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Start ShoppingMIKUNI F4/042-145 Hex Main Jet - 145 Size Precision Brass Jet for Carburetor Tuning
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Description
Upgrade your carburetor system with the MIKUNI F4/042-145 Hex Main Jet - a precision-engineered solution for optimizing fuel flow and engine performance. Designed for riders who demand reliability and control, this brass jet delivers consistent metering for enhanced power and efficiency.
Key Features
- Precision-Drilled Brass Orifice: Ensures accurate fuel flow for optimal engine performance and responsiveness.
- Hexagonal Design: Simplifies installation and adjustment with a secure fit for carburetor compatibility.
- Lightweight Construction: Minimal weight (under 1 oz) reduces strain on engine components without compromising durability.
- Standard Dimensions: 0.5-inch length for universal fit with most MIKUNI carburetor systems.
Why Choose This Product
Engineers and tuners rely on MIKUNI jets for their precision and reliability. This Hex Main Jet offers superior fuel metering, ensuring your engine runs smoothly under various conditions. The brass material resists corrosion, while the precision-drilled orifice maintains consistent flow rates. Whether you're modifying a dirt bike, ATV, or off-road vehicle, this jet provides the accuracy needed for peak performance without unnecessary weight.
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Upgrade your carburetor system with the MIKUNI F4/042-145 Hex Main Jet - a precision-engineered solution for optimizing fuel flow and engine performance. Designed for riders who demand reliability and control, this brass jet delivers consistent metering for enhanced power and efficiency.
Key Features
- Precision-Drilled Brass Orifice: Ensures accurate fuel flow for optimal engine performance and responsiveness.
- Hexagonal Design: Simplifies installation and adjustment with a secure fit for carburetor compatibility.
- Lightweight Construction: Minimal weight (under 1 oz) reduces strain on engine components without compromising durability.
- Standard Dimensions: 0.5-inch length for universal fit with most MIKUNI carburetor systems.
Why Choose This Product
Engineers and tuners rely on MIKUNI jets for their precision and reliability. This Hex Main Jet offers superior fuel metering, ensuring your engine runs smoothly under various conditions. The brass material resists corrosion, while the precision-drilled orifice maintains consistent flow rates. Whether you're modifying a dirt bike, ATV, or off-road vehicle, this jet provides the accuracy needed for peak performance without unnecessary weight.
| SKU | GM12EF332C |
|---|---|
| MPN | F4/042-145 |
| Brand | MIKUNI |
| Category | Jets |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Various Japanese | Carbureted motorcycles/ATVs (e.g., Yamaha YZ, Honda XR, Kawasaki KX) | 1980-2025 |
| Suzuki | RM/DR-Z series | 1990-2010 |
Frequently Asked Questions
The 145 refers to the jet size/orifice diameter in hundredths of a millimeter. A 145 jet has a 1.45mm orifice and is considered a larger main jet for richer fuel mixture.
Jet selection depends on altitude, temperature, engine modifications, and carburetor model. Signs you need a larger jet: engine runs lean (pops on deceleration, poor acceleration). Signs you need smaller jet: black smoke, fouled plugs, poor fuel economy.
Yes, if you're comfortable removing and reinstalling your carburetor. The jet itself is simple to change, but carburetor removal varies by vehicle. Consult your service manual.
Hex jets have a hexagonal head for easier removal/installation with a hex wrench. Non-hex jets typically require a jet removal tool. Hex design is generally more user-friendly.
Possibly. Performance modifications (air filter, exhaust, porting) often require rejetting to maintain proper fuel-air ratio. Consult tuning guides specific to your modifications.
Installation Guide
Difficulty
Medium
Est. Time
15 min
Tools Required
- Carburetor removal tools (varies by application)
- Small hex wrench or jet removal tool
- Gasket scraper
- Clean rags
Pro Tips
- Take photos during disassembly for reference
- Clean carburetor thoroughly while disassembled
- Verify jet size matches your tuning requirements
- Use proper hex tool to avoid stripping jet
- Let carburetor dry completely before reassembly
Common Mistakes to Avoid
- Over-tightening jet (can damage brass)
- Installing jet upside down
- Not cleaning carburetor passages before reinstalling
- Failing to verify correct jet size for application
Durability & Warranty
Expected Lifespan
Indefinite if not damaged; brass construction is durable
Warranty
Typically covered under manufacturer warranty if defective
Maintenance
No maintenance required; replace only if damaged or for tuning purposes
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