Fuel System 2005-2011 Honda FourTrax Foreman TRX500 FE/FPE/FM/FPM/TM ATVs
The fuel system of the 2005-2011 Honda FourTrax Foreman TRX500 ATVs is designed to deliver optimal performance and efficiency. However, at high altitudes, the standard carburetor air-fuel mixture may become too rich, leading to decreased performance, increased fuel consumption, fouled spark plugs, and hard starting.
To address this issue and ensure optimum performance at high altitudes, specific modifications to the carburetor are recommended. Operating the ATV at altitudes above 6,500 feet warrants performing this carburetor modification.
Even with carburetor modification, it's important to note that engine horsepower will decrease by about 3.5% for each 1,000-foot increase in altitude. However, without carburetor modification, the effect of altitude on horsepower will be even greater.
High Altitude Carburetor Adjustment
The high altitude carburetor adjustment for the Honda FourTrax Foreman TRX500 ATVs can be performed as follows:
- Remove the carburetor float chamber.
- Replace the standard main jet with the high altitude main jet: #158.
- Check the O-ring on the float chamber and replace it if necessary.
- Install the float chamber and carburetor.
- Screw in the pilot screw the specified number of turns from the factory preset position using the special tool.
- Set the high altitude pilot screw opening to 3/8 turn in from the factory preset position.
Following these steps will ensure that the ATV's fuel system is optimized for high altitude performance, meeting emission standards throughout its useful life.
Impact on Performance
By making these high altitude carburetor adjustments, the Honda FourTrax Foreman TRX500 ATVs can deliver improved performance at higher elevations. The modifications help to maintain an appropriate air-fuel mixture, preventing the issues associated with a rich mixture, such as decreased power and increased fuel consumption.
It's essential for ATV owners and operators to be aware of the impact of altitude on engine performance and make the necessary adjustments to ensure the best possible performance and efficiency, especially when consistently operating the ATV at high altitudes.
Conclusion
The fuel system of the 2005-2011 Honda FourTrax Foreman TRX500 FE/FPE/FM/FPM/TM ATVs is designed to offer reliable and efficient performance across various conditions, including high altitudes. By performing the recommended high altitude carburetor adjustments, ATV owners can ensure that their vehicles deliver optimal performance and meet emission standards, enhancing the overall ATV experience.
