for continuity and voltage.
  • Test the charging system: Use a multimeter to check the output voltage of the stator and regulator/rectifier.
  • Clean and protect connections: Clean all electrical connections with electrical contact cleaner and apply dielectric grease to prevent corrosion.

3. Overheating: Keeping Your Cool Under Pressure

Overheating can cause serious damage to your Grizzly 660's engine. Common causes of overheating include:

  • Low coolant: Check the coolant level regularly and top it off as needed.
  • Clogged radiator: Mud, dirt, and debris can clog the radiator fins, reducing its ability to dissipate heat.
  • Faulty thermostat: A stuck or malfunctioning thermostat can prevent coolant from circulating properly.
  • Water pump failure: A failing water pump can reduce coolant flow, leading to overheating.

Preventing overheating:

  • Regular coolant checks: Check the coolant level before each ride and top it off as needed. Use the correct type of coolant as specified in your owner's manual.
  • Radiator cleaning: Regularly clean the radiator fins with a soft brush and water. Avoid using high-pressure washers, as they can damage the fins.
  • Thermostat replacement: Replace the thermostat every few years as part of routine maintenance.
  • Water pump inspection: Inspect the water pump for leaks or damage. Replace it if necessary.

4. Transmission Troubles: Shifting Gears and Avoiding Grinding

While the Grizzly 660's transmission is generally robust, it can still experience problems, such as:

  • Difficulty shifting: Hard shifting can be caused by worn shift linkage, low transmission fluid, or internal transmission damage.
  • Slipping: Slipping can occur when the clutches are worn or the transmission fluid is contaminated.
  • Noise: Unusual noises, such as grinding or whining, can indicate internal transmission damage.

Maintaining your transmission:

  • Regular fluid changes: Change the transmission fluid according to the manufacturer's recommendations. Use the correct type of fluid as specified in your owner's manual.
  • Shift linkage adjustment: Adjust the shift linkage as needed to ensure smooth and precise shifting.
  • Clutch inspection: Inspect the clutches for wear and damage. Replace them if necessary.

5. Suspension Woes: Bumps in the Road (and Trail)

The Grizzly 660's suspension is designed to provide a comfortable ride and good handling, but it can be prone to wear and tear. Common suspension problems include:

  • Worn bushings and ball joints: Worn bushings and ball joints can cause excessive play in the suspension, leading to poor handling and tire wear.
  • Leaking shocks: Leaking shocks can reduce damping performance, resulting in a bouncy or unstable ride.
  • Broken springs: Broken springs can cause the suspension to sag and bottom out easily.

Maintaining your suspension:

  • Regular inspection: Inspect the suspension components regularly for wear and damage.
  • Grease fittings: Grease the suspension fittings regularly to lubricate the bushings and ball joints.
  • Shock replacement: Replace worn or leaking shocks as needed.
  • Spring replacement: Replace broken or sagging springs as needed.

Preventative Maintenance: The Key to Longevity

The best way to avoid many of these problems is to perform regular preventative maintenance. This includes:

  • Following the manufacturer's recommended maintenance schedule: Consult your owner's manual for the recommended maintenance intervals for various components.
  • Using high-quality fluids and parts: Don't skimp on quality when it comes to fluids and parts. Using high-quality components can help extend the life of your ATV and prevent problems.
  • Storing your ATV properly: When storing your ATV for extended periods, take steps to protect it from the elements and prevent fuel degradation.
  • Regular cleaning: Keep your ATV clean to prevent dirt and debris from damaging components.

Frequently Asked Questions

  • Why is my Grizzly 660 hard to start in cold weather? A common culprit is a dirty or poorly adjusted carburetor. Cold weather exacerbates fuel delivery problems.
  • What kind of fuel should I use in my Grizzly 660? Use fresh, high-quality gasoline with an octane rating of 87 or higher. Avoid ethanol-blended fuels if possible, or use a fuel stabilizer.
  • How often should I change the oil in my Grizzly 660? Change the oil every 100 hours of riding or at least once a year, whichever comes first.
  • Why is my Grizzly 660 overheating? Check the coolant level, radiator for blockages, and thermostat for proper function. A faulty water pump could also be the cause.
  • What does it mean when my Grizzly 660 backfires? Backfiring often indicates a lean fuel mixture, which can be caused by a dirty carburetor or vacuum leak.

Conclusion

The Yamaha Grizzly 660 is a capable and reliable ATV, but like any machine, it's susceptible to certain problems. By understanding these common issues and performing regular preventative maintenance, you can keep your Grizzly running smoothly for years to come. Remember, a little bit of preventative care can save you a lot of headaches (and money) down the road.