Keihin carburetor for Honda GX390 GX340 — OEM 16100-Z5T-901 replacement, direct bolt-on, restores factory fuel metering

Keihin 16100-Z5T-901 is a genuine OEM replacement carburetor designed to restore reliable fuel delivery to compatible Honda GX390 and GX340 engines.

This carburetor carries Honda part number 16100-Z5T-901 and is supplied by Keihin as an authentic, factory-style replacement. It fits a range of GX390 variants and the WT40XK3 model, offering the precise tolerances and mounting points required for correct installation. If your engine is running rough, flooding, or has poor throttle response, swapping to this OEM unit is a direct way to return the fuel system to specification without custom modification.

Which engines and models will this carburetor fit?

This Keihin carburetor replaces Honda part 16100-Z5T-901 and is compatible with multiple GX390 configurations and related models. Always cross-check your engine’s parts manual or the stamped part number before purchase to ensure fitment.

• Compatible with GX390K2, GX390R2, GX390RT2, GX390T2, GX390U2, GX390UT2
• Also fits WT40XK3—verify throttle and choke cable routing
• Direct bolt-on design matching OEM mounting holes and linkages

How does this OEM carburetor improve engine performance?

Replacing a worn or damaged carburetor with this OEM unit helps restore correct air-fuel mixture and idle stability. Because it follows Honda’s original specifications, you should see steadier throttle response and more consistent starting compared with patched or aftermarket mismatched carbs.

• Restores factory fuel metering and float level tolerances
• Reduces stumbling, sputter, and hard-start issues caused by leaks or wear
• Preserves OEM vacuum and linkage geometry for reliable throttle control

What should I inspect before installing the new carburetor?

Proper installation helps avoid recurring problems. Before fitting the carburetor, check the intake manifold gasket, throttle cable play, fuel line condition, and the air filter for contamination.

• Replace cracked or compressed intake manifold gaskets for a proper seal
• Install new fuel hose and clamps if the existing lines are brittle or leaking
• Ensure choke and throttle linkages move freely and are correctly adjusted

Will I need special tools or jetting adjustments?

Most installations require only standard hand tools and basic tune-up adjustments. Because this is an OEM-spec part, jetting typically matches factory settings; re-jetting is not usually necessary unless engine modifications have been made.

• Standard wrenches and screwdrivers for removal and fitting
• Carburetor adjustment screwdriver for idle and mixture fine-tuning
• Re-jet only if intake/exhaust modifications or altitude changes require it

Who is this for: This Keihin-supplied, Honda OEM carburetor is aimed at professional mechanics and DIY owners who need an exact replacement for GX390-series engines or WT40XK3 applications. If you value factory fit, reliable fuel metering, and a straightforward installation that restores original performance, this part is an appropriate choice. It is not intended for engines needing performance tuning; use the stock jetting and linkage unless you’ve planned modifications.