A neighbor of mine recently bought a used Bennche Bighorn 700 that seemed to be in great shape. During the first few months of use he had zero issues or complaints with it. And then one day, seemingly out of the blue, that all changed.
Lucky for him, it was a fairly simple fix. But it took us quite a few hours of research and tinkering to figure out what the issue was in the first place. Throughout that process, we discovered quite a number of owners experiencing some of the same common Bennche Bighorn 700 problems.
Bennche Bighorn 700 Problems
If you’re experiencing an issue with your Bennche Bighorn 700, it’s most likely one of the following:
- Overheating
- Engine Won’t Start
- Transmission Problems
- Loss of Speed & Acceleration
- Rough Idling or Stalling in Idle
This guide will take detailed look at the causes of these issues as well as proven fixes.
Bennche Bighorn 700 Overheating
One of the most common issues with the Bennche Bighorn 700, which happened to be the issue my neighbor experienced, is overheating. If you’re experiencing an overheating problem, it’s likely due in part to one of the following:
Temperature Sensor
The engine in the Bennche Bighorn 700 is flawed in that it is factory-set so that the temperature sensor on the radiator will not trigger the fan until reaching a temperature that is sometimes too high for the engine to withstand, leading to repeated overheating. This more frequently affects those living in warmer climates.
As such, owners have resorted to bypassing the fan switch on their machines so that the fan either runs constantly while the engine is on or can be turned on as desired by way of a toggle switch on the dash.
Both methods reportedly work well to overcome the issue with the temperature sensor and fan.
Air Blockage In Coolant System
An air pocket blockage somewhere in the coolant system is another cause of overheating for the Bighorn 700.
When the engine overheats, it can allow air into the system. That air usually finds its way to the water pump. As the water pump can’t pump air, it generally then has a hard time pumping enough coolant as well, which results in the radiator staying cool and the engine ultimately overheating.
When an air pocket forms in your system, your engine will not stop overheating until that air is bled back out. To bleed the air from the system of your UTV, follow the steps below.
- Raise the front end of your UTV about a foot higher than the back end by parking on a hill or with a lift
- Ensure the engine is cold
- Remove the 10mm bleeder bolt from the radiator
- Remove radiator cap
- Fill it until coolant comes out of the bleeder
- Reinstall the bleeder bolt
- Continue filling radiator until it overflows
- You may need to repeat steps above for any overflow reservoir as well
- Start the engine and let idle – you’ll most likely see some bubbles
- Once bubbles stop, shut off engine and replenish coolant if necessary
- Repeat this process until you no longer see bubbles
- Reinstall radiator cap (and reservoir cap if applicable)
Following this process enabled us to bleed the air from my neighbor’s Bighorn 700 and should do the same for yours. However, if you see excessive bubbling from the radiator fill cap area that will not subside, you likely have a blown head gasket.
Blown Head Gasket
Any overheating the engine experiences puts your head gaskets at risk of blowing. And blown head gaskets will lead to recurring overheating. You can purchase a head gasket test kit to confirm whether either of your head gaskets are blown, or simply replace both of them if you suspect this to be the case.
Bennche Bighorn 700 Engine Won’t Start
There are a number of reasons your Bighorn 700 turns over but won’t start, or shows no signs of life at all. Some of the most common causes of this include issues with your valves, faulty spark plugs, a dead battery or loose battery cables, and degraded fuel.
Valves
The Bighorn 700 has both an intake and an exhaust valve. The most common occurrence is that these valves tighten too much creating an issue, but they can also loosen too much. Both tightening and loosening affects your valve clearance, which if not maintained at the proper level, can result in your machine not firing up.
The proper valve clearances can be found on a placard under the driver’s side fender of your machine, or in your service manual. Check to ensure both valves are set at their proper clearances, and make the proper adjustments if not.
Spark Plugs
If you use your machine for many trips that are shorter in duration, you most likely have a spark plug issue if you find that your engine won’t start one day. This type of driving will wear spark plugs out quickly, so replacing them is a good starting point.
Check your spark plugs to ensure they are not coated with a foreign substance such as fuel, oil, or coolant. You should also inspect the tips to ensure they do not look like they are burned, which would indicate spark plug fouling.
Battery
The stock batteries in Bennche machines are unfortunately known for draining fairly quickly, especially if supporting added electronics.
Test your battery’s voltage to ensure it is at 12+ volts. If your Bennche UTV is fuel injected, the fuel injection is heavily reliant upon your battery getting 12 volts to run properly.
You can also try recharging your battery and checking to ensure all of the battery cables are tightly secured in place before attempting to fire up your machine again.
Degraded Fuel
Another common culprit of your engine not firing up is old fuel that has been sitting for a while and degraded. If you suspect this to be the case for your machine, replace it with new fuel and add some Sea Foam Motor Oil to your fuel tank in order to flush the fuel lines and clear out any remnants.
Bennche Bighorn 700 Transmission Problems
If you experience a grinding noise when shifting into low or high gear, you’re not alone as this is another common issue experienced among owners of the Bighorn 700.
This problem generally comes about after around 100 hours of riding and occurs due to your shift linkage needing an adjustment. Fortunately, this is a fairly simple fix.
To adjust your shift linkage, you’ll need to remove both the seats and the center console to expose the turnbuckle shift linkage that’s responsible for changing your gears.
Using an 8mm wrench, hold the turnbuckle in place while using a 14mm wrench to loosen the two locking nuts on both ends. Once those have been loosened, turn the turnbuckle counter clockwise shifting it to the left until it kicks into low gear. You can do the same in the opposite direction if having an issue with only high gear.
You can then test it out by turning on the ignition switch and attempting to shift gears to ensure it’s in the correct position and is no longer grinding when you do. The gear lights on the dashboard should activate letting you know which position it is in as your adjust it.
Once you’ve confirmed it to be in the correct position, tighten your locking nuts to hold it in place and reinstall the center console and seats. You should hear no more grinding. If you do, you’ll need to adjust it further until the grinding subsists completely as this is not normal.
Bennche Bighorn 700 Loss of Speed & Acceleration
Some Bighorn 700 owners have experienced an overall lack of speed, power, and acceleration after varying total hours of use on their machines. This seems to be more prevalent when carrying heavy loads or climbing hills.
The most common causes of this issue are a failing fuel pump, a clogged fuel filter/screen, and faulty spark plugs.
The fuel pump is most likely to blame in this case. You can test it by removing the hose and firing up your machine to inspect whether fuel sprays out as it should. If not, you’ll want to replace it, and ensure that it fits and stays firmly in place once installed so there is no fuel delivery issue moving forward.
You’ll also want to inspect the fuel filter/screen cover. If it appears to be turning the color of the dirt you’ve been riding through, it is most likely clogged and needs to be replaced. Even a slightly clogged fuel filter/screen cover can negatively affect engine performance.
The spark plugs may be an issue in this case as well. Inspect them and replace them as necessary.
Bennche Bighorn 700 Rough Idling or Stalling in Idle
Some Bighorn 700 owners have experienced sputtering or the engine stalling out when in idle. The two main causes of this are a gummed up throttle body or a bad fuel injector.
Gummed Up Throttle Body
Idling issues can also be a result of a buildup of carbon deposits (black soot), dirt, and grime inside the throttle body of your machine. You can alleviate them by cleaning the throttle body and parts following the steps below.
- Remove the throttle body from your Bighorn
- Spray it down using a can of WD-40 Carb/Throttle Body Cleaner (or something similar) and scrub down using a toothbrush or scrub pad.
- Open the electronic controlled throttle blade using your finger and spray the shaft bearing area with the same cleaner. Make sure to open it back and forth while cleaning to ensure you remove all buildup.
- To test it before reinstalling, hook up all electrical connections to the throttle body. Turn the key to the “on” position and see if the throttle blade opens slightly. If it does, you should be good to go. Reinstall the throttle body and start up your Bighorn.
Bad Fuel Injector
Your fuel injector will be located in close proximity to the throttle body. To inspect it, remove the injector and turn the key switch on. If the spray pattern is a fine mist, you have a properly functioning fuel injector. If it sprays two streams of fuel instead, it is either plugged or gone bad and should be replaced.
Conclusion
Though some of these common Bennche Bighorn 700 problems are completely out of the owners’ hands, many others can be addressed by ensuring proper ongoing maintenance and preventative care for your UTV.
And while we came across a number of regularly reported issues with the Bennche Bighorn 700 during our research, we also encountered plenty of owners who expressed a positive experience with their machines.
