Kawasaki Brute Force 650 Problems, Symptoms, and Fixes

Have you noticed your Kawasaki Brute Force 650 ATV acting up lately? Does it stall frequently, lose power under load, or overheat on long rides? As a popular and rugged ATV, the Brute Force 650 is built for off-road adventures. But even the best quads experience problems from time to time.

So what are the most common issues with the Kawasaki Brute Force 650, and how can you diagnose and fix them?

The good news is many Brute Force 650 problems can be repaired at home with basic mechanical skills and a good repair manual. Others may require the expertise of a professional ATV mechanic if major engine or transmission repairs are needed.

In this detailed guide, we’ll overview the top Kawasaki Brute Force 650 problems owners commonly face based on repair stats and owner reports. We’ll explore the symptoms, possible causes, and steps to troubleshoot and fix each issue yourself or determine if it’s time to take your ATV to the shop. specific issues covered include:

• Frequent stalling and starting problems
• Loss of power under load
• Transmission slipping and jerking
• Overheating problems
• Loose steering and unstable handling

Gaining an understanding of common Brute Force 650 problems can help you stay on top of maintenance, make timely repairs, and keep your ATV running strong for years of off-road enjoyment. Let’s get started diagnosing and fixing the most common issues with one of Kawasaki’s most popular ATVs.

Frequent Stalling, Rough Idling, and Starting Problems

One of the most frustrating issues Brute Force owners report is the engine stalling or dying unexpectedly, idling rough, or having difficulty starting. An ATV that keeps stalling can leave you stranded miles from home on the trail.

So what causes a Brute Force 650 to stall or run rough? There are a few key maintenance items and components to inspect if you experience frequent stalling issues:

• Dirty air filter – The air filter is one of the most common causes of stalling and starting issues. Over time it can become clogged with dirt, dust and debris. This restricts proper airflow to the carburetor and engine. Replace the air filter or clean it per your owner’s manual. Use Kawasaki part #11013-0051 for a direct OEM replacement filter.
• Faulty fuel pump – The fuel pump delivers gasoline from the tank to the injectors. If it fails, you may notice difficult starting or the Brute Force 650 dying shortly after startup. Test the pump’s pressure and volume per the factory service manual. If output is low, replace it. OEM part number is 51085-0004 for models up to 2013 and 51080-0009 for 2014+ ATVs.
• Clogged fuel injectors – The fuel injectors spray fuel into the engine for combustion. But over time they can get gummed up with old fuel varnish and debris. This restricts proper fuel flow, potentially causing stalling. Run a good fuel injector cleaner like Yamaha Y-CAT through the system per the label directions to free up stuck injectors.
• Weak battery – The battery is responsible for providing current to crank the starter motor. A worn out or failing battery may lack sufficient charge to turn over the engine. Use a voltmeter to test battery voltage. Recharge if low or replace the battery if it no longer holds a charge.
• Damaged spark plugs – Faulty spark plugs can lead to misfires, poor combustion and rough running. Inspect the plugs and replace them if the electrode is worn or heavy carbon fouling is present. For optimal performance, replace the spark plugs every 100 hours or annually. Use Champion RC12YC plugs as OEM replacements.
• Compression issues – If the piston rings, cylinders or valves are worn it can lead to low compression and difficult starting. Perform a compression test per the factory service manual. Low readings indicate worn piston rings, cylinders or valves that require repair.

By methodically inspecting each of these engine components, you can troubleshoot and fix the cause of frequent stalling and starting problems on your Brute Force ATV. Simple maintenance like cleaning the air filter or replacing worn spark plugs can often resolve issues and get you back on the trails.

Loss of Power Under Load

The Brute Force 650 delivers excellent mid-range and top-end power for conquering trails and hauling loads. But if you notice a lack of power when climbing hills or lugging heavy loads, several issues may be to blame.

• Clogged air filter – Just like with stalling problems, a dirty, clogged air filter can significantly reduce engine power. Without enough airflow, the engine can’t produce adequate power when placed under load. Inspect and replace the air filter if needed.
• Fouled or damaged spark plugs – Faulty spark plugs that misfire under load robs the engine of power. Inspect the plugs and replace any with heavy carbon fouling or excessive electrode wear. Also make sure you have the recommended heat range plug, like Champion RC12YC.
• Low engine compression – Compression helps generate powerful combustion. Low compression, often due to worn piston rings or leaking head gasket, reduces power delivery. Do a compression test and service the engine if needed.
• Exhaust restriction – Problems in the exhaust like a crushed pipe, catalytic converter failure or muffler damage can create backpressure. This chokes airflow, significantly reducing power. Inspect the exhaust and replace any damaged components.
• Incorrect valve clearance – The valves on the Brute Force 650 need periodic adjustment per the factory specs. Incorrect clearance can hinder performance. Inspect and adjust the valves if they are noisy or out of spec.
• Low octane fuel – Always use the recommended minimum octane fuel, typically 87 octane for most Brute Force models. Lower octane gasoline can cause potentially damaging engine knock.

With routine maintenance to components like the air filter, spark plugs and valves, you can keep your 650 delivering excellent power even under heavy loads. Adjust the valves every 20-40 hours. Inspect plugs, filters and compression at 100 hour intervals.

Transmission Slipping or Jerking

The transmission transfers engine power to turn the wheels. Signs of slipping or jerky/slow shifting indicate potential issues with transmission components. Here are a few common causes of Brute Force 650 transmission problems:

• Low transmission fluid – Insufficient fluid prevents smooth seamless gear changes. It allows premature clutch and gear wear. Check the fluid levels per the owner’s manual and top off if needed. Use only recommended fluids like SAE 10W-40 for most models.
• Clutch wear – The clutch pack contains stacks of friction plates and steel plates that engage via the clutch actuator. Over time, these plates can wear, causing slippage under power. Replacing the clutch pack restores solid hookup and smooth shifting.
• Worn shift fork – The shift forks slide the gears into place during shifts. Bent or worn forks cause sluggish shifting and difficulty getting into gear. Inspect the shift components and replace any worn parts.
• Faulty clutch actuator – The actuator extends and retracts to engage/disengage the clutch. If sticks or doesn’t fully engage, it leads to clutch slippage. Test the actuator operation and replace if faulty.
• Bent or loose shift lever – The shift lever allows you to change gears. A bent or loose shift lever can prevent solid gear engagement. Inspect the shift linkage and tighten or replace components as needed.
• Damaged gears – Broken, chipped or excessively worn gears make for difficult shifting between speeds. Disassemble the transmission to inspect each gear. Replace any that are damaged. This usually requires a mechanic for overhaul.

Slow, jerky shifting or gears slipping under load is annoying and reduces performance. Identifying and replacing worn transmission parts restores solid, crisp shifting on your Brute Force 650 ATV again. Sticking with the prescribed transmission fluid change intervals helps maintain proper operation.

Overheating Problems

As a powerful high performance ATV, the Brute Force 650 requires effective engine cooling. Overheating issues can leave you stranded as the motor temperature climbs to dangerous levels. Signs of overheating include:

• High temperature warning light
• Steam or mist from radiator overflow bottle
• Loss of power
• Sweet smelling white exhaust smoke

Frequent overheating can seriously damage your ATV’s motor. Here are some common cooling system issues to inspect on the Brute Force 650:

• Leaking or damaged radiator hoses – The hoses circulate engine coolant through the radiator. Cracked, loose or deteriorated hoses allow coolant leaks. Inspect all radiator and bypass hoses. Tighten connections or replace leaking hoses.
• Faulty radiator cap – The cap seals the cooling system, maintaining the proper pressure needed for a high boiling point. A cap unable to hold pressure allows coolant to escape while also lowering the boiling point. Replace the cap if old or faulty.
• Compromised waterpump – The waterpump maintains coolant circulation. A seized, leaking or damaged water pump impairs coolant flow, leading to overheating, especially at low speeds. Replace water pump if any issues are found.
• Plugged radiator – The radiator must stay clear to effectively shed heat. Mud or debris buildup causes clogs, reducing critical airflow. Carefully clean the radiator of any obstructions to restore cooling capacity.
• Blocked thermostat – The thermostat regulates coolant flow to the radiator. If stuck shut, it prevents circulation, leading to overheating. Replace the thermostat if any evidence it’s not opening properly.
• Low coolant – Inadequate coolant volume leads to overheating. Check levels regularly and top up as needed with the recommended 50/50 antifreeze and water mix. Pressure test system to check for leaks if low.

Neglected cooling systems are the most common cause of Brute Force overheating. Stay proactive with visual inspections, pressure tests and regular coolant changes to ensure your ATV runs cool on every ride. Consult your repair manual for proper procedures.

Loose Steering/Unstable Handling

Precise, confident steering and handling is crucial when riding challenging trails. Signs of loose steering, shimmying or wandering can indicate issues with steering and suspension parts.

• Low tire pressure – Incorrect tire pressure is the most common cause of unstable Brute Force handling. Too little pressure allows tires to flex and wander. Always inflate ATV tires to the recommended PSI for your model and riding conditions.
• Worn tie rod ends – The tie rods connect to the knuckles to steer the wheels. Worn tie rod end ball joints introduce play, making the steering loose with a wandering sensation. Inspect tie rod ends and replace if excessive play is found.
• Damaged wheel bearings – Worn, loose wheel bearings also lead to noticeable front end shimmy and wobble, especially at higher speeds. Check bearings for play by rocking the wheels top to bottom. Replace bearings with excessive freeplay.
• Bent control arms – A bent lower or upper control arm on an independent suspension Brute Force can be difficult to spot. Even subtle bends change suspension geometry and handling. Inspect for any control arm damage and replace as needed.
• Shock issues – Malfunctioning shocks with oil leaks or blown seals degrade suspension performance. Test shock function and inspect for leaks. Rebuild or replace as necessary.
• Ball joint wear – The lower and upper ball joints pivot during suspension movement. Excessive play from worn parts causes instability and vague steering. Test ball joint play and replace if out of spec.

It takes regular inspection, tuning and maintenance of steering and suspension parts to keep your Brute Force planted and stable across rough trails. Always set tire pressure accurately before hitting the trails. Inspect control arms, bearings, ball joints and shocks each ride. Identify and replace any loose, worn or damaged parts right away.

Other Issues to Watch For

Beyond the major problems detailed above, a few other issues sporadically impact the Kawasaki Brute Force 650:

• Leaking front differential – Water contamination and worn seals lead to differential leaks. Reseal the diff or replace the seals to stop leaks if discovered. Monitor oil level and look for water contamination.
• Brake problems – Contaminated pads, leaking calipers, and air in the lines are common brake issues. Inspect pads and rotors. Bleed the system if poor brake performance.
• Electrical gremlins – Faulty switches, connectors, relays and frayed wiring lead to electrical faults. Check all connections. Repair/replace components and wiring as needed. Use dielectric grease.
• Noisy valvetrain – Excessive valve noise indicates wear, low oil or improper lash. Adjust valve clearance if needed. Low oil causes valvetrain noise on startup. Maintain proper oil level.
• Fuel pump buzzing – Excessive fuel pump noise can indicate a failing pump. Listen for loud whining or buzzing. Test pump operation and pressure. Replace if erratic or weak.

Being aware of potential problems before they occur gives you the chance to prevent major repairs. Address any issues promptly to keep your Brute Force running like new.

Maintaining Your Kawasaki Brute Force 650

The best way to avoid problems and keep your Brute Force 650 running flawlessly is to stick to the prescribed factory maintenance schedule. Follow the hourly based intervals for all inspections, fluid changes, filter replacements and valve adjustments recommended in your owner’s manual.

Some of the key maintenance tasks include:

• Change engine oil and filter every 100 hours. Check levels each ride.
• Inspect/adjust valve clearance every 20-40 hours.
• Replace air filter every 100 hours or more frequently if riding in dusty conditions.
• Change front/rear differential oil every 100 hours.
• Replace fuel filter every 100 hours.
• Check/clean spark plugs every 100 hours. Replace if worn or fouled.
• Change coolant every 2 years or 200 hours. Pressure test system annually.
• Adjust carburetor when experiencing performance issues or after significant altitude/climate changes.
• Lubricate all pivot points and cables every ride.

Keeping up with factory recommended service intervals helps prevent problems and also extends the life of your ATV. Invest in quality OEM or OEM equivalent replacement parts when needed. Avoid cheap aftermarket parts that don’t meet Kawasaki’s specifications.

Knowing When to Seek Repair Shop Service

While routine maintenance tasks and minor repairs can be handled at home, major engine or transmission issues often require shop service. Seek out a qualified ATV repair shop if you experience:

• Loss of compression indicating internal engine damage
• Knocking, smoking or seizing engine
• Grinding noises from transmission/gears
• Major oil or coolant leaks you can’t resolve
• Persistent electrical faults despite part replacement
• Significant frame damage or cracks

A good ATV mechanic has the skills, tools and experience to accurately diagnose problems and make complex repairs beyond what’s feasible in a home garage. Seeking timely professional service helps avoid additional damage and costly repairs down the road.

Keep Your Kawasaki Brute Force Running Strong

While occasional issues can arise, the Kawasaki Brute Force 650 is designed for years of rugged and reliable use when properly maintained. Stay ahead of problems by inspecting key components and following factory service intervals. Make repairs promptly when problems first arise to avoid cascading damage.

Equipped with quality OEM parts, proper tools and service data, many problems can be resolved in your own garage. But don’t hesitate to use a professional mechanic for complex repairs or anything beyond your technical skill level. Keeping your Brute Force 650 well-maintained ensures you get the most enjoyment from this powerful and versatile ATV.