10pcs M4 Main Jets GY6 50cc Mikuni Keihin CVK PZ19 Carburetor

10-Pack M4 Main Jets for GY6 50cc Scooter & Motorcycle Carburetors

Keep your GY6 50cc scooter or motorcycle running at peak performance with this convenient 10-pack of M4 main jets. Precision-machined to 4mm, these round-head injector nozzles are designed to deliver consistent, reliable fuel metering for a wide range of popular carburetor models including Mikuni, Keihin, CVK24–26, and PZ19 setups. Having a full set on hand means you're always ready for tuning, replacement, or maintenance without delay.

Made in Mainland China.

Key Features

• Pack of 10: Great value — stock up for tuning sessions or future replacements
• M4 Thread / 4mm Size: Precise fit for GY6 50cc 139QMB engines
• Wide Compatibility: Fits Mikuni, Keihin, CVK24, CVK26, and PZ19 carburetors
• Round Head Design: Standard nozzle profile for easy installation and removal
• Durable Construction: Machined brass for corrosion resistance and long service life
• Ideal for Tuning: Swap jets quickly to dial in the perfect air-fuel mixture for your ride

Compatibility

• GY6 50cc 139QMB engine scooters and motorcycles
• Mikuni-style carburetors
• Keihin-style carburetors
• CVK24 and CVK26 carburetors
• PZ19 carburetors

Specifications

• Thread Size: M4
• Jet Diameter: 4mm
• Head Style: Round Head
• Quantity: 10 pieces per pack
• Material: Brass
• Country of Origin: Mainland China

For general guidance on carburetor maintenance and small engine safety, visit the U.S. Consumer Product Safety Commission (CPSC) for relevant safety tips and standards.

Frequently Asked Questions

Q: What carburetors are compatible with these M4 main jets?

A: These M4 4mm main jets are compatible with Mikuni-style, Keihin-style, CVK24, CVK26, and PZ19 carburetors commonly found on GY6 50cc 139QMB scooters and motorcycles.

Q: Why would I need to replace or change my carburetor main jet?

A: Main jets control the fuel flow through your carburetor at mid-to-full throttle. Replacing a worn jet or switching to a different size jet allows you to fine-tune your air-fuel mixture for better performance, fuel efficiency, or to compensate for altitude and temperature changes.

Q: Are these jets easy to install at home?

A: Yes. These round-head M4 jets use a standard thread and can be swapped with basic hand tools. Simply drain the carburetor bowl, remove the old jet, and thread in the new one. Having 10 in a pack lets you experiment with tuning without worrying about running out of spares.

Q: What material are these main jets made from?

A: These jets are machined from brass, which offers excellent corrosion resistance and durability in fuel-contact environments, ensuring a long service life even with regular use.