As Kawasaki’s biggest and most powerful quad, the Brute Force 750 has been a mainstay in the ATV industry since 2005.
And similar to the reputation of Kawasaki Mules, it’s about as durable and dependable as you’ll find in the industry.
You’ll even find a Brute Force on the list of best ATVs for the money for this year.
Even so, seven common problems seem to recur in many Brute Force 750 models, including:
- Problems with Front and Rear Differentials
- Fuel Pump Issues
- Flooded Airbox
- Clogged Air Filter
- Valves Causing Compression Loss
- Gear Shift Sticking & Grinding Noise
This guide will explore each problem and the likely causes, along with proven fixes.
Problems With Front and Rear Differentials
A number of issues with the Brute Force 750 originate with the front and rear differentials, including:
- Oil seals on the differentials leaking
- Locking nut coming loose
- Lock lever being pulled while riding
Causes & Fixes
Oil Seals and Oil Changes
Both differentials take a small amount of oil, and the stock oil seals on both are prone to leaking.
A lack of oil from a leaking front oil seal can cause the front differential to lock up. The only real fix for this is to continuously keep an eye on the oil seals and replace them as needed.
It’s also important to change the differential oil as recommended in the owner’s manual, with a best practice being to change the differential fluids after any wet rides.
Rear Differential Ring and Pinion
The rear differential ring and pinion locking nut is also prone to coming loose in older Brute Force 750 models.
In order to fix this, owners should apply a red loctite to the nut and ensure it is torqued to the proper specs.
Front Differential Lock Lever
The yellow front differential lock lever should only be pulled and engaged when the quad is stopped.
Pulling this lever when in motion is hard on the front differential and can lead to complete failure.
Brute Force 750 Fuel Pump Issues
Faulty fuel pumps are common in the Brute Force 750, and symptoms include stalling, backfiring, hard starting and the engine even failing to fire up.
The two fuel filters are the main cause of the fuel pumps going bad in these models, which are one of the main causes of problems with the Brute Force 650 as well.
Causes & Fixes
External Fuel Filter
The external fuel pump in the Brute Force 750 resembles a tea bag, and it is known to become clogged rather easily.
You’ll need to inspect the external fuel pump periodically to make sure it’s not turning the color of dirt, which indicates it’s becoming clogged.
When it clogs up, it can eventually lead to the drive motor in the fuel pump failing, which will lead to a failure of the fuel pump.
Internal Fuel Filter
The internal fuel filter is just a screen.
This screen becomes clogged very easily, which can restrict fuel flow and lead to backfiring or hard starting.
Owners should either poke holes in this screen to better enable fuel flow, or remove it altogether and install an inline fuel filter.
If this internal filter is clogged, even a brand new fuel pump will not function.
Testing The Fuel Pump
If you constantly check your fuel filters and they’re working as they should be, you’ll be able to avoid most fuel pump problems.
But you can also test your fuel pump to be sure it’s working properly by removing the hose and starting the quad to see if fuel sprays out.
If it does, your fuel pump should be in good shape. If it doesn’t, this is likely your issue and you should replace it.
One of the most common issues experienced among owners of older Brute Force 750 models is the tendency for the airbox to flood with water and mud.
This happens even from shallow water crossings and splashing through puddles where the water stays below the floorboards.
The issue is that the air intake is located just below the handle bars, and the larger engine in the quad tends to suck in so much air that any water or mud that may be airborne in the front end area will wind up in the airbox and potentially flood it.
To overcome this issue, owners have turned to either installing a special air box cover that shields it from this airborne water and mud, or to installing a full snorkel kit to extend the air intake higher.
Both of these options seem to work in overcoming this issue.
Clogged Air Filter
The powerful Kawasaki Brute Force 750 engine loves it some airflow, so the air filters need to work overtime in ensuring this air doesn’t come through the engine intake system along with dust and debris.
As such, the air filters tend to clog rather quickly, with a review of the Brute Force 300 highlighting the issue as well.
To ensure they continue to function properly, owners should be cleaning the air filter after every extended ride.
Once cleaned, a best practice is to reinstall the air filter with some grease on the bottom to ensure a tight seal.
Valves Causing Compression Loss
Any hard starting, rough idling, or stalling experienced with your Brute Force 750 may be caused by the intake valves.
The intake valves tend to be affected in these models due to the large amount of dirt and debris that gets sucked into the engine and occasionally finds its way through the air filter.
This wears down the intake valves over time, which will tighten them up to the point of compression loss and lead to the machine not running or starting properly.
This is a common issue in the Brute Force 300 model as well.
As mentioned in the problem above, this makes it even more important to clean your air filter after every ten or so hours of riding.
But it’s also important to check your valve clearance on both the intake and exhaust valves regularly to ensure they’re adjusted properly.
Running a compression or leak-down test will help you to identify issues with your valves and valve clearance.
Gear Shift Sticking & Grinding Noise
Another common issue in these models is for the gear shift to stick and need a good bit of pressure behind it to actually transfer it to another gear.
When this starts to happen, there’s a good chance you’ll also hear a grinding noise from the gears right after making a shift.
These are tell-tale signs that either the shift linkage needs to be adjusted back into place, or the motor mount bolts need to be tightened.
Causes & Fixes
Motor Mount Bolts
The motor mount bolts have been known to loosen and cause issues with the gears.
Go over each of them and ensure they are fully tightened, even well over the recommended torque setting in the owner’s manual.
If you’re lucky, this will fix your issue. If not, you’ll need to adjust your shift linkage.
Shift Linkage Adjustment
Your shift linkage is responsible for moving your quad into the correct gears as you move the shifter.
The shift linkage is held in place under your quad by two lock nuts on either end.
These lock nuts have a tendency to vibrate loose over time from riding, and when that happens your shift linkage can transfer to an incorrect position and result in the symptoms mentioned above.
To fix this, you’ll need to transfer the shift linkage back into place and then tighten down the locking nuts so that it stays put.
This should result in your gear shift moving easily as it should, and eliminate the grinding noise when changing gears.
The engine in the Brute Force 750 is prone to overheating, which can occur for various reasons.
- Radiator clogged
- Fan not activating in time
- Air blockage in coolant system
- Head gasket blown
Causes & Fixes
The radiators in the Brute Force 750 are a bit lower to the ground than you’ll find in some other competitive models, which results in them being more prone to clogging with mud while out riding.
When your radiator clogs, your engine is much more prone to overheating.
Many owners have taken steps to actually relocate the radiator to help minimize this issue, but being sure to clean the radiator fins and grill out frequently should help as well.
Soaking the grill in Simple Green after muddy rides is recommended.
Fan Not Activating In Time
The fan on the radiator is programmed in the ECU not to engage until the engine reaches temps of 200+ degrees.
The problem is that if you’re riding on a hot day or at a high elevation, the fan won’t engage in time to keep the engine temp around that mark, which leads to overheating.
You can have your ECU tuned to lower the temperature that the fan will engage at, which will fix this issue.
Air Blockage In Coolant System
Any time your Brute Force 750’s engine overheats, it’s at risk of allowing air into the coolant system.
This air will block the water pump from pumping coolant properly, which will then lead to more overheating.
If this is your issue, you’ll need to bleed the air from your radiator fill area until you no longer see bubbles.
Once the bubbles have stopped, you should be good. But if they won’t seem to subside, you may have blown a head gasket.
Blown Head Gasket
A blown head gasket can happen any time your engine overheats, which will then lead to it continuing to overheat until the faulty head gasket is replaced.
You can use a head gasket test kit to confirm whether this is your issue, and make a replacement if needed.
While the Kawasaki Brute Force 750 is known for being one of the better overall ATVs you can buy, it’s not without its share of drawbacks.
For more on Kawasaki models, check out the following before you go: