4 Common CFmoto CForce 400 Problems and Their Solutions:

CFMoto CForce 400 is an ATV vehicle reputed because of its higher performance, but this is not the only reason behind its fame. Many owners also prefer this one because of its affordable prices. However, we all know there is no such thing called perfect, and this same goes for CFMoto CForce 40 as its owners also have to face many problems while riding it. 

CFMoto CForce 400 Problems

So these are some common CFMoto CForce 40 problems that we have found worth mentioning so you can not only identify the issues on your own but also fix them.

Problem #1-Vapor Lock Stalling Issues

The first problem we have found most of the CFMoto CForce 400’s owners struggling with is its Vapor Lock. This occurs when gas enters the vent line of the fuel tank and disturbs the air supply functioning, causing the engine to chock up and end up in Vapor lock stalling.

Possible Solutions: 

  • Loosen the Gap Cap- If it has happened for the first time and is temporary, then for the time being, you can get rid of your problem by loosening the gas cap to relieve the pressure build-up. However, if it is repeatedly happening, you’ve to adjust both EVAP System and the fuel tank vent line.
  • Bypassing The EVAP System- All CFMoto vehicles have installed EVAP Systems to ensure fuel vapors aren’t escaping from the fuel tank into the atmosphere. This system is integrated into the regulations of the state of California. As mentioned above EVAP system could be the main reason behind the Vapor Lock Issue.

So if you’re living outside California, you can bypass and delete the EVAP system to resolve your issue. For this, find the vacuum hose covered by the tail light integrated into the engine’s left-hand side right below the seat. Once you’ve located the vacuum hose, disconnect it from the throttle body connector, which will also disconnect it from the canister. Now you can take out the vacuum hose and canister together if you don’t want to keep them in the same place after disconnecting them. 

  • Adjusting The Fuel Tank Vent Line- If the problem continues, it must be because of a vent line issue in the fuel tank. So for this, first unplug the vent line. You’ll see a one-way check valve at the end of this line which you’ve to remove. Once you’re done, redirect the unplugged vent line toward the bottom of your vehicle and ensure the opening is hanging only above the ground so the vent line can breathe. 

Hopefully, these adjustments will help you permanently eliminate your vapor lock problems.

Problem #2- Extremely Hot Pipe Vents:

We have found that this issue is common among those owners who are used to running their vehicles in low gear and at slower speeds. Their concern is the exhaust pipe vent which makes its side extremely hot because of the exhausted heat. The heat caused the outer plastic shell and plastic fuel tank cover to be heated up so that it didn’t even let the driver take off their leg from that side without any burns.

Possible Solution:

  • Install heat shield or wrap- So if you’re having such an issue, I would recommend you call the dealer and ask him to install a heat shield or wrap in your vehicle over the exhaust pipe as it will prevent the plastic shell from getting a lot of heat so you can ride it comfortably.

Problem # 3-Poor Throttle Response

The following common CFMoto CForce 400 problem occurs because of poor throttle response, which is usually felt when your ATV is in high gear. At that time, the vehicle fails to get instant responses from the engine, and the RPMs also get lower than it is supposed to be. 

Because of this issue, the high gear becomes useless as owners have to keep their machine in the low gear, which often leaves them frustrated. This frustration and poor throttle response cause several problems within the stock clutch system. Sample problem in CFMoto UForce 1000.

Possible Solutions:

  • Upgrade the Weights and Springs- First, you can solve this by replacing the primary clutch with new springs and weights, which will help with the stock clutch issue. Or buy a new aftermarket clutch kit that includes all the upgraded elements.
  • Reclocked the Secondary Clutch- Next, you can make additional changes in the secondary clutch and reclock it to a different setting that will increase the throttle response and help you relieve your frustration.

The settings include three different letter settings and four different number settings. To solve this problem, you have to factory reset the settings and set it to B1, which can also be adjusted at C1 for a better experience.

CFMoto CForce 600 Problems 

Problem #4- Engine start-up failure:

In this case, the engine delines even to get started, which has happened with many CForce 400 owners. This could be because of many reasons, such as because of problems in:

  • Terminals/Wiring
  • Battery
  • Valves
  • Spark Plugs


Start your procedure of resolving this issue with the terminals/wirings, as the battery terminal could be a major reason behind this issue. 

Possible Solutions:
  • So first, you need to inspect them, clean them, and ensure no debris or corrosions are affecting their functioning. 
  • On the safer side, apply dielectric grease or petroleum jelly to prolong the lifespan of these battery terminals.
  • Also, make sure that the grounding wires are connected to the battery. If they aren’t, they could also be a leading cause of this issue. That’s why checking at the first step is recommended to save you from the next complex procedure.


The battery could also be a problem because all CForce motors are well-known for getting battery drainage quicker than others.

Possible Solutions:
  • First, test the battery’s voltage and ensure it is at 12+ volts, as its functioning relies on getting at least 12 volts to work. 
  • Then you can also opt to resolve this issue by recharging the battery and ensuring the wirings are tightly connected in their places.


Valves can surely cause engine starting issues in CForce 400 because it is where intake and exhaust take place. 

Possible Solutions:
  • The problem could have happened when either you tightened the valves or loosened the valves much more than needed, as tightening could cause the valves to create compression loss.

So make sure the valves are at the proper values, which you can confirm from the manual you’ve got with your vehicles. If they are even a bit tightened or loosened from their required values, make the adjustments accordingly. 

Spark Plugs

Spark plugs could also be the reason why your engine is not starting up at all because they may have gotten burned or fouled. 

So make sure the plugs aren’t coated with any foreign substance such as oil, coolant, or fuel. The issue can also be inspected if the color has changed, and if it is, this will indicate that plug has been burnt and causing fouling. 

Possible Solutions:
  • Now if you have found that there is something wrong with your spark plugs, replace them with the new high-quality iridium spark plug.

Final Verdicts:

CFMoto CForce 400, just like many other ATVs, also comes with many problems, such as Vapor Lock stalling issues, extremely hot pipe vents, poor throttle response, and engine start-up failure. But don’t worry. You can fix all those on your own with the help of our following guidelines.

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