The Yamaha Ag 200: a workhorse, a legend, and for many farmers and rural riders, an indispensable part of their daily lives. But even the most reliable machines can have their quirks, and the Ag 200 is no exception. While known for its rugged simplicity and dependability, certain issues tend to crop up more often than others, and understanding these common problems is key to keeping your Ag 200 running smoothly for years to come. Let's dive into the common issues and how to tackle them.

Starting Troubles: When Your Ag 200 Refuses to Wake Up

One of the most frustrating issues Ag 200 owners face is difficulty starting, especially after the bike has been sitting idle for a while. This can manifest in several ways, from a slow crank to absolutely nothing happening when you hit the starter. What's going on?

The Usual Suspects:

  • Battery Blues: This is the first place to check. A weak or dead battery is a common culprit, especially in older Ag 200s. Cold weather significantly impacts battery performance, so a battery that was fine in summer might struggle in winter. Test the battery voltage with a multimeter. If it's below 12.4 volts when fully charged, it might be time for a replacement.
  • Carburetor Clogs: The Ag 200's carburetor is relatively simple, but it's also susceptible to clogs, particularly if the bike isn't used regularly or if the fuel system isn't properly maintained. Old fuel can break down and leave deposits in the carburetor's jets and passages, restricting fuel flow.
  • Spark Plug Issues: A fouled or worn spark plug can prevent the engine from firing. Remove the spark plug and inspect it. A black, oily plug indicates a rich running condition (too much fuel), while a white or light gray plug suggests a lean condition (not enough fuel). A damaged or heavily worn plug should be replaced.
  • Fuel Delivery Problems: Check the fuel lines for kinks or blockages. Make sure the fuel tap is open and that fuel is flowing freely from the tank. A clogged fuel filter can also restrict fuel flow.
  • Electrical Gremlins: Less common, but still possible, are issues with the ignition system, such as a faulty ignition coil or a broken wire. These problems can be harder to diagnose and may require a professional mechanic.

What You Can Do:

  1. Charge the Battery: Start by fully charging the battery.
  2. Clean the Carburetor: If the bike has been sitting for a while, cleaning the carburetor is a good idea. You can find carburetor cleaner at most auto parts stores. Follow the instructions on the cleaner.
  3. Replace the Spark Plug: A new spark plug is a cheap and easy fix that can often resolve starting problems.
  4. Check Fuel Flow: Disconnect the fuel line at the carburetor and check that fuel is flowing freely from the tank.
  5. Inspect Wiring: Look for any obvious breaks or damage to the wiring harness, especially around the battery and ignition system.

Idling Issues: When the Ag 200 Won't Stay Running

Another common complaint is an Ag 200 that won't idle properly or stalls frequently. This can be incredibly frustrating, especially when you're trying to work.

Possible Causes:

  • Idle Speed Adjustment: The idle speed may simply be set too low. There's usually an idle speed adjustment screw on the carburetor that you can use to increase the idle speed.
  • Carburetor Problems (Again!): A dirty or improperly adjusted carburetor is often the culprit behind idling issues. Even if you cleaned it recently, small particles can still clog the jets.
  • Vacuum Leaks: A vacuum leak can disrupt the air-fuel mixture and cause the engine to stall. Check the intake manifold and carburetor for any cracks or loose connections. Spraying a small amount of carburetor cleaner around these areas while the engine is running can help you identify a leak. If the engine speed changes when you spray a particular area, you've found a leak.
  • Air Filter Woes: A dirty air filter can restrict airflow and cause the engine to run rich, leading to idling problems. Clean or replace the air filter regularly.
  • Valve Clearance Problems: While less common, incorrect valve clearances can affect engine performance and cause idling issues. This is more likely to be a problem if the bike has not had regular maintenance.

Troubleshooting Steps:

  1. Adjust the Idle Speed: Turn the idle speed adjustment screw clockwise to increase the idle speed.
  2. Clean the Carburetor (Thoroughly!): If adjusting the idle speed doesn't work, the carburetor likely needs a more thorough cleaning. Consider disassembling the carburetor and cleaning each jet and passage individually.
  3. Check for Vacuum Leaks: Inspect all vacuum lines and connections for leaks.
  4. Clean or Replace the Air Filter: A clean air filter is essential for proper engine performance.
  5. Check Valve Clearances: If you're comfortable working on engines, check the valve clearances according to the manufacturer's specifications. If not, take the bike to a mechanic.

Suspension Sag: When Your Ag 200 Feels Like a Lowrider

The Ag 200's suspension is designed to handle rough terrain, but over time, the springs can sag, and the shocks can lose their damping ability. This can make the bike feel unstable and uncomfortable to ride.

Why It Happens:

  • Wear and Tear: Like any mechanical component, suspension parts wear out over time. Springs lose their tension, and shocks lose their ability to control the movement of the suspension.
  • Heavy Loads: Regularly carrying heavy loads can accelerate the wear and tear on the suspension.
  • Lack of Maintenance: Neglecting suspension maintenance, such as lubricating the suspension linkages, can also contribute to premature wear.

Solutions:

  • Replace the Springs: Replacing the springs is a relatively straightforward way to restore the suspension's ride height and load-carrying capacity. Heavier-duty springs are available if you frequently carry heavy loads.
  • Rebuild or Replace the Shocks: Rebuilding the shocks involves replacing the worn seals and oil. This can restore the shock's damping ability. If the shocks are too worn to rebuild, you may need to replace them.
  • Upgrade the Suspension: If you're looking for improved performance, you can upgrade the suspension with aftermarket components. This can be a more expensive option, but it can significantly improve the bike's handling and comfort.

Rusty Tanks and Fuel System Corrosion: The Silent Killer

The Ag 200's fuel tank, especially on older models, is prone to rust, particularly if the bike is stored for extended periods with little or no fuel in the tank. Rust particles can clog the fuel system and cause a variety of problems.

Prevention is Key:

  • Keep the Tank Full: When storing the bike for an extended period, fill the fuel tank to the top to minimize the amount of air inside. This will help prevent rust from forming.
  • Use a Fuel Stabilizer: Add a fuel stabilizer to the fuel before storing the bike. Fuel stabilizers prevent the fuel from breaking down and forming deposits.
  • Drain the Tank: If you're not planning on using the bike for a very long time (several months or more), drain the fuel tank completely.

Dealing with Rust:

  • Fuel Tank Cleaner: There are several commercially available fuel tank cleaners that can remove rust. Follow the instructions on the cleaner carefully.
  • DIY Cleaning: You can also try cleaning the tank yourself using a mixture of gravel, nuts, and bolts, along with a degreaser or rust remover. Shake the tank vigorously to dislodge the rust. Be sure to rinse the tank thoroughly afterward.
  • Fuel Filter: Install a fuel filter to prevent rust particles from reaching the carburetor. Replace the fuel filter regularly.
  • Tank Coating: After cleaning the tank, consider coating the inside with a fuel tank sealant to prevent future rust formation.

Chain and Sprocket Wear: Keeping the Power Connected

The chain and sprockets are critical components of the Ag 200's drivetrain. Regular maintenance is essential to prevent premature wear and ensure reliable performance.

Common Issues:

  • Stretching Chain: Chains stretch over time due to wear. A stretched chain can cause the sprockets to wear prematurely and can even break.
  • Worn Sprockets: Sprockets wear down as the chain rubs against them. Worn sprockets can cause the chain to skip or jump.
  • Lack of Lubrication: Insufficient lubrication can accelerate the wear of both the chain and sprockets.

Maintenance Tips:

  • Lubricate the Chain Regularly: Lubricate the chain every few hundred miles, or more often if you're riding in dusty or muddy conditions. Use a chain lubricant specifically designed for motorcycles.
  • Adjust the Chain Tension: Check the chain tension regularly and adjust it as needed. The chain should have a small amount of slack.
  • Replace the Chain and Sprockets as a Set: When the chain or sprockets are worn, replace them as a set. Replacing only one component will cause the new component to wear prematurely.

Electrical System Quirks: When the Lights Go Out

The Ag 200's electrical system is relatively simple, but it can still be a source of problems.

Potential Problems:

  • Blown Fuses: Blown fuses are often caused by short circuits. Locate and repair the short circuit before replacing the fuse.
  • Faulty Wiring: Broken or corroded wires can cause a variety of electrical problems. Inspect the wiring harness for any damage.
  • Weak Battery (Again!): A weak battery can cause dim lights and starting problems.
  • Faulty Bulbs: Burned-out bulbs are a common problem. Replace the bulbs as needed.

Troubleshooting Tips:

  • Check the Fuses: Start by checking the fuses. Replace any blown fuses with the correct amperage rating.
  • Inspect the Wiring: Look for any obvious breaks or damage to the wiring harness.
  • Test the Battery: Check the battery voltage with a multimeter.
  • Check the Bulbs: Make sure the bulbs are properly seated in their sockets and that the filaments are intact.

Frequently Asked Questions (FAQ)

  • Why is my Ag 200 hard to start when it's cold? Cold temperatures reduce battery performance and make it harder for the engine to vaporize fuel. Consider using a battery tender and ensuring the carburetor is properly adjusted.
  • How often should I change the oil in my Ag 200? Change the oil every 1000-1500 miles, or more often if you're riding in dusty or muddy conditions. Regular oil changes are crucial for engine longevity.
  • What type of oil should I use in my Ag 200? Use a motorcycle-specific oil with a viscosity of 20W-40 or 20W-50. Avoid using automotive oil, as it may not provide adequate protection for the engine's wet clutch.
  • How do I adjust the chain tension on my Ag 200? Loosen the axle nut and use the chain adjusters to tighten or loosen the chain. The chain should have about 1 inch of slack.
  • Where can I find parts for my Ag 200? Parts are available from Yamaha dealers, online retailers, and aftermarket suppliers. Be sure to purchase quality parts from reputable sources.

In conclusion, while the Yamaha Ag 200 is a reliable machine, addressing the common issues promptly will ensure it continues to serve you well. Regular maintenance, careful observation, and a little bit of mechanical know-how are your best tools for keeping this legendary farm bike running strong.