Carburetor Fuel Tuning Kit
Carburetor Fuel Tuning Kit
Carburetor Fuel Tuning Kit
Carburetor Fuel Tuning Kit
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  • Carburetor Fuel Tuning Kit
  • Carburetor Fuel Tuning Kit
  • Carburetor Fuel Tuning Kit
  • Carburetor Fuel Tuning Kit
KEYSTER

Carburetor Fuel Tuning Kit

Product # FH-6084N

5 (1 reviews)

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30.11 USD (4,800 JPY)

Webike Point: +48 pt  (0.3 USD)

Delivery Information

  • If manufacturer have in stock, ships around 27th Jun. 2026

Quantity
Ask about this product

FITMENT

HONDA

  • Bross 400

    NT400J [Fitting and other information] (NC25)

Open Fit Model Information Table

Product detail

Quantity: For 1 carburetor (1 cylinder)
【Set Contents】
Needle valve
Idle screw (Air screw)
Float chamber gasket
Pilot jet: 3 sizes
Main jet: 6 sizes
Jet needle: 4 sizes
etc.

** Set contents vary by product. Please refer to the product image.
* Specifications are subject to change by the manufacturer without notice..


Here's a list of motorcycle good mood diagnostics to help you troubleshoot (manufacturer's website).
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Keyster carburetor fuel tuning kits contain almost all parts necessary for repairing and adjusting carburetors. This includes needle valves, idle screws (air screws), float chamber gaskets, and more. A key feature is the extensive range of fuel tuning parts: 3 sizes of pilot jets, 6 sizes of main jets, and 4 sizes of jet needles.
The rubber-tipped needle valves utilize the award-winning "AA Needle," which offers performance far exceeding that of OEM parts.
Conventional aftermarket jet sets typically feature evenly spaced sizes (e.g., increments of 5 or 10). However, the jets in this kit are not evenly spaced. They are designed to work in combination with the jet needles to allow for effective and precise adjustments to the air-fuel ratio.

The first purpose of the fuel tuning kit is troubleshooting (improving malfunctions). It is used to repair motorcycles with fuel supply issues.
Generally, to increase the air-fuel ratio, all three components (pilot jet, jet needle, and main jet) should be adjusted in the L direction; conversely, to decrease the ratio, they should be adjusted in the R direction. However, the combination of L, S, and R settings varies depending on which range (low, mid, or high speed) you wish to adjust. This is the essence of carburetor tuning.

The second purpose of the fuel tuning kit is motorcycle tune-up (performance improvement).
Note that a carburetor does not generate power on its own, so adjusting the carburetor alone will not yield significant performance gains. Understand that performance improves by adjusting the carburetor to match engine modifications or changes to intake/exhaust components. For example, if you replace the air filter to increase airflow or the muffler to reduce exhaust resistance, the engine's air-fuel mixture requirements will change. This is where carburetor adjustment becomes necessary, and the fuel tuning kit makes this process easier.

Points of Attention

* If there may be an instruction manual included, it will be written in Japanese.

MODEL PAGE LINKS

HONDA

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KEYSTER

Carburetor Fuel Tuning Kit

Fits:HONDA BROS 400 BROS 400 NT400J [Other Fitment Info] (NC25)

Excellent

Nov 15, 2022

Ease of use

Great item with a guide for carb setting / tuning / partial rebuild for my BROS / NT 400About quality and texture - 5/5About the feeling of use - 5/5Products to buy together - N/ADifficulty of installation - 5 being the most difficult - 3 out of 5Cost performance and comparison with other products - Great value when user has no idea about the numbers for the main jet, pilot jet, and needle as the guide gives idea on how to use itAbout shipping and packaging: 5/5Any concerns, cautions, or advice when purchasing: Since bike is V-Twin. I bought 2 of it

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