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Start ShoppingMIKUNI F4/042-380 Hex Main Jets - Precision Brass Fuel Jet for High-Performance Powersports Engines
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Description
Upgrade your powersports engine's fuel delivery system with MIKUNI's precision-crafted F4/042-380 Hex Main Jets. This durable brass main jet delivers consistent fuel flow for enhanced performance, responsiveness, and reliability in high-output engines.
Key Features
- Material: Solid brass construction for corrosion resistance and long-lasting durability
- Thread Type: Hex head design with M5 x 0.75 thread for secure, leak-free installation
- Orifice Size: 4mm precision orifice ensures accurate fuel metering
- Jet Diameter: 3.80mm main jet for optimal fuel-air mixture balance
- Weight: Lightweight 0.1 oz design reduces engine strain without compromising performance
- Dimensions: 10mm hex head for easy handling and precise installation
Why Choose This Product
MIKUNI's F4/042-380 main jets are engineered for extreme performance environments. The brass material resists clogging and maintains flow accuracy under high temperatures. The hex head design simplifies installation while ensuring a secure fit in carburetor systems. This jet's precise 3.80mm diameter delivers consistent fuel delivery, improving throttle response and engine efficiency for off-road motorcycles, ATVs, and other powersports vehicles.
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Upgrade your powersports engine's fuel delivery system with MIKUNI's precision-crafted F4/042-380 Hex Main Jets. This durable brass main jet delivers consistent fuel flow for enhanced performance, responsiveness, and reliability in high-output engines.
Key Features
- Material: Solid brass construction for corrosion resistance and long-lasting durability
- Thread Type: Hex head design with M5 x 0.75 thread for secure, leak-free installation
- Orifice Size: 4mm precision orifice ensures accurate fuel metering
- Jet Diameter: 3.80mm main jet for optimal fuel-air mixture balance
- Weight: Lightweight 0.1 oz design reduces engine strain without compromising performance
- Dimensions: 10mm hex head for easy handling and precise installation
Why Choose This Product
MIKUNI's F4/042-380 main jets are engineered for extreme performance environments. The brass material resists clogging and maintains flow accuracy under high temperatures. The hex head design simplifies installation while ensuring a secure fit in carburetor systems. This jet's precise 3.80mm diameter delivers consistent fuel delivery, improving throttle response and engine efficiency for off-road motorcycles, ATVs, and other powersports vehicles.| SKU | GM70033D92 |
|---|---|
| MPN | F4/042-380 |
| Brand | MIKUNI |
| Category | Jets |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Various (Suzuki, Yamaha, Honda, Kawasaki) | Models with Mikuni VM/PF/BS carburetors (e.g., Suzuki RM250/DRZ400, Yamaha YZ250/WR450, Honda CRF450, Kawasaki KX250) | 1980-2025 |
Frequently Asked Questions
Fits most Mikuni round-slide carbs like VM26-VM44, BS32-40, PF series. Confirm your carb model.
Check stock jet size or use a jet kit chart based on mods/elevation. #380 is common for high-flow setups.
Yes, OEM Mikuni hex main jet, not aftermarket.
No, threading differs. Mikuni jets are specific to Mikuni carbs.
Installation Guide
Difficulty
Easy
Est. Time
5 min
Tools Required
- Flathead screwdriver
- 12mm socket or wrench
Pro Tips
- Use carb cleaner to clear jets before swapping. Mark old jet size. Test plug chop after install to verify tuning.
Common Mistakes to Avoid
- Installing wrong jet size
- Not cleaning carb passages before install
Comparison vs Stock/OEM
Direct OEM replacement or upgrade for stock Mikuni jets
Improvements
- Precise fuel metering for better performance
- Hex head for easier tool-free removal
Considerations
- Larger sizes like #380 for modified engines/higher altitude
Durability & Warranty
Expected Lifespan
Indefinite with proper cleaning; replace if clogged
Warranty
Limited lifetime (manufacturer defect)
Maintenance
Clean with carb cleaner every service; inspect during jetting changes
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