Mikuni Large Round Main Jets - 4/PK #165

Mikuni large round main jets (#165) for V-twin carburetors, sold in a 4-pack for tuning fuel delivery. These genuine Mikuni jets meter fuel volume into the carburetor's main circuit at cruise and part-throttle RPM ranges.

Features

• Genuine Mikuni large round jets
• #165 main jet size
• 4-pack quantity
• Precision-drilled orifice

Specifications

• Brand: Mikuni
• Manufacturer Part #: FN100604-165
• Quantity: 4 per pack
• Country of Origin: Japan

Fitment

Fits V-twin motorcycles equipped with Mikuni large-round carburetors. Verify your current jet size and carburetor type before ordering.

Frequently Asked Questions

What does a main jet do?

The main jet controls fuel mixture at cruise and part-throttle RPMs. Larger numbers (like #165) richen the mixture; smaller numbers lean it out.

How do I know which jet size I need?

Check your carburetor manual or current jet stamp. Jetting depends on altitude, air temperature, and engine tune — consult your carb spec sheet.

Are these OEM Mikuni parts?

Yes — these are genuine Mikuni jets manufactured to OEM specifications.

Can I mix jet sizes if I'm tuning?

Yes. Many riders install larger or smaller jets to dial in mixture for their climate and setup. Always test and verify engine performance after any jet change.