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Start ShoppingMIKUNI FN100604-122.5 Large Round Main Jets - High-Performance Fuel Jet for Powersports Engines
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Description
Upgrade your powersports engine's fuel delivery system with MIKUNI's FN100604-122.5 Large Round Main Jets. These high-performance fuel jets deliver precise fuel metering for improved throttle response, consistent power output, and reliable engine operation in demanding off-road and on-road conditions.
Key Features
- Large Round Design: Optimized fuel flow for high-performance engines and heavy-duty applications.
- Exact Fitment: Precision-machined for seamless compatibility with MIKUNI carburetor systems.
- Durable Construction: Cast brass alloy withstands extreme temperatures and corrosion.
- Easy Installation: Simple replacement for quick performance upgrades.
- Adjustable Settings: Fine-tune fuel delivery for specific riding conditions and engine tuning.
Why Choose This Product
MIKUNI jets are engineered for maximum efficiency and reliability in powersports applications. The large round main jet design ensures consistent fuel flow across wide RPM ranges, while the durable brass construction resists wear and maintains accuracy over time. Whether you're modifying a dirt bike, ATV, or off-road motorcycle, these jets provide the precision needed for optimal engine performance without compromising durability.
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Upgrade your powersports engine's fuel delivery system with MIKUNI's FN100604-122.5 Large Round Main Jets. These high-performance fuel jets deliver precise fuel metering for improved throttle response, consistent power output, and reliable engine operation in demanding off-road and on-road conditions.
Key Features
- Large Round Design: Optimized fuel flow for high-performance engines and heavy-duty applications.
- Exact Fitment: Precision-machined for seamless compatibility with MIKUNI carburetor systems.
- Durable Construction: Cast brass alloy withstands extreme temperatures and corrosion.
- Easy Installation: Simple replacement for quick performance upgrades.
- Adjustable Settings: Fine-tune fuel delivery for specific riding conditions and engine tuning.
Why Choose This Product
MIKUNI jets are engineered for maximum efficiency and reliability in powersports applications. The large round main jet design ensures consistent fuel flow across wide RPM ranges, while the durable brass construction resists wear and maintains accuracy over time. Whether you're modifying a dirt bike, ATV, or off-road motorcycle, these jets provide the precision needed for optimal engine performance without compromising durability.
| SKU | GME313D389 |
|---|---|
| MPN | FN100604-122.5 |
| Brand | MIKUNI |
| Category | Jets |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Various | Mikuni TM/VM/PF Series Carburetors | 1980-2025 |
| Honda | CRF450R, XR400R, XR650R | 1990-2024 |
| Yamaha | YZ250F, WR250F, YZ450F | 1985-2020 |
| Kawasaki | KX450F, KLX300 | 1990-2024 |
| Suzuki | RMZ450, DRZ400 | 2000-2024 |
Frequently Asked Questions
Fits Mikuni TM series (38/40), VM series (26-428), BS32/40, HSR42/45, and most large round main jet applications.
Use Mikuni jetting charts based on your elevation, temperature, air filter, and exhaust mods. Start with stock size and adjust.
This is genuine OEM Mikuni part number FN100604-122.5.
No, this is specifically for Mikuni carbs with large round main jets. Keihin uses different sizing.
Often yes - main jet change may require pilot jet and needle adjustment for complete tune.
Installation Guide
Difficulty
Easy
Est. Time
5 min
Tools Required
- Small flathead screwdriver
- Jet cleaning wire or guitar string
Pro Tips
- Clean carb thoroughly first
- Use jetting chart for your elevation/temp
- Mark your stock jet size
Common Mistakes to Avoid
- Not cleaning jet passages before install
- Incorrect jet size for current conditions
Comparison vs Stock/OEM
This is the genuine OEM Mikuni replacement for stock main jets
Improvements
- Precision machined for exact flow rates
- Consistent quality control
- Proper material for fuel resistance
Considerations
- Must match your specific tuning needs vs stock jetting
Durability & Warranty
Expected Lifespan
Indefinite with proper cleaning (replace only for tuning)
Warranty
Mikuni lifetime against manufacturing defects
Maintenance
Clean with carb cleaner every 10-20 hours riding, inspect for damage
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