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Start ShoppingMikuni F4/042-85 Hex Main Jet - 85 Size Brass Carburetor Jet for Enhanced Performance
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Description
Upgrade your carburetor's fuel delivery precision with Mikuni's F4/042-85 Hex Main Jet. This 85-size brass jet delivers consistent performance while its hex-head design makes installation and maintenance faster than traditional slotted jets.
Key Features
- Hex-Head Design: Simplifies jet removal and installation without damaging the carburetor body
- Brass Construction: Ensures durability and resistance to fuel corrosion for long-lasting performance
- 85 Size Compatibility: Precision-engineered for Mikuni carburetor systems requiring 85 jet sizing
Why Choose This Product
Whether you're tuning a high-performance engine or maintaining a classic powersport vehicle, this Mikuni jet offers unmatched reliability. The hex-head design eliminates the need for specialized tools, saving time during maintenance. Brass material ensures consistent fuel flow resistance, while the precise 85 sizing guarantees optimal air-fuel ratios. Perfect for riders who demand precision and durability in their carburetor systems.
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Upgrade your carburetor's fuel delivery precision with Mikuni's F4/042-85 Hex Main Jet. This 85-size brass jet delivers consistent performance while its hex-head design makes installation and maintenance faster than traditional slotted jets.
Key Features
- Hex-Head Design: Simplifies jet removal and installation without damaging the carburetor body
- Brass Construction: Ensures durability and resistance to fuel corrosion for long-lasting performance
- 85 Size Compatibility: Precision-engineered for Mikuni carburetor systems requiring 85 jet sizing
Why Choose This Product
Whether you're tuning a high-performance engine or maintaining a classic powersport vehicle, this Mikuni jet offers unmatched reliability. The hex-head design eliminates the need for specialized tools, saving time during maintenance. Brass material ensures consistent fuel flow resistance, while the precise 85 sizing guarantees optimal air-fuel ratios. Perfect for riders who demand precision and durability in their carburetor systems.
| SKU | GME5AAEC12 |
|---|---|
| MPN | F4/042-85 |
| Brand | MIKUNI |
| Category | Jets |
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Frequently Asked Questions
The '85' indicates the jet size/orifice diameter. Larger numbers = richer fuel mixture. Jet sizing is critical for proper carburetor tuning.
Signs of incorrect jetting include: poor idle, hesitation on acceleration, black spark plugs (too rich), white spark plugs (too lean), or poor fuel economy. Consult your carburetor manual or a tuning guide.
No. Jets are carburetor-specific. Verify your exact carburetor model (VM, TMX, etc.) before purchasing. Using wrong jets can damage the carburetor or cause poor performance.
Hex jets use a hex wrench for installation (easier, less likely to strip). Slotted jets use a flathead screwdriver. Functionally identical, but hex design is more user-friendly.
Individual jets can be purchased, but many tuners buy jet kits with multiple sizes for testing and tuning purposes.
Installation Guide
Difficulty
Easy
Est. Time
5 min
Tools Required
- Hex wrench or socket (appropriate size for F4/042-85)
- Small flathead screwdriver (to access carburetor)
Pro Tips
- Keep old jet for reference/comparison
- Clean carburetor thoroughly while disassembled
- Test run after installation to verify correct jetting
- Document original jet size for future reference
Common Mistakes to Avoid
- Over-tightening jet (can strip brass threads)
- Installing wrong jet size (verify F4/042-85 is correct for your carb)
- Not cleaning carburetor passages before reinstalling
Durability & Warranty
Expected Lifespan
Indefinite (brass component, no wear)
Warranty
Typically covered under Mikuni's standard warranty
Maintenance
No maintenance required - jets do not wear out
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