The Suzuki GS500, a beloved motorcycle for new riders and seasoned veterans alike, enjoys a reputation for reliability and affordability. However, like any machine, the GS500 isn't without its quirks and potential problems. Understanding these common issues can help you keep your GS500 running smoothly and avoid unexpected headaches.

A Little History & Why This Matters

The GS500, produced from 1989 to 2009 (with some variations in different markets), earned its stripes as a dependable, easy-to-maintain motorcycle. Its air-cooled, parallel-twin engine is known for its forgiving nature, making it an excellent choice for learning the ropes of motorcycling. But even the most robust engines can suffer from wear and tear, especially as these bikes age. Knowing what to look for will save you time, money, and frustration in the long run.

The Carburetor Conundrum: A Common GS500 Headache

The GS500 relies on carburetors to mix air and fuel, a technology that, while simple, can be susceptible to issues. Carburetor problems are arguably the most frequent complaints among GS500 owners, especially on bikes that have been sitting for extended periods.

What are the telltale signs of carburetor trouble?

  • Rough idling: The engine struggles to maintain a steady idle speed, often fluctuating or stalling.
  • Hesitation or bogging: The engine feels sluggish or unresponsive when you twist the throttle, especially at lower RPMs.
  • Poor fuel economy: You're filling up more often than you used to.
  • Difficulty starting: The bike takes longer to start than usual, or it refuses to start altogether.
  • Backfiring: Loud pops or bangs from the exhaust, indicating incomplete combustion.

Why do carburetors cause so much trouble?

Several factors can contribute to carburetor problems on the GS500:

  • Clogged jets: Small passages within the carburetors can become blocked by debris, affecting fuel flow. This is especially common if the bike has been sitting unused for a while, allowing fuel to evaporate and leave behind residue.
  • Dirty fuel: Contaminated fuel can introduce dirt and grime into the carburetors, leading to blockages and performance issues.
  • Vacuum leaks: Air leaks around the carburetors or intake manifolds can disrupt the air-fuel mixture, causing lean running and poor performance.
  • Float level issues: Incorrect float levels can affect the amount of fuel in the carburetor bowls, leading to rich or lean running conditions.
  • Diaphragm problems: The carburetors use diaphragms to control fuel flow. These diaphragms can crack or become brittle over time, affecting performance.

How to address carburetor problems:

  • Clean the carburetors: This is often the first step in resolving carburetor issues. Disassemble the carburetors carefully, clean all the jets and passages with carburetor cleaner, and reassemble them.
  • Replace the jets: If cleaning doesn't solve the problem, the jets may be damaged or worn and need replacement.
  • Check for vacuum leaks: Inspect the intake manifolds and carburetor boots for cracks or damage. Use carburetor cleaner or starting fluid to spray around the intake area while the engine is running. If the engine speed changes, you've found a vacuum leak.
  • Adjust the float levels: Consult the service manual for the correct float level settings.
  • Replace the diaphragms: If the diaphragms are cracked or damaged, replace them with new ones.
  • Consider a professional carburetor rebuild: If you're not comfortable working on carburetors yourself, take the bike to a qualified mechanic for a professional rebuild.

The Charging System Challenge: Keeping the Battery Alive

Another common problem area on the GS500 is the charging system. A healthy charging system is crucial for keeping the battery charged and powering the bike's electrical components.

What are the signs of a charging system problem?

  • Weak battery: The battery struggles to start the bike, especially after sitting for a few days.
  • Dim headlights: The headlights appear dim or flicker.
  • Electrical issues: The turn signals, horn, or other electrical components malfunction.
  • Battery won't hold a charge: The battery drains quickly, even after being fully charged.

What components make up the charging system, and what can go wrong?

  • Battery: The battery stores electrical energy. It can fail due to age, sulfation, or internal damage.
  • Stator: The stator generates electricity. It can fail due to overheating, short circuits, or physical damage.
  • Regulator/Rectifier: The regulator/rectifier regulates the voltage and converts AC power to DC power. It can fail due to overheating or electrical overload.

How to diagnose and fix charging system problems:

  • Check the battery: Use a multimeter to check the battery voltage. A fully charged battery should read around 12.6 volts. If the voltage is low, charge the battery and retest it. If the battery still won't hold a charge, it may need to be replaced.
  • Check the charging voltage: With the engine running, use a multimeter to check the charging voltage at the battery terminals. The charging voltage should be between 13.5 and 14.5 volts. If the charging voltage is too low or too high, the regulator/rectifier may be faulty.
  • Test the stator: Use a multimeter to test the stator output. Consult the service manual for the correct testing procedure and voltage readings. If the stator output is low or non-existent, the stator may need to be replaced.
  • Check the wiring: Inspect the wiring harness for loose connections, damaged wires, or corrosion. Clean and tighten any loose connections, and repair or replace any damaged wires.

Suspension Woes: A Bumpy Ride

The GS500's suspension, while adequate for basic riding, can feel a bit soft and underdamped, especially for heavier riders or aggressive riding.

What are the common suspension complaints?

  • Soft front forks: The front forks dive excessively under braking.
  • Bouncy rear shock: The rear shock feels bouncy or uncontrolled over bumps.
  • Poor handling: The bike feels unstable or difficult to handle in corners.

How to improve the GS500's suspension:

  • Fork oil change: Changing the fork oil can improve the damping performance. Use a heavier weight fork oil or add preload spacers to stiffen the front forks.
  • Fork springs: Upgrading to aftermarket fork springs can provide a significant improvement in handling and stability.
  • Rear shock replacement: Replacing the rear shock with an aftermarket unit can improve damping and handling.
  • Progressive springs: These springs offer a variable spring rate, providing a softer ride over small bumps and a stiffer ride during aggressive riding.

Electrical Gremlins: Chasing Intermittent Issues

Like any older motorcycle, the GS500 can suffer from electrical gremlins. These intermittent issues can be frustrating to diagnose and repair.

What are some common electrical problems?

  • Intermittent starting problems: The bike starts sometimes, but not others.
  • Flickering lights: The headlights, turn signals, or other lights flicker or cut out.
  • Loss of power: The engine suddenly loses power or stalls.

How to track down electrical problems:

  • Check the wiring harness: Inspect the wiring harness for loose connections, damaged wires, or corrosion. Pay close attention to the connectors and ground points.
  • Check the fuses: Make sure all the fuses are in good condition and are the correct amperage.
  • Check the switches: Test the switches for continuity. A faulty switch can cause intermittent electrical problems.
  • Use a multimeter: A multimeter is an essential tool for diagnosing electrical problems. Use it to check for voltage drops, continuity, and resistance.
  • Clean the connections: Corrosion can cause electrical problems. Clean all the electrical connections with a wire brush or sandpaper.

Rust Never Sleeps: Dealing with Corrosion

Older GS500s are susceptible to rust, especially if they've been exposed to the elements.

Where does rust typically appear on a GS500?

  • Fuel tank: Rust inside the fuel tank can clog the fuel filter and cause carburetor problems.
  • Frame: Rust on the frame can weaken the structure.
  • Exhaust system: Rust on the exhaust system can cause leaks and reduce performance.
  • Fasteners: Rust on fasteners can make them difficult to remove.

How to prevent and treat rust:

  • Store the bike indoors: Keep the bike stored in a dry, covered area when not in use.
  • Wash the bike regularly: Wash the bike regularly to remove dirt, salt, and other contaminants.
  • Apply rust inhibitor: Apply a rust inhibitor to exposed metal surfaces.
  • Remove rust: Remove rust with a wire brush, sandpaper, or chemical rust remover.
  • Paint or coat the affected areas: After removing rust, paint or coat the affected areas to prevent further corrosion.

Frequently Asked Questions

  • Why does my GS500 idle rough? This is often due to dirty or clogged carburetors. Cleaning the carburetors is usually the first step.
  • My GS500 is hard to start. What could be the problem? Possible causes include a weak battery, dirty carburetors, or a faulty charging system. Start by checking the battery voltage.
  • What's the best way to clean the carburetors? Disassemble the carburetors carefully and clean all the jets and passages with carburetor cleaner. Refer to the service manual for detailed instructions.
  • How often should I change the oil on my GS500? Suzuki recommends changing the oil every 3,500 miles or annually, whichever comes first.
  • What kind of oil should I use in my GS500? Use a motorcycle-specific 10W-40 oil that meets the API SG or higher specification.

Keeping Your GS500 Alive and Kicking

The Suzuki GS500, despite its age, remains a fantastic motorcycle. By understanding the common problems and taking proactive steps to maintain your bike, you can enjoy years of reliable service. Regular maintenance, proper storage, and prompt attention to any issues that arise will keep your GS500 running smoothly.