Cvk Main Jet (# 142) for Scooters & Mopeds

Cvk Main Jet (#142) for 139QMB and GY6 Scooters

This Cvk Main Jet (#142) suits 139QMB and GY6 engine scooters and mopeds. It works with most CVK carburetors that take a 5mm main jet, so it is a flexible option for many setups. If you are browsing carburetors and jets for scooters, this part helps with engine tuning. Getting the jetting dialed in may take a few tweaks, and more guidance is available if you need it.

Compatibility and Performance

This main jet works with engines in the 50cc, 125cc, 150cc, and 169cc range. It covers several engine codes, so it fits a broad selection of models. Finding the right jetting usually takes some trial and error, so plan to test a few adjustments to get the best result.

Construction Details

This jet follows a Keihin round-style design and is built to firm quality standards. It measures M5x0.80 for the thread and 8mm overall in length. These dimensions allow it to seat securely in its carburetor slot, which supports steady fuel flow and efficient combustion.

Specifications

• Type: Main Jet
• Thread Size: M5x0.80
• Overall Length: 8mm
• Fits: 139QMB-based 50cc/80cc GY6 engines and 157QMJ-based 125cc/150cc/169cc engines with a 5mm main jet slot CVK

Fitment

Fits:

• 139QMA, 139QMB, 1P39QMB, 1P39QMA-2, YN139QMB, JJ1P39QMB, 139FMA-2, BD1P39QMB, BN139QMB, 147QMD engines (50cc/80cc)
• Other QMA and QMB engines (5mm main jet slot CVK carburetor)
• 157QMJ, 161QMK, 152QMI, 1P61QMK, YN1P57QMJ, 1P52FMI, 154FMI, JJ157QMJ, 1P57QMJ, BN157QMJ, BN161QMK-A engines (125cc/150cc/169cc)
• Other QMJ, QMK and QMI engines (5mm main jet slot CVK carburetor)

How to choose: Compare the engine code on your motor with the list above, or confirm that your carburetor has a 5mm main jet slot. This jet has M5x0.80 threads and measures 8mm in length.

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