5 Common Kubota RTV 400 Problems (How to Fix)

The Kubota RTV 400 is equipped with a powerful single-cylinder fuel engine and electronic fuel injection. Cold start, automatic RTV 400 Plus drive, and other technology are also featured for efficient operation.

The most common Kubota RTV 400 problems are starter issues, backfiring, lack of power, clogged air filters, and oil leaking.

However, if you follow the steps listed below, these issues are relatively simple to fix. In this article, the topics mentioned above will be explained with solutions.

Kubota RTV 400 Problems 

Kubota RTV 400 Problems

Users of the Kubota RTV 400 frequently complain about some issues. Here are the common ones:

1. Starter Issue

Several consumers claim that the Kubota RTV 400 has a problem with the starter. A weak or dead battery might occasionally cause this issue.

Age, repeated short excursions, leaving lights or other accessories on, or a broken alternator can all cause the battery to expire.

Additionally, on occasion, if the starter motor is in charge of turning the engine over to start it. The starting motor might not be able to turn the engine over if it is malfunctioning.

The engine may also be unable to start due to a fuel filter that is blocked, which restricts the flow of fuel.    


Firstly, examine the battery’s voltage and charging system, to ascertain if this is the problem. A new battery may be required if the current one is weak or dead.

In addition, before replacing the battery, you must identify and fix whatever issues exist with the charging system. To discover if the starting motor is the problem, test it.

Check the fuel pressure and fuel pump relay. Fuel pumps need to be changed if they have jammed. Drain the fuel system, remove the old filter, and replace it. 

2. Frequently Backfires

Some Kubota RTV 400 models from 2012 have received complaints about tending to backfire. The unburned fuel may ignite in the exhaust system and create a backfire if the engine’s fuel mixture is excessively rich.

A bad carburetor or an unclean air filter may be the culprits.  

If the O2 sensor is not working correctly, the engine may run excessively richly or too leanly, which might result in a backfire. O2 sensor issues or engine control module (ECM) problems may be to blame for this. 


First, inspect the fuel filter of your Kubota RTV 400 with the proper tools.

If the fuel mixture is too rich, 

  • Check and replace the air filter
  • Replace the fuel injectors
  • Adjust the carburetor

If the fuel mixture is too lean, 

  • Check and replace the fuel filter and fuel pump
  • Check for vacuum leaks

Replacing any defective parts, such as an oxygen sensor, an EGR valve, or an engine control module, will assist avoid backfire.

3. Lack of Power

Some customers claimed that the Kubota RTV 400 from 2012 exhibited a lack of power when used in the woods. While they were attempting to transport the RTV to the hill, it was showing virtually no power.

The engine could not be powerful enough to manage the demands of climbing hills, which could be the cause of this. It could find it difficult to sustain the pace and could lose power if the engine is underpowered.

Additionally, a lack of power could result from the transmission not being properly geared for hill climbing. A lack of power may also result from improper or slippery transmission shifts. 


As the engine is not powerful enough in the Kubota RTV 400, upgrading the engine or adding a turbocharger may increase its power.

Also if the transmission is not properly geared for hill climbing, changing the gear ratio may help improve power. Repairing any transmission issues, such as slipping or shifting problems, may also help.

Make sure the load capacity of the ATV is not exceeded. Redistribute the cargo if necessary. 

4. Clogged Air Filter

The Kubota RTV 400’s air filter will provide you with a host of problems. Customers claim that the air filter typically becomes blocked. The reasons are:

  • Dust and debris
  • Lack of maintenance
  • Water ingress
  • Engine issues
  • Extreme weather conditions
  • Improper use
  • Poor-quality air filters

The potential warning signs are listed below:

  • Reduced performance
  • Decreased fuel efficiency
  • Unusual engine sounds
  • Visibly dirty air filter
  • Black smoke from the exhaust


In this situation, sometimes all you need to do is slightly adjust the carburetor.  Even with a clean air filter, a carburetor that is tuned too richly might be the reason.

For any indications of blockages, inspect the complete air intake system and remove them as necessary.

Cleaning or replacing an air filter is the most typical solution for a blocked filter. If the filter is only a little bit dirty, you might be able to clean it with some soft brushes or compressed air. The filter might need to be completely changed if it is heavily blocked, though.

 5. Oil Leakage

There are a few reasons why the Kubota RTV 400 frequently has oil leaks. Them being:

  • Damaged gaskets
  • Loose oil drain plug
  • Cracked oil pan
  • Faulty oil filter
  • Overfilled oil level
  • Faulty piston rings or engine seals 

The cautionary clues you may encounter are:

  • Oil spots under the ATV
  • Low oil level
  • Burning oil smell and smokey exhaust
  • Poor engine performance and noises
  • Dirty engine
  • Oil pressure warning light


The possible fix which may help you to ease the issue of your Kubota RTV 400 are listed here:

  • Replace the deteriorated gaskets and seals
  • Tighten the loose bolts
  • Replace damaged parts such as the valve cover 
  • Use a stop-leak additive that can help seal a small leak
  • Clean the engine if it is dirty due to oil leaks. It’s important to clean it to prevent future leaks

Which Year Kubota RTV 400 Has the Most Problems?

Customers claim that the 2012 model has one the most significant Kubota RTV 400 Problems of all the models. The ATV’s engine problems cause it to occasionally not start and to frequently backfire.

It is said that the Kubota RTV 400 from 2012 is challenging to drive in any rough terrain. Just a minor modification to the ATV can solve the issues.

According to several customers, the most typical oil leakage issue with the 2005 and 2006 Kubota RTV 400 may be resolved with the right information and skills.

Tips for Buying a Used Kubota RTV 400

The Kubota RTV 400 has frequent engine problems.  It is best to be well-informed about the condition of the engine and carburetor before purchasing an old RTV 400.

Examine the condition of the engine properly. Be sure to properly inspect the fuel filter and transmission. Beware of the signs of oil leakage and clogged carburetor.

The frequent oil leakage is previously a prevalent concern for the Kubota RTV 400. Check every component of the ATV before buying and better to take help from any professional.

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