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Start ShoppingMIKUNI F4/042-340 Hex Main Jets - Precision Fuel Delivery for High-Performance Engines
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Description
Upgrade your carburetor's fuel delivery system with MIKUNI's F4/042-340 Hex Main Jets. These precision-engineered jets ensure accurate fuel-air mixture ratios, enhancing engine performance, responsiveness, and fuel efficiency for a wide range of powersports applications.
Key Features
- Hexagonal Design: Ensures secure fitment and easy adjustment for precise fuel flow control.
- High-Quality Steel: Durable construction resists corrosion and maintains accuracy under extreme operating conditions.
- Universal Compatibility: Designed for MIKUNI carburetor systems, suitable for motorcycles, ATVs, and off-road vehicles.
- Performance Optimization: Fine-tunes fuel delivery for improved throttle response and power output.
Why Choose This Product
MIKUNI main jets deliver reliable performance with their precision-machined components and corrosion-resistant materials. The hexagonal design simplifies installation and adjustment, while the optimized fuel flow enhances engine efficiency. Whether you're tuning a high-performance motorcycle or modifying an off-road vehicle, these jets provide the accuracy needed for peak engine operation.
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Upgrade your carburetor's fuel delivery system with MIKUNI's F4/042-340 Hex Main Jets. These precision-engineered jets ensure accurate fuel-air mixture ratios, enhancing engine performance, responsiveness, and fuel efficiency for a wide range of powersports applications.
Key Features
- Hexagonal Design: Ensures secure fitment and easy adjustment for precise fuel flow control.
- High-Quality Steel: Durable construction resists corrosion and maintains accuracy under extreme operating conditions.
- Universal Compatibility: Designed for MIKUNI carburetor systems, suitable for motorcycles, ATVs, and off-road vehicles.
- Performance Optimization: Fine-tunes fuel delivery for improved throttle response and power output.
Why Choose This Product
MIKUNI main jets deliver reliable performance with their precision-machined components and corrosion-resistant materials. The hexagonal design simplifies installation and adjustment, while the optimized fuel flow enhances engine efficiency. Whether you're tuning a high-performance motorcycle or modifying an off-road vehicle, these jets provide the accuracy needed for peak engine operation.
| SKU | GM32372E3F |
|---|---|
| MPN | F4/042-340 |
| Brand | MIKUNI |
| Category | Jets |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Various Japanese | Models with Mikuni TM/RD series carbs (e.g., Yamaha YZ/WR, Honda CR/XR, Kawasaki KX/KLX) | 1980-2025 |
| Suzuki | RM/DR-Z series | 1990-2010 |
Frequently Asked Questions
Fits most Mikuni round slide carbs like TM38, TM40, TM42, BS34-38, HSR42/45. Check your carb model.
Yes, direct OEM-style replacement for factory Mikuni jets.
Use a jet kit recommendation chart based on elevation, mods, and plug reading. #340 is for richer mid-high RPM mixtures.
No, threading and sizing are Mikuni-specific.
Installation Guide
Difficulty
Easy
Est. Time
10 min
Tools Required
- Small flathead screwdriver
- Jet cleaning needle or wire
Pro Tips
- Remove float bowl, note stock jet size, use carb cleaner on old jet. Torque gently to avoid stripping threads.
Common Mistakes to Avoid
- Not cleaning carb passages before install
- Installing wrong size jet
Comparison vs Stock/OEM
Identical to OEM Mikuni jets used from factory
Improvements
- Precision machined for consistent flow
- Hex head easier to install/remove than slotted
Considerations
- None; exact OEM spec
Durability & Warranty
Expected Lifespan
Indefinite with proper cleaning; lasts multiple rebuilds
Warranty
Limited lifetime from Mikuni against defects
Maintenance
Clean with carb cleaner or ultrasonic every 10-20 hours; inspect for wear/clogging
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