Keihin Scooter Carburetor Idle / Pilot / Slow Jet - M6x0.75mm

Keihin Idle Jet for Genuine and GY6 50cc Scooters

The Keihin idle jet, sometimes called a pilot jet, controls fuel flow inside the scooter's carburetor. It helps the engine run smoothly when the throttle is barely open. If your scooter stumbles when you accelerate or has trouble staying running at idle, this jet could be the cause. You can find it among scooter carburetors & jets, where it helps restore the correct fuel mixture for your engine.

Performance Improvement

This idle jet controls the fuel mixture from 0% to roughly 25% throttle, so it has a direct effect on how the scooter behaves at low RPM. A blocked or wrongly sized jet often causes rough idling and a throttle that feels slow to respond. Made from high-grade brass with precise calibration, it supports steady fuel flow and more stable tuning.

When to Replace Your Idle Jet

After fitting a high-performance exhaust or a larger cylinder, you might need a bigger jet to prevent a lean running condition. The usual step is up one size, for example from a #38 to a #40. It's worth inspecting the idle jet for blockages whenever you notice poor low-speed performance.

Specifications

• Type: Keihin PB / CVK Idle Jet
• Material: Machined Brass
• Available Sizes: #38, #40, #42
• Fits: Scooter Co 50cc 2-stroke models and Chinese GY6 50cc scooters with Keihin PB or CVK-style carburetors

Fitment

Fits:

• Buddy 50 (50cc 2-stroke)
• RoughHouse 50 (50cc 2-stroke)
• Rattler 50 (50cc 2-stroke)
• Black Cat 50 (50cc 2-stroke)
• TaoTao, Wolf, Ice Bear and Bintelli GY6 50cc scooters (139QMB, PD18J or CVK-style carburetor)
• Keihin PB series carburetors
• Most 18mm-20mm CVK clone carburetors

How to choose: Pick the jet size based on your scooter's engine setup, selecting #38, #40 or #42 as required. If you've upgraded the exhaust or bore, go up one size, such as from #38 to #40.

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