Polaris Ultra 680 Problems

The Polaris Ultra 680. The name alone conjures images of raw power and exhilarating speed on the snow. Released in the mid-1990s, this triple-cylinder snowmobile was a beast, boasting impressive horsepower and a reputation that preceded it. However, beneath the surface of this legendary machine lay a complex engine and design that, unfortunately, led to a series of well-documented problems. Understanding these issues is crucial for anyone looking to restore, maintain, or even simply appreciate the Polaris Ultra 680.

The Ultra's Allure: Power and Performance

Before we dive into the problems, it's important to understand why the Ultra 680 was so desirable in the first place. This snowmobile was a powerhouse, packing a 679cc liquid-cooled, triple-cylinder engine that delivered a significant punch. Riders loved the immediate throttle response and the sheer acceleration it offered. It was a sled designed for those who craved speed and demanded performance.

The Ultra's suspension, typically a trailing arm front suspension and a coupled rear suspension, aimed to provide a comfortable ride even on rough terrain. This combination of power and relatively plush suspension contributed to its popularity among performance-oriented riders. However, all that performance came at a price, and that price was reliability.

The Elephant in the Room: Engine Issues

The heart of the Ultra 680, that magnificent triple-cylinder engine, was also the source of many of its headaches. These issues stemmed from several factors, including:

Heat Management: The triple-cylinder design, especially with its centrally located cylinder, struggled to dissipate heat effectively. This often led to overheating, particularly in warmer conditions or during prolonged high-speed runs. Overheating could, in turn, cause piston damage, cylinder scoring, and even complete engine failure.
Carburetor Calibration: The Ultra 680 used three separate carburetors, one for each cylinder. Properly synchronizing and calibrating these carburetors was absolutely critical for smooth operation and optimal performance. However, it was also a complex and time-consuming process. If the carburetors were out of sync or improperly jetted, it could lead to lean conditions (too much air, not enough fuel) in one or more cylinders, resulting in engine damage.
Crankshaft Problems: The crankshaft, the backbone of the engine, was another common failure point. The Ultra 680's crankshaft was susceptible to bearing failure, especially if the engine was frequently run at high RPMs or if proper lubrication wasn't maintained. A failing crankshaft could cause catastrophic engine damage.
Ignition System Quirks: The ignition system, responsible for delivering the spark to ignite the fuel-air mixture, could also be problematic. Issues with the CDI (Capacitor Discharge Ignition) unit, coils, or spark plug caps could lead to misfires, poor performance, and difficulty starting.

These engine-related issues were so prevalent that they became almost synonymous with the Polaris Ultra 680. Many owners spent countless hours troubleshooting and repairing their engines, and a significant portion of Ultras ended up with rebuilt or even replaced engines.

Suspension Woes: A Bumpy Ride

While the engine problems were the most notorious, the Ultra 680's suspension wasn't without its flaws.

Rear Suspension Sag: The rear suspension, designed for a comfortable ride, could be prone to sagging over time, especially with heavier riders or after years of use. This sagging could negatively impact handling and ride quality.
Front Suspension Wear: The front suspension components, such as the trailing arm bushings and shock absorbers, were also subject to wear and tear. Worn bushings could lead to sloppy handling, while worn shocks could result in a harsh and uncomfortable ride.
Coupler Block Issues: The rear suspension's coupling blocks, designed to control weight transfer, could sometimes break or wear out. This could affect the sled's ability to transfer weight effectively, impacting acceleration and handling.

Addressing these suspension issues typically involved replacing worn components and ensuring proper lubrication. Upgrading to aftermarket shocks or heavier-duty springs could also improve performance and durability.

Fuel System Foibles: Starving for Power

Beyond the carburetors themselves, the Ultra 680's fuel system presented its own set of challenges.

Fuel Pump Problems: The fuel pump, responsible for delivering fuel from the tank to the carburetors, could fail or become weak over time. A weak fuel pump could starve the engine of fuel, leading to poor performance and potential engine damage.
Fuel Line Deterioration: The fuel lines, exposed to the elements and fuel additives, could deteriorate and crack, leading to fuel leaks and a loss of fuel pressure.
Fuel Filter Clogging: The fuel filter, designed to prevent contaminants from entering the carburetors, could become clogged with debris. A clogged fuel filter could restrict fuel flow and negatively impact performance.

Regularly inspecting and replacing fuel lines and the fuel filter was crucial for maintaining a healthy fuel system. Upgrading to a higher-quality fuel pump could also improve reliability.

Electrical Gremlins: A Spark of Trouble

The Ultra 680's electrical system, while not as problematic as the engine or fuel system, could still present its share of challenges.

Wiring Harness Issues: The wiring harness, responsible for connecting all the electrical components, could be prone to damage from vibration, chafing, and exposure to the elements. Damaged wiring could lead to shorts, open circuits, and a variety of electrical problems.
Lighting Problems: The headlights and taillights could sometimes fail due to bulb burnout or wiring issues.
Starter Motor Issues: The electric starter motor, used to start the engine, could fail or become weak over time.

Regularly inspecting the wiring harness for damage and ensuring proper connections was essential for preventing electrical problems. Replacing burned-out bulbs promptly and maintaining the starter motor could also improve reliability.

Keeping Your Ultra Alive: Maintenance is Key

Given the inherent problems associated with the Polaris Ultra 680, diligent maintenance is absolutely critical for keeping it running reliably. Here are some key maintenance tips:

Regular Carburetor Synchronization and Cleaning: Ensure the carburetors are properly synchronized and cleaned regularly. This will help ensure optimal performance and prevent lean conditions.
Proper Cooling System Maintenance: Keep the cooling system in top condition by ensuring the coolant is fresh, the radiator is clean, and the thermostat is functioning properly. This will help prevent overheating.
High-Quality Oil and Lubrication: Use high-quality oil and grease all moving parts regularly. This will help reduce wear and tear and extend the life of the engine and suspension.
Regular Inspection and Replacement of Wear Items: Regularly inspect and replace wear items such as fuel lines, spark plugs, and suspension bushings.
Monitor Engine Temperature: Pay close attention to the engine temperature gauge and avoid running the engine at high RPMs for extended periods, especially in warmer conditions.
Consider an Aftermarket Cooling Kit: If you frequently ride in warmer conditions or at high speeds, consider installing an aftermarket cooling kit to improve heat dissipation.

Is the Ultra Worth the Trouble?

Despite its well-documented problems, the Polaris Ultra 680 still holds a special place in the hearts of many snowmobile enthusiasts. Its raw power and exhilarating performance are undeniable. However, owning an Ultra 680 requires a certain level of mechanical aptitude and a willingness to invest time and effort in maintenance and repairs.

If you're prepared to tackle the challenges, the Ultra 680 can be a rewarding machine to own. But if you're looking for a trouble-free snowmobile, you might want to consider a different option.

Frequently Asked Questions

Why does my Ultra 680 overheat? The Ultra 680's triple-cylinder design struggles to dissipate heat effectively, especially in warmer conditions. Ensure your cooling system is functioning correctly and consider an aftermarket cooling kit.
How do I synchronize the carburetors on my Ultra 680? Carburetor synchronization requires specialized tools and knowledge. Consult a service manual or a qualified mechanic for assistance.
What kind of oil should I use in my Ultra 680? Use a high-quality two-stroke oil designed for snowmobile engines. Refer to your owner's manual for specific recommendations.
Why is my Ultra 680 hard to start? Hard starting can be caused by a variety of factors, including a weak battery, a faulty starter motor, or carburetor problems. Check these components and ensure they are functioning properly.
Are Ultra 680 parts hard to find? Some Ultra 680 parts can be difficult to find, but many are still available through aftermarket suppliers and online retailers.

Final Thoughts

The Polaris Ultra 680 is a snowmobile that demands respect. Its powerful engine and exhilarating performance are balanced by its inherent reliability issues. By understanding these problems and implementing a comprehensive maintenance plan, you can keep your Ultra 680 running strong for years to come. Careful maintenance and proactive troubleshooting are the keys to enjoying this iconic machine.