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Start ShoppingMikuni FN100604-77.5 Large Round Main Jet - Precision Fuel Metering for High-Performance Engines
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Description
Upgrade your engine's fuel delivery system with Mikuni's premium Large Round Main Jet (77.5). This critical component ensures precise fuel metering for maximum power, efficiency, and reliability in two-stroke and four-stroke engines.
Key Features
- Brass Construction: Durable, corrosion-resistant material for long-lasting performance in harsh environments
- 77.5 Size: Precisely calibrated for optimal fuel-air mixture in high-output engines
- Large Round Shape: Ensures consistent fuel flow and reduces clogging risks
- Manufactured by Mikuni: Trusted brand known for precision-engineered fuel system components
Why Choose This Product
Whether you're tuning a racing engine or enhancing your off-road machine, this Mikuni main jet delivers unmatched accuracy. Its brass construction resists wear and corrosion, while the 77.5 size ensures proper fuel metering for smooth power delivery. The large round design minimizes flow restrictions, making it ideal for high-performance applications where reliability is critical.
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Upgrade your engine's fuel delivery system with Mikuni's premium Large Round Main Jet (77.5). This critical component ensures precise fuel metering for maximum power, efficiency, and reliability in two-stroke and four-stroke engines.
Key Features
- Brass Construction: Durable, corrosion-resistant material for long-lasting performance in harsh environments
- 77.5 Size: Precisely calibrated for optimal fuel-air mixture in high-output engines
- Large Round Shape: Ensures consistent fuel flow and reduces clogging risks
- Manufactured by Mikuni: Trusted brand known for precision-engineered fuel system components
Why Choose This Product
Whether you're tuning a racing engine or enhancing your off-road machine, this Mikuni main jet delivers unmatched accuracy. Its brass construction resists wear and corrosion, while the 77.5 size ensures proper fuel metering for smooth power delivery. The large round design minimizes flow restrictions, making it ideal for high-performance applications where reliability is critical.| SKU | GM74FF3928 |
|---|---|
| MPN | FN100604-77.5 |
| Brand | MIKUNI |
| Category | Jets |
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Frequently Asked Questions
The main jet controls fuel flow at mid-to-high throttle positions. It's the primary fuel metering component in cruise and acceleration conditions.
Signs you need jetting changes: engine runs too lean (hesitation, popping on decel) or too rich (black smoke, fouled plugs). Jet size increases fuel flow; larger numbers = richer mixture.
77.5 is a mid-range main jet size. Common sizes range from 60-120+. Your specific carburetor model determines the appropriate range.
Yes, if you're comfortable removing and disassembling your carburetor. It requires basic mechanical skills and a clean workspace. Consider a carburetor rebuild kit if replacing multiple components.
Yes. Performance modifications (air filter, exhaust, porting) typically require jetting adjustments to maintain proper fuel-air ratio.
Installation Guide
Difficulty
Medium
Est. Time
15 min
Tools Required
- Small screwdriver set
- Carburetor removal tools (if replacing in-situ)
- Clean workspace
- Gasket scraper or soft brush
Pro Tips
- Label all jets during removal to track original sizes
- Clean jet passages with carburetor cleaner before installation
- Use gentle pressure when seating jet - brass is soft
- Keep jets organized by size in a labeled container
- Take photos during disassembly for reference
Common Mistakes to Avoid
- Installing jet upside down
- Over-tightening jet (can damage brass)
- Not cleaning carburetor passages before installation
- Mixing up jet sizes during rebuild
Durability & Warranty
Expected Lifespan
Indefinite if not damaged; brass jets don't wear out under normal use
Warranty
Typically covered under manufacturer defect warranty
Maintenance
No maintenance required; inspect for clogging during carburetor service
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