KEIHIN 019-816 Jet N424-25B 50

( Brand: Keihin ), ( Manufacturer Part Number: 019-816 ), ( Part Type: Jet ), ( Country Of Origin: Us ), ( Item Length: 4.000 ), ( California Prop 65 Warning: Warning )

Review KEIHIN Jet 50 fits PILOT

The **Keihin N424-25B Pilot Jet 50** is a high-performance, precision-engineered fuel injection system designed specifically for high-output, high-revving engines, making it an ideal choice for performance enthusiasts, drag racers, and tuners seeking reliable and efficient fuel delivery. Part of Keihin s renowned **Pilot Jet** series, this component is engineered to deliver consistent, atomized fuel under demanding conditions, ensuring optimal combustion and power output while maintaining durability across a wide range of operating pressures. The **N424-25B** designation indicates a specific orifice size (25B) paired with a **N424** body style, which is optimized for engines with moderate to high fuel demands, such as those running nitrous oxide, forced induction, or aggressive camshafts. Crafted from high-grade aluminum with a robust, corrosion-resistant finish, this pilot jet is built to withstand the extreme heat and pressure encountered in aggressive driving scenarios, reducing the risk of clogging or failure even under prolonged high-load conditions.

What sets the **Pilot Jet 50** apart is its **dual-orifice design**, which allows for precise fuel metering while minimizing the risk of vapor lock or lean spikes during transient throttle events a common issue in high-performance applications. The **50** in the model name refers to its compatibility with Keihin s **50-series** fuel injectors, which are known for their superior flow characteristics and compatibility with modern ECU tuning systems. This pilot jet is particularly well-suited for engines with **naturally aspirated or turbocharged setups**, as well as those utilizing **direct port injection (DPI) or sequential fuel injection**, where consistent fuel delivery is critical for performance and drivability. Whether installed in a **muscle car, street rod, or high-revving twin-cam engine**, the N424-25B ensures that fuel is delivered in the correct proportion to air intake, promoting smoother operation, reduced carbon buildup, and enhanced throttle response even under extreme power demands.

For tuners and builders, the **N424-25B** offers flexibility in calibration, as its orifice size can be adjusted to match specific fuel system requirements, whether fine-tuning for a **high-flow fuel pump** or optimizing for a **nitrous-assisted engine**. Keihin s reputation for reliability and precision engineering ensures that this pilot jet maintains its performance characteristics over extended use, even in demanding environments where other aftermarket components might fail. When paired with compatible Keihin injectors, fuel rails, and ECU tuning, the **Pilot Jet 50** becomes a cornerstone of a high-performance fuel system, delivering the consistency and efficiency needed to unlock an engine s full potential without compromising on durability. Whether for a **street machine, track car, or high-performance daily driver**, this component is a testament to Keihin s commitment to performance fuel delivery solutions that push the boundaries of what s possible in automotive engineering.

### **Pros and Cons of buying a Keihin 019-816 N424-25B Pilot Jet (50mm) for a Carbureted Engine**

1. **High Performance and Efficiency** The N424-25B is a high-performance pilot jet designed for improved throttle response, better fuel atomization, and optimized fuel-air mixture. It is particularly effective in high-RPM applications, such as racing or modified engines, where smooth acceleration and power delivery are critical.

2. **Durability and Quality** Keihin is a well-regarded brand in the performance engine industry, known for producing reliable and precision-engineered components. The N424-25B is made from high-quality materials, ensuring longevity and resistance to wear.

3. **Compatibility with Aftermarket Mods** This jet is often used in conjunction with other Keihin parts, such as the CV carburetors (e.g., CV3, CV4, or CV5), making it a versatile choice for tuners and racers. It works well with engines that have been modified for increased power, such as those with forced induction or upgraded camshafts.

4. **Adjustability and Tuning Potential** The N424-25B is part of Keihin s line of adjustable pilot jets, allowing for fine-tuning of the fuel mixture. This can help achieve optimal performance across different driving conditions, from street use to track racing.

5. **Reduced Hiccups and Surges** A properly sized pilot jet like this one can minimize fuel delivery issues, such as stumbling or hesitation, by ensuring a consistent and fine fuel spray into the intake manifold.

6. **Widely Available and Supported** Keihin parts are widely distributed, and there is a wealth of tuning resources, forums, and aftermarket support available for this specific jet. This makes troubleshooting and adjustments easier for DIY enthusiasts.

7. **Cost-Effective Upgrade** Compared to full carburetor replacements or major engine modifications, swapping out a pilot jet is a relatively inexpensive way to improve performance and drivability.

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1. **Potential for Overfueling or Lean Conditions** If not properly paired with the main jets or tuned, the N424-25B could lead to an overly rich or lean mixture. A rich mixture wastes fuel and can cause carbon buildup, while a lean mixture may result in overheating or engine damage. This requires careful calibration.

2. **Requires Engine Tuning Knowledge** Unlike plug-and-play solutions, adjusting pilot jets demands an understanding of carburetor tuning principles. Mismatching the jet size without proper adjustments to the main jets or idle system can lead to poor performance or engine issues.

3. **Not Ideal for Stock or Mildly Modified Engines** The N424-25B is designed for performance applications. On a stock or lightly modified engine, it may not provide noticeable benefits and could even cause minor drivability issues if the engine is not adequately prepared for the change.

4. **Compatibility Issues with Some Carburetors** While it works well with Keihin CV carbs, it may not be the best fit for other brands or older carburetors without modifications. Always verify compatibility with your specific carburetor model.

5. **Risk of Voiding Warranty** On some vehicles, modifying carburetor components like pilot jets may void the manufacturer s warranty, especially if the engine is still under warranty.

6. **Potential for Clogging** Pilot jets are small and can clog over time if the fuel system is dirty or if low-quality fuel is used. Regular maintenance, such as cleaning the carburetor and using fuel additives, is necessary to prevent this.

7. **Learning Curve for Installation** Swapping a pilot jet requires removing the carburetor, which may involve disconnecting fuel lines, vacuum hoses, and throttle linkages. While not overly complex, it does require some mechanical skill and patience.

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The **Keihin 019-816 N424-25B Pilot Jet** is an excellent choice for enthusiasts looking to enhance the performance of a carbureted engine, particularly those involved in racing, high-RPM applications, or significant modifications. Its high-quality construction, tuning potential, and compatibility with Keihin s performance carburetors make it a valuable upgrade. However, it is not a universal fix and requires proper tuning, knowledge of carburetor setups, and compatibility checks to avoid issues.

- **Racing or heavily modified engines** (e.g., forced induction, big cams, or high-compression builds).

- **Enthusiasts comfortable with carburetor tuning** who can adjust main jets and idle systems accordingly.

- **Users who prioritize throttle response and smooth power delivery** over stock drivability.

For **stock or mildly modified engines**, a more conservative pilot jet (e.g., a stock or slightly larger size) may be more appropriate. Always pair this jet with a professional tune or thorough research to ensure optimal results.

If you are modifying a carbureted engine for performance and have experience with carburetor tuning, the **Keihin N424-25B Pilot Jet** is a strong choice. Pair it with the correct main jets, idle system, and fuel system maintenance to avoid issues. If you are unsure about tuning, consult a carburetor specialist or performance shop to ensure proper installation and calibration.

For **stock or beginner-friendly applications**, consider a more conservative pilot jet or focus on other modifications first. Always prioritize safety and proper preparation when working with carbureted engines.

Details:

High quality aftermarket jets for Keihin carburetors. Direct replacement fit for compatible Keihin applications. Durable brass construction. Pilot Jet size 50 for precise carburetor tuning.

Built for consistent fuel delivery and dependable performance, this brass jet is a great choice maintenance, tuning, or replacement. Untitled Document. Features: Genuine Keihin replacement part. Single unit listing: 1 jet per order.

Menu Keihin N424-25B Pilot Jet 50 MPN 019-816: Series 50: Quality replacement Pilot jet for carburetors.

part #: 019816 prices

• $18.62-$24.99

specifications intakefuelmotorcycle:

• for models: Pilot
• brand: Keihin
• mpn: 019-816
• part type: Jet
• country of origin: Us
• item length: 4.000
• california prop 65 warning: Warning

seller intakefuelmotorcycle:

• rating: 99.4%
• # reviews: 50074
• city: Midvale, Utah

general intakefuelmotorcycle:

• Motorcycle Scooter Parts Accessories > Air Intake Fuel Delivery > Other Air Intake Fuel Delivery
• condition: New

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• type: Fixed

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• availability: In Stock
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• started: April 5, 2026
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