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Start ShoppingMIKUNI F4/042-580 Hex Main Jets - Precision Fuel Flow Control for High-Performance Engines
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Description
Upgrade your engine's fuel delivery system with MIKUNI's F4/042-580 Hex Main Jets. These precision-machined components deliver consistent fuel flow for enhanced throttle response, power output, and reliable performance across a wide range of riding conditions.
Key Features
- Hexagonal Design: Ensures secure fitment and precise fuel metering in MIKUNI carburetor systems
- High-Quality Brass: Durable construction resists corrosion and maintains accuracy under extreme temperatures
- Compatibility: Specifically engineered for MIKUNI carburetors with F4/042-580 specifications
- Easy Installation: Standardized threading simplifies replacement without specialized tools
Why Choose This Product
Whether you're fine-tuning a racing engine or optimizing your off-road rig, these main jets provide the critical fuel flow control needed for peak performance. Their precise engineering ensures consistent metering across wide-open throttle ranges, while the durable brass construction guarantees long-term reliability. Perfect for riders seeking to maximize power delivery without compromising engine longevity.
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Upgrade your engine's fuel delivery system with MIKUNI's F4/042-580 Hex Main Jets. These precision-machined components deliver consistent fuel flow for enhanced throttle response, power output, and reliable performance across a wide range of riding conditions.
Key Features
- Hexagonal Design: Ensures secure fitment and precise fuel metering in MIKUNI carburetor systems
- High-Quality Brass: Durable construction resists corrosion and maintains accuracy under extreme temperatures
- Compatibility: Specifically engineered for MIKUNI carburetors with F4/042-580 specifications
- Easy Installation: Standardized threading simplifies replacement without specialized tools
Why Choose This Product
Whether you're fine-tuning a racing engine or optimizing your off-road rig, these main jets provide the critical fuel flow control needed for peak performance. Their precise engineering ensures consistent metering across wide-open throttle ranges, while the durable brass construction guarantees long-term reliability. Perfect for riders seeking to maximize power delivery without compromising engine longevity.
| SKU | GM4CA1D5EB |
|---|---|
| MPN | F4/042-580 |
| Brand | MIKUNI |
| Category | Jets |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Various (Mikuni VM/PF/BS series carbs) | TM/H/SN/BS carburetors | 1985-2024 |
| Yamaha | YZ250F/YZ450F | 2000-2010 |
| Honda | CR250R/CRF450R | 1998-2008 |
| KTM | SX/EXC 250/450 | 2004-2012 |
Frequently Asked Questions
Fits Mikuni VM26-VM34, PF, BS, TM, H, SN series round/flat slide carbs on 2-stroke/4-stroke dirt bikes, ATVs.
Yes, OEM-style hex main jet for factory Mikuni carbs; #580 size for richer mid-high fueling.
Often yes for complete rejetting after airbox/exhaust mods; this is main jet only.
Measure old jet with gauge or consult jetting chart based on mods/elevation.
Installation Guide
Difficulty
Easy
Est. Time
5 min
Tools Required
- Small flathead screwdriver
- Jet gauge (recommended)
Pro Tips
- Remove carb float bowl, unscrew old jet with screwdriver, note position. Use jet kit for full rejet. Verify size with micrometer.
Common Mistakes to Avoid
- Installing wrong size jet
- Not cleaning carb passages before install
Comparison vs Stock/OEM
Direct OEM replacement; identical to factory Mikuni jets
Improvements
- Precision machined for consistent flow
- Hex head for easy install/removal
Considerations
- None; exact spec match
Durability & Warranty
Expected Lifespan
Indefinite with proper jetting (no wear parts)
Warranty
Limited lifetime (Mikuni OEM)
Maintenance
Inspect during carb cleans; replace if clogged
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