Dynojet Q627 Jet Kit Instruction Manual

1. Product Overview

The Dynojet Q627 Jet Kit is designed to optimize the carburetion of your Arctic Cat 400 DVX (2004 model year). This kit aims to enhance power delivery and throttle response across the entire engine rev range, while maintaining efficient fuel consumption. It provides a comprehensive solution for fine-tuning your vehicle's fuel system.

Figure 1: Dynojet Q627 Jet Kit components and packaging. The image displays various brass jets, silver needles, small washers, a spring, and a clear plastic storage case. The product packaging, a white and yellow box with the 'Dynojet' logo and 'JET KIT' prominently displayed, is also visible. The box highlights 'IMPROVED Driveability, Throttle Response, Horsepower' and shows a graph illustrating performance gains.

2. Safety Information

• Installation of this jet kit involves working with fuel systems and engine components. It is recommended that installation be performed by a qualified mechanic or an individual with appropriate experience.
• Always disconnect the battery before beginning any work on the vehicle's electrical system.
• Ensure the engine is cool before working on the carburetor to prevent burns.
• Work in a well-ventilated area and keep fire extinguishers nearby when handling fuel.
• Refer to your vehicle's service manual for specific disassembly and reassembly procedures.
• Wear appropriate personal protective equipment, including safety glasses and gloves.

3. Package Contents

Verify that all components are present and undamaged before beginning installation. Your Dynojet Q627 Jet Kit should include:

• Assortment of Main Jets
• Jet Needles
• Washers/Spacers
• Spring (if applicable for your specific kit configuration)
• Clear Plastic Storage Case
• Detailed Installation Instructions (separate document, not part of this manual)

4. Setup and Installation

The Dynojet Q627 Jet Kit offers two primary configurations: Stage 1 and Stage 2. The choice depends on your vehicle's current modifications.

4.1. Stage 1 Kit Configuration

Stage 1 kits are designed for motorcycles with a stock engine, utilizing the original airbox, air filter, and exhaust system. This configuration focuses on improving throttle response and driveability with an approximate 5% power increase across the power band.

• Application: Stock engine, stock airbox, stock air filter, stock exhaust pipe.
• Benefits: Improved throttle response, enhanced driveability, approximately 5% power increase.

4.2. Stage 2 Kit Configuration

Stage 2 kits are intended for motorcycles with a stock or mildly tuned engine that use a well-designed aftermarket exhaust pipe, a modified airbox, and a stock replacement air filter. This stage is particularly suitable for applications where individual air filters cannot be installed, and airbox modification significantly improves engine performance. Power increases of approximately 8% can be achieved with this setup.

• Application: Stock or mildly tuned engine, aftermarket exhaust, modified airbox, stock replacement air filter.
• Benefits: Significant performance improvement, approximately 8% power increase, optimized for modified air intake.

4.3. General Installation Steps (Consult Detailed Instructions)

Each Dynojet jet kit includes comprehensive, step-by-step installation and testing procedures. It is crucial to follow these specific instructions for your vehicle model to ensure correct setup and optimal performance. The general process typically involves:

1. Carburetor Removal: Safely remove the carburetor from the vehicle.
2. Disassembly: Carefully disassemble the carburetor to access the jetting components.
3. Jet and Needle Replacement: Replace the stock jets and needles with the appropriate Dynojet components as specified in the detailed instructions for your chosen stage.
4. Airbox Modification (Stage 2 only): Perform any necessary modifications to the airbox as outlined in the instructions.
5. Reassembly: Reassemble the carburetor and reinstall it into the vehicle.
6. Testing and Adjustment: Follow the testing procedures to fine-tune the carburetion for optimal performance.

Note: The specific jet sizes and needle settings will vary based on your vehicle, altitude, and modifications. Always refer to the detailed instructions provided with your kit for precise recommendations.

5. Operating Instructions

After proper installation and tuning of the Dynojet Q627 Jet Kit, your Arctic Cat 400 DVX should exhibit improved engine characteristics:

• Enhanced Throttle Response: Expect a more immediate and smoother reaction to throttle input.
• Increased Power: Noticeable gains in horsepower and torque, particularly throughout the mid-range and top-end.
• Improved Driveability: The vehicle should feel more responsive and easier to control across various RPMs.
• Optimized Fuel Economy: While performance is enhanced, the kit is designed to maintain optimum fuel economy under normal operating conditions.

It is recommended to perform a test ride in a safe, controlled environment to familiarize yourself with the vehicle's new performance characteristics. Pay attention to engine sound, acceleration, and overall feel.

6. Maintenance

Regular maintenance of your carburetor and air intake system is crucial for sustained performance after installing the jet kit. Follow your vehicle manufacturer's recommended service intervals for:

• Air Filter Cleaning/Replacement: A clean air filter is essential for proper air-fuel mixture.
• Fuel System Inspection: Regularly check fuel lines, filters, and connections for leaks or blockages.
• Carburetor Cleaning: Periodically clean the carburetor to prevent deposits from affecting jetting performance.
• Spark Plug Inspection: Inspect spark plugs for proper combustion and replace as needed.

Environmental factors such as significant changes in altitude or temperature may require minor adjustments to the jetting. Consult the detailed instructions or Dynojet support for guidance on such adjustments.

7. Troubleshooting

If you experience performance issues after installing the Dynojet Q627 Jet Kit, consider the following common troubleshooting steps:

• Poor Performance/Hesitation:
  • Verify that the correct jets and needles for your chosen stage (Stage 1 or Stage 2) and specific conditions (altitude, temperature) have been installed.
  • Check for air leaks in the intake system or around the carburetor.
  • Ensure the air filter is clean and properly seated.
  • Inspect spark plugs for signs of rich or lean conditions.
• Excessive Fuel Consumption:
  • Re-check jetting specifications; you might be running too rich.
  • Ensure the float level in the carburetor is set correctly.
• Difficulty Starting:
  • Confirm proper choke operation.
  • Check for correct pilot jet size and air screw adjustment.

For persistent issues or advanced troubleshooting, refer to the detailed instructions provided with your kit or contact Dynojet customer support.

8. Specifications

9. Warranty and Support

Dynojet provides comprehensive instructions with each jet kit, ensuring a proper setup. Additionally, free telephone and Internet support are available to Dynojet customers for assistance with installation, tuning, and any questions regarding the product.

For specific warranty details, please refer to the documentation included with your purchase or visit the official Dynojet website. Keep your proof of purchase for any warranty claims.