Yamaha Big Bear 350 Common Problems & Solutions Explored

The Yamaha Big Bear 350 is a well-known and celebrated all-terrain vehicle (ATV) that was first introduced in 1987. Known for its reliability and power, the Big Bear quickly gained popularity among outdoor enthusiasts who needed a robust vehicle for off-road activities. However, as with any mechanical device, the Big Bear 350 comes with its own set of common problems that users may encounter. Listed below are the most frequent issues, along with detailed guides to help users fix these problems and enjoy their Yamaha Big Bear 350 to the fullest.

1. Carburetor Issues

a. Dirty Carburetor

One of the most common problems with the Yamaha Big Bear 350 is a dirty carburetor. Dirt and debris can get lodged in the carburetor, affecting the ATV’s performance and causing it to run poorly. To fix this issue, follow these steps:

  1. Remove the gas tank and air filter to gain access to the carburetor.
  2. Disconnect the throttle cable, choke cable, and fuel lines.
  3. Unscrew and disassemble the carburetor carefully.
  4. Use a carb cleaner and a toothbrush to clean the components thoroughly.
  5. Soak the parts in carb cleaner for an hour to get rid of any stubborn dirt.
  6. Reassemble the carburetor and install it back into the ATV.
  7. Reconnect all cables and fuel lines and reinstall the gas tank and air filter.

b. Improper Carburetor Adjustment

In some cases, an improperly adjusted carburetor may lead to performance issues in the Big Bear 350. To make sure the carburetor is adjusted properly, follow these steps:

  1. Warm up the engine by running the ATV for a few minutes.
  2. Locate the idle adjustment screw on the carburetor.
  3. Turn the screw clockwise or counterclockwise to adjust the idle speed. The ideal idle speed should be around 1,500 RPMs.
  4. Test the engine to ensure it’s running smoothly. If needed, fine-tune the idle adjustment screw.

2. Electrical Issues

a. Dead Battery

A dead battery is a common problem for ATVs, including the Yamaha Big Bear 350. If your ATV is not starting or running properly, the battery may need to be replaced. To change the battery, follow these simple steps:

  1. Locate and remove the battery cover.
  2. Disconnect the negative terminal first, followed by the positive terminal.
  3. Remove the old battery and replace it with a new one.
  4. Connect the positive terminal first, followed by the negative terminal.
  5. Reinstall the battery cover and start the engine to ensure proper functioning.

b. Faulty Ignition System

A malfunctioning ignition system can also cause problems with the Big Bear 350, leading to difficulties starting the engine or power loss while running. To fix this issue, follow these steps:

  1. Inspect the spark plug and its wire for signs of wear or damage.
  2. Replace the spark plug if necessary.
  3. Test the ignition coil using a multimeter for any electrical failure.
  4. If the coil fails the test, replace it with a new one.
  5. Check the ignition switch and wiring for any damage, and repair or replace as needed.

3. Brake Problems

a. Worn Brake Pads

The brake pads on the Yamaha Big Bear 350 can wear down over time, causing the brakes to become less effective. To replace worn brake pads, follow these steps:

  1. Jack up the ATV and remove the wheel to gain access to the brake caliper.
  2. Remove the caliper mounting bolts and slide the caliper off the rotor.
  3. Remove the old brake pads from the caliper.
  4. Install new brake pads and reassemble the brake caliper.
  5. Reinstall the wheel and lower the ATV.
  6. Repeat this process for the other brakes as needed.

b. Spongy Brakes

If the brakes on your Big Bear 350 feel spongy or unresponsive, there may be air trapped in the brake lines. This can occur if brake fluid has leaked, or during routine maintenance. To resolve this issue, bleed the brakes using these steps:

  1. Locate the brake bleeding nipple on the brake caliper and attach a hose.
  2. Place the other end of the hose into a container to catch the expelled fluid.
  3. Ask a friend to pump the brake lever several times and then hold it in place.
  4. Loosen the bleeding nipple to release the trapped air and fluid.
  5. Once the brake lever is fully compressed, tighten the bleeding nipple.
  6. Repeat this process until no more air bubbles appear in the expelled fluid.
  7. Top off the brake fluid reservoir as needed and reinstall the cap.

In conclusion, while the Yamaha Big Bear 350 is a reliable and capable ATV, users may still experience some common problems. However, with the proper knowledge and maintenance, these issues can be easily resolved, ensuring your Big Bear performs at its best for years to come.

Frequently Asked Questions

1. What years did Yamaha make the Big Bear 350?

Yamaha produced the Big Bear 350 from 1987 to 1999. The model had multiple changes throughout the years, including power and suspension upgrades.

2. Is the Yamaha Big Bear automatic?

The Yamaha Big Bear 350 and 400 models had both automatic and manual transmission options. The automatic models were known for their reliability and ease of use.

3. What is the top speed of a 2003 Yamaha Big Bear 400 4×4?

The top speed of a 2003 Yamaha Big Bear 400 4×4 is around 45-50 mph. However, various factors such as the riding terrain and weight of the rider can affect the maximum speed that can be attained.

4. How long is a Yamaha Big Bear 400?

The length of a Yamaha Big Bear 400 depends on the specific model and year. The standard length of a Big Bear 400 is around 81-82 inches, while the width is approximately 45-47 inches.

5. What are some common problems with Yamaha Big Bear 350?

Some common problems with the Yamaha Big Bear 350 include worn transmission bearings, faulty ignition switches, and weak charging systems. It’s also common for the carburetor to become clogged or dirty, which can cause engine performance issues.

6. How much does a Yamaha Big Bear 400 weigh?

The weight of a Yamaha Big Bear 400 depends on the model and year. The average weight for a Big Bear 400 4×4 is around 600-650 pounds, while the 2×4 models weigh around 500-550 pounds.

7. What is the difference between Yamaha Big Bear 350 and Grizzly?

The Yamaha Grizzly is a larger ATV than the Big Bear 350 and 400 models. The Grizzly has a more powerful engine, advanced suspension system, and better features than the Big Bear. Additionally, the Grizzly is designed for more aggressive off-road use than the Big Bear.

8. How often does the oil need to be changed in a Yamaha Big Bear?

The frequency of oil changes in a Yamaha Big Bear depends on the model and year. As a general rule, oil should be changed every 50-100 hours of operation or every 6-12 months, whichever comes first. Always refer to the owner’s manual for specific service intervals.

9. What is the fuel capacity of a Yamaha Big Bear 400?

The fuel capacity of a Yamaha Big Bear 400 is approximately 4.2 gallons. This should be enough for a full day of riding, but it’s always best to keep a spare gas can on hand, just in case.

10. How do I troubleshoot electrical problems in my Yamaha Big Bear?

If you’re experiencing electrical problems with your Yamaha Big Bear, the first step is to check the battery and charging system. Make sure the battery is fully charged and clean the terminals if necessary. If the battery and charging system are working properly, check the fuses and wiring connections. If you’re still having issues, it’s best to have a professional mechanic or technician diagnose the problem.

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