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Start ShoppingMIKUNI F4/042-420 Hex Main Jets - High-Performance Airflow Control for Racing & Off-Road Vehicles
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Description
Upgrade your engine's airflow management with MIKUNI's F4/042-420 Hex Main Jets, designed to deliver precise fuel-air mixture control for maximum power and responsiveness. These critical carburetor components are essential for riders seeking to fine-tune their powersports equipment's performance.
Key Features
- Precision-Crafted Hex Design: Ensures optimal airflow regulation for consistent throttle response and improved engine efficiency.
- Universal Compatibility: Fits standard MIKUNI carburetor systems, making them a versatile upgrade for various powersports vehicles.
- High-Quality Brass Construction: Durable material resists corrosion and maintains accuracy under extreme operating conditions.
Why Choose This Product
These main jets are engineered for riders who demand peak performance from their engines. The hex design allows for precise adjustment, while the durable brass construction ensures long-lasting reliability. Whether you're competing in racing events or conquering off-road trails, these jets provide the control needed to enhance power delivery and fuel efficiency. Their straightforward installation makes them an ideal choice for both seasoned mechanics and performance enthusiasts looking to elevate their powersports experience.
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Upgrade your engine's airflow management with MIKUNI's F4/042-420 Hex Main Jets, designed to deliver precise fuel-air mixture control for maximum power and responsiveness. These critical carburetor components are essential for riders seeking to fine-tune their powersports equipment's performance.
Key Features
- Precision-Crafted Hex Design: Ensures optimal airflow regulation for consistent throttle response and improved engine efficiency.
- Universal Compatibility: Fits standard MIKUNI carburetor systems, making them a versatile upgrade for various powersports vehicles.
- High-Quality Brass Construction: Durable material resists corrosion and maintains accuracy under extreme operating conditions.
Why Choose This Product
These main jets are engineered for riders who demand peak performance from their engines. The hex design allows for precise adjustment, while the durable brass construction ensures long-lasting reliability. Whether you're competing in racing events or conquering off-road trails, these jets provide the control needed to enhance power delivery and fuel efficiency. Their straightforward installation makes them an ideal choice for both seasoned mechanics and performance enthusiasts looking to elevate their powersports experience.
| SKU | GM061194B7 |
|---|---|
| MPN | F4/042-420 |
| Brand | MIKUNI |
| Category | Jets |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Various (Suzuki, Yamaha, Kawasaki, Honda) | Multiple carbureted models (e.g., Suzuki RM250, Yamaha YZ250, Kawasaki KX250) | 1980-2025 |
Frequently Asked Questions
Fits most Mikuni round-slide carbs like VM26-VM34, BS32-42, TM series. Check your carb model.
Use plug chop method or wideband O2 sensor. #420 is for richer mixtures, typically high altitude or modded engines.
Yes, OEM Mikuni part number F4/042-420.
No, Mikuni jets have different threading; use Keihin jets for Keihin carbs.
Installation Guide
Difficulty
Easy
Est. Time
5 min
Tools Required
- Small flathead screwdriver
- Jet needle tool or pick
Pro Tips
- Remove float bowl completely for access. Clean jet orifice with carb cleaner before installing. Always rejet in pairs for main and pilot
Common Mistakes to Avoid
- Not cleaning carb passages before install
- Incorrect jet size selection
Comparison vs Stock/OEM
Direct OEM replacement for factory Mikuni carbs
Improvements
- Precise fuel metering for performance tuning
- Pure brass for corrosion resistance
Considerations
- Requires proper sizing for engine mods; stock may be leaner
Durability & Warranty
Expected Lifespan
Indefinite with proper maintenance (jets rarely wear out)
Warranty
Manufacturer defect warranty through retailer
Maintenance
Inspect/clean during carb service (every 20-50 hours)
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